A method for evaluating reservoir connectivity based on lithofacies model

Abstract

The present application provides a reservoir connectivity evaluation method based on a lithofacies model, comprising the steps of: obtaining reservoir interpretation data of a study area, and establishing a lithofacies model according to the reservoir interpretation data; assigning values ​​to each three-dimensional grid point of the lithofacies model according to the reservoir interpretation data, wherein the three-dimensional grid points include sandstone grid points and mudstone grid points; identifying sandstone grids in the lithofacies model; and stacking each layer of sandstone grids layer by layer to form a number of independent sandstone three-dimensional connected bodies and their grid numbers; calculating evaluation parameters according to the grid numbers of the sandstone three-dimensional connected bodies, and evaluating the connectivity of the reservoir according to the evaluation parameters. Evaluating the connectivity of the reservoir according to the evaluation parameters can well evaluate the connectivity of the reservoir, which has a good benefit for the exploration of oil reserves and can improve the accuracy of the development of oil reserves.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploration, and in particular to a reservoir connectivity evaluation method based on a lithofacies model. Background Art

[0002] The geological model can give the spatial variation of the reservoir and quantitatively evaluate the reservoir, especially for the characterization of the heterogeneity of the reservoir properties, which is applied to numerical simulation and provides a good basis for quantitatively characterizing the fluid flow in the reservoir. At the same time, by forming different sections, the heterogeneity characteristics of the reservoir can be vividly characterized. However, when evaluating the reservoir, it is often necessary to evaluate its connectivity. The relevant technology cannot evaluate the connectivity of the reservoir well, which will also bring many inconveniences to the exploration and development of oil reserves. Summary of the invention

[0003] The purpose of the present invention is to overcome the above technical deficiencies, provide a reservoir connectivity evaluation method based on a lithofacies model, and solve the technical problem that the effect of evaluating the connectivity of reservoirs in the prior art is poor.

[0004] In order to achieve the above technical objectives, in a first aspect, the technical solution of the present invention provides a reservoir connectivity evaluation method based on a lithofacies model, comprising the following steps:

[0005] Obtain reservoir interpretation data in the study area and establish a lithofacies model based on the reservoir interpretation data;

[0006] Assigning a value to each three-dimensional grid point of the lithofacies model according to the reservoir interpretation data, the three-dimensional grid points including sandstone grid points and mudstone grid points;

[0007] Identify the sandstone grids in the lithofacies model, and stack each layer of sandstone grids layer by layer to form a plurality of independent three-dimensional sandstone connected bodies, and calculate the number of grids of the three-dimensional sandstone connected bodies;

[0008] An evaluation parameter is calculated according to the number of grids of the three-dimensional connected sandstone body, and the connectivity of the reservoir is evaluated according to the evaluation parameter.

[0009] Compared with the prior art, the reservoir connectivity evaluation method based on the lithofacies model provided by the present invention has the following beneficial effects:

[0010] A reservoir is a rock formation that can store and infiltrate fluids. A rock formation that can store and infiltrate fluids must have good storage space (porosity) and storage space connectivity (permeability), and the permeability and porosity of sandstone are better than mudstone. The more connected grids there are in sandstone, the better the permeability and porosity of large-scale connected sandstones will be, and the better the reservoir connectivity in the area. The reservoir connectivity evaluation method based on the lithofacies model provided by the present invention performs three-dimensional geological modeling on the study area, uses the model to analyze the area where the sandstone is located in the three-dimensional geological model, and the larger the volume of the three-dimensional connected sandstone body, the better the connectivity of the sandstone. The evaluation parameters are calculated based on the number of connected grids of the three-dimensional sandstone body of the sandstone grid points in each sandstone area, and the connectivity of the reservoir is evaluated based on the evaluation parameters. The connectivity of the reservoir can be well evaluated, which has a good benefit for the exploration of oil reserves, can improve the accuracy of the development of oil reserves, and improve work efficiency.

[0011] According to some embodiments of the present invention, after calculating the number of grids of the three-dimensional connected body of sandstone, the method includes the following steps:

[0012] The connected volume of each three-dimensional sandstone connected body is calculated according to the number of grids of the three-dimensional sandstone connected body;

[0013] The evaluation parameter is calculated based on the three-dimensional connected volume of the sandstone, and the connectivity of the reservoir is evaluated based on the evaluation parameter.

[0014] According to some embodiments of the present invention, the three-dimensional grid points are polygonal 3D grids in the lithofacies model.

[0015] According to some embodiments of the present invention, the step of obtaining geological parameters of a reservoir location includes the following steps:

[0016] Obtain well data, layer data, fault data, and sedimentary facies data for reservoir locations.

