A method and device for locating remaining sweet spots of a tight sandstone oil and gas reservoir

Abstract

The application provides a method and device for positioning remaining dessert of tight sandstone oil and gas reservoir, and belongs to the field of oil and natural gas exploration and development, which comprises the following steps: establishing a block three-dimensional geological model according to block two-dimensional seismic data; analyzing orogenic movement of the block to obtain orogenic movement mechanical characteristic information corresponding to a large number of reservoir natural fractures; analyzing single well geomechanics to obtain rock mechanical behavior characteristic parameters; establishing a three-dimensional finite element model, calculating natural fracture damage mechanics values according to the three-dimensional finite element model, and obtaining natural fracture distribution data in the reservoir; comparing the natural fracture distribution data in the reservoir with phenomena reflected in observation phenomena; superimposing well site distribution of existing high-yield wells and natural fracture damage mechanics value distribution map to obtain the position of the remaining dessert of the tight sandstone oil and gas reservoir. The method and device for positioning remaining dessert of tight sandstone oil and gas reservoir have high accuracy and high efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration and development, and in particular relates to a method and apparatus for locating the remaining sweet spot in tight sandstone oil and gas reservoirs. Background Technology

[0002] Due to factors such as low reservoir permeability, the volume of oil and gas reservoirs usable after hydraulic fracturing in tight sandstone oil and gas fields remains limited. Even after initial development and the establishment of numerous production wells, there are still untapped sweet spots rich in oil and gas waiting to be developed. The current challenges are: 1) the high heterogeneity of the reservoirs makes it difficult to infer the location of untapped sweet spots based on existing ones; 2) existing technologies have limitations in locating untapped sweet spots, as conventional techniques based on seismic data to calculate natural fractures are insufficient to locate microfracture zones. This is a common technical challenge in the current oil development industry, characterized by high cost, low efficiency, and significant time consumption. Summary of the Invention

[0003] The purpose of this invention is to provide a method and apparatus for locating remaining sweet spots in tight sandstone oil and gas reservoirs. Using damage mechanics, the method simulates the process of natural fracture formation during orogenic movements to determine the location and distribution of natural fractures, i.e., sweet spots, in tight oil and gas reservoirs. Then, by combining this with existing well oil and gas production data, the location of remaining sweet spots is determined.

[0004] To achieve the above objectives, the present invention provides a method for locating the remaining sweet spot in tight sandstone oil and gas reservoirs, comprising the following steps:

[0005] Acquire 2D seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data for the block;

[0006] A three-dimensional geological model of the block was established based on the block's two-dimensional seismic data.

[0007] Based on the analysis of the history of orogenic movement and stratigraphic sedimentary history, the orogenic movement of the block was analyzed, and a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir was obtained.

[0008] Based on the analysis of single-well geomechanics using well logging data, rock mechanical behavior parameters are obtained;

[0009] A three-dimensional finite element model is established based on the block's three-dimensional geological model, the mechanical characteristics of orogenic movement, and the parameters of rock mechanical behavior.

[0010] Based on the three-dimensional finite element model, the numerical damage mechanics of natural fractures are calculated, and the distribution cloud map of the numerical damage mechanics of natural fractures in the reservoir and the distribution information of natural fractures are obtained.

[0011] Compare the data on the distribution of natural fractures within the reservoir with the phenomena observed in the observations;

[0012] If the distribution data of natural fractures in the reservoir is consistent with the observed phenomena, the mechanical values ​​of natural fracture damage are considered to be true; otherwise, the data of orogenic mechanical characteristics are modified and recalculated.

[0013] When the mechanical damage values ​​of natural fractures are true, the well location distribution of existing high-yield wells is compared with the distribution of mechanical damage values ​​of natural fractures. Figure 2 By superimposing these, the remaining sweet spot locations of tight sandstone oil and gas reservoirs can be obtained.

