Method and device for determining secondary energy supplement injection rate of oil reservoir horizontal well

Abstract

The invention discloses a method and device for determining the secondary energy supplement injection rate of an oil reservoir horizontal well, and relates to the technical field of oil reservoir development. According to the method, the associated well group where the volume fractured horizontal well is located is determined firstly, then the injection amount of the secondary energy supplement injection medium is calculated according to the accumulated oil production, the accumulated water production and the accumulated fracturing fluid injection amount of the associated well group, and the injection amount of secondary energy supplement can be accurately obtained; the reservoir stratum deficit is reasonably supplemented, the stratum recovers the initial energy supplementing pressure, and then the productivity in the later period of reservoir development is improved.

Description

Technical Field

[0001] This invention relates to the field of reservoir development technology, and in particular to a method and apparatus for determining the secondary energy injection volume of horizontal wells in reservoirs. Background Technology

[0002] In the development of unconventional reservoirs using horizontal well volumetric fracturing, initial fracturing fluid replenishment is performed on the horizontal well during the initial development phase, resulting in high production capacity. However, as development progresses, the formation pressure gradually decreases, leading to a significant drop in production capacity. To maintain high production in the later stages of development, secondary fracturing fluid replenishment is necessary to restore the formation pressure to the level at the time of initial replenishment. The injection volume for this secondary replenishment must be precise; insufficient injection will fail to restore formation pressure, while excessive injection can cause formation damage. Summary of the Invention

[0003] This invention solves the technical problem of how to accurately determine the injection volume for secondary energy replenishment in horizontal wells of oil reservoirs by providing a method and apparatus for determining the injection volume.

[0004] On the one hand, the present invention provides the following technical solution:

[0005] A method for determining the secondary energy injection volume in a horizontal well of an oil reservoir, comprising:

[0006] Determine the associated well group to which the horizontal well belongs, the associated well group including the horizontal well and adjacent wells where fluid volume fluctuations occur after volumetric fracturing of the horizontal well;

[0007] Obtain the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume of the associated well group;

[0008] The injection volume of the secondary energy replenishment injection medium is calculated based on the cumulative oil production, the cumulative water production, and the cumulative injected fracturing fluid volume.

[0009] Optionally, the adjacent wells are the first-line oil wells surrounding the horizontal well.

[0010] Optionally, the injection medium may include water and / or gas.

[0011] Optionally, the gas may include nitrogen, natural gas, carbon dioxide, or oxygen-depleted air.

[0012] Optionally, the injection medium is water;

[0013] The calculation of the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, the cumulative water production, and the cumulative injected fracturing fluid volume includes:

[0014] According to the formula V=N P / ρ o·B o +W P -F calculates the injection volume, where V is the injection volume and N is the injection volume. p ρ represents the cumulative oil production. o B represents the density of crude oil. o W is the crude oil volume coefficient. p The cumulative water production is denoted as F, and the cumulative injected fracturing fluid volume is denoted as F.

[0015] Optionally, the injection medium is a gas;

[0016] The calculation of the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, the cumulative water production, and the cumulative injected fracturing fluid volume includes:

[0017] According to the formula V=(N) P / ρ o ·B o +W P -F)·Z calculates the injection volume, where V is the injection volume and N is the injection volume. p ρ represents the cumulative oil production. o B represents the density of crude oil. o W is the crude oil volume coefficient. p The cumulative water production is F, the cumulative injected fracturing fluid volume is Z, and the gas compressibility factor is Z.

[0018] Optionally, after calculating the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, the cumulative water production, and the cumulative injected fracturing fluid volume, the method further includes:

[0019] The injection medium is determined based on the water sensitivity index of the oil reservoir.

[0020] On the other hand, the present invention provides the following technical solution:

[0021] A device for determining the secondary energy injection volume of a horizontal well in an oil reservoir, comprising:

[0022] A determination module is used to determine the associated well group to which the horizontal well belongs, the associated well group including the horizontal well and adjacent wells where fluid volume fluctuations occur after volumetric fracturing of the horizontal well;

[0023] The acquisition module is used to acquire the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume of the associated well group;

[0024] The calculation module is used to calculate the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, the cumulative water production, and the cumulative injected fracturing fluid volume.

[0025] On the other hand, the present invention provides the following technical solution:

[0026] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of a method for determining the secondary energy injection volume of a horizontal well in an oil reservoir.

[0027] On the other hand, the present invention also provides the following technical solution:

[0028] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of a method for determining the secondary energy injection volume of a horizontal well in any oil reservoir.

