Method and device for determining water drive front edges of strips with different permeability rates in river channel sand reservoir

Abstract

The invention provides a method and a device for determining water drive front edges of strips with different permeability of a river channel sand reservoir, and belongs to the technical field of oil-gas field development, and the method comprises the following steps: obtaining water drive basic data of the river channel sand reservoir; generating a water content curve based on the oil-water relative permeability and the oil-water viscosity; determining the water saturation of the water drive front based on the water content curve; and determining the positions of the water-driven front edges of the strips with different permeability based on the water saturation of the water-driven front edges and the amount of water injected into the strips with different permeability in unit time. The device comprises an acquisition module, a water content curve generation module, a water saturation determination module and a water drive front edge position determination module. According to the method provided by the invention, the front edge positions of the waterflooding strips with different permeability in waterflooding development of the river sand reservoir and the average water saturation of the two-phase seepage area before water breakthrough can be accurately calculated, and key technical indexes are provided for oilfield development.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and specifically, to a method for determining the water drive front of different permeability zones in a channel sand reservoir, a device for determining the water drive front of different permeability zones in a channel sand reservoir, an electronic device, and a computer-readable storage medium. Background Art

[0002] Channel sand reservoirs are typical river-shaped distributed reservoirs, with characteristics such as narrow channel width, long extension, and thin thickness. For channel sand reservoirs, water flooding development by arranging injection wells and production wells at the channel positions is an effective development method, which can effectively improve the oil recovery rate. During the water flooding process, accurate prediction and calculation of the water drive front can effectively support the design of injection and production wells, injection volume, etc. in the water flooding development plan, contribute to improving the water flooding development effect, and are of great significance.

[0003] The prior art can simulate the water flooding development process through geological modeling and reservoir numerical simulation, and optimize the water flooding development plan. However, geological modeling and reservoir numerical simulation require a large amount of detailed and accurate data such as geological fluids, and at the same time, it takes a large amount of human and time costs to complete modeling and history matching, etc. The water flooding development process of channel sand reservoirs is not complex, and reservoir engineering methods can be used to calculate the water drive front of channel sand reservoirs. However, existing studies are all for homogeneous sand bodies and do not consider the situation of different permeability zones.

[0004] Therefore, it is necessary to establish a method for determining the water drive front of different permeability zones in a channel sand reservoir to accurately calculate the water drive front of different permeability zones. Summary of the Invention

[0005] Aiming at the technical problem that different permeability zones are not considered when using reservoir engineering methods to calculate the water drive front of channel sand reservoirs in the prior art, the present invention provides a method for determining the water drive front of different permeability zones in a channel sand reservoir. Using this method, the front position of the water drive of different permeability zones and the average water saturation in the two-phase seepage zone before water breakthrough during the water flooding development of channel sand reservoirs can be accurately calculated, providing key technical indicators for oilfield development.

[0006] To achieve the above object, a first aspect of the present invention provides a method for determining the water drive front position of different permeability zones in a channel sand reservoir, comprising the following steps: obtaining the basic data of water drive in the channel sand reservoir, where the basic data of water drive in the channel sand reservoir includes: the permeability of the channel sand body zones, the relative permeability of oil and water, the viscosities of oil and water, the sandstone porosity, the water injection time, the water injection volume, the positions of the injection wells and production wells, the length, width and thickness of the channel sand body; generating a water cut curve based on the relative permeability of oil and water and the viscosities of oil and water; determining the water saturation at the water drive front based on the water cut curve; and determining the water drive front position of different permeability zones based on the water saturation at the water drive front and the water volume injected into different permeability zones per unit time.

[0007] In an exemplary embodiment of the present invention, the determining the water saturation at the water drive front based on the water cut curve may include: making a tangent to the water cut curve starting from the irreducible water saturation, and determining the water saturation corresponding to the tangent point in the water cut curve as the water saturation at the water drive front.

[0008] In an exemplary embodiment of the present invention, the calculation formula for the water drive front position of different permeability zones may be:

[0009]

[0010]

[0011] where, x f1 -x p is the water drive front position of the low permeability zone, x f2 -x p is the water drive front position of the high permeability zone, f w is the water cut, S wf is the water saturation at the water drive front, A1 is the cross-sectional area of the low permeability zone, A2 is the cross-sectional area of the high permeability zone, φ is the porosity, t p is the time when the water drive front reaches the front ends of the high and low permeability zones, Q1 is the water volume injected into the low permeability zone per unit time, and Q2 is the water volume injected into the high permeability zone per unit time.