[0014] Preferably, a three-dimensional geological model of the block is established based on the two-dimensional seismic data of the block, including the following steps:

[0015] Import block 2D seismic data, which includes 2D seismic data, logging curves of existing wells, drilling logging geological stratification information, and well data information;

[0016] Using well logging curves and drilling logging formation information, the formation information obtained from the analysis of two-dimensional seismic data was compared, confirmed, checked, and adjusted.

[0017] Based on stratigraphic information, time-depth calibration, two-dimensional profile interpretation and characterization are performed, and a three-dimensional time-domain block structure map is generated. Then, the time-depth conversion and correction of the obtained three-dimensional seismic data are performed.

[0018] Preferably, the mechanical characteristics of orogenic movement include the tensile and compressive properties of orogenic movement, and the main tensile and compressive direction angles.

[0019] Preferably, the rock mechanical behavior parameters include parameters such as the elastic modulus value, as well as the rock damage mechanical constitutive property parameters;

[0020] Preferably, the method for determining the remaining sweet spot location in tight sandstone oil and gas reservoirs is as follows: The distribution of existing high-yield well locations is compared with the numerical distribution of damage mechanics of natural fractures. Figure 2 The areas with high density of natural fractures are considered sweet spots, the areas with high-yield wells are considered developed sweet spots, and the undeveloped sweet spots are considered remaining sweet spots.

[0021] A residual sweet spot location device for tight sandstone oil and gas reservoirs, comprising:

[0022] The data acquisition module is used to acquire block-specific two-dimensional seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data;

[0023] The model building module is used to build a three-dimensional geological model of the block based on the block's two-dimensional seismic data;

[0024] The analysis module is used to analyze the orogenic movement of the block, obtain a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir; analyze the geomechanics of a single well, and obtain rock mechanical behavior parameters; establish a three-dimensional finite element model based on the three-dimensional geological model of the block, the orogenic mechanical characteristic information and the rock mechanical behavior parameters; calculate the damage mechanical values ​​of natural fractures based on the three-dimensional finite element model, and obtain the distribution cloud map of the damage mechanical values ​​of natural fractures in the reservoir and the distribution information of natural fractures.

[0025] The comparison module is used to compare the distribution data of natural fractures in the reservoir with the phenomena reflected in the observations.

[0026] The positioning module is used to match the well location distribution of existing high-yield wells with the natural fracture damage mechanical value distribution when the natural fracture damage mechanical value is true. Figure 2 By superimposing these, the remaining sweet spot locations of tight sandstone oil and gas reservoirs can be obtained.

[0027] Therefore, the present invention employs the above-mentioned method and apparatus for locating the remaining sweet spot in a tight sandstone oil and gas reservoir, and the technical effects are as follows:

[0028] A three-dimensional geological model was built using two-dimensional seismic data as input parameters. This saved on the cost of three-dimensional seismic data.

[0029] The method of calculating the location distribution of natural fractures by simulating orogenic movement using damage mechanics does not require fault displacement as input data. It can detect fracture zones with very small or even no fault displacement, and has high accuracy and efficiency. Attached Figure Description

[0030] Figure 1 This is a flowchart of a method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir according to the present invention;

[0031] Figure 2 This refers to the existing information data of single wells and block production wells obtained in Example 2; Figure 2 (a) shows the logging curves for a single well; Figure 2 (b) Production information for existing wells within the block;

[0032] Figure 3 The three-dimensional geological model in Example 2: Figure 3 (a) Two-dimensional lines interpreted in three dimensions; Figure 3 (b) Three-dimensional geological model;

[0033] Figure 4 This refers to the single-well geomechanical analysis in Example 2;

[0034] Figure 5 3D geological model meshing for the block; Figure 5 (a) is a plan view of the geological model of the block; Figure 5(b) is a three-dimensional view of the block's geological model;

[0035] Figure 6 For block finite element model;

[0036] Figure 7 Numerical solution contour plot of natural cracks in the damage mechanics of the block model: planar view;

[0037] Figure 8 Results of comparing the distribution of natural fractures within the reservoir with the distribution of production sizes of existing wells: Comparison of all sweet spots with known sweet spots. Detailed Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0040] Example 1

[0041] like Figure 1 As shown, a method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir includes the following steps:

[0042] Step 1: Obtain 2D seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data for the block;

[0043] Step 2: Establish a three-dimensional geological model of the block based on the two-dimensional seismic data, including the following steps:

[0044] Import block 2D seismic data, which includes 2D seismic data, logging curves of existing wells, drilling logging geological stratification information, and well data information;

[0045] Using well logging curves and drilling logging formation information, the formation information obtained from the analysis of two-dimensional seismic data was compared, confirmed, checked, and adjusted.

