A dynamic characterization method for oil-water interface

Abstract

A method for dynamic characterization of oil-water interface, involving the field of reservoir engineering, includes: establishing a fine geological model; establishing a fine numerical simulation model; predicting the dynamic oil-water interface of a single well; analyzing the sensitivity of the water body to obtain high-precision historical fitting results; integrating the prediction results of the dynamic oil-water interface of a single well, combining with the high-precision historical fitting results, determining the changes of the oil-water interface in the plane and in the vertical direction, and then determining the current oil-water interface. The present invention integrates multi-disciplinary and multi-attribute information, depicts the spatial changes of oil and water movement in the reservoir from the initial to the present for oilfield developers, and provides technical support for the optimization of development strategies. The present invention is suitable for the characterization of oil-water interfaces of different reservoir types and different development stages, and provides a scientific basis for reservoir engineering personnel to carry out screening of old well measures, optimization of new well locations and completion strategies.

Description

Technical Field

[0001] The invention relates to the technical field of oil reservoir engineering, in particular to a dynamic characterization method of an oil-water interface. Background Art

[0002] After a long period of development, the original oil-water interface of the oil field has changed. At the same time, due to the different injection volumes of water injection wells and liquid production of oil wells in different areas, the changes in the oil-water interface in different areas are also different. The water saturation test results of the cores and flooded wells also confirm this.

[0003] At present, the characterization of the dynamic oil-water interface is mainly based on observation wells, core wells, and various test methods to characterize the oil-water interface of a single well, lacking the spatial characterization of the water interface of an oil field or oil layer. Therefore, it is necessary to develop a dynamic oil-water interface characterization method to solve the above problems. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a dynamic characterization method for the oil-water interface, which integrates the static and production dynamic effects on the oil-water interface, and solves the problem that the prior art is limited to the description of test data but cannot characterize the spatial changes of the oil-water interface.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] A method for dynamic characterization of an oil-water interface of the present invention comprises the following steps:

[0007] Step 1: Establish a detailed geological model;

[0008] Step 2: Establish a detailed numerical simulation model;

[0009] Step 3: Single well dynamic oil-water interface prediction;

[0010] Step 4: Analyze the sensitivity of water bodies and obtain high-precision history fitting results;

[0011] Step 5: Integrate the single-well dynamic oil-water interface prediction results and combine them with the high-precision historical fitting results to determine the changes in the oil-water interface in the plane and vertical direction, and then determine the current oil-water interface.

[0012] Furthermore, in step one, the detailed geological model includes the distribution relationship of each sublayer in the plane and in the vertical direction: in the plane, the fault information, sedimentary information, single well phase and logging interpretation results are integrated to clarify the plane distribution and thickness changes of the reservoir; in the vertical direction, the initial oil-water interface of each sublayer is clarified.

[0013] Furthermore, in step 1, the fine geological model integrates the porosity, permeability and saturation of a single well, and determines the spatial distribution of reservoir properties under the control of reservoir inversion and sedimentary microfacies.

[0014] Furthermore, in step 2, according to the fine geological model, the pressure data at the oil-water interface, the production data of the oil-water wells and the perforation data are input to establish a fine numerical simulation model to characterize the oil-water relationship distribution under the initial conditions of the reservoir.

[0015] Furthermore, in step three, the original logging interpretation results show the initial oil-water interface, and the new well test results show the current oil-water interface. By analyzing the oil-water interface in different time periods, the vertical changes of the oil-water interface can be clarified.

[0016] Furthermore, in step 4, the history matching method is used to fit the liquid production, oil production, water content and pressure of the block and the single well to determine the energy of the initial reservoir.

[0017] Compared with the prior art, the method for dynamic characterization of oil-water interface provided by the present invention has the following beneficial effects:

[0018] ① The present invention constructs a spatial framework for oil and water movement in oil reservoirs based on a fine numerical simulation model, integrating information such as small faults, sand body boundaries, and single sand body characterization.

[0019] ② The present invention integrates production dynamic data and combines test data such as single well water saturation, pressure, water absorption profile, and liquid production profile to characterize the oil-water interface from the perspectives of point-line-surface-body.

[0020] ③ The present invention is based on high-precision numerical simulation technology, integrating dynamic and static data information to depict the dynamic oil-water interface.

[0021] ④ The present invention integrates multi-disciplinary and multi-attribute information to depict the spatial changes of oil and water movement in the reservoir from the initial stage to the present for oilfield developers, providing technical support for the optimization of development strategies.

