List of abbreviations

Introduction

1. General part

1.3 Tectonic structure

1.4 Oil and gas potential

2.Special part

3. Design part

3.3 Apparatus and equipment

3.4 Methodology for processing and interpreting field materials

4.Special task

4.1 AVO analysis

4.1.1 Theoretical aspects of AVO analysis

4.1.2 AVO classification of gas sands

4.1.3 AVO crossplotting

4.1.4 Elastic inversion in AVO analysis

4.1.5 AVO analysis in anisotropic media

4.1.6 Examples practical application AVO analysis

Conclusion

List of sources used

stratigraphic seismic field anisotropic

List of abbreviations

GIS-geophysical surveys of wells

MOV reflected wave method

CDP method with total point depth

NGK-oil and gas complex

Oil and gas bearing area

NGR-oil and gas bearing area

OG-reflective horizon

CDP - common depth point

PV explosion point

PP reception point

seismic exploration party

Hydrocarbons

Introduction

This bachelor's thesis provides for the justification of CDP-3D seismic exploration work in the Vostochno-Michayuskaya area and consideration of AVO analysis as a special issue.

Seismic exploration and drilling data carried out in recent years have established the complex geological structure of the work area. Further systematic study of the East Michayu structure is necessary.

The work involves studying the area in order to clarify the geological structure of seismic exploration work CDP-3D.

The bachelor's thesis consists of four chapters, an introduction, a conclusion, is presented on pages of text, contains 22 figures, 4 tables. The bibliographic list contains 10 titles.

1. General part

1.1 Physiographical sketch

The East Michayuskaya area (Figure 1.1) is administratively located in the Vuktylsky district.

Figure 1.1 - Map of the area of ​​East Michayuskaya Square

Not far from the study area is the town of Vuktyl and the village of Dutovo. The work area is located in the Pechora River basin. The area is a hilly, gently undulating plain, with pronounced valleys of rivers and streams. The work area is swampy. The climate of the region is sharply continental. Summers are short and cool, winters are harsh with strong winds. Snow cover sets in in October and disappears at the end of May. In terms of seismic work, this area falls into category 4 of difficulty.

1.2 Lithological and stratigraphic characteristics

The lithological and stratigraphic characteristics of the section (Figure 1.2) of the sedimentary cover and foundation are given based on the results of drilling and seismic logging of wells 2-, 4-, 8-, 14-, 22-, 24-, 28-Michayu, 1 - S. Savinobor, 1 - Dinho-Savinobor.

Figure 1.2 - Lithological-stratigraphic section of the East Michayuskaya area

Paleozoic erathema - PZ

Devonian system - D

Middle Devonian Division - D 2

The carbonate rocks of the Silurian sequence are unconformably overlain by terrigenous formations of the Middle Devonian and Givetian stage.

Givetian deposits with a thickness in the well. 1-Dinho-Savinobor 233 m are represented by clays and sandstones in the volume of the Stary Oskol superhorizon (I - in the formation).

Upper Devonian Division - D 3

The Upper Devonian is identified within the Frasnian and Famennian stages. The franc is represented by three sub-tiers.

The Lower Frasnian deposits are formed by the Yaran, Dzhier and Timan horizons.

Frasnian Stage - D 3 f

Upper Tefranian substage - D 3 f 1

Yaransky horizon - D 3 jr

The section of the Yaransky horizon (thickness 88 m in KV. 28-Mich.) is composed of sandy layers (from bottom to top) V-1, V-2, V-3 and interstratal clays. All layers are inconsistent in composition, thickness and number of sand layers.

Dzhersky horizon - D 3 dzr

At the base of the Dzhiersky horizon there are clayey rocks; higher up the section there are sandy layers Ib and Ia, separated by a member of clays. The thickness of the dzhier varies from 15 m (KV. 60 - Yu.M.) to 31 m (KV. 28 - M.).

Timan horizon - D 3 tm

The deposits of the Timan horizon, 24 m thick, are composed of clayey-siltstone rocks.

Middle Frasnian substage - D 3 f 2

The Middle Frasnian substage is represented in the volume of the Sargaevsky and Domanik horizons, composed of dense, silicified, bituminous limestones with interlayers of black shale. The thickness of Sargai is 13 m (well 22-M) - 25 m (well 1-Tr.), domanik - 6 m in well. 28-M. and 38 m in the well. 4-M.

Upper Frasnian substage - D 3 f 3

Undivided Vetlasyan and Sirachoi (23 m), Evlanovo and Liven (30 m) deposits make up the section of the Upper Frasnian substage. They are formed of brown and black limestones with layers of clayey shale.

Famennian Stage - D 3 fm

The Famennian stage is represented by the Volgograd, Zadonsk, Yelets and Ust-Pechora horizons.

Volgograd skyline - D 3 vlg

Zadonsk horizon - D 3 zd

The Volgograd and Zadonsk horizons are composed of clayey-carbonate rocks with a thickness of 22 m.

Yelets horizon - D 3 el

The deposits of the Yelets horizon are formed by limestones, organogenic-clastic areas, in the lower part there are highly clayey dolomites, at the base of the horizon there are marls and calcareous, dense clays. The thickness of the sediments varies from 740 m (wells 14-, 22-M) to 918 m (well 1-Tr.).

Ust-Pechora horizon - D 3 up

The Ust-Pechora horizon is represented by dense dolomites, black mudstone-like clays and limestones. Its thickness is 190m.

Coal system - C

Above this, deposits of the Carboniferous system lie unconformably in the lower and middle sections.

Lower Carboniferous Division - C 1

Visean Stage - C 1 v

Serpukhovian Stage - C 1 s

The lower section consists of the Visean and Serpukhovian stages, formed by limestones with interlayers of clays, with a total thickness of 76 m.

Upper Carboniferous Division - C 2

Bashkirian Stage - C 2 b

Moscow tier - C 2 m

The Bashkir and Moscovian stages are represented by clayey-carbonate rocks. The thickness of the Bashkir deposits is 8 m (borehole 22-M.) - 14 m (borehole 8-M.), and in borehole. 4-, 14-M. they are missing.

The thickness of the Moscow stage varies from 24 m (borehole 1-Tr) to 82 m (borehole 14-M.).

Permian system - P

Moscow deposits are unconformably overlain by Permian ones, in the volume of the lower and upper sections.

Lower Perm Division - R 1

The lower section is represented in full and is composed of limestones and clayey marls, and in the upper part there are clays. Its thickness is 112m.

Upper Permian department - R 2

The upper section is formed by the Ufa, Kazan and Tatar stages.

Ufimian Stage - P 2 u

Ufa deposits with a thickness of 275 m are represented by interbedded clays and sandstones, limestones and marls.

Kazan Stage - P 2 kz

The Kazan stage is composed of dense and viscous clays and quartz sandstones; rare interlayers of limestone and marls are also found. The thickness of the tier is 325 m.

Tatarian stage - P 2 t

The Tatarian stage is formed by terrigenous rocks with a thickness of 40 m.

Mesozoic erathema - MZ

Triassic system - T

Triassic deposits in the lower section are composed of alternating clays and sandstones with a thickness of 118 m (borehole 107) - 175 m (borehole 28-M.).

Jurassic System - J

The Jurassic system is represented by terrigenous formations with a thickness of 55 m.

Cenozoic erathema - KZ

Quaternary system - Q

The section is completed by loams, sandy loams and sands of Quaternary age, 65 m thick in well 22-M. and 100 m in well 4-M.

1.3 Tectonic structure

In tectonic terms (Figure 1.3), the work area is located in the central part of the Michayu-Pashninsky swell, which corresponds to the Ilych-Chiksha fault system along the foundation. The fault system is also reflected in the sedimentary cover. Tectonic disturbances in the work area are one of the main structure-forming factors.

Figure 1.3 - Copy from the tectonic map of the Timan-Pechora province

Three zones of tectonic disturbances are identified in the work area: western and eastern areas of submeridional strike, and, in the southeast, areas of northeast strike.

Tectonic disturbances observed in the west of this area can be traced along all reflecting horizons, and disturbances in the east and southeast attenuate, respectively, in Famennian and Frasnian times.

Tectonic disturbances in the western part are a graben-like trough. The subsidence of the horizons is most clearly visible on profiles 40990-02, 40992-02, -03, -04, -05.

The amplitude of vertical displacement along the horizons ranges from 12 to 85 m. In terms of plan, the disturbances have a northwestern orientation. They extend in a southeast direction from the reporting area, limiting the Dinya-Savinobor structure from the west.

The disturbances probably separate the axial part of the Michayu-Pashninsky swell from its eastern slope, which is characterized by continuous subsidence of sediments in an eastern direction.

In geophysical fields g, disturbances correspond to intense zones of gradients, the interpretation of which made it possible to identify a fault here deep, separating the Michayu-Pashninskaya uplift zone along the foundation from the relatively lowered Lemju step and is probably the main structure-forming fault (Krivtsov K.A., 1967, Repin E.M., 1986).