[0046] Based on stratigraphic information, time-depth calibration, two-dimensional profile interpretation and characterization are performed, and a three-dimensional time-domain block structure map is generated. Then, the time-depth conversion and correction of the obtained three-dimensional seismic data are performed.

[0047] Step 3: Analyze the orogenic history and stratigraphic sedimentary history of the block to obtain a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoirs. This information includes the tensile and compressive characteristics of the orogenic movement, and the main tensile and compressive direction angles. The analysis involves first examining the orogenic history and stratigraphic sedimentary history information in existing geological data, then analyzing the orogenic phases corresponding to the target layer, and finally deriving the corresponding orogenic mechanical characteristic information through numerical simulation and phenomenon fitting.

[0048] Step 4: Analyze the geomechanics of a single well based on the logging data to obtain the rock mechanical behavior parameters, including parameters such as the elastic modulus value and the damage mechanical constitutive properties of the rock.

[0049] Step 5: Based on the three-dimensional geological model of the block, the mechanical characteristics of orogenic movement, and the parameters of rock mechanical behavior, establish a three-dimensional finite element model;

[0050] Step 6: Calculate the numerical values ​​of natural fracture damage based on the three-dimensional finite element model to obtain the distribution cloud map of the numerical solution of natural fracture damage in the reservoir and the distribution information of natural fractures.

[0051] Step 7: Compare the data on the distribution of natural fractures in the reservoir with the phenomena observed in the observations;

[0052] If the distribution data of natural fractures in the reservoir is consistent with the observed phenomena, the mechanical values ​​of natural fracture damage are considered to be true; otherwise, the data of orogenic mechanical characteristics are modified and recalculated.

[0053] Step 8: When the mechanical values ​​of natural fracture damage are true, compare the well location distribution of existing high-yield wells with the distribution of mechanical values ​​of natural fracture damage. Figure 2 By superimposing these, the remaining sweet spot locations of tight sandstone oil and gas reservoirs can be obtained.

[0054] The method for determining the remaining sweet spot location in tight sandstone oil and gas reservoirs is as follows: The distribution of existing high-yield well locations is compared with the numerical distribution of damage mechanics of natural fractures. Figure 2 The areas with high density of natural fractures are considered sweet spots, the areas with high-yield wells are considered developed sweet spots, and the undeveloped sweet spots are considered remaining sweet spots.

[0055] A residual sweet spot location device for tight sandstone oil and gas reservoirs, comprising:

[0056] The data acquisition module is used to acquire block-specific two-dimensional seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data;

[0057] The model building module is used to build a three-dimensional geological model of the block based on the block's two-dimensional seismic data;

[0058] The analysis module is used to analyze the orogenic movement of the block, obtain a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir; analyze the geomechanics of a single well, and obtain rock mechanical behavior parameters; establish a three-dimensional finite element model based on the three-dimensional geological model of the block, the orogenic mechanical characteristic information and the rock mechanical behavior parameters; calculate the damage mechanical values ​​of natural fractures based on the three-dimensional finite element model, and obtain the distribution cloud map of the damage mechanical values ​​of natural fractures and the distribution information of natural fractures.

[0059] The comparison module is used to compare the distribution data of natural fractures in the reservoir with the phenomena reflected in the observations.

[0060] The positioning module is used to match the well location distribution of existing high-yield wells with the natural fracture damage mechanical value distribution when the natural fracture damage mechanical value is true. Figure 2 By superimposing these, the remaining sweet spot locations of tight sandstone oil and gas reservoirs can be obtained.

