Optimization design method for edge expanding well of multi-layer-series multi-fault complex fault block

Abstract

The invention discloses a multi-layer-series multi-fault complex fault block edge-expanded well optimization design method, which comprises the following steps: according to a regional stratum layering mode, carrying out whole-region stratification comparative analysis, obtaining a well position deployment target layer, according to a target layer deposition cycle, obtaining an oil layer group, a sandstone group and a single sand body layering standard in combination with a 214 comparison method, finely calibrating earthquake and geologic horizon, and carrying out the optimization design of a multi-layer-series multi-fault complex fault block edge-expanded well. An isochronous stratigraphic framework is established, complex fault block boundary faults and internal inter-well minor faults are subjected to fine recognition, and meanwhile the up-and-down current situation of a target reservoir structure is obtained; the target sand body development condition of an unknown area is obtained, and then complex fault block target reservoir sand body distribution characteristics are obtained; on the basis of the obtained complex fault block oil reservoir data information, the design scheme of the well position in the oil reservoir is optimized; a slave well platform is planned on the ground, that is, three to five wells are drilled on one platform. According to the method, the most effective deployment well position can be determined, and efficient development of the complex fault block is ensured; and the reservoir drilling success rate and the new well utilization rate are improved.

Description

Technical Field

[0001] The invention relates to the technical field of well expansion optimization, and in particular to an optimization design method for well expansion with complex fault blocks having multiple layers and multiple faults. Background Art

[0002] In recent years, due to various factors such as high exploration level in old areas, perfect well network, high recovery level, severe flooding, and difficulty in economic evaluation, well site deployment has been difficult. As a result, production capacity construction can only be implemented in complex blocks with many faults, complex structures, multiple layers of formations, and incomplete understanding of geological bodies.

[0003] For conventional oil reservoirs, the geological bodies are fully understood and the well site design is relatively simple. Well sites are generally deployed in areas with high structures and thick oil layers. The existing fault system is complex, with many interpreted faults and complex structures. In addition, the well area is affected by sedimentation, the reservoir changes rapidly, and the oil and water distribution law has not been effectively implemented. Therefore, the well site deployment method of general oil reservoirs is no longer suitable for complex fault blocks with many characteristics of mutual pinching of sand bodies. Summary of the invention

[0004] The purpose of the present invention is to provide a method for optimizing the design of well expansion in multi-layer, multi-fault complex fault blocks, which can determine the most effective well deployment location and ensure the efficient development of complex fault blocks; utilize high-angle, double or multi-target geological design to connect multiple sets of reservoirs, improve the success rate of reservoir drilling and the utilization rate of new wells.

[0005] To achieve the above purpose, the technical solution of the present application is: a multi-layer multi-fault complex fault block expansion well optimization design method, including:

[0006] According to the regional stratigraphic stratification model, a comparative analysis of the whole region is carried out to obtain the target layer for well deployment. According to the sedimentary cycle of the target layer, the "214" comparison method is combined to obtain the stratification standards of the oil layer group, sandstone group and single sand body, and each single sand body layer is finely divided. At the same time, old wells are selected to make synthetic seismic records and VSP tests to form a grid-type networked high-precision seismic profile to make up for the lack of resolution of three-dimensional seismic data, extract accurate velocity parameters, finely calibrate seismic and geological layers, and establish an isochronous stratigraphic framework to provide reliable basic data for seismic interpretation and reservoir inversion, realize fine tracking of single sand bodies, and make the description of oil-water relationship more reasonable;

[0007] Finely identify the boundary faults of complex fault blocks and the internal small faults between wells, and obtain the current status of the structural ups and downs of the target reservoir;

[0008] Obtain the development of target sand bodies in unknown areas, and then obtain the distribution characteristics of sand bodies in target reservoirs of complex fault blocks;

[0009] Based on the obtained complex fault-block reservoir data, optimize the design of well locations in the reservoir;

[0010] Furthermore, it also includes full consideration of factors such as economic benefits, geological requirements, ground environment, and construction difficulty. Ground planning starts from the well platform, that is, one platform implements drilling of 3 to 5 wells. It can effectively reduce the time and cost of ground land acquisition, well site expansion, road paving, drilling rig relocation, production pipeline installation, centralized management of oil wells, etc. Under limited ground conditions, more geological reservoirs can be utilized to ensure the smooth implementation and production of new wells, thereby realizing the benefit of oil reservoirs to increase reserves and build production.