The western zone of tectonic faults is complicated by feathering faults of northeastern strike, due to which individual uplifted blocks are formed, as in profiles 40992-03, -10, -21.

The amplitude of the vertical displacement along the horizons of the eastern zone of disturbances is 9-45 m (project 40990-05 pc 120-130).

The southeastern zone of disturbances is presented in the form of a graben-shaped trough, the amplitude of which is 17-55 m (project 40992-12 pc 50-60).

The western tectonic zone forms an elevated near-fault structural zone, consisting of several tectonically limited folds - Srednemichayuskaya, East Michayuskaya, Ivan-Shorskaya, Dinyu-Savinoborskaya structures.

The deepest horizon OG III 2-3 (D 2-3), along which structural constructions were carried out, is confined to the interface between Upper Devonian and Middle Devonian deposits.

Based on structural constructions, analysis of time sections and drilling data, the sedimentary cover has a rather complex geological structure. Against the background of submonoclinal subsidence of layers in the eastern direction, the East Michayu structure is identified. It was first identified as an open complication of the “structural nose” type using materials from case 8213 (Shmelevskaya I.I., 1983). Based on work from the 1989-90 season. (s\p 40990) the structure is presented in the form of a near-fault fold, contoured along a sparse network of profiles.

Reporting data has established the complex structure of the East Michayu structure. According to OG III 2-3, it is represented by a three-dome, linearly elongated, anticlinal fold of northwestern strike, the dimensions of which are 9.75 x 1.5 km. The northern dome has an amplitude of 55 m, the central one - 95 m, the southern one - 65 m. From the west, the East Michayu structure is limited by a graben-like trough of northwestern strike, from the south - a tectonic disturbance, with an amplitude of 40 m. In the north, the East Michayu anticlinal fold is complicated by an uplifted block (project 40992-03), and in the south - a downthrown block (project 40990-07, 40992-11), due to feathering faults of north-eastern strike.

To the north of the East Michayu uplift, the Sredne Michayu near-fault structure has been identified. We assume that it closes to the north of the reporting area, where work was previously carried out on 40991 and structural construction was carried out along reflecting horizons in the Permian deposits. The Middle Michayu structure was considered within the East Michayu uplift. According to the work on settlement 40992, the presence of a deflection was revealed between the East Michayuskaya and Srednemichayuskaya structures on prospects 40990-03, 40992-02, which is confirmed by the reporting work.

In the same structural zone with the uplifts discussed above, there is the Ivan-Shor anticlinal structure, identified by the works of s\p 40992 (Misyukevich N.V., 1993). From the west and south it is framed by tectonic disturbances. The dimensions of the structure according to OG III 2-3 are 1.75×1 km.

To the west of the Srednemichayuskaya, East Michayuskaya and Ivan-Shorskaya structures are the South Lemyuskaya and South Michayuskaya structures, which are affected only by the western ends of the reporting profiles.

Southeast of the South Michayu structure, a low-amplitude East Tripanyel structure has been identified. It is represented by an anticlinal fold, the dimensions of which according to OG III 2-3 are 1.5 x 1 km.

In the western edge of the graben of submeridional strike in the north of the reporting area, small near-fault structures are isolated. To the south, similar structural forms are formed due to small tectonic disturbances of various strikes, complicating the graben zone. We have united all these small structures in the blocks lowered relative to the East Michayu uplift under the general name Central Michayu structure and require further study by seismic exploration.

Benchmark 6 is associated with OG IIIf 1 at the top of the Yaranian horizon. The structural plan of the reflecting horizon IIIf 1 is inherited from OG III 2-3. The dimensions of the East Michayu near-fault structure are 9.1×1.2 km; in the contour of the isohypsum - 2260 m, the northern and southern domes are distinguished with an amplitude of 35 and 60 m, respectively.

The dimensions of the Ivan-Shor fault fold are 1.7 x 0.9 km.

The structural map of OG IIId reflects the behavior of the base of the Domanik horizon of the Middle Frasnian substage. In general, there is an uplift of the structural plan to the north. To the north of the reporting area, the base of the domanik was penetrated by a well. 2-North Michayu, 1-North Michayu at absolute levels - 2140 and - 2109 m, respectively, to the south - in the well. 1-Dinyu-Savinobor at an elevation of 2257 m. The East Michayu and Ivan-Shor structures occupy an intermediate hypsometric position between the North Michayu and Dinyu-Savinobor structures.

At the level of the Domanik horizon, the feathering disturbance on profile 40992-03 dies out; in place of the raised block, a dome has formed, covering the neighboring profiles 40990-03, -04, 40992-02. Its dimensions are 1.9 x 0.4 km, amplitude - 15 m. To the south of the main structure, a small dome is closed by an isohypsum -2180 m to another feathering fault on Project 40992-10. Its dimensions are 0.5 x 0.9, amplitude is 35 m. The Ivan-Shor structure is located 60 m below the Vostochno-Michayuskaya structure.

The structural plan of the OG Ik confined to the top of the Kungurian carbonates differs significantly from the structural plan of the underlying horizons.

The graben-like trough of the western zone of disturbances on the time sections has a bowl-shaped shape, in connection with this there was a restructuring of the structural plan of OG Ik. There is a displacement of the screening tectonic faults and the arch of the East Michayu structure to the east. The dimensions of the East Michayu structure are significantly smaller than those of the underlying deposits.

A northeast-trending tectonic disturbance splits the East Michayu structure into two parts. Two domes stand out in the contour of the structure, and the amplitude of the southern one is greater than that of the northern one and is 35 m. The dimensions of the East Michayu uplift according to OG Ik (P 1 k) are 5.2 x 0.9 km.

To the south is the Ivan-Shor fault uplift, which now represents a structural nose, in the north of which a small dome stands out. The disturbance that screens the Ivan-Shor anticlinal fold in the south along the lower horizons is fading.

The eastern flank of the South Lemju structure is complicated by a small tectonic disturbance of submeridional strike.

Throughout the entire area, small rootless tectonic disturbances are observed, with an amplitude of 10-15 m, which do not fit into any system.

Sand formation B-3, productive in the North Savinoborskoye, Dinyu-Savinoborskoye, Michayuskoye fields, is located below benchmark 6, with which OG IIIf1 is identified, at 18-22 m, and in the well. 4-Mich. at 30 m.

On the structural plan of the roof of the V-3 formation, the highest hypsometric position is occupied by the Michayuskoye field, the northeastern part of which is confined to the South Lemyus structure. The OWC of the Michayusky field passes at a level of - 2160 m (Kolosov V.I., 1990). The East Michayu structure is closed by an isohypse - 2280 m, a raised block at a level of 2270 m, a lowered block at the southern end at a level of 2300 m.

At the level of the East Michayu structure, to the south there is the North-Savinoborskoye field with an OWC at a level of - 2270 m. The Dinyu-Savinoborskoye field is located another 100 m lower, the OWC in the well. 1-Dinho-Savinobor is determined at a level of 2373 m.

Thus, the East Michayu structure, located in the same structural zone with the Dinho-Savinobor structure, is located significantly higher than it and may well be a good trap for hydrocarbons. The screen is a graben-like trough of northwestern strike of asymmetrical shape.

The western side of the graben runs along low-amplitude fault faults, with the exception of individual profiles (projects 40992-01, -05, 40990-02). The disturbances on the eastern side of the graben, the most depressed part, which is located on avenues 40990-02, 40992-03, are high-amplitude. According to them, the supposed permeable layers are in contact with the Sargaevsky or Timan formations.

To the south, the amplitude of the disturbance decreases and at the level of profile 40992-08 the graben closes from the south. Thus, the southern pericline of the East Michayu structure appears to be in a downthrown block. In this case, the B-3 formation may be in contact along a fault with the interstratal clays of the Yaransky horizon.

To the south in this zone there is the Ivan-Shor fault structure, which is intersected by two meridional profiles 13291-09, 40992-21. The absence of seismic profiles across the strike of the structure does not allow us to judge the reliability of the object identified by the work of s\p 40992.

The graben-like trough, in turn, is broken by tectonic disturbances, due to which isolated uplifted blocks are formed within its boundaries. We named them the Central Michayu structure. On profiles 40992-04, -05, fragments of the East Michayu structure were reflected in the downthrown block. There is a small low-amplitude structure at the intersection of profiles 40992-20 and 40992-12, which we called the East Tripanyelskaya.

1.4 Oil and gas potential

The work area is located in the Izhma-Pechora oil and gas region within the Michayu-Pashninsky oil and gas region.

In the fields of the Michayu-Pashninsky region, a wide complex of terrigenous-carbonate sediments from the Middle Devonian to the Upper Permian inclusive is oil-bearing.

Near the area under consideration are the Michayuskoye and Yuzhno-Michayuskoye fields.