[0061] Example 2

[0062] Step 1: Obtain data on the tight sandstone oil and gas reservoir in Block Y of Gas Field X, including 2D seismic data, logging data from hundreds of drilled wells, production data, and core data, such as... Figure 2 As shown, where, Figure 2 (a) is the conventional logging curve of an existing well in the block, including gamma, sonic, density, resistivity and other curves. Figure 2 (b) The relative location and production information of existing wells within the block: high-yield wells are marked with red symbols, and low-yield wells are marked with black symbols.

[0063] Step 2: Based on the tight sandstone oil and gas reservoir data of Block Y in the X gas field, establish a three-dimensional geological model of the block. First, establish 39 framework profiles, complete stratigraphic correlation and inspection, and interpret the two-dimensional lines in three dimensions to obtain the three-dimensional geological model, as shown below. Figure 3 As shown.

[0064] The 3D geological model comprises 7 strata, with layer 4 being the target layer; model length: 33.5 km; width: 20 km; height: 1.61 km; total number of grid cells: 865,954. Grid size: 150 x 150 meters in planar view. Minimum thickness: 5 meters. Figure 5 As shown in the diagram, the red dots represent the wellheads of wells 1, 2, 3, and 4, which are known to have high production rates.

[0065] Step 3: Analyze the orogenic movement of the block based on the history of orogenic movement and stratigraphic sedimentary history to obtain a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir.

[0066] Orogenic azimuth: After repeated calculations, the distribution of fracture zones when the orogenic compression azimuth alfa = 15° is closest to the distribution of natural fractures corresponding to the distribution of high-yield wells.

[0067] Step 4: Single-well geomechanical analysis: Provide distribution curves of parameters such as the elastic modulus of each rock layer, such as... Figure 4 As shown, this provides input data for the three-dimensional finite element model.

[0068] Step 5: Based on the three-dimensional geological model of the block, the mechanical characteristics of orogenic movement, and the parameters of rock mechanical behavior, establish a three-dimensional finite element model. The block finite element model, such as... Figure 6 As shown, including

[0069] Total number of cells: 865,954, C3D8R cells. Total number of nodes: 907,200.

[0070] Four-sided and bottom surface displacement boundary conditions: normal zero displacement constraint.

[0071] Loads: Gravity loads and orogenic displacement loads.

[0072] Step 6: Calculate the damage mechanical values ​​of natural fractures based on the three-dimensional finite element model to obtain the distribution information of natural fractures in the reservoir and the distribution map of the damage mechanical values ​​of natural fractures.

[0073] Numerical solution of damage mechanics of natural cracks: Figure 7 The red dots represent the wellhead and bottom locations of the known high-yield wells 1, 2, 3, and 4.

[0074] Step 7: Compare the distribution data of natural fractures in the reservoir with the phenomena observed to obtain the remaining sweet spots of tight sandstone oil and gas reservoirs.

[0075] The results show that the numerical solution for natural fractures obtained using the method in Example 1 is in high agreement with the production rates of existing wells. Areas with high density of natural fractures are identified as "sweet spots."

[0076] Wells in the blue area, which lacks natural fractures, are large black spots and have very low production.

[0077] Low-yield wells can also occur in areas with high density of natural fractures. This is understood to be due to factors such as water-bearing formations.

[0078] Remaining sweet spots: Sweet spots not affected by hydraulic fracturing and not yet used: Sweet spots more than 300 meters away from the well site.

[0079] The remaining desserts are Figure 8 The area circled in red dotted circle.