[0022] ⑤ The present invention is suitable for the characterization of oil-water interfaces in different reservoir types and development stages, and provides a scientific basis for reservoir engineering personnel to carry out screening of old well measures, optimization of new well locations and completion strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the stratigraphic stratification results map.

[0024] Figure 2 The fault model.

[0025] Figure 3 The sedimentary phase model.

[0026] Figure 4 For the attribute model.

[0027] Figure 5 is the water saturation model.

[0028] Figure 6 The saturation test results, liquid production profile test results, water absorption profile test results, etc. show the current oil-water interface. Figure 6 In the figure, UNDEF indicates mudstone layer, Open indicates production layer, Oil indicates oil layer, HWF indicates strong water flooding, MWF indicates moderate water flooding, and LWF indicates weak water flooding.

[0029] Figure 7 This is a diagram showing the changes in the oil-water interface at the well point. Figure 7 In the figure, the horizontal axis is the well name, and the vertical axis is the depth. Gumry-45, Gumry-44_ST, Gumry-1, Gumry-7, and Gumry-M_1 respectively represent the well names.

[0030] Figure 8 This is the fitting result of the well point pressure. Figure 8 In the figure, Y_IV, Y_IV_2, Y_V, Y_V_2, Y_V_3, Y_VI, Y_VI_2, Y_VI_3, Y_VII and Y_VII_2 respectively represent the names of small layers.

[0031] Fig. 9 is the historical matching result. Fig. 9 A represents the daily liquid production fitting result of the block, and B represents the cumulative oil production fitting result of the block. Fig. 9 C represents the daily oil production fitting result, and D represents the block pressure change, such as Fig. 9 E in the figure represents the fitting result of water content, and F represents the fitting result of the cumulative fluid production of the block.

[0032] Fig.10 This is the moisture content distribution diagram. Fig.10 In the figure, Gumry-1 to Gumry-45, Gumry_M-1, Gumry-2H and Gumry-20_ST respectively represent the well names. DETAILED DESCRIPTION

[0033] In a method for dynamic characterization of an oil-water interface of the present invention, the characterization of the dynamic oil-water interface is mainly to outline the spatial framework of the oil-water operation in the reservoir, and to combine the production data and test data of the oil and water wells, and use interpretation methods, high-precision numerical simulation technology, etc. to describe the dynamic changes of the oil-water interface from point-line-surface-body. Among them, the point is the test result of the water saturation of a single well; the line is to outline the water invasion front in combination with the production conditions of each single well, structural lines, etc.; the surface is to characterize the oil-water interface in the horizontal and vertical sections running through the entire reservoir; the body is to integrate the results of points, lines, surfaces, etc., and integrate dynamic and static data to form the dynamic changes of the oil-water interface that change with time.

[0034] A dynamic characterization method of an oil-water interface of the present invention mainly comprises the following steps:

[0035] Step 1: Establish a detailed geological model;

[0036] The established detailed geological model reflects the distribution relationship of each sublayer in the plane and vertical direction: in the plane, it integrates fault information, sedimentary information, single well phase and logging interpretation results to clarify the planar distribution and thickness changes of the reservoir; in the vertical direction, it clarifies the initial oil-water interface of each sublayer.

[0037] The established fine geological model integrates the porosity, permeability, saturation, etc. of a single well, and determines the spatial distribution of reservoir properties under the control of reservoir inversion and sedimentary microfacies.

[0038] like Figure 1 As shown in the figure, it is the stratigraphic stratification result map. Figure 1 It can be seen that the stratum distribution is stable.

[0039] like Figure 2 As shown in the figure, it is a fault model diagram. Figure 2 It can be seen that the fitting results of faults and single well breakpoints are good.

[0040] like Figure 3 As shown in the figure, it is a sedimentary phase diagram. Figure 3 It can be seen that the planar sedimentary facies distribution also controls the planar attribute distribution.

[0041] like Figure 4 As shown in the figure, it is the attribute model diagram. Figure 4 It can be seen that the distribution of block attributes in the plane and vertical direction.

[0042] Step 2: Establish a detailed numerical simulation model;

[0043] On the basis of the fine geological model, the pressure data at the oil-water interface and the production data of the oil-water wells (daily liquid production, daily oil production, daily water production) and perforation data are input to establish a fine numerical simulation model to characterize the oil-water relationship distribution under the initial conditions of the reservoir.