Deep prospecting and exploration drilling carried out in 1961 - 1968. at the Michayu field, wells No. 1-Yu. Lemyu, 6, 7, 11, 14, 16, 18, 19, 21, 23, 24 discovered an oil deposit confined to the sandstones of the B-3 formation, which lies in the upper part of the Yaransky horizon of the Frasnian tiers. The deposit is layered, domed, partly floating. The height of the deposit is about 25 m, dimensions are 14 x 3.2 km.

In the Michayuskoye field, commercial oil content is associated with sandy layers lying at the base of the Kazanian stage. For the first time, oil from the Upper Permian deposits in this field was obtained in 1982 from well 582. Testing in it established the oil-bearing capacity of the P 2 -23 and P 2 -26 layers. Oil deposits in the P 2 -23 formation are confined to sandstones, presumably of channel origin, stretching in the form of several submeridional strips across the entire Michayuskoye field. Oil content was established in the well. 582, 30, 106. Light oil, with a high content of asphaltenes and paraffin. The deposits are confined to a trap of structural-lithological type.

Oil deposits in the layers P 2 -24, P 2 -25, P 2 -26 are confined to sandstones, presumably of channel genesis, stretching in the form of strips through the Michayuskoye field. The width of the strips varies from 200 m to 480 m, the maximum thickness of the layer is from 8 to 11 m.

Reservoir permeability is 43 mD and 58 mD, porosity 23% and 13.8%. Initial inventory cat. A+B+C 1 (geol./mineralization) are equal to 12176/5923 thousand tons, category C 2 (geol./mineralization) 1311/244 thousand tons. Residual reserves as of 01/01/2000 in categories A+B+C 1 are 7048/795 thousand tons, in category C 2 1311/244 thousand tons, accumulated production is 5128 thousand tons.

The Yuzhno-Michayu oil field is located 68 km northwest of the city of Vuktyl, 7 km from the Michayu oil field. It was discovered in 1997 by well 60 - Yu.M., in which an oil influx of 5 m 3 /day was obtained from the interval 602 - 614 m by PU.

The oil reservoir is stratified, lithologically screened, confined to the sandstones of the P 2 -23 formation of the Kazan stage of the Upper Permian.

The depth of the formation roof in the arch is 602 m, the reservoir permeability is 25.4 mD, the porosity is 23%. The oil density is 0.843 g/cm 3, the viscosity in reservoir conditions is 13.9 MPa. s, content of resins and asphaltenes 12.3%, paraffins 2.97%, sulfur 0.72%.

Initial inventories are equal to remaining inventories as of 01/01/2000. and amount to 1,742/112 thousand tons for categories A+B+C, and 2,2254/338 thousand tons for category C.

At the Dinyu-Savinoborskoye field, an oil deposit in terrigenous sediments of the B-3 formation of the Yaran horizon of the Frasnian stage of the Upper Devonian was discovered in 2001. well 1-Dinho-Savinobor. In the well section, 4 objects were tested (Table 1.2).

When testing the interval 2510-2529 m (formation V-3), an influx (solution, filtrate, oil, gas) was obtained in a volume of 7.5 m 3 (of which oil - 2.5 m 3).

When testing the interval 2501-2523 m, oil was obtained with a flow rate of 36 m3/day through a choke with a diameter of 5 mm.

When testing the overlying reservoir layers of the Yaran and Dzher horizons (layers Ia, Ib, B-4) (test interval 2410-2490 m), no oil shows were observed. A solution in a volume of 0.1 m3 was obtained.

To determine the productivity of the V-2 formation, a test was carried out in the interval of 2522-2549.3 m. As a result, a solution, filtrate, oil, gas and formation water in a volume of 3.38 m 3 was obtained, of which 1.41 m was due to leakage of the tool 3, inflow from the reservoir - 1.97 m3.

When studying Lower Permian deposits (test interval 1050 - 1083.5 m), a solution in a volume of 0.16 m 3 was also obtained. However, during the drilling process, according to core data, signs of oil saturation were noted in the specified interval. In the interval 1066.3-1073.3, the sandstones are inequigranular and lens-shaped. In the middle of the interval, oil effusions were observed, 1.5 cm - a layer of oil-saturated sandstone. In the intervals of 1073.3-1080.3 m and 1080.3-1085 m, sandstone interlayers with oil exudations and thin (in the interval 1080.3-1085 m, core removal 2.7 m) interlayers of polymictic oil-saturated sandstone were also noted.

Signs of oil saturation according to core data in the well. 1-Dinho-Savinobor were also noted in the top of the Zelenets horizon member of the Famennian stage (core sampling interval 1244.6-1253.8 m) and in layer Ib of the Dzhiersky horizon of the Frasnian stage (core sampling interval 2464.8-2470 m).

In formation B-2 (D3 jr) there are sandstones with a hydrocarbon odor (core sampling interval 2528.7-2536 m).

Information on testing results and oil shows in wells is given in Tables 1.1 and 1.2.

Table 1.1 - Well testing results

Table 1.2 - Information about oil shows

2. Special part

2.1 Geophysical work carried out in this area

The report was compiled based on the results of re-processing and reinterpretation of seismic survey materials obtained in the northern block of the Dinho-Savinobor field in different years by seismic parties 8213 (1982), 8313 (1984), 41189 (1990), 40990 (1992), 40992 (1993) according to the agreement between Kogel LLC and Dinyu LLC. The methodology and technique of work are shown in Table 2.1.

Table 2.1 - Information about the field work methodology

The East Michayu tectonically limited structure identified by the work of s/p 40991 was transferred to drilling along the Lower Frasnian, Lower Famennian and Lower Permian deposits in 1993, s/p 40992. Seismic exploration work was generally focused on studying the Permian part of the section, structural structures in the lower part of the section performed only on the reflecting horizon III f 1.

To the west of the work area are the Michayuskoye and Yuzhno-Michayuskoye oil fields. The industrial oil and gas potential of the Michayuskoye field is associated with Upper Permian deposits; the oil deposit is contained in the sandstones of the B-3 formation in the upper Yaransky horizon.

In 2001, southeast of the East Michayu structure, the 1-Dinyu-Savinobor well discovered an oil deposit in the Lower Frasnian sediments. The Dinho-Savinoborskaya and East Michayu structures are located in the same structural zone.

In connection with these circumstances, it became necessary to revise all available geological and geophysical materials.

Reprocessing of seismic data was carried out in 2001 by V.A. Tabrina. in the ProMAX system, the volume of reprocessing amounted to 415.28 km.

Pre-processing consisted of converting the data into the internal ProMAX format, assigning geometry and restoring amplitudes.

The interpretation of seismic material was carried out by leading geophysicist Mingaleeva I.Kh., geologist Matyusheva E.V., geophysicist I category Oborina N.S., geophysicist Gorbacheva D.S. The interpretation was carried out in the Geoframe exploration system on the SUN 61 workstation. The interpretation included the correlation of reflective horizons, the construction of isochrone, isohypsum, and isopach maps. IN workstation Digitized logging diagrams for wells 14-Michayu and 24-Michayu were downloaded. To convert the logging curves to the time section scale, we used velocities obtained from seismic logging of the corresponding wells.

The construction of isochrone, isohypsum, and isopach maps was carried out automatically. If necessary, they were adjusted manually.

The velocity models necessary to transform isochrone maps into structural ones were determined from drilling and seismic data.

The cross-section of isohypses was determined by the error of the constructions. In order to preserve the features of the structural plans and for better visualization, the isohypsum section was taken to be 10 m along all reflecting horizons. Map scale 1:25000. The stratigraphic assignment of reflecting horizons was carried out using seismic logging of wells 14-, 24-Michayu.

6 reflective horizons were traced in the area. Structural constructions were presented for 4 reflecting horizons.

OG Ik is confined to benchmark 1, identified by analogy with the Dinyu-Savinobor well in the upper Kungurian stage, 20-30 m below the Ufimian deposits (Figure 2.1). The horizon is well correlated in the positive phase, the reflection intensity is low, but the dynamic features are consistent over the area. The next reflecting horizon II-III is identified with the boundary of Carboniferous and Devonian deposits. GO is quite easily recognized in the profiles, although in some places interference of two phases is observed. At the eastern ends of the latitudinal profiles above OG II-III, an additional reflection appears, which pinches out to the west according to the type of plantar onlap.

OG IIIfm 1 is confined to benchmark 5, identified at the bottom of the Yelets horizon of the Lower Famennian. In wells 5-M., 14-M, benchmark 5 coincides with the base of the Yelets horizon, identified by TP NIC; in other wells (2,4,8,22,24,28-M) it is 3-10 m above the official breakdown of the base D 3 el. The reflecting horizon is a reference horizon, has pronounced dynamic features and high intensity. Structural constructions for OG IIIfm 1 are not provided for by the program.

OG IIId is identified with the base of the Domanik deposits and is confidently correlated in time sections along the negative phase.

