Horizontal well layering and structure modeling method based on multi-stage constraint

Abstract

The invention relates to a multilevel constraint horizontal well layering and structure modeling method, which belongs to the field of oil and gas field development geology in the petroleum industry, and comprises the following steps: determining a division comparison standard of stratigraphic units according to stratigraphic data and stratigraphic information in a research area, so that vertical well layering three-dimensional closing in the whole area is realized, and a vertical well stratigraphic comparison profile is obtained; projecting the horizontal well to a position close to a single sand layer of a judgment horizontal section in the vertical direction according to a vertical well stratigraphic contrast profile, and preliminarily judging a single sand body layer position of the horizontal section; and constructing a three-dimensional geologic model applying the data of the whole-area vertical well, projecting a horizontal section track into the model, and finally determining a division scheme of a single sand layer near the horizontal well according to a crossing point where the horizontal section track is intersected with a structural plane and the trend and form of a single sand layer interface. And utilizing the single sand layer division scheme near the horizontal well to correct the defects of the stratum microstructure between the vertical wells in the whole area, and establishing a more accurate three-dimensional geologic model.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field development geology in the petroleum industry, and specifically relates to a multi-level constrained horizontal well stratification and structural modeling method. Background Art

[0002] In oil and gas development operations at home and abroad, well logging and seismic are almost the most common means of operation, which play a vital role in detecting the location of underground oil and gas accumulation. After the exact location is detected, the wellhead is used for development operations. From the initial vertical well development, it was gradually discovered that horizontal wells can effectively increase the contact area of ​​oil and gas reservoirs, which can greatly increase the production, recovery rate and economic benefits of single wells, and began to be promoted and applied on a large scale in industrialization. At present, there are more than 1,300 horizontal wells in the Liaohe Oilfield in China. With 6.8% of the wells, it supports 26.8% of the annual production, which has become an important means of development of the oilfield.

[0003] However, with the deepening of development, the remaining oil is relatively concentrated in non-main layers and thin layers, and the development accuracy is gradually increasing. The existing understanding and production development of sedimentary reservoirs in many blocks are based on small layers, but multiple sets of superimposed sand bodies are still developed inside the small layers, forming a large amount of remaining oil and gas resources. How to tap the potential and develop the remaining oil is a problem that needs to be solved urgently. Therefore, it is necessary to further refine the stratification, sedimentary microfacies and sand body distribution law research to explore the main controlling factors of oil and gas distribution. Horizontal well A target has high-precision vertical geological data like vertical wells, while B target has data on nearly parallel stratigraphic deposition, which supplements the lack of inter-well data and has great research significance for the lateral distribution of sand bodies in sparse well areas. Therefore, it is crucial to clarify the location of horizontal wells and their drilling layers and carry out distribution prediction of reservoir sand bodies. The key point and difficulty of the study is that the horizontal sections of horizontal wells are mostly distributed at the same depth / layer, the characteristics of the logging curve are unclear, and it is basically impossible to judge the sedimentary rhythm. After the stratification is refined, it is difficult to determine its specific location.

[0004] At present, the application of horizontal wells at home and abroad is mainly to increase production capacity and recovery rate, and to suppress bottom water and gas cap. In terms of horizontal well stratification technology, there are relatively few methods at present.

[0005] The invention patent application with announcement number CN111852459B discloses a shale gas reservoir structure modeling method and device. It mainly stratifies horizontal wells based on the well logging information of vertical wells in the work area, calculates the top and bottom structural depth values ​​of the target layer using the average thickness of the target layer of the vertical well, and establishes the top and bottom structural planes of the target layer in combination with the seismic data interpretation data. Then, the target layer is split according to the total thickness of the target layer and the average thickness of each small layer, and the structural planes of each small layer are established, thereby establishing a structural model. Although this method takes into account the stratification data of horizontal wells and calculates the top and bottom structural data using the average thickness of the target layer of the vertical well, the average thickness is used, which has limitations on the requirements for the formations in the study area. It can only be used in stable formations without structural development. If the local formations are eroded and faulted due to regional tectonic movement, this method is no longer applicable; at the same time, using the average thickness of the formation to establish the structural plane will also cause the formation thickness between wells to be too stable, which is inconsistent with the sedimentary environment and has low accuracy. In addition, since the horizontal section of the horizontal well is not always drilled in the target layer, there will be layer penetration, which will cause the horizontal well data to be different from the ideal situation, resulting in reduced modeling results. The patent failed to describe in detail the process of determining the horizontal well stratification using vertical well logging information, and did not take into account the actual stratigraphic division of the horizontal section after the horizontal section penetrated the layer. The horizontal section stratification data was not used to update the structural model, and the constructed structural model had deviations. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-level constrained horizontal well stratification and structural modeling method to solve the problems of poor depiction accuracy and inaccurate modeling of inter-well structural surfaces in the prior art.