[0017] According to some embodiments of the present invention, the step of establishing a lithofacies model according to the geological parameters comprises the following steps:

[0018] Establishing the fault model according to the well data and the fault data;

[0019] Establishing layer model based on layered data and well interpolation method;

[0020] Establish a structural model based on the combination of fault model and layer model;

[0021] Based on the structural model, the lithofacies model was established by combining sedimentary facies data and simulation methods.

[0022] According to some embodiments of the present invention, the well data includes: well location coordinates, well depth, well deviation data, well logging curves, patching elevation, and seismic network data;

[0023] Layered data include: layer group division and comparison data of each well, layer data interpreted from seismic data, and well logging data;

[0024] Fault data include: fault location, attitude, fault distance, fault polygon and fault interpretation data;

[0025] Sedimentary facies data include: single well facies data, logging facies data and lithofacies data.

[0026] In a second aspect, the technical solution of the present invention provides a reservoir connectivity evaluation system based on a lithofacies model, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements a reservoir connectivity evaluation method based on a lithofacies model as described in any one of the first aspects.

[0027] In a third aspect, the technical solution of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute a reservoir connectivity evaluation method based on a lithofacies model as described in any one of the first aspects.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, wherein the abstract drawings are identical to one of the drawings in the specification:

[0030] Figure 1 A flow chart of a reservoir connectivity evaluation method based on a lithofacies model provided in one embodiment of the present invention;

[0031] Figure 2 A schematic diagram of a first layer cross section of a reservoir connectivity evaluation method based on a lithofacies model provided in another embodiment of the present invention;

[0032] Figure 3 A schematic diagram of a second layer cross section of a reservoir connectivity evaluation method based on a lithofacies model provided by another embodiment of the present invention;

[0033] Figure 4 A vertically superimposed plan view of a first layer section and a second layer section of a reservoir connectivity evaluation method based on a lithofacies model provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0036] The present invention provides a reservoir connectivity evaluation method based on a lithofacies model, which can well evaluate the reservoir connectivity, has good benefits for the exploration of oil reserves, can improve the accuracy of oil reserve development, and improve work efficiency.

[0037] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0038] Reference Figure 1 , Figure 1 A flow chart of a reservoir connectivity evaluation method based on a lithofacies model provided for one embodiment of the present invention; the reservoir connectivity evaluation method based on a lithofacies model includes but is not limited to steps S110 to S140.

[0039] Step S110, obtaining reservoir interpretation data of the study area, and establishing a lithofacies model according to the reservoir interpretation data;

[0040] Step S120, assigning a value to each three-dimensional grid point of the lithofacies model according to the reservoir interpretation data, the three-dimensional grid points including sandstone grid points and mudstone grid points;

[0041] Step S130, identifying the sandstone grids in the lithofacies model, and stacking each layer of sandstone grids layer by layer to form a number of independent three-dimensional sandstone connected bodies, and calculating the number of grids of the three-dimensional sandstone connected bodies;

[0042] Step S140, calculating evaluation parameters according to the number of grids of the three-dimensional connected sandstone body, and evaluating the connectivity of the reservoir according to the evaluation parameters.

[0043] In one embodiment, a reservoir connectivity evaluation method based on a lithofacies model includes the following steps: obtaining reservoir interpretation data of a study area, and establishing a lithofacies model according to the reservoir interpretation data; assigning values ​​to each three-dimensional grid point of the lithofacies model according to the reservoir interpretation data, wherein the three-dimensional grid points include sandstone grid points and mudstone grid points; identifying sandstone grids in the lithofacies model, and stacking each layer of sandstone grids layer by layer to form a number of independent sandstone three-dimensional connected bodies, and calculating the number of sandstone three-dimensional connected body grids; calculating an evaluation parameter according to the number of sandstone three-dimensional connected body grids, and evaluating the connectivity of the reservoir according to the evaluation parameter. The reservoir connectivity evaluation method based on a lithofacies model provided in this embodiment models the study area, uses the model to analyze the sandstone area in the lithofacies model, calculates the sand body unit grid volume according to the number of sandstone three-dimensional connected grids of the sandstone grid points of each sandstone area, and then calculates the evaluation parameter according to the size of the sand body unit grid volume, and evaluates the connectivity of the reservoir according to the evaluation parameter, which can well evaluate the connectivity of the reservoir, has a good benefit for the exploration of oil reserves, can improve the accuracy of the development of oil reserves, and improve work efficiency.

[0044] The reserves of each sand body unit are evaluated to assess the economic benefits of the development process. Comprehensive consideration of the economic benefits of oil well exploitation is conducive to the rational development of oil mines and has great practical value.