GO IIIf 1 is associated with reference 6 at the top of the Yaranian horizon of the Lower Frasnian. Benchmark 6 stands out quite confidently in all wells 10-15 m below the base of the Dzher deposits. Reflecting horizon IIIf 1 is well observed, despite the fact that it has low intensity.

The sand reservoir B-3, which is productive in the Michayuskoe and Dinyu-Savinoborskoe fields, is located 18-22 m below the OG IIIf 1, only in well 4-M. the thickness of the deposits enclosed between OG IIIf 1 and formation V-3 increased to 30 m.

Figure 2.1 - Comparison of sections of wells 1-C. Michayu, 24-Michayu, 14-Michayu and binding of reflective horizons

The following reflecting horizon III 2-3, traced near the top of the Middle Devonian terrigenous deposits, is weakly expressed in the wave field. OG III 2-3 is correlated in the negative phase as an erosion surface. In the southwest of the reporting area, there is a decrease in temporary power between OG IIIf 1 and III 2-3, which is especially clearly visible in profile 8213-02 (Figure 2.2).

Structural constructions (Figure 2.3 and 2.4) were made along the reflecting horizons Ik, IIId, IIIf 1, III 2-3, an isopach map was constructed between OG IIId and III 2-3, a structural map was presented along the top of the sand layer B-3, for the entire Dinho -Savinoborskoye field.

Figure 2.2 - Fragment of a time section along profile 8213-02

2.2 Results of geophysical research

As a result of reprocessing and reinterpretation of seismic data on the northern block of the Dinho-Savinobor field.

We studied the geological structure of the northern block of the Dinyu-Savinobor field based on Permian and Devonian deposits,

Figure 2.3 - Structural map for reflecting horizon III2-3 (D2-3)

Figure 2.4 - Structural map for reflecting horizon III d (D 3 dm)

- 6 reflecting horizons were traced and linked across the area: Ik, II-III, IIIfm1, IIId, IIIf1, III2-3;

Structural constructions were carried out on a scale of 1:25000 for 4 OGs: Ik, IIId, IIIf1, III2-3;

We constructed a general structural map for the top of the B-3 formation for the Dinyu-Savinobor structure and the northern block of the Dinyu-Savinobor field, and an isopach map between OG IIId and III2-3;

Constructed deep seismic sections (horizon scale 1:12500, ver. 1:10000) and seismic-geological sections (horizon scale 1:25000, ver. 1:2000);

We constructed a comparison scheme for Lower Frasnian deposits based on wells in the Michayuskaya area, well. 1-Dinho-Savinobor and 1-Tripanjel on a scale of 1:500;

The geological structure of the East Michayu and Ivan-Shor structures was clarified;

Srednemichayuskaya, Central Michayuskaya, East Tripanyelskaya structures were identified;

We traced a graben-like trough of northeastern strike, which is a screen for the northern block of the Dinyu-Savinobor structure.

In order to study the oil prospects of the Lower Frasnian deposits within the central block of the East Michayu structure, drill exploration well No. 3 on profile 40992-04 pk 29.00 with a depth of 2500 m until the opening of the Middle Devonian deposits;

On the southern block - exploration well No. 7 at the cross of profiles 40990-07 and 40992 -21 with a depth of 2550 m;

On the northern block - exploration well No. 8, profile 40992-03 pk 28.50, depth 2450 m;

Carrying out detailed seismic surveys within the Ivan-Shor structure;

Conduct reprocessing and reinterpretation of seismic exploration work on the Yuzhno-Michayuskaya and Srednemichayuskaya structures.

2.3 Rationale for choosing 3D seismic

The main reason justifying the need to use a rather complex and rather expensive 3D areal seismic technology at the exploration and detailing stages is the transition in most regions to the study of structures and fields with increasingly complex reservoirs, which leads to the risk of drilling empty wells. It has been proven that with an increase in spatial resolution of more than an order of magnitude, the cost of 3D work compared to detailed 2D survey (~2 km/km 2) increases by only 1.5-2 times. At the same time, the detail and overall volume of information from 3D shooting is higher. An almost continuous seismic field will provide:

· Higher detail in the description of structural surfaces and mapping accuracy compared to 2D (errors are reduced by 2-3 times and do not exceed 3-5 m);

· Unambiguity and reliability of tracking the area and volume of tectonic disturbances;

· Seismic facies analysis will provide identification and tracking of seismic facies in the volume;

· Possibility of interpolation of parameters of productive formations (layer thickness, porosity, boundaries of reservoir development) into the interwell space;

· Clarification of oil and gas reserves by detailing structural and calculation characteristics.

This indicates the possible economic and geological feasibility of using three-dimensional surveys on the East Michayu structure. When choosing economic feasibility, it is necessary to keep in mind that the economic effect of applying 3D to the entire complex of exploration and development of fields also takes into account:

· increase in reserves in categories C1 and C2;

· savings by reducing the number of low-informative exploration and low-yield production wells;

· optimization of the development mode by refining the model of the productive reservoir;

· increase in C3 resources due to the identification of new objects;

· cost of 3D survey, data processing and interpretation.

3. Design part

3.1 Justification of the CDP work methodology - 3D

The choice of an observation system is based on the following factors: tasks to be solved, features of seismic geological conditions, technical capabilities, economic benefits. The optimal combination of these factors determines the observation system.

In the Vostochno-Michayuskaya area, CDP-3D seismic exploration will be carried out for the purpose of a detailed study of the structural-tectonic and lithological-facial features of the structure of the sedimentary cover in sediments from the Upper Permian to the Silurian; mapping zones of development of lithological-facial heterogeneities and improved reservoir properties, fault tectonic disturbances; studying the geological history of development based on paleostructural analysis; identification and preparation of oil-promising objects.

To solve the problems, taking into account the geological structure of the area, the factor of minimal impact on the natural environment and the economic factor, an orthogonal observation system with excitation points located between the reception lines (i.e. with overlapping reception lines) is proposed. Well explosions will be used as excitation sources.

3.2 Example of calculation of a cross-type observing system

A "cross" type observation system is formed due to the sequential overlap of mutually orthogonal arrangements, sources and receivers. Let us illustrate the principle of forming an area system using the following idealized example. Let's assume that geophones (a group of geophones) are evenly distributed along the observation line coinciding with the X axis.

Along the axis intersecting the arrangement of geophones in the center, the sources are placed evenly and symmetrically. The pitch of sources DU and geophones DH is the same. Signals excited by each source are received by all geophones in the array. As a result of such processing, a field of m 2 middle reflection points is formed. If you sequentially shift the arrangement of geophones and the line of sources orthogonal to it along the X axis by step dx and repeat the registration, then the result will be achieved - a multiple overlap of the strip, the width of which is equal to half the excitation base. Consecutive displacement of the excitation and reception base along the Y axis by a step leads to an additional multiple overlap, and the total overlap will be. Naturally, in practice, more technologically advanced and economically feasible versions of the system with mutually orthogonal lines of sources and receivers should be used. It is also obvious that the overlap ratio must be selected in accordance with the requirements determined by the nature of the wave field and processing algorithms. As an example, Figure 3.1 shows an eighteen-fold areal system, for the implementation of which one 192-channel seismic station is used, sequentially receiving signals from 18 excitation pickets. Let's consider the parameters of this system. All 192 geophones (groups of geophones) are distributed on four parallel profiles (48 on each). The step dx between receiving points is 0.05 km, the distance dx between receiving lines is 0.05 km. The step of Sy sources along the Y axis is 0.05 km. We will call a fixed distribution of sources and receivers a block. After receiving oscillations from all 18 sources, the block is shifted by step x (in this particular case, equal to 0.2 km), reception from all 18 sources is repeated again, etc. This is how a strip is processed along the X axis from the beginning to the end of the study area. The next strip of four receiving lines is placed parallel to the previous one so that the distance between the adjacent (closest) receiving lines of the first and second strips is equal to the distance between the receiving lines in the block (?y = 0.2 km). In this case, the source lines of the first and second bands overlap by half the excitation base. When working on the third strip, the source lines of the second and third strips overlap by half, etc. Consequently, in this version of the system, the receiving lines are not duplicated, and at each source point (excluding the extreme ones) the signals are excited twice.

Let us write down the basic relationships that determine the parameters of the system and its multiplicity. To do this, following Figure 8, we introduce additional notation:

W - number of receiving lines,

m x - number of receiving points on each receiving line of a given block;

m y - number of sources on each excitation line of a given block,

P is the width of the interval in the center of the excitation line, within which the sources are not located,

L - the amount of offset (displacement) along the X axis of the line of sources from the nearest receiving points.