[0044] The established detailed numerical simulation model is as follows Figure 5 As shown in the figure, it is the water saturation distribution diagram. Figure 5 It can be seen that the initial oil-water distribution relationship of the block is the initial oil-water interface.

[0045] Step 3: Single well dynamic oil-water interface prediction;

[0046] The original logging interpretation results show the initial oil-water interface, and the new well test results, such as saturation test results, liquid production profile test results, water absorption profile test results, etc., show the current oil-water interface. Figure 6 As shown, after years of development, the original oil-water interface on the single well has risen to the currently interpreted oil-water interface, indicating that part of the strata in the single well has been flooded. After flooding, the oil-water interface (i.e., the current oil-water interface) is unbalanced at the well point, and the original oil-water interface (i.e., the initial oil-water interface) is a horizontal plane.

[0047] The oil-water interface at different time periods was analyzed to clarify the vertical changes of the oil-water interface. The results are as follows: Figure 7 As shown, compared with the original oil-water interface, the current oil-water interface at different well points changes differently, and the oil-water interface changes from the original horizontal plane to the current oil-water interface with different depths at a single well point.

[0048] Step 4: Analyze the sensitivity of water bodies and obtain high-precision history fitting results;

[0049] By fitting various data of blocks and single wells measured at different time periods, the energy of the initial reservoir is determined. By fitting the pressure test results of single wells at different production stages, the energy of the initial reservoir is determined. Figure 8 As shown, by fitting the well point pressure and the production data of a single well, the oil and water changes during the oil field production process are simulated to obtain high-precision history fitting results.

[0050] Specifically, the data of block and single well liquid production, oil production, water content, pressure, etc. are fitted through the history fitting method to determine the energy of the initial reservoir, making the fine numerical simulation model more reasonable and more representative of the actual reservoir characteristics.

[0051] The historical matching results are as follows Fig. 9 As shown, historical fitting is performed on the daily liquid production, cumulative liquid production, daily oil production, water content, cumulative oil production, etc. of the block. When the fitting accuracy meets the requirements, the numerical simulation model results can show the current oil-water interface.

[0052] Step 5: Integrate the single-well dynamic oil-water interface prediction results in step 3 and combine them with the high-precision history fitting results to determine the changes in the oil-water interface in the plane and vertical direction, and then determine the current oil-water interface. The results are as follows: Fig.10 As shown in the figure, the current oil-water interface shows uneven advancement due to the influence of edge water intrusion, bottom water cone intrusion, and injected water monolayer intrusion.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for dynamic characterization of an oil-water interface, characterized in that: The following steps are involved: Step 1: Establish a detailed geological model; Step 2: Establish a detailed numerical simulation model; Step 3: Prediction of dynamic oil-water interface of a single well; Step 4: Analyze the sensitivity of water bodies and obtain high-precision history fitting results; Step 5: Integrate the single well dynamic oil-water interface prediction results and combine them with the high-precision history fitting results to determine the changes in the oil-water interface in the plane and vertical direction, and then determine the current oil-water interface; Among them, in step 1, the fine geological model includes the distribution relationship of each sublayer in the plane and vertical direction: in the plane, the fault information, sedimentary information, single well phase and logging interpretation results are integrated to clarify the plane distribution and thickness change of the reservoir; in the vertical direction, the initial oil-water interface of each sublayer is clarified; In step 1, the fine geological model integrates the porosity, permeability and saturation of a single well, and determines the spatial distribution of reservoir properties under the control of reservoir inversion and sedimentary microfacies; In step 2, according to the fine geological model, the pressure data at the oil-water interface, the production data of the oil-water wells and the perforation data are input to establish a fine numerical simulation model to characterize the oil-water relationship distribution under the initial conditions of the reservoir; In step 3, the original logging interpretation results show the initial oil-water interface, and the new well test results show the current oil-water interface. By analyzing the oil-water interface at different time periods, the vertical changes of the oil-water interface are clarified; Among them, in step 4, the sensitivity of water bodies is analyzed to obtain high-precision historical fitting results, which specifically include: determining the energy of the initial oil reservoir by fitting the liquid production, oil production, water content and pressure of the blocks and single wells measured in different time periods; fitting the pressure test results of different production stages of a single well; simulating the changes in oil and water during the production process of the oil field by fitting the well point pressure and the production data of a single well, and obtaining high-precision historical fitting results.

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