[0029] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0030] This invention first determines the associated well group where the volumetric fracturing horizontal well is located, and then calculates the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, cumulative water production and cumulative injected fracturing fluid volume of the associated well group. This can accurately obtain the injection volume of the secondary energy replenishment, which is beneficial for reasonably replenishing the reservoir formation deficit, restoring the formation to the initial energy replenishment pressure, and thus improving the production capacity in the later stage of reservoir development. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of the method for determining the secondary energy injection volume of a horizontal well in an oil reservoir, as described in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the associated well group in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the formation pressure variation curve in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the device for determining the secondary energy injection volume of a horizontal well in an oil reservoir, as described in an embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 10 - Oil reservoir; 20 - Associated well group; 21 - Horizontal well; 22 - Adjacent well; 30 - Artificial fracture. Detailed Implementation

[0038] The embodiments of the present invention provide a method and apparatus for determining the secondary energy injection volume of a horizontal well in an oil reservoir, thereby solving the technical problem of how to accurately determine the secondary energy injection volume of a horizontal well in an oil reservoir.

[0039] To better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] First, it should be clarified that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0041] like Figure 1 As shown, the method for determining the secondary energy injection volume of a horizontal well in an oil reservoir according to an embodiment of the present invention includes:

[0042] Step S1: Determine the associated well group to which the horizontal well belongs. The associated well group includes the horizontal well and the adjacent wells where fluid volume fluctuations occur after volumetric fracturing of the horizontal well.

[0043] Step S2: Obtain the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume of the associated well group;

[0044] Step S3: Calculate the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume.

[0045] like Figure 2 The diagram shows a well group associated with a horizontally fractured well. Volumetric fracturing can create artificial fractures and provide initial formation energy replenishment; the fracturing fluid can compensate for some formation deficiencies in the oil reservoir. Fluid fluctuations in adjacent wells indicate fluid flow within the formation, demonstrating a dynamic response. These adjacent wells can be considered first-line oil wells surrounding the horizontally fractured well. Of course, dynamic responses can be observed in more than just adjacent wells; a comprehensive spatial analysis is necessary to ensure complete and accurate coverage of the associated well group.

[0046] The purpose of secondary energy replenishment in horizontal wells is to replenish the formation void in the reservoir and restore the formation pressure to the initial energy replenishment pressure. Therefore, determining the formation void volume allows us to determine the injection volume of the secondary energy replenishment medium. The formation void volume is the volume of fluid lost in the formation, calculated as the sum of the cumulative oil production and cumulative water production of the associated well group minus the cumulative injected fracturing fluid volume, i.e., Formation Void Volume = N P / ρ o ·B o +W P -F, N p Cumulative oil production, in units of ×10 4m 3 ;ρ o Crude oil density, in t / m³ 3 B o This is the crude oil volume factor, in cubic meters (m³). 3 / m 3 W p Cumulative water production, in units of ×10 4 m 3 F represents the cumulative injected fracturing fluid volume, in units of ×10. 4 m 3 .

[0047] The injection medium in step S3 may include water and / or gas; that is, the injection medium may be entirely water, entirely gas, or partially water and partially gas. When the injection medium includes gas, the gas may include nitrogen, natural gas, carbon dioxide, or deoxygenated air. Considering that carbon dioxide has a swelling and viscosity-reducing effect on crude oil, if the formation conditions are miscible, carbon dioxide has a stronger permeability and can displace fluids within micropores, which is beneficial for increasing production and improving oil recovery in unconventional reservoirs. Therefore, carbon dioxide can be given priority when the injection medium includes gas.

[0048] The formation void volume of the oil reservoir is the subsurface volume, and the injection volume of the injected medium is the surface volume. When the injected medium is entirely water, since the surface volume of water is approximately the same as the subsurface volume, the injection volume of water equals the formation void volume. Therefore, step S3 includes: according to the formula V = N... P / ρ o ·B o +W P -F calculates the injection volume of the injection medium, where V is the injection volume of the injection medium. When the injection medium is entirely gas, the gas volume at the surface will be compressed after entering the formation. Therefore, it is necessary to convert the formation void volume into the surface volume based on the gas compressibility coefficient. That is, multiply the formation void volume by the gas compressibility coefficient to obtain the injection volume of the injection medium. In this case, step S3 includes: according to the formula V = (N P / ρ o ·B o +W P -F)·Z calculates the injection volume of the injection medium, where Z is the gas compressibility coefficient. Different gases have different compressibility coefficients in reservoirs at different temperatures and pressures. For example, in a reservoir with a temperature of 113℃ and a formation pressure of 35MPa, the gas compressibility coefficient of nitrogen is 221, and that of carbon dioxide is 366.

[0049] If the injected medium is partly water and partly gas, for example, half water and half gas, then the injected water volume is half of the formation void volume; the injected gas volume is half of the formation void volume multiplied by the gas compressibility coefficient.