[0007] To achieve the above object, the solution of the present invention includes:

[0008] A multi-level constrained horizontal well stratification and structural modeling method of the present invention comprises the following steps:

[0009] (1) Based on the stratigraphic data and stratification information in the study area, the division and comparison standards of stratigraphic units are determined to make the vertical well strata in the whole area three-dimensionally closed and obtain the vertical well stratigraphic comparison profile;

[0010] (2) Based on the vertical well stratigraphic comparison section, the horizontal well is projected to the vertical direction to determine the position of the adjacent single sand layer in the horizontal section, and the single sand body layer in the horizontal section in the prediction standard is preliminarily determined;

[0011] (3) constructing a three-dimensional geological model using the data of the vertical wells in the entire area, projecting the horizontal section trajectory into the model, and then finally determining the single sand layer division scheme near the horizontal well in the prediction standard based on the intersection point of the horizontal section trajectory with the structural surface and the trend and shape of the single sand layer interface;

[0012] (4) The single sand layer division scheme near the horizontal well is used to correct the deficiencies of the microstructure of the strata between the vertical wells and establish a more accurate three-dimensional geological model.

[0013] Furthermore, the stratigraphic data and layer information in step (1) include cyclicity, mud interlayer distribution and logging curve combination characteristics.

[0014] Furthermore, in step (2), the position of the single sand layer adjacent to the drilling point at the beginning of the horizontal section is determined by using the logging data constraint to determine the position of the single sand layer adjacent to the horizontal section.

[0015] Furthermore, in step (2), the combined features of the sedimentary cycle and the well logging curve are used to determine the position of the adjacent single sand layer of the drilling point at the beginning of the horizontal section by projecting the horizontal well to the vertical direction.

[0016] Furthermore, in step (1), the three-dimensional closure of vertical wells in the whole area is completed, and a regional stratigraphic framework is constructed. The wells to be layered are arranged side by side with adjacent wells according to their geographical locations, so that the horizontal wells are projected into the vertical direction.

[0017] Furthermore, in step (3), the seismic data is used to perform secondary constraints on the regional stratigraphic framework to establish the three-dimensional geological model.

[0018] Furthermore, in step (3), the exact position of the penetration point is determined based on the intersection of the horizontal section trajectory and the structural surface, as well as the trend and shape of the single sand layer interface, and ultimately the single sand layer division scheme near the horizontal well is determined.

[0019] Furthermore, in step (3), the intersection of the horizontal section trajectory and the structural surface is determined by using the lithology changes reflected by the logging curve of the horizontal well; and the trend and shape of the single sand layer interface are determined by seismic inversion profile.

[0020] Furthermore, the distance between the selected adjacent well and the well to be stratified does not exceed 2500m.

[0021] The location of the horizontal well drilling point is determined by stratifying the adjacent vertical wells, and the number and rough position of the intersections between the horizontal well trajectory and the formation are determined by projecting them onto the model. The precise penetration position of the horizontal well is determined by the lithological changes reflected by the logging data. That is, the stratification results are matched with the production data and sedimentary patterns through the commonly used multi-level constraint method of geological data to match them with the actual morphology. A high-precision three-dimensional geological model is then established based on the stratification data of vertical and horizontal wells, thus laying a solid foundation for subsequent sedimentary phases, interlayers, reserve calculations, and numerical simulation studies. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a step diagram of a construction modeling method according to an embodiment of the present invention;

[0023] Figure 2 It is the single-layer division standard well stratification of the embodiment of the present invention;

[0024] Figure 3 The horizontal well to be stratified and the adjacent well stratification in the embodiment of the present invention;

[0025] Figure 4 It is the intersection point between the projection of the horizontal well trajectory and the plane of the three-dimensional geological model in the embodiment of the present invention;

[0026] Figure 5 is the horizontal section logging curve of the horizontal well dgg in the embodiment of the present invention;

[0027] Figure 6 is the DGG seismic inversion profile of the horizontal well in the embodiment of the present invention;

[0028] Figure 7 It is a fine three-dimensional geological modeling section constructed in combination with horizontal well data in an embodiment of the present invention;

[0029] Figure 8 It is a comparison diagram of the horizontal well data of the embodiment of the present invention and the fine three-dimensional geological modeling profile constructed only by vertical wells. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1 As shown, the purpose of the present invention is to propose a new idea and method for horizontal well stratification, clarify the lateral distribution law of sand bodies through existing horizontal well data, and through multi-level constraints (single well interpretation conclusions, field outcrop statistics, geological sedimentary laws), match the stratification results with production data and sedimentary patterns, and match them with the actual morphology, thereby establishing an updated high-precision geological structure model based on horizontal well stratification. It solves the problems of insufficient use of horizontal well data and difficulty in characterizing stratum microstructures in traditional modeling methods, improves the characterization accuracy of inter-well structural surfaces and the accuracy of the model, and lays a solid foundation for subsequent research on the distribution of oil and gas resources.

[0032] An embodiment of a multi-level constrained horizontal well stratification and structural modeling method:

[0033] The method described in the present invention is used to carry out the division of single sand layers in horizontal wells in a certain study area Z on the northern edge of the Ordos Basin.