[0011] Furthermore, the “214” comparison method is equal in deposition time, equal in thickness in adjacent wells, and unified in well-seismic data, which is consistent with structural interpretation, depositional laws, reservoir-forming characteristics, and production dynamics.

[0012] Furthermore, the boundary faults of complex fault blocks and the internal small faults between wells are finely identified, and the ups and downs of the target reservoir structure are obtained. The specific method is as follows:

[0013] Geoeast seismic software is applied, single sand body layer data, accurate velocity parameters, and grid-type high-precision seismic profiles are used to conduct integrated structural interpretation of the overlying and underlying target reservoirs. Seismic interpretation and stratigraphic comparison are applied comprehensively, and the interpretation conclusions of drilling, logging, and well logging, as well as production and development dynamic data, are combined to achieve fine identification of complex block boundary faults and internal small faults between wells, and at the same time obtain the current status of the structural ups and downs of the target reservoir.

[0014] Furthermore, an integrated structural interpretation of the overlying and underlying target reservoirs is performed according to the step length of the two seismic traces.

[0015] Furthermore, the development of target sand bodies in unknown areas is obtained, and then the distribution characteristics of target reservoir sand bodies in complex fault blocks are obtained. The specific method is as follows:

[0016] By comparing the results and parameters of stratification and structural interpretation, the geological data are closely integrated with the seismic data, and the display of the target sand body in the seismic data is accurately calibrated and identified. The seismic iso-axis is accurately tracked using seismic data interpretation, and the development of the target sand body in the unknown area is inferred by analogy from the reflection of the completed drilling target layer in the seismic. The distribution characteristics of the sand body in the target reservoir of the complex fault block are obtained, which solves the problem of unclear understanding of the phase changes between the various layers or single sand bodies in the complex fault block.

[0017] Furthermore, the design scheme for optimizing the well location in the reservoir is specifically designed in the following manner: adopting a high-angle, dual or multi-target oil well design scheme to make the oil well trajectory close to the cross-section and accurately tap the remaining oil at the edge of the fault.

[0018] Furthermore, high-angle, dual or multi-target oil well design can be used to deepen the overlying reservoir while taking into account the underlying reservoir, or to drill the overlying reservoir when there are risks in drilling and exploring the underlying reservoir, so as to increase the reservoir drilling rate of a single well and avoid the risk of a single well not drilling a reservoir or the risk of a drilled reservoir not being able to achieve economic development.

[0019] Furthermore, when the overlying and underlying reservoirs of a small fault-block reservoir are displaced greatly in the plane, the conventional approach is to drill new wells separately. However, the design of high-angle, dual or multi-target wells can ensure the thickness of the new well oil layer while accurately tapping the remaining oil in the two sets of reservoirs and improving the utilization rate of reservoir reserves.

[0020] Due to the adoption of the above technical scheme, the present invention can achieve the following technical effects: The optimization design method of multi-layer system multi-fault complex fault block expansion wells of the present application can meet the needs of overall re-evaluation and development of oil reservoir geological bodies with such characteristics as complex fault systems, fast reservoir phase changes, complex oil-water relationships, and small reserve areas. The design scheme of personalized high-angle, double or multi-target oil wells can ensure the thickness of the new well oil layer while accurately tapping the potential of the remaining oil at the edge of the fault, improve the single well reservoir drilling rate and the degree of oil reservoir reserve utilization, and avoid the risk of a single well not drilling a reservoir or drilling a reservoir that cannot achieve economic development. Planning a slave well platform can effectively realize the waiting time and investment costs of oil wells in various time periods such as deployment, pre-drilling, drilling, commissioning, and post-management, improve the production time rate of oil wells, mobilize more geological reservoirs under limited ground conditions, ensure the smooth implementation and production management of new wells, and achieve efficient reserve increase and production construction of oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 This is the schematic diagram of the optimization design method for the well expansion in complex fault blocks with multiple layers and multiple faults.

[0023] Figure 2 It is a schematic diagram of the grid-type high-precision seismic profile in this design method.

[0024] Figure 3 It is a schematic diagram of structural interpretation based on the step size of 2 seismic traces in this design method.

[0025] Figure 4 This is a schematic diagram of the design method for accurately tracking earthquake co-axial axes using seismic data interpretation.