[0045] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0046] Reference Figures 2 to 4 , Figure 2 A schematic diagram of a first layer cross section of a reservoir connectivity evaluation method based on a lithofacies model provided in another embodiment of the present invention; Figure 3 A schematic diagram of a second layer cross section of a reservoir connectivity evaluation method based on a lithofacies model provided by another embodiment of the present invention; Figure 4 A vertically superimposed plan view of a first layer section and a second layer section of a reservoir connectivity evaluation method based on a lithofacies model provided in another embodiment of the present invention.

[0047] In one embodiment, a method for evaluating the degree of reservoir connectivity based on a lithofacies model includes the following steps: obtaining reservoir interpretation data of a study area, and establishing a lithofacies model based on the reservoir interpretation data; assigning a value to each three-dimensional grid point of the lithofacies model based on the reservoir interpretation data, wherein the three-dimensional grid points include sandstone grid points and mudstone grid points; identifying sandstone grids in the lithofacies model; and stacking each layer of sandstone grids layer by layer to form a number of independent three-dimensional sandstone connected bodies and their grid numbers; calculating evaluation parameters based on the number of grids of the three-dimensional sandstone connected bodies, and evaluating the degree of connectivity of the reservoir based on the evaluation parameters.

[0048] After the model was initially built, the faults were corrected and the size of the three-dimensional grids in each block in the model was clarified. The first two layers of the model were used for comparison. Figure 2 and Figure 3 When the overlap is complete, there are vertically overlapping and connected areas of sandstone, areas of sand-mud overlap, and areas of mudstone overlap.

[0049] Will Figure 2 The sandstone in Block A is named S1, and the sandstone in Block B is named S2. Figure 3 The sandstone in Block C is named S3, and the sandstone in Block D is named S4; Figure 2 , Lower Figure 3 Stack them one-to-one to obtain a vertical stacking plan.

[0050] Will Figure 2 The S1 sandstone in Block A Figure 3 The S3 sandstone in block C is superimposed and connected, and its sandstone is named after the sandstone of the upper layer S1. Naturally, block C is also renamed block A.

[0051] Will Figure 3 The sandstone superimposed on S4 in block D and S2 in block B is named after the sandstone of the upper layer S2, that is, S2. Naturally, block D is also renamed block B.

[0052] The model is stacked layer by layer, and the upper sandstone unit is vertically stacked with the lower sandstone unit, so the name of the lower unit is attributed to the name of the upper unit. (With the sandstone block as the center, as long as a sandstone grid in the previous block is positively stacked with any sandstone grid in the next block, this situation can be stacked into a body and named as the upper sandstone block and sandstone name). Therefore, the vertical volume range and shape of the sand body in each block in the entire model can be clearly defined.

[0053] Analyze the number of connected sand bodies in a single-layer block and the connectivity of sand bodies after vertical stacking:

[0054] Usually, the vertical connectivity of the sand body cannot be seen in the entire large model. If each layer is taken out separately, Figure 2 The connectivity number of S1 sandstone is 3, and that of S2 sandstone is 4; Figure 3 The connectivity number of S3 sandstone is 4, and the connectivity number of S4 sandstone is 6.

[0055] According to the vertically stacked blocks, we can more intuitively understand the vertical connectivity of each block. As can be seen from the table, single layer (A+C) = stacking A; single layer (B+D) = stacking B.

[0056] Therefore, it can be seen that there are more sandstones in Block B. The more vertically superimposed connected grids there are, the larger the volume area may be, the wider the range of the connected body may be, and the larger the range of the underground reservoir may be. However, for specific problems, the size of the three-dimensional connected body of the sandstone shall prevail. The shape and side length of each sandstone mudstone grid are different. The larger the vertical connected volume of the sandstone, the wider the reservoir range, and the wider the reservoir range is, the more advantageous the reservoir is.

[0057] The first two layers are instances of the model. In the overall model, the values ​​are assigned layer by layer in this way. The overall model formula is:

[0058] M=N1+N2+N3+....N n

[0059] M-Overall Model

[0060] N1 - First layer model

[0061] N n - nth layer model

[0062] In this way, the size of the three-dimensional connected sandstone body can be effectively deduced based on the vertically connected body grid on the geological model.

[0063] In one embodiment, a reservoir connectivity evaluation method based on a lithofacies model includes the following steps: obtaining reservoir interpretation data of a study area, and establishing a lithofacies model based on the reservoir interpretation data; assigning values ​​to each three-dimensional grid point of the lithofacies model based on the reservoir interpretation data, wherein the three-dimensional grid points include sandstone grid points and mudstone grid points; identifying sandstone grids in the lithofacies model; and stacking each layer of sandstone grids layer by layer to form a number of independent sandstone three-dimensional connected bodies and their grid numbers; calculating evaluation parameters based on the grid numbers of the sandstone three-dimensional connected bodies, and evaluating the connectivity of the reservoir based on the evaluation parameters. The three-dimensional grid points in the lithofacies model are polygonal 3D grids, and the polygonal 3D grids can be cubes, cuboids, rhombuses, or other shapes.