[0034] (1) Based on the stratigraphic data and stratification information in the study area, a single-layer level division scheme is established for the area. Figure 2), and based on the standard wells, complete the three-dimensional closure of vertical wells in the whole area, build a regional stratigraphic framework, and place the wells to be layered side by side with the adjacent wells according to their geographical locations, so that the well trajectory curve is projected to the vertical direction ( Figure 3 ) to determine the approximate location of the horizontal segment.

[0035] (2) Use the quadratic constraints of seismic data to construct a three-dimensional geological model. Project the trajectory of the horizontal well onto it. (It can be observed that the well has two intersections with the geological model layer.) Figure 4 ).

[0036] (3) According to the lithology changes reflected by the logging curve, the location of the single sand layer was determined at 4120 m ( Figure 5 ). Then the seismic inversion profile of the horizontal well is used to determine the direction and shape of the layer position ( Figure 6 ).

[0037] (4) Use the existing horizontal well stratification information to construct a detailed three-dimensional geological model ( Figure 7 ), after horizontal well correction, the structural surface has vertical floating of 0.5m-5m and horizontal floating of 1m-300m ( Figure 8 ), further consolidated the existing geological understanding and laid the foundation for subsequent modeling and numerical modeling work.

[0038] The present invention makes full use of the commonly used seismic and logging data in oil and gas fields to construct a three-dimensional geological model, effectively determines the drilling position and layer of the horizontal wells in the dense horizontal well development area, and can continuously refine the existing geological structure model based on the existing stratification results, making up for the lack of horizontal well lateral data utilization in conventional modeling work, which can be more conducive to the study of subsequent sedimentary phases, interlayer distribution, reserve calculation and numerical modeling work. The method of the present invention has low requirements for the required data and information, and uses logging and seismic data to achieve fine development of oil and gas fields through modeling methods, effectively solves the problem of oil and gas distribution, supplements the lack of data between vertical wells, and is suitable for complex structural areas. It has good research significance for the subsequent fine development of oil and gas in horizontal well areas and has broad promotion and application value.

Claims

1. A multi-level constrained horizontal well stratification and structural modeling method, characterized in that: The steps include: (1) Based on the stratigraphic data and stratification information in the study area, the division and comparison standards of stratigraphic units are determined to make the vertical well strata in the whole area three-dimensionally closed and obtain the vertical well stratigraphic comparison profile; (2) Based on the vertical well stratigraphic comparison section, the horizontal well is projected to the vertical direction to determine the position of the adjacent single sand layer in the horizontal section. Preliminary determination of the single sand body layer in the horizontal section; (3) constructing a three-dimensional geological model using the data of the vertical wells in the entire area, projecting the horizontal section trajectory into the model, and then finally determining the single sand layer division scheme near the horizontal well based on the intersection point of the horizontal section trajectory with the structural surface and the trend and shape of the single sand layer interface; (4) The single sand layer division scheme near the horizontal well is used to correct the deficiencies in the microstructure of the strata between vertical wells in the entire area and establish a more accurate three-dimensional geological model.

2. The multi-level constrained horizontal well stratification and structural modeling method according to claim 1, characterized in that: The stratigraphic data and layer information described in step (1) include cyclicity, mud interlayer distribution and logging curve combination characteristics.

3. The multi-level constrained horizontal well stratification and structural modeling method according to claim 1, characterized in that: In step (2), the position of the single sand layer adjacent to the drilling point at the beginning of the horizontal section is determined by using the logging data constraint to determine the position of the single sand layer adjacent to the horizontal section.

4. The multi-level constrained horizontal well stratification and structural modeling method according to claim 3, characterized in that: In step (2), the combined characteristics of sedimentary cycles and well logging curves are used to determine the position of the adjacent single sand layer of the drilling point at the beginning of the horizontal section by projecting the horizontal well to the vertical direction.

5. The multi-level constrained horizontal well stratification and structural modeling method according to claim 4, characterized in that: In step (1), complete the three-dimensional closure of vertical wells in the whole area, construct the regional stratigraphic framework, and place the wells to be layered side by side with the adjacent wells according to their geographical locations so that the horizontal wells are projected into the vertical direction.

6. The multi-level constrained horizontal well stratification and structural modeling method according to claim 5, characterized in that: In step (3), the seismic data is used to perform secondary constraints on the regional stratigraphic framework to establish the three-dimensional geological model.

7. The multi-level constrained horizontal well stratification and structural modeling method according to claim 1, characterized in that: In step (3), the intersection point between the horizontal section trajectory and the structural surface is determined using the lithology changes reflected by the logging curve of the horizontal well.

8. The multi-level constrained horizontal well stratification and structural modeling method according to claim 7, characterized in that: In step (3), the exact position of the penetration point is determined based on the intersection of the horizontal section trajectory and the structural surface, as well as the trend and shape of the single sand layer interface, and finally the single sand layer division scheme near the horizontal well is determined.

9. The multi-level constrained horizontal well stratification and structural modeling method according to claim 8, characterized in that: In step (3), the strike and shape of the single sand layer interface are determined by seismic inversion profile.

10. The multi-level constrained horizontal well stratification and structural modeling method according to claim 5, characterized in that: The distance between the selected adjacent well and the well to be layered shall not exceed 2500m.

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