[0050] Using the injection medium volume calculated in step S3 and the injection medium volume obtained from experience to simulate the formation pressure changes during secondary energy replenishment in actual oil wells, the results are as follows: Figure 3 The formation pressure variation curve is shown. Figure 3 The injection medium is carbon dioxide. Figure 3 The 11000t, 8000t, 5000t, and 3000t figures are empirically derived carbon dioxide injection amounts, while 6000t is the carbon dioxide injection amount calculated in step S3. After the initial fracturing and recharging, the formation pressure increases from the original 30MPa to 35.8MPa, meaning the initial recharging pressure is 35.8MPa. As production progresses, the formation pressure gradually decreases to 32.7MPa. It can be seen that injecting 11000t, 8000t, 6000t, 5000t, and 3000t of carbon dioxide raises the formation pressure to 38.6MPa, 37MPa, 36MPa, 35.4MPa, and 34.4MPa, respectively. The carbon dioxide injection amount calculated in step S3 makes the formation pressure closest to the initial recharging pressure, indicating that the calculated carbon dioxide injection amount is accurate.

[0051] As can be seen from the above, the method for determining the secondary energy injection volume of horizontal wells in reservoirs according to the embodiments of the present invention first determines the associated well group where the volumetric fracturing horizontal well is located, and then calculates the injection volume of the secondary energy injection medium based on the cumulative oil production, cumulative water production and cumulative injected fracturing fluid volume of the associated well group. This method can accurately obtain the injection volume of the secondary energy injection, which is beneficial for reasonably replenishing reservoir formation deficits, restoring the formation to the initial energy injection pressure, and thus improving the production capacity in the later stages of reservoir development.

[0052] This embodiment of the invention also requires determining the injection medium. Considering that water injection is not possible in reservoirs with high water sensitivity, the injection medium can be determined based on the reservoir's water sensitivity. That is, after step S3, the method for determining the secondary energy injection volume of a horizontal well in the reservoir can further include: determining the injection medium based on the water sensitivity index of the reservoir. Further, determining the injection medium based on the water sensitivity index of the reservoir can include: if the water sensitivity index is greater than a first threshold, then the injection medium is determined to be gas; if the water sensitivity index is between a second threshold and a first threshold, then the injection medium is determined to be gas or the injection medium includes water and gas; if the water sensitivity index is less than a second threshold, then the injection medium is determined to be water or the injection medium includes water and gas. The first threshold can be 0.7, and the second threshold can be 0.3. A water sensitivity index greater than the first threshold indicates that the reservoir has high water sensitivity and cannot be injected with water, therefore all injection is with gas; a water sensitivity index between the second threshold and a first threshold indicates that the reservoir has moderate water sensitivity, and gas or alternating gas and water injection is possible; a water sensitivity index less than the second threshold indicates that the reservoir has low water sensitivity, and water or alternating gas and water injection is possible.

[0053] like Figure 4 As shown, this embodiment of the invention also provides a device for determining the secondary energy injection volume of a horizontal well in an oil reservoir, comprising:

[0054] The determination module is used to determine the associated well group to which the horizontal well belongs. The associated well group includes the horizontal well and adjacent wells where fluid volume fluctuations occur after volumetric fracturing of the horizontal well.

[0055] The acquisition module is used to acquire the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume of the associated well group;

[0056] The calculation module is used to calculate the injection volume of the secondary energy replenishment injection medium based on the cumulative oil production, cumulative water production, and cumulative injected fracturing fluid volume.

[0057] Furthermore, adjacent wells can be the first-line oil wells surrounding the horizontal well.

[0058] Furthermore, the injection medium may include water and / or gas.

[0059] Furthermore, the gas may include nitrogen, natural gas, carbon dioxide, or oxygen-depleted air.

[0060] Furthermore, the injection medium is water;

[0061] The calculation module can be specifically used for:

[0062] According to the formula V=N P / ρ o ·B o +W P -F calculates the injection volume, where V is the injection volume and N is the injection volume. p To accumulate oil production, ρ o B represents the density of crude oil. o W is the crude oil volume coefficient. p F represents the cumulative water production, and F represents the cumulative injected fracturing fluid volume.

[0063] Furthermore, the injection medium is gas;

[0064] The calculation module can also be specifically used for:

[0065] According to the formula V=(N) P / ρ o ·B o +W P -F)·Z calculates the injection volume, where V is the injection volume and N is the injection volume. p To accumulate oil production, ρ o B represents the density of crude oil. o W is the crude oil volume coefficient. p F represents the cumulative water production, F represents the cumulative injected fracturing fluid volume, and Z represents the gas compressibility coefficient.

[0066] Furthermore, the determination module can also be used to: determine the injection medium based on the water sensitivity index of the oil reservoir.