In all cases, the intervals ?x, ?y and L are multiples of the step dx. This ensures the uniformity of the network of midpoints corresponding to each source-receiver pair, i.e. do it! requirement of the condition necessary to generate common midpoint (CMP) gathers. Wherein:

Ax=Nдx N=1, 2, 3…

tSy-MdyM=1, 2, 3…

L=q dxq=1, 2, 3…

Let us explain the meaning of the parameter P. The shift between the lines of the midpoints is equal to half the step?y. If the sources are distributed evenly (there is no gap), then for similar systems the overlap ratio along the Y axis is equal to W (the number of receiving lines). To reduce the overlap ratio along the Y axis and to reduce costs due to fewer sources, a gap is made in the center of the excitation line by an amount P equal to:

Where, k = 1,2,3...

When k=1.2, 3, respectively, the overlap ratio decreases by 1, 2, 3, i.e. becomes equal to W-K.

General formula linking the multiplicity of overlaps n y with system parameters

hence the expression for the number of sources m y on one excitation line can be written as follows:

For the observation system (Figure 3.1), the number of sources on the excitation line is 18.

Figure 3.1 - Cross-type observation system

From expression (3.3) it follows that since the profile step?y is always a multiple of the source step dy, the number of sources my for this type of system is an even number. Distributed on a straight line parallel to the Y axis symmetrically to the reception profiles included in this block, the excitation points either coincide with the reception points or are shifted relative to the reception points by 1/2·dy. If the overlap ratio n y in a given block is an odd number, the sources always do not coincide with the receiving points. If n y is an even number, two situations are possible: ?у/дн - an odd number, the sources coincide with the receiving points, ?у/дн - an even number, the sources are shifted relative to the receiving points by y/2. This fact should be taken into account when synthesizing the system (selecting the number of reception profiles W and the step?y between them), since it depends on whether the vertical times necessary to determine the static corrections will be recorded at the reception points.

The formula that determines the multiplicity of overlaps n x along the X axis can be written similarly to formula (3.2)

thus, the total number of overlaps n xy in area is equal to the product of n x and n y

In accordance with the accepted values ​​of mx, dx and?x, the multiplicity of overlaps n x along the X axis, calculated using formula (3.4), is equal to 6, and the total multiplicity n xy = 13 (Figure 3.2).

Figure 3.2 - Multiplicity of overlaps nх =6

Along with an observation system that provides for overlapping sources without overlapping receiving lines, in practice systems are used in which the excitation lines do not overlap, but part of the receiving lines is duplicated. Let's consider six receiving lines, on each of which geophones receiving signals sequentially excited by sources are evenly distributed. When developing the second band, three receiving lines are duplicated by the next block, and the source lines are in the form of a continuation of the orthogonal profiles of the first band. Thus, the technology used does not provide for duplication of excitation points. When receiving lines overlap twice, the multiplicity n y is equal to the number of overlapping receiving lines. The full equivalent of a system of six profiles followed by overlapping of three receiving lines is a system with overlapping sources, the number of which is doubled to achieve the same multiplicity. Therefore, systems with overlapping sources are economically unprofitable, because This technique requires a large volume of drilling and blasting work.

Transition to 3D seismic exploration.

The design of a 3D survey is based on knowledge of a number of characteristics of the seismological section of the work site.

Information about the geoseismic section includes:

· 2D shooting frequency

· maximum depths of target geological boundaries

· minimal geological boundaries

· minimal horizontal size local geological objects

maximum frequencies of reflected waves from target horizons

average velocity in the layer lying on the target horizon

· time of registration of reflections from the target horizon

· size of research area

To register the time field in COGT-3D, it is rational to use telemetry stations. The number of profiles is selected depending on the multiplicity n y =н.

The distance between the common midpoints on the reflective surface along the X and Y axes determines the bin size:

The maximum permissible minimum offset of the source line is selected based on the minimum depth of the reflecting boundaries:

Minimum offset.

Maximum offset.

To ensure the multiplicity nx, the distance between the excitation lines?x is determined:

For the recording unit, the distance between the receiving lines?y:

Taking into account the technology of work with double overlap of the receiving line, the number of sources m y in one block to ensure the multiplicity n y:

Figure 3.3 - Multiplicity ny =2

Based on the results of 3D survey planning, the following data set is obtained:

· distance between channels dx

number of active channels on one receiving line m x

· total number of active channels m x · ь

· minimum offset Lmin

bin size

· total multiplicity n xy

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Topic 6. Methods and technology of seismic exploration 8 hours, lectures No. 16 and No. 19 Lecture No. 17
Common Depth Point Method (CDMT)
Observation systems in MOGT-2D

Basics of the Common Depth Point Method

The essence of the CDP method

Schematic example of attenuation of multiple reflections when summing traces with a 6-fold CDP system.

Basic requirements for the OGT technique

CDP hodographs of single and multiple reflected waves

CDP hodographs of multiple reflected waves

Quantitative characteristics of the observing system

Monitoring systems MOGT 2D

(fundamentals of the theory of elasticity, geometric seismicity, seismoelectric phenomena; seismic properties of rocks (energy, attenuation, wave velocities)

Applied seismic exploration originates from seismology, i.e. a science that deals with recording and interpreting waves generated during earthquakes. She is also called explosive seismology- seismic waves are excited in certain places by artificial explosions in order to obtain information about the regional and local geological structure.

That. seismic survey is a geophysical method for studying the earth's crust and upper mantle, as well as exploring mineral deposits, based on the study of the propagation of elastic waves excited artificially, using explosions or impacts.

Rocks, due to the different nature of their formation, have different speeds of propagation of elastic waves. This leads to the formation of reflected and refracted waves at different speeds at the boundaries of layers of different geological environments, which are recorded on the earth's surface. After interpreting and processing the received data, we can obtain information about the geological structure of the area.

Huge successes in seismic exploration, especially in the field of observation techniques, began to be seen after the 20s of the outgoing century. About 90% of the funds spent on geophysical exploration in the world are on seismic exploration.

Seismic exploration technique is based on the study of wave kinematics, i.e. on study travel times of various waves from the excitation point to geophones, which amplify oscillations at a number of points in the observation profile. The vibrations are then converted into electrical signals, amplified and automatically recorded on magnetograms.

As a result of processing magnetograms, it is possible to determine wave speeds, the depth of seismic geological boundaries, their incidence, and strike. Using geological data, it is possible to establish the nature of these boundaries.

There are three main methods in seismic exploration:

reflected wave method (REW);

method of refracted waves (MW or CMW - correlation) (this word is missed for abbreviation).

transmitted wave method.

In these three methods, a number of modifications can be distinguished, which, due to special techniques for carrying out work and interpreting materials, are sometimes considered independent methods.

These are the following methods: MRNP - method of controlled directional reception;

Adjustable directional reception method

It is based on the idea that in conditions where the boundaries between layers are rough or formed by heterogeneities distributed over the area, interference waves are reflected from them. At short receiving bases, such oscillations can be split into elementary plane waves, the parameters of which more accurately determine the location of inhomogeneities and the sources of their occurrence than interference waves. In addition, MPRP is used to resolve regular waves simultaneously arriving at the profile in different directions. The means of resolving and splitting waves in MRNP are adjustable multi-time rectilinear summation and variable frequency filtering with emphasis on high frequencies.

The method was intended for exploration of areas with complex structures. Its use for exploration of gently lying platform structures required the development of a special technique.

The areas of application of the method in oil and gas geology, where it was most widely used, are areas with the most complex geological structure, the development of complex folds of marginal troughs, salt tectonics, and reef structures.

RWM - refracted wave method;

CDP - common depth point method;

MPOV - method of transverse reflected waves;

MOWW - converted wave method;

MOG - inverted hodograph method, etc.

Inverted hodograph method. The peculiarity of this method is to immerse the geophone into specially drilled (up to 200 m) or existing (up to 2000 m) wells below the zone (ZMS) and multiple boundaries. Oscillations are excited near the day surface along profiles located longitudinally (relative to the wells), non-longitudinally, or area-wise. From the general wave pattern, linear and inverted surface wave hodographs are distinguished.

IN COGT Linear and area observations are used. Areal systems are used in separate wells to determine the spatial position of reflecting horizons. The length of the inverted hodographs for each observation well is determined experimentally. Typically, the hodograph length is 1.2 - 2.0 km.

For a complete picture, it is necessary that the hodographs overlap, and this overlap would depend on the depth of the recording level (usually 300 - 400 m). The distance between PVs is 100 - 200 m, under unfavorable conditions - up to 50 m.

Downhole methods are also used in the search for oil and gas fields. Downhole methods are very effective in studying deep boundaries, when, due to intense multiple waves, surface interference and the complex deep structure of the geological section, the results of surface seismic exploration are not reliable enough.

Vertical seismic profiling - this is an integral seismic logging performed by a multichannel probe with special clamping devices that fix the position of seismic receivers at the well wall; they allow you to get rid of interference and correlate waves. VSP is an effective method for studying wave fields and the process of propagation of seismic waves in internal points of real media.