[0080] Therefore, the present invention employs the above-mentioned method and apparatus for locating residual sweet spots in tight sandstone oil and gas reservoirs, which does not require fault displacement as input data and can discover fracture zones with very small or even no fault displacement, with high accuracy and high efficiency.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir, characterized in that, Includes the following steps: Acquire 2D seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data for the block; A three-dimensional geological model of the block was established based on the block's two-dimensional seismic data. Based on the analysis of the history of orogenic movement and stratigraphic sedimentary history, the orogenic movement of the block was analyzed, and a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir was obtained. Based on the analysis of single-well geomechanics using well logging data, rock mechanical behavior parameters are obtained; A three-dimensional finite element model is established based on the block's three-dimensional geological model, the mechanical characteristics of orogenic movement, and the parameters of rock mechanical behavior. Based on the three-dimensional finite element model, the numerical damage mechanics of natural fractures are calculated, and the distribution cloud map of the numerical damage mechanics of natural fractures in the reservoir and the distribution information of natural fractures are obtained. Compare the data on the distribution of natural fractures within the reservoir with the phenomena observed in the observations; If the distribution data of natural fractures in the reservoir is consistent with the observed phenomena, the mechanical values ​​of natural fracture damage are considered to be true; otherwise, the data of orogenic mechanical characteristics are modified and recalculated. When the mechanical values ​​of natural fracture damage are true, the distribution of existing high-yield wells and the distribution map of mechanical values ​​of natural fracture damage are superimposed to obtain the remaining sweet spot locations of tight sandstone oil and gas reservoirs.

2. The method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir according to claim 1, characterized in that, Establishing a three-dimensional geological model of the block based on the block's two-dimensional seismic data includes the following steps: Import block 2D seismic data, which includes 2D seismic data, logging curves of existing wells, drilling logging geological stratification information, and well data information; Using well logging curves and drilling logging formation information, the formation information obtained from the analysis of two-dimensional seismic data was compared, confirmed, checked, and adjusted. Based on stratigraphic information, time-depth calibration, two-dimensional profile interpretation and characterization are performed, and a three-dimensional time-domain block structure map is generated. Then, the time-depth conversion and correction of the obtained three-dimensional seismic data are performed.

3. The method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir according to claim 1, characterized in that, The mechanical characteristics of orogenic movements include the tensile and compressive properties of orogenic movements, and the tensile and compressive direction angles.

4. The method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir according to claim 1, characterized in that, Rock mechanical behavior parameters include elastic modulus parameters and rock damage mechanical constitutive properties parameters.

5. The method for locating the remaining sweet spot in a tight sandstone oil and gas reservoir according to claim 1, characterized in that, The method for determining the remaining sweet spot locations in tight sandstone oil and gas reservoirs is as follows: superimpose the distribution of existing high-yield well locations with the numerical distribution map of natural fracture damage mechanics. The locations with high natural fracture density are the sweet spot locations, the locations of high-yield wells are the developed sweet spot locations, and the undeveloped sweet spot locations are the remaining sweet spot locations.

6. A device for locating the remaining sweet spot in a tight sandstone oil and gas reservoir, characterized in that, For performing the method of claim 1, including The data acquisition module is used to acquire block-specific two-dimensional seismic data, orogenic history and stratigraphic sedimentary history information, and well logging data; The model building module is used to build a three-dimensional geological model of the block based on the block's two-dimensional seismic data; The analysis module is used to analyze the orogenic movement of the block and obtain a large amount of orogenic mechanical characteristic information corresponding to natural fractures in the reservoir. The geomechanics of a single well was analyzed to obtain the parameters of rock mechanical behavior. Based on the three-dimensional geological model of the block, the mechanical characteristics of orogenic movement, and the parameters of rock mechanical behavior, a three-dimensional finite element model was established. The damage mechanical values ​​of natural fractures were calculated based on the three-dimensional finite element model to obtain the distribution information of natural fractures in the reservoir and the distribution map of natural fracture damage mechanical values. The comparison module is used to compare the distribution data of natural fractures in the reservoir with the phenomena reflected in the observations. The positioning module is used to overlay the distribution of existing high-yield wells with the distribution map of natural fracture damage mechanical values ​​when the natural fracture damage mechanical values ​​are true, in order to obtain the remaining sweet spot location of tight sandstone oil and gas reservoirs.

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