[0026] Figure 5 It is a schematic cross-sectional view of a high-angle dual-target oil well in this design method.

[0027] Figure 6 This is a schematic diagram of a slave well platform.

[0028] Among them: A—fault, B—high-angle oil well, C, D—target points, E—co-axis, F—vertical well, a, b, c—oil layers. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] This embodiment is the Dalinghe oil reservoir in the Shahejie Formation Sha3 section of a certain oil field block. The Dalinghe reservoir of this oil reservoir has three sets of oil layer groups, two of which have a history of oil production and are the target layers of this study. The vertical burial depth difference between the two sets of oil layer groups exceeds 500 meters. In addition, the overall fault system of the oil reservoir is complex, with many interpreted faults, deep-water turbidity deposits, rapid reservoir phase change, many single sand bodies, and unclear understanding of the oil and water distribution law. Since the oil reservoir was put into development, measures have been mainly used to tap potential, and there is a lack of overall understanding and evaluation of the geological body of the oil reservoir. By implementing the multi-layer system and multi-fault complex block expansion well optimization design method on the two sets of reservoir blocks developed in the oil reservoir, preliminary development results have been achieved; Figure 1-6 As shown, the design method specifically includes:

[0031] Step 1. According to the regional stratigraphic stratification model, a comparative analysis of the whole area was carried out, and it was found that the area was the Dalinghe oil reservoir in the third member of the Shahejie Formation. According to the sedimentary cycle of the Dalinghe oil reservoir, the stratification standards of the oil layer group, sandstone group and single sand body were obtained in combination with the "214" comparison method. The reservoir was divided into 3 oil layer groups and 5 sandstone groups. At the same time, old wells were selected to make synthetic seismic records and VSP tests, extract accurate velocity parameters, finely calibrate seismic and geological layers, establish an isochronous stratigraphic framework, realize fine tracking of single sand bodies, and determine the oil-water interface of each reservoir, so that the oil-water relationship is more reasonable.

[0032] Step 2. Using Geoeast seismic software and the data obtained in step 1, the overlying and underlying target reservoirs were interpreted in an integrated manner with a step length of 2 in the seismic data. The seismic interpretation and stratigraphic comparison were applied comprehensively, and the interpretation conclusions of drilling, logging, well logging, and other interpretations and production and development dynamic data were combined to achieve the fine identification of the boundary faults of the overlying and underlying fault blocks and the internal inter-well small faults of the reservoir. On the basis of the original understanding, 3 faults were cancelled, 4 faults were added, and 3 faults were corrected, which improved the inheritance and occurrence of the internal faults in the block.

[0033] Step 3. Use the stratification data obtained in step 1 and the structural interpretation conclusions obtained in step 2 to closely combine the two, use the display of the completed drilling target layer in the area in the seismic data, and track the same axis through seismic tracking to realize the distribution characteristics of the sand body of the target reservoir in the location area, and solve the problem of unclear understanding of the phase changes between the various layers or single sand bodies in the well area.

[0034] Step 4. Using the layered data obtained in step 1, the structural interpretation conclusions obtained in step 2, and the sand body distribution characteristics obtained in step 3, the well site is deployed, the trajectory design of the new well is optimized, and the personalized high-angle, double or multi-target oil well program design is adopted to make the oil well trajectory close to the cross section and accurately tap the remaining oil at the edge of the fault. This design controls 1 well, the target layer is the underlying reservoir, and the overlying reservoir is taken into account. 4 development wells are designed, the target layer is the overlying reservoir, and the underlying reservoir is deepened and taken into account. A total of 5 oil wells are drilled to achieve accurate drilling of 10 targets, which improves the single well reservoir drilling rate and avoids the risk of single wells not encountering reservoirs or drilling reservoirs that cannot achieve economic development. At the same time, due to the plane displacement of the overlying and underlying strata exceeding 500 meters, compared with the conventional vertical well single target design, 5 drilling wells are saved. While ensuring the thickness of the new well oil layer, this program design accurately taps the remaining oil in the two sets of strata reservoirs and improves the utilization of reservoir reserves.

[0035] Step 5. Taking into full consideration economic benefits, geological requirements, ground environment, construction difficulty and other factors, the ground planning is carried out from the well platform. In the design of the new well, two old platforms are selected to implement the new well, so as to shorten the waiting time and investment cost of the oil well in various time periods such as deployment, pre-drilling, drilling, production and post-management, improve the production time rate of the oil well, mobilize more geological reservoirs under limited ground conditions, ensure the smooth implementation and production management of the new well, and realize the efficient increase of reserves and production of the oil reservoir.