The quality of the studied data depends on the correct choice of excitation conditions and their constancy during the research process. VSP (vertical profile) observations are determined by the depth and technical condition of the well. VSP data is used to assess the reflective properties of seismic boundaries. From the ratio of the amplitude-frequency spectra of the direct and reflected waves, the dependence of the reflection coefficient of the seismic boundary is obtained.

Piezoelectric reconnaissance method is based on the use of electromagnetic fields that arise during the electrification of rocks by elastic waves excited by explosions, impacts and other pulsed sources.

Volarovich and Parkhomenko (1953) established the piezoelectric effect of rocks containing piezoelectric minerals with electrical axes oriented in a certain way. The piezoelectric effect of rocks depends on piezoelectric minerals, patterns of spatial distribution and orientation of these electrical axes in textures; sizes, shapes and structure of these rocks.

The method is used in surface, borehole and mine versions when searching and exploring quartz ore deposits (gold, tungsten, molybdenum, tin, rock crystal, mica).

One of the main tasks when researching this method is the choice of observation system, i.e. relative positions of explosion points and receivers. In ground conditions, an observation system of three profiles is rational, in which the central profile is the profile of explosions, and the two outer ones are profiles of receiver placement.

According to the tasks seismic exploration is solved divided into:

deep seismic exploration;

structural;

oil and gas;

ore; coal;

engineering-hydrogeological seismic exploration.

According to the method of carrying out work, they are distinguished:

ground,

borehole types of seismic exploration.

Keywords

annotation scientific article on Earth sciences and related environmental sciences, author of the scientific work - Maksimov L.A., Vedernikov G.V., Yashkov G.N.

Information is provided on the technology of passive-active seismic exploration using the common depth point method (CDMP), which solves the problem direct search for hydrocarbon deposits according to the dynamic parameters emitted by these deposits induced geodynamic noise. It has been shown that the use of this technology can prevent the drilling of unproductive wells. Materials and methods The proposed PAS CDP technology combines the registration and interpretation of waves emitted by hydrocarbon deposits and waves reflected from seismic boundaries. This ensures high efficiency in studying the geometry of reflecting boundaries and recording hydrocarbons emitted by deposits induced geodynamic noise. Results The PAS CDP technology has been tested at dozens of hydrocarbon fields in Western and Eastern Siberia and has shown its effectiveness: all fields are marked by anomalies in the intensity of geodynamic noise and the absence of such anomalies outside the fields. Conclusions The above-mentioned capabilities of the PAS COGT technology are very relevant at the present time, when the economic crisis continues to intensify. This technology will allow oil workers to drill hydrocarbon traps rather than structures, which will increase the efficiency of geological exploration work (manifold) when searching for oil and gas.

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  2016 / Shaidurov G.Ya., Kudinov D.S., Potylitsyn V.S.

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• Using the method of detecting microseismic noise fields in prospecting and exploration work in the oil and gas complex to reduce environmental consequences

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The information on the technology of passive and active seismic using the common-depth-point method (hereinafter “the PAS CDPM”), solving the problem of direct explorationof hydrocarbon accumulations using the amplitude information of induced geodynamic noise emitted by these accumulations is containing. It is shown that the use of this technology can prevent drilling of nonproductive wells. Materials and methods The proposed PAS CDPM technology complexes registration and interpretation of inducedgeodynamic noises emitted by hydrocarbon accumulations, and waves reflected from the seismic horizons. This provides high efficiency of studying of reflectors geometryand registration of induced geodynamic noises emitted by hydrocarbon accumulations. Results The PAS CDPM technology tested in dozens of hydrocarbon accumulations of Western and Eastern Siberia has proven its efficiency, namely all accumulations have displayed intensity anomalies of geodynamic noises, and no such anomalies have been observed outside accumulations. Conclusions The above mentioned PAS CDPM technology capability is relevant nowadays, when the economic crisis is gathering pace. The defined technology will make it possible for petroleum experts to drill traps instead of drilling structures that will increaseseveralfold efficiency of oil and gas geological exploration.

Text of scientific work on the topic "Geodynamic noise of hydrocarbon deposits and passive-active seismic exploration of CDP"

GEOPHYSICS

Geodynamic noise of hydrocarbon deposits and passive-active seismic exploration of CDP

L.A. Maksimov

Ph.D., Art. teacher1 [email protected]

G.V. Vedernikov

Doctor of Geology and Mineralogy, Deputy Director of Science2 [email protected]

G.N. Yashkov

Ch. geophysicist2 [email protected]

Novosibirsk State University, Novosibirsk, Russia 2NMT-Seis LLC, Novosibirsk, Russia

Information is provided on the technology of passive-active seismic exploration using the common depth point method (CDC), which solves the problem of direct search for hydrocarbon deposits based on the dynamic parameters emitted by these deposits of induced geodynamic noise. It has been shown that the use of this technology can prevent the drilling of unproductive wells.

Materials and methods

The proposed PAS CDP technology combines the registration and interpretation of induced geodynamic noise emitted by hydrocarbon deposits and waves reflected from seismic boundaries. This ensures high efficiency in studying the geometry of reflecting boundaries and recording induced geodynamic noise emitted by hydrocarbon deposits.

Keywords

CDP seismic survey, direct search for hydrocarbon deposits, induced geodynamic noise, success rate of exploratory drilling

The main task of currently used seismic methods is to study the spatial distribution of physical parameters and indicators of spontaneous seismic activity.

Seismic exploration today is the main method of preparing objects for prospecting and exploration drilling. It reveals with a sufficient degree of reliability structures that, under certain favorable conditions, may or may not contain oil deposits. Only a well will confirm this uncertainty, but at what cost?

The success of searching for oil and gas deposits was within 10...30% in the past (in the USSR and the USA), and remains within these limits today (Fig. 1). And it will continue to do so tomorrow and the day after tomorrow, and until the oil workers move from searching for structures to searching for oil-containing traps. The point of increasing the efficiency of prospecting and exploration works comes down to the obvious task - to divide the structures identified by seismic exploration into productive and unproductive oil and gas traps. If this problem is solved, then huge amounts of money are saved, which are spent on prospecting and exploration drilling on obviously unproductive structures.

It is known that oil and gas deposits, being unstable thermodynamic systems, emit increased level spontaneous and induced geodynamic noise. To analyze such noise for the purpose of direct search for hydrocarbon (HC) deposits, the innovative technology of passive-active seismic exploration using the common depth point method (PAS CDP), developed at NMT-Seis LLC (analogous to the active version of the ANCHAR technology), can be used.

Modern standard CDP seismic exploration is essentially passive-active. Indeed, on the seismic route in the area before the first arrivals of regular waves, microseisms and geodynamic noise are recorded - a passive component of the record. On the rest of the record, together with microseisms and geodynamic noise, oscillations of regular waves are recorded - the active component of the record, containing information about the geometry of seismic boundaries in the earth's strata. The passive component contains information about the presence (absence) of hydrocarbon deposits emitting geodynamic noise.

The proposed PAS MOGT technology integrates registration and

Rice. 1 - Dynamics of changes in the success rate (in%) when drilling prospecting and exploration wells in the USA

Rice. 2 - Seismic time section (A), amplitude-frequency spectrum of microseisms (B) and spectrum intensity graphs in frequency bands (C)

interpretation of artificially induced geodynamic noise emitted by hydrocarbon deposits and waves reflected from seismic boundaries. This ensures both high efficiency in studying the geometry of reflecting boundaries and the velocities between them due to repeated tracking of waves reflected from these boundaries, and high efficiency in searching for hydrocarbon deposits due to repeated exposure to seismic waves and registration of induced geodynamic noise emitted by them. An important advantage of the method is the possibility of independent parallel extraction of information from wave fields that have a fundamentally different nature and are recorded almost simultaneously in one place. In principle, the PAS CDP technology is one of the modifications of multi-wave seismic exploration, in a broader sense of the term “multi-wave seismic exploration” - that is, not only waves of different polarization. Thus, having carried out a joint interpretation of reflected waves and noise, we will have information about the geometry of boundaries in the medium and the presence of shock waves in the medium, i.e., we will be able to solve the problem of direct searches for shock wave traps, and not structures, as is done today. And this point is very important, since it becomes possible to solve the main problem in exploratory drilling. At the same time, the success of drilling increases sharply (by several times).

The PAS CDP technology has been tested at dozens of hydrocarbon fields in Western and Eastern Siberia and has shown its effectiveness: all fields are marked by anomalies

intensity of geodynamic noise (Fig. 2) and the absence of such anomalies outside the fields (Fig. 3).