[0064] In one embodiment, obtaining geological parameters of a reservoir location includes the steps of obtaining well data, layer data, fault data, and sedimentary phase data of the reservoir location.

[0065] In one embodiment, the geological parameters of the reservoir are obtained, including the steps of: obtaining well data, layer data, fault data and sedimentary phase data of the reservoir. The lithofacies model is established according to the geological parameters, including the steps of: establishing a fault model according to the well data and fault data; establishing a layer model according to the layer data and the well interpolation method; establishing a structural model by combining the fault model and the layer model; and establishing a lithofacies model based on the structural model and combining the sedimentary phase data and the simulation method.

[0066] In one embodiment, obtaining geological parameters at the location of the reservoir includes the steps of obtaining well data, layer data, fault data and sedimentary phase data at the location of the reservoir. Well data include: well location coordinates, well depth, well deviation data, logging curve, core elevation, seismic network data; layer data include: layer group division and comparison data of each well, layer data interpreted by seismic data and logging data; fault data include: fault location, occurrence, fault distance, fault polygon and fault interpretation data; sedimentary phase data include: single well phase data, logging phase data and lithofacies data.

[0067] The present invention also provides a reservoir connectivity evaluation system based on a lithofacies model, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the reservoir connectivity evaluation method based on the lithofacies model as described above is implemented.

[0068] The processor and the memory may be connected via a bus or other means.

[0069] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0070] It should be noted that the reservoir connectivity evaluation system based on lithofacies model in this embodiment may include a business processing module, an edge database, a server version information register, and a data synchronization module. When the processor executes the computer program, it implements the reservoir connectivity evaluation method based on lithofacies model as applied in the reservoir connectivity evaluation system based on lithofacies model as mentioned above.

[0071] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0072] In addition, an embodiment of the present invention also provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are executed by a processor or controller, for example, by a processor in the above-mentioned terminal embodiment, so that the above-mentioned processor can execute the reservoir connectivity evaluation method based on the lithofacies model in the above-mentioned embodiment.

[0073] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0074] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

[0075] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A reservoir connectivity evaluation method based on a lithofacies model, characterized in that: The following steps are involved: Obtain reservoir interpretation data in the study area and establish a lithofacies model based on the reservoir interpretation data; Assigning a value to each three-dimensional grid point of the lithofacies model according to the reservoir interpretation data, the three-dimensional grid points including sandstone grid points and mudstone grid points; Identify the sandstone grids in the lithofacies model, and stack each layer of sandstone grids layer by layer to form a number of independent three-dimensional sandstone connected bodies, and calculate the number of grids of the three-dimensional sandstone connected body. Specifically, the model is stacked layer by layer, and the upper sandstone unit is vertically stacked with the lower sandstone unit. Then the name of the lower unit is attributed to the name of the upper unit. With the sandstone block as the center, as long as a sandstone grid in the upper block is positively stacked with any sandstone grid in the next block, this situation can be stacked into a body and named as the upper sandstone block and sandstone name, thereby clarifying the vertical volume range and shape of the sand body in each block in the entire model; The connected volume of each three-dimensional sandstone connected body is calculated according to the number of grids of the three-dimensional sandstone connected body; The evaluation parameters are calculated based on the three-dimensional connected volume of the sandstone, and the connectivity of the reservoir is evaluated based on the evaluation parameters. The three-dimensional grid points in the lithofacies model are polygonal 3D grids. The acquisition of reservoir interpretation data in the study area includes the following steps: Obtain well data, layer data, fault data, and sedimentary facies data for reservoir locations.

2. The reservoir connectivity evaluation method based on the lithofacies model according to claim 1, characterized in that: The method of establishing a lithofacies model according to the reservoir interpretation data comprises the following steps: Establish a fault model based on well data and fault data; Establishing layer model based on layered data and well interpolation method; Establish a structural model based on the combination of fault model and layer model; Based on the structural model, the lithofacies model was established by combining sedimentary facies data and simulation methods.

3. A reservoir connectivity evaluation method based on a lithofacies model according to claim 2, characterized in that: Well data include: well location coordinates, well depth, well deviation data, logging curves, core elevation, and seismic network data; Fault data include: fault location, attitude, fault distance, fault polygon and fault interpretation data; Layered data include: layer group division and comparison data of each well, layer data interpreted from seismic data, and well logging data; Sedimentary facies data include: single well facies data, logging facies data and lithofacies data.

4. A reservoir connectivity evaluation system based on a lithofacies model, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the reservoir connectivity evaluation method based on the lithofacies model as described in any one of claims 1 to 3 is implemented.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the reservoir connectivity evaluation method based on the lithofacies model as described in any one of claims 1 to 3.

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