[0067] Furthermore, the determination module can also be specifically used to: determine that the injection medium is gas if the water sensitivity index is greater than the first threshold; determine that the injection medium is gas or includes water and gas if the water sensitivity index is between the second threshold and the first threshold; and determine that the injection medium is water or includes water and gas if the water sensitivity index is less than the second threshold.

[0068] Based on the same inventive concept as the method for determining the secondary energy injection volume of a horizontal well in an oil reservoir described above, this embodiment of the invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of any of the methods for determining the secondary energy injection volume of a horizontal well in an oil reservoir described above.

[0069] The bus architecture (represented by a bus) can include any number of interconnected buses and bridges, linking various circuits including one or more processors (represented by a processor) and memory (represented by memory). The bus can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface between the bus and receivers and transmitters. Receivers and transmitters can be the same element, a transceiver, providing a unit for communicating with various other devices over a transmission medium. The processor is responsible for managing the bus and general processing, while memory can be used to store data used by the processor during operation.

[0070] Since the computer equipment described in this embodiment of the invention is the computer equipment used to implement the method for determining the secondary energy injection volume of a horizontal well in the reservoir according to this embodiment of the invention, those skilled in the art can understand the specific implementation methods and various variations of the computer equipment in this embodiment of the invention based on the method for determining the secondary energy injection volume of a horizontal well in the reservoir according to this embodiment of the invention. Therefore, how the computer equipment implements the method in this embodiment of the invention will not be described in detail here. Any computer equipment used by those skilled in the art to implement the method for determining the secondary energy injection volume of a horizontal well in the reservoir according to this embodiment of the invention falls within the scope of protection of this invention.

[0071] Based on the same inventive concept as the above-mentioned method for determining the secondary energy injection volume of a horizontal well in an oil reservoir, the present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of any of the aforementioned methods for determining the secondary energy injection volume of a horizontal well in an oil reservoir.

[0072] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0073] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0074] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0075] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0076] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0077] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for determining the secondary energy injection rate of a horizontal well in a reservoir, characterized in that, The method comprises the following steps: determining an associated well group in which a horizontal well is located, the associated well group comprising the horizontal well and a neighboring well in which liquid volume fluctuation occurs after volume fracturing of the horizontal well; obtaining cumulative oil production, cumulative water production and cumulative injected fracturing fluid volume of the associated well group; calculating an injection volume of a secondary energy supplement injection medium according to the cumulative oil production, the cumulative water production and the cumulative injected fracturing fluid volume.

2. The method of claim 1, wherein, The neighboring well is a row of oil wells around the horizontal well.

3. The method of claim 1, wherein, The injection medium comprises water and / or gas.

4. The method of claim 3, wherein, The gas comprises nitrogen, natural gas, carbon dioxide or oxygen-reduced air.

5. The method of claim 1, wherein, The injection medium is water. The calculating an injection volume of a secondary energy supplement injection medium according to the cumulative oil production, the cumulative water production and the cumulative injected fracturing fluid volume comprises: According to the formula V=N P / ρ o ·B o +W P -F calculates the injection volume, where V is the injection volume and N is the injection volume. p ρ represents the cumulative oil production. o B represents the density of crude oil. o W is the volume coefficient of crude oil. p The cumulative water production is denoted as F, and the cumulative injected fracturing fluid volume is denoted as F.

6. The method of claim 1, wherein, The injection medium is gas. The calculating an injection volume of a secondary energy supplement injection medium according to the cumulative oil production, the cumulative water production and the cumulative injected fracturing fluid volume comprises: According to the formula V=(N) P / ρ o ·B o +W P -F)·Z calculates the injection volume, where V is the injection volume and N is the injection volume. p ρ represents the cumulative oil production. o B represents the density of crude oil. o W is the volume coefficient of crude oil. p The cumulative water production is F, the cumulative injected fracturing fluid volume is Z, and the gas compressibility factor is Z.

7. The method of claim 1, wherein, After the calculating an injection volume of a secondary energy supplement injection medium according to the cumulative oil production, the cumulative water production and the cumulative injected fracturing fluid volume, the method further comprises: determining the injection medium according to a water sensitivity index of a reservoir.

8. A device for determining the secondary energy injection rate for a horizontal well in a reservoir, characterized in that The method comprises the following steps: a determining module configured to determine an associated well group in which a horizontal well is located, the associated well group comprising the horizontal well and a neighboring well in which liquid volume fluctuation occurs after volume fracturing of the horizontal well; an obtaining module configured to obtain cumulative oil production, cumulative water production and cumulative injected fracturing fluid volume of the associated well group; a calculating module configured to calculate an injection volume of a secondary energy supplement injection medium according to the cumulative oil production, the cumulative water production and the cumulative injected fracturing fluid volume.

9. A computer device, comprising: The computer program is executed by the processor to implement the steps of the method of any one of claims 1-7.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1-7.

Images