Over the past 7 years, work has been carried out under State contracts jointly with the Federal State Unitary Enterprise SNIIGGiMS to forecast oil and gas accumulation zones in Western and Eastern Siberia in a volume of over 13 thousand linear meters. km of profiles and shows the effectiveness of using the PAS CDP technology at all stages of geological exploration:

During regional work - identification of promising areas for prospecting and exploration work;

At the pre-exploration stage - preparation of information packages for licensing subsoil areas;

During prospecting and exploration work

Identification and ranking of promising objects, especially non-anticlinal types;

When planning drilling operations

The fundamental feature of PAS CDP technologies is the excitation of vibrations and registration of microseisms and regular waves using the multiple overlap technique. The consequence of this is the following unique advantages of these technologies compared to the ANCHAR technology: 1. Multiple (rather than single) pulse-wave (rather than monoharmonic) long-term external

impact on hydrocarbon deposits by waves created by a man-made source. The multiplicity of such an impact is equal to the multiplicity of the CDP observation system. The duration of exposure with an average time interval for excitation of oscillations from PV to PV, equal to 2-3 minutes, is 60-180 minutes (1-3 hours). As a result, hydrocarbon deposits are exposed to a continuous train of seismic waves for 1-3 hours with an increase in their intensity periodically repeated every 2-3 minutes. This provides a higher, in a frequency band of up to 40 Hz, intensity of induced geodynamic noise from hydrocarbon deposits, which can be recorded using standard seismic equipment.

2. Microseisms are registered by a multi-channel CDP observation system, which ensures a high density of PPs on the profile with a registration duration of microseisms at each PP of about 2-6 hours. This

increases the amount of information received about geodynamic noise by an order of magnitude or more and increases the reliability and accuracy of their identification without additional costs for such work.

3. This technology can also be implemented based on the results of previously carried out CDP work, using stock materials. This allowed from 2006 to 2014. without the cost of special field work, process CDP data in the amount of about 13,000 linear meters using this technology. km obtained in many areas

Rice. 3 - Time seismic section (A) and characteristics of microseisms (B, C) in the area of ​​unproductive wells

Rice. 5 - Location of geodynamic noise zones 1-5 and structural plan of the B10 formation at the Alenkinsky license area

Rice. 4 - A typical example of the location of a hydrocarbon deposit on the wings of a fold. South of the West Siberian Lowland

Rice. 6 - Time section (A) and noise spectrum (B) in the transition zone from oil to gas deposits

Western and Eastern Siberia, including the areas of more than 30 known fields with the presence of more than 200 productive and “empty” wells. It was found that by the location of sections (on the profile) and zones (on the area) of geodynamic noise, it is possible to determine the contours of hydrocarbon deposits (Fig. 2) and the type of traps (anticlinal, non-anticlinal) (Fig. 4, 5). Based on such features of the noise spectrum as their overall intensity, predominant frequency and modality, it is possible to predict the relative volume of hydrocarbon reserves in an object and a forecast about the presence of the type of fluid (oil, gas, condensate) in the object (Fig. 6).

The above-mentioned capabilities of PAS COGT technology are very relevant at the present time, when the crisis in the economy continues to intensify. The use of this technology will allow oil workers to drill hydrocarbon traps rather than structures, which will increase the efficiency of geological exploration work (manifold) when searching for oil and gas.

In Russia, 6,500 exploration wells were drilled in 2013, and 5,850 wells in 2014. The cost of drilling one exploratory well in the Russian Federation ranges from

100 to 500 million rubles. depending on the geographical location wells, structures, existing infrastructure, etc.; average cost is about 300 million rubles. With a drilling success rate of 10..30% in 2013, out of 6,500 wells drilled, 3,900 wells turned out to be unproductive; about 1.2 trillion rubles were spent on their drilling.

The PAS CDP technology has been tested at dozens of hydrocarbon fields in Western and Eastern Siberia and has shown its effectiveness: all fields are marked by anomalies in the intensity of geodynamic noise and the absence of such anomalies outside the fields.

The above-mentioned capabilities of PAS COGT technology are very relevant at the present time, when the crisis in the economy continues to intensify. This technology will allow oil workers to drill hydrocarbon traps rather than structures, which will increase the efficiency of geological exploration work (manifold) when searching for oil and gas.

Bibliography

1. Puzyrev N.N. Methods and objects

seismic research. Introduction to general seismology. Novosibirsk: SO

RAS; NIC OIGGM, 1997. 301 p.

2. Timurziev A.I. Current state practices and methodology of oil exploration - from the misconceptions of stagnation to a new worldview of progress // Geology, geophysics and development of oil and gas fields. 2010. No. 11.

3. Grafov B.M., Arutyunov S.A., Kazarinov

B.E., Kuznetsov O.L., Sirotinsky Yu.V., Suntsov A.E. Analysis of geoacoustic radiation of oil and gas deposits using ANCHAR technology // Geophysics. 1998. No. 5. pp. 24-28.

4. Patent No. 2 263 932 C1 in 01 U/00 Russian Federation. Seismic exploration method. Application 07/30/2004.

5. Vedernikov G.V. Methods of passive seismic exploration // Instruments and systems of exploration geophysics. 2013. No. 2.

6. Vedernikov G.V., Maksimov L.A., Chernyshova T.I., Chusov M.V. Innovative technologies. What does the experience of seismic exploration work on the Shushukskaya area say? //Geology and mineral resources of Siberia. 2015. No. 2 (22). pp. 48-56.

Geodynamic noise of hydrocarbon pools and passive and active seismic CDPM

Leonid A. Maksimov - Ph. D., lecturer1; [email protected] Gennadiy V. Vedernikov - Sc. D., deputy of science work2; [email protected] Georgiy N. Yashkov - chief geoscientist2; [email protected]

Novosibirsk State University, Novosibirsk, Russian Federation 2"NMT-Seis" LLC, Novosibirsk, Russian Federation

The information on the technology of passive and active seismic using the common-depth-point method (hereinafter "the PAS CDPM"), solving the problem of direct exploration of hydrocarbon accumulations using the amplitude information of induced geodynamic noise emitted by these accumulations is containing .

It is shown that the use of this technology can prevent drilling of nonproductive wells.

Materials and methods

The proposed PAS CDPM technology complexes registration and interpretation of induced

geodynamic noises emitted by hydrocarbon accumulations, and waves reflected from the seismic horizons. This provides high efficiency of studying of reflectors geometry and registration of induced geodynamic noises emitted by hydrocarbon accumulations.

The PAS CDPM technology tested in dozens of hydrocarbon accumulations of Western and Eastern Siberia has proven its efficiency, namely all accumulations have displayed intensity anomalies of geodynamic noises, and no such anomalies have been observed outside accumulations.

The above mentioned PAS CDPM technology capability is relevant nowadays, when the economic crisis is gathering pace. The defined technology will make it possible for petroleum experts to drill traps instead of drilling structures that will increase severalfold efficiency of oil and gas geological exploration.

CDPM seismic, direct hydrocarbon exploration, induced geodynamic noise, prospecting and exploratory drilling success ratio

1. Puzyrev N.N. Metody i ob"ekty seysmicheskikh issledovaniy. Vvedenie v obshchuyu seysmologiyu. Novosibirsk: SO RAN; NITs OIGGM, 1997, 301 p.

2. Timurziev A.I. Sovremennoe sostoyanie praktiki i metodologii poiskov nefti

Otzabluzhdeniyzastoya k novomu mirovozzreniyu progressa. Geology,

geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2010, issue 11, pp. 20-31.

3. Grafov B.M., Arutyunov S.A., Kazarinov V.E., Kuznetsov O.L., Sirotinskiy Yu.V., Suntsov A.E. Analiz geoakusticheskogo izlucheniya neftegazovoyzalezhi pri ispol "zovanii tekhnologiiANChAR. Geofizika, 1998, issue 5, pp. 24-28.

4. Patent Russian Federation No. 2 263 932 CI G 01 V/00 Sposob seysmicheskoy razvedki. Declared 07/30/2004.

5. Vedernikov G.V. Metody passive ceysmorazvedki. Pribory i systemy razvedochnoygeofiziki, 2013, issue 2, pp. 30-36.

6. Vedernikov G.V., Maksimov L.A., Chernyshova T.I., Chusov M.V. Innovatsionnye tekhnologii. O chem govorit opytseysmorazvedochnykh rabot na Shushukskoy ploshchadi. Geologiya i mineral"no-syr"evye resursy Sibiri, 2015, issue 2 (22), pp. 48-56.

The experience of conducting field seismic exploration using the classical technique and the high-performance Slip-Sweep technique by Samaraneftegeofizik is considered.

The experience of conducting field seismic exploration using the classical technique and the high-performance Slip-Sweep technique by Samaraneftegeofizika is considered.

The advantages and disadvantages of the new technique are revealed. The economic indicators of each of the methods are calculated.

Currently, the productivity of field seismic exploration depends on many factors:

Land use intensity;

Traffic of automobiles and railways Vehicle, through the study area;

Activity on the territory of settlements located in the study area; influence of meteorological factors;

Rough terrain (ravines, forests, rivers).

All of the above factors significantly reduce the speed of seismic exploration.