[0036] In this embodiment, one control well and four development wells were deployed in the fault block, and all the target points were designed to encounter reservoirs. The new wells have encountered a total of 406.0 meters of reservoirs, and the average single well has encountered a reservoir of 81.2 meters. Five new wells have been put into production, with a daily output of more than 100 tons. The cumulative oil production has exceeded 20,000 tons and the cumulative gas production has exceeded 10 million cubic meters. The efficient development effect has been achieved in the stage, which can be promoted in major oil fields.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0038] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optimization design method for well expansion in complex fault blocks with multiple layers and multiple faults, characterized by: include: According to the regional stratigraphic stratification model, a comparative analysis of the whole region was conducted to obtain the target layer for well deployment. According to the sedimentary cycle of the target layer, the "214" comparison method was combined to obtain the stratification standards of the oil layer group, sandstone group and single sand body, and each single sand body layer was finely divided. At the same time, old wells were selected to make synthetic seismic records and VSP tests to form a grid-type networked high-precision seismic profile, extract accurate velocity parameters, finely calibrate seismic and geological layers, and establish an isochronous stratigraphic framework; Finely identify the boundary faults of complex fault blocks and the internal small faults between wells, and obtain the current status of the structural ups and downs of the target reservoir; Obtain the development of target sand bodies in unknown areas, and then obtain the distribution characteristics of sand bodies in target reservoirs of complex fault blocks; Based on the obtained complex fault-block reservoir data, the design plan of well location in the reservoir is optimized.

2. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 1 is characterized in that: It also includes planning a slave well platform on the ground, that is, one platform to drill 3 to 5 wells.

3. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 1 is characterized in that: The "214" correlation method is equal in deposition time, equal in thickness in adjacent wells, and unified in well-seismic data, which is consistent with structural interpretation, sedimentary laws, reservoir-forming characteristics, and production dynamics.

4. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 1 is characterized in that: The boundary faults of complex fault blocks and the internal small faults between wells are precisely identified, and the ups and downs of the target reservoir structure are obtained. The specific methods are as follows: Geoeast seismic software is used to interpret the structure of the overlying and underlying target reservoirs using single sand body layer data, accurate velocity parameters, and grid-type high-precision seismic profiles. The seismic interpretation and stratigraphic comparison are applied in combination with the drilling, logging, and well logging interpretation conclusions and production and development dynamic data to achieve fine identification of complex block boundary faults and internal small faults between wells, and obtain the current status of the target reservoir structure ups and downs.

5. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 4 is characterized in that: An integrated structural interpretation of the overlying and underlying target reservoirs is performed according to the step length of the two seismic traces.

6. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 1 is characterized in that: Obtain the development of target sand bodies in unknown areas, and then obtain the distribution characteristics of target reservoir sand bodies in complex fault blocks. The specific methods are as follows: By comparing the results and parameters of stratification and structural interpretation, the geological data are closely integrated with the seismic data, the display of the target sand body in the seismic data is accurately calibrated and identified, and the seismic iso-axis is accurately tracked using seismic data interpretation. The development of the target sand body in the unknown area is inferred by analogy from the reflection of the completed drilling target layer in the seismic, and the sand body distribution characteristics of the target reservoir in the complex fault block are obtained.

7. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 1 is characterized in that: The above-mentioned design scheme for optimizing the well position in the oil reservoir is specifically designed in the following manner: adopting a high-angle, double or multi-target oil well design scheme to make the oil well trajectory close to the cross-section and accurately tap the remaining oil at the edge of the fault.

8. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 7 is characterized in that: The design of high-angle, dual or multi-target oil wells is adopted to deepen the overlying reservoir while taking into account the underlying reservoir, or to drill the overlying reservoir while taking into account the drilling and exploration of the underlying reservoir when there are risks.

9. The optimization design method for multi-layer multi-fault complex fault block well expansion according to claim 7 is characterized in that: When the overlying and underlying reservoirs of a small fault-block reservoir are displaced greatly in plane, a high-angle, dual or multi-target oil well design is adopted to accurately tap the remaining oil in the two sets of reservoirs while ensuring the thickness of the oil layer in the new well.

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