In fact, during the day there are 5-6 hours of night time left for seismic observations. This is critical and insufficient to complete the volumes within the stipulated time frame, and also significantly increases the cost of work.

The time of work, first of all, depends on the following stages:

Topogeodetic preparation of the observation system - installation of profile pickets on the ground;

Installation and adjustment of seismic receiving equipment;

Excitation of elastic vibrations, recording of seismic data.

One way to reduce the time spent is to use the Slip-Sweep technique.

This technique allows you to significantly speed up the production of the excitation stage - recording seismic data.

Slip-sweep is a high-performance seismic survey system based on the overlapping sweep method, in which vibrators operate simultaneously.

In addition to increasing the speed of field work, this technique allows for the compaction of explosion points, thereby increasing the density of observations.

This improves the quality of work and increases productivity.

The Slip-Sweep technique is relatively new.

The first experience in conducting CDP-3D seismic exploration using the Slip-Sweep technique was obtained in an area of ​​only 40 km 2 in Oman (1996).

As you can see, the Slip-Sweep technique was used mainly in desert areas, with the exception of work in Alaska.

In Russia, in pilot mode (16 km 2), the Slip-Sweep technology was tested in 2010 by the forces of Bashneftegeofizika.

The article presents the experience of conducting field work using the Slip-Sweep method and comparing indicators with the standard method.

The physical basis of the method and the possibility of compacting the observation system simultaneously with the use of Slip-Sweep technology are shown.

The primary results of the work are presented and the shortcomings of the method are identified.

In 2012, Samaraneftegeofizik carried out 3D work using the Slip-Sweep method at the Zimarnoy and Mozharovsky license areas of Samaraneftegaz in the amount of 455 km 2 .

The increase in productivity due to the Slip-Sweep technique at the excitation-recording stage in the conditions of the Samara region occurs due to the use of short-term periods of time allotted for recording seismic data during the daily cycle of work.

That is, the task of performing the largest number of physical observations in a short time is performed by the Slip-Sweep technique most effectively by increasing the productivity of recording physical observations by 3-4 times.

The Slip-Sweep technique is a high-performance seismic exploration system based on the method of overlapping vibration sweep signals, in which vibration installations on different PVs operate simultaneously, registration is continuous. Vibration excitations on different PVs are performed with a time delay, so simultaneously operating vibrators emit elastic vibrations at different frequencies ranges (Fig. 1).

The emitted sweep signal is one of the operators of the cross-correlation function in the process of obtaining a coregram from a vibrogram.

At the same time, in the correlation process, it is also a filter operator that suppresses the influence of frequencies other than the frequency emitted at a given time, which can be used to suppress emissions from simultaneously operating vibrators.

With a sufficient delay time for the operation of vibration installations, their emitted frequencies will be different, thereby completely eliminating the influence of neighboring vibration emissions (Fig. 2).

Consequently, with correctly selected slip-time, the influence of simultaneously operating vibration installations is eliminated in the process of converting the vibrogram into a coregram.

Rice. 1. Slip-time delay. Simultaneous emission of different frequencies.

Rice. 2. Evaluation of the use of an additional filter for the influence of neighboring vibration radiation: A) corellogram without filtering; B) corelogram filtered by vibrogram; B) frequency-amplitude spectrum of filtered (green light) and unfiltered (red color) coregrams.

The use of one vibrator instead of a group of 4 vibrators is based on the sufficiency of the energy of vibration radiation from one vibrator to form reflected waves from target horizons (Fig. 3).

Rice. 3. Sufficient vibration energy from one vibration installation. A) 1 vibration installation; B) 4 vibration units.

The Slip-Sweep technique is more effective when using compaction surveillance systems.

For the conditions of the Samara region, a 4-fold compaction of the observation system was applied. 4-fold division of one physical observation (f.n.) into 4 separate f.n. based on the equality of the distance between the vibrator plates (12.5 m) with a group of 4 vibrators, a PV pitch of 50 m and the use of one vibrator with a PV pitch of 12.5 m (Fig. 4).

Rice. 4. Compaction of the surveillance system with 4-fold separation of physicalobservations.

In order to combine the results of observation using the standard technique and the slip-sweep technique with 4-fold compaction, the principle of parity of the total energies of vibration radiation is considered.

The parity of vibration energy can be assessed by the total time of vibration.

Total time of vibration exposure:

St = Nv * Nn * Tsw * dSP,

where Nv is the number of vibration units in the group, Nn is the number of accumulations, Tsw is the duration of the sweep signal, dSP is the number of f.n. within the basic step PV=50m.

For the traditional method (PV step = 50m, group of 4 sources):

St = 4 * 4 * 10 * 1 = 160 sec.

For the slip-sweep method:

St = 1 * 1 * 40 * 4 = 160 sec.

The result of parity of energies for equality of total time shows the same result in the total Bin of 12.5m x 25m.

To compare methods, Samara geophysicists received two sets of seismograms: 1st set - 4 seismograms processed by one vibrator (Slip-Sweep technique), 2nd set - 1 seismogram processed by 4 vibrators (standard technique). Each of the 4 seismograms of the first set is approximately 2-3 times weaker than the seismogram of the second set (Fig. 3). Accordingly, the signal-microseism ratio is 2-3 times lower. However, more quality result is the use of compacted 4 relatively weak in energy individual seismograms (Fig. 5).

In the case of joining areas worked out by different methods, using processing procedures oriented to the wave field of the standard method, the result was practically equivalent (Fig. 6, Fig. 7). However, if we apply processing parameters adapted for the Slip-Sweep technique, the result will be time sections with increased time resolution.

Rice. 5. Fragment of the primary summary time section according to INLINE (without filtering procedures) at the junction of two areas developed using the slip-sweep method (left) and standard technique (right).

A comparison of time sections and spectral characteristics of the standard technique and the Slip-Sweep technique shows high comparability of the resulting data (Fig. 8). The difference lies in the presence of higher energies of the high-frequency component of the Slip-Sweep seismic data signal (Fig. 7).

This difference is explained by the high noise immunity of the compacted observation system and the high multiplicity of seismic data (Fig. 6).

Also important point is the point impact of one vibrator instead of a group of vibrators and its single impact instead of the sum of vibration impacts (accumulations).

The use of a point source of excitation of elastic vibrations instead of a group of sources expands the spectrum of recorded signals in the high-frequency region, reduces the energy of near-surface interference waves, which affects the increase in the quality of the recorded data and the reliability of geological constructions.

Rice. 6. Amplitude-frequency spectra from seismograms processed using differentmethods (based on processing results): A) slip-sweep technique; B) Standard technique.

Rice. 7. Comparison of time sections worked out using different methods(based on processing results): A) Slip-sweep technique; B) Standard technique.

Advantages of the Slip-Sweep technique:

1. High productivity of work, expressed in increased productivity of registration of f.n. 3-4 times, increasing overall productivity by 60%.

2. Improved quality of field seismic data due to PV compaction:

High noise immunity of the surveillance system;

High frequency of observations;

Possibility of increasing spatial;

Increasing the share of the high-frequency component of the seismic signal by 30% due to point excitation (vibration).

Disadvantages of using the technique.

Working in the Slip-Sweep technique mode is working in a “conveyor” mode in a streaming information environment with non-stop recording of seismic data. With non-stop recording, the seismic complex operator's visual control over the quality of seismic data is significantly limited. Any failure can lead to mass defects or work stoppage. Also, at the stage of subsequent monitoring of seismic data at the field computer center, the use of more powerful field computing systems for the preparation and preliminary field processing of data is required. However, the costs of purchasing computer equipment, as well as equipment for retrofitting the recording complex, are recouped within the scope of the work contractor’s profit due to a reduction in the time required for their completion. Among other things, more efficient logistical procedures are required for preparing profiles for testing physical observations.

When carrying out work by Samaraneftegeofizika using the Slip-Sweep method in 2012, the following economic indicators were obtained (Table 1).

Table 1.

Economic indicators for comparing work methods.

These data allow us to draw the following conclusions:

1. With the same amount of work, the overall productivity of Slip-Sweep work is 63.6% higher than when carrying out work using the “standard” method.

2. Increased productivity directly affects the duration of work (decrease by 38.9%).

3. When using the Slip-Sweep technique, the cost of field seismic exploration is 4.5% lower.

Literature

1. Patsev V.P., 2012. Report on the implementation of work on the object of field seismic exploration work MOGT-3D within the Zimarny license area of ​​Samaraneftegaz OJSC. 102 pp.

2. Patsev V.P., Shkokov O.E., 2012. Report on the implementation of work on the object of field seismic exploration MOGT-3D within the Mozharovsky license area of ​​Samaraneftegaz OJSC. 112 p.

3. Gilaev G.G., Manasyan A.E., Ismagilov A.F., Khamitov I.G., Zhuzhel V.S., Kozhin V.N., Efimov V.I., 2013. Experience in seismic exploration MOGT-3D using the Slip-Sweep technique. 15 s.