[0012] In an exemplary embodiment of the present invention, the calculation formula for the water volume injected into different permeability zones per unit time may be:

[0013]

[0014]

[0015] Wherein, Q1 is the water volume injected into the low-permeability strip per unit time, Q2 is the water volume injected into the high-permeability strip per unit time, m is the ratio of the water volumes injected into the high- and low-permeability strips, and Q is the cumulative water injection volume.

[0016] In an exemplary embodiment of the present invention, the method may further include: determining the average water cut saturation in the two-phase seepage zone before water breakthrough based on the water cut saturation at the water drive front.

[0017] In an exemplary embodiment of the present invention, the calculation formula for the average water cut saturation in the two-phase seepage zone before water breakthrough may be:

[0018]

[0019] Wherein, is the average water cut saturation in the two-phase seepage zone before water breakthrough, f w is the water cut, S wf is the water cut saturation at the water drive front, S wc is the irreducible water saturation.

[0020] In an exemplary embodiment of the present invention, the determining the average water cut saturation in the two-phase seepage zone before water breakthrough based on the water cut saturation at the water drive front may include: making a tangent line to the water cut curve starting from the irreducible water saturation, and determining the water cut saturation corresponding to the intersection point of the tangent line and the straight line f w = 1 in the water cut curve as the average water cut saturation in the two-phase seepage zone before water breakthrough.

[0021] The second aspect of the present invention provides a device for determining the water drive front of different permeability strips in a channel sand reservoir. The device includes: an acquisition module, a water cut curve generation module, a water cut saturation determination module, and a water drive front position determination module; the acquisition module is used to acquire the basic water drive data of the channel sand reservoir, and the basic water drive data of the channel sand reservoir includes: the permeability of the channel sand body strip, the relative permeability of oil and water, the viscosity of oil and water, the sandstone porosity, the water injection time, the water injection volume, the positions of the injection well and the production well, the length, width, and thickness of the channel sand body; the water cut curve generation module is used to generate a water cut curve based on the relative permeability of oil and water and the viscosity of oil and water; the water cut saturation determination module is used to determine the water cut saturation at the water drive front based on the water cut curve; the water drive front position determination module is used to determine the water drive front positions of different permeability strips based on the water cut saturation at the water drive front and the water volume injected into different permeability strips per unit time.

[0022] In a third aspect of the present invention, there is provided an electronic device, which includes a processor and a memory. At least one computer program is stored in the memory, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors, so that the processor executes the method for determining the water drive front of different permeability zones in a channel sand reservoir as described above.

[0023] In a fourth aspect of the present invention, there is provided a computer-readable storage medium, which stores at least one program code, and the program code is loaded and executed by a processor, so that a computer executes the method for determining the water drive front of different permeability zones in a channel sand reservoir as described above.

[0024] Through the technical solution provided by the present invention, the present invention has at least the following technical effects:

[0025] (1) The method for determining the water drive front of different permeability zones in a channel sand reservoir provided by the present invention is applicable to heterogeneous channel sand reservoirs, and can accurately calculate the front position of water drive in different permeability zones and the average water cut saturation in the two-phase seepage zone before water breakthrough in a channel sand reservoir during water injection development, providing key technical indicators for oilfield development and support for the design of water drive development plans;

[0026] (2) The method for determining the water drive front of different permeability zones in a channel sand reservoir provided by the present invention is easy to implement and has a high accuracy of results.

[0027] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific implementation to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0029] Figure 1 It is a schematic diagram of water drive in the case of high and low permeability zones provided by an embodiment of the present invention;

[0030] Figure 2 It is a flow chart of the method for determining the water drive front of different permeability zones in a channel sand reservoir provided by an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of a given water cut curve provided by an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the water cut curve of a certain section of channel sand body in the TH channel sand reservoir provided by an embodiment of the present invention;

[0033] Figure 5Schematic diagram of the relationship curve between the water drive front position and the water injection time of strips with different permeabilities provided by the embodiments of the present invention;

[0034] Figure 6 Schematic diagram of the structure of a device for determining the water drive front of different permeability strips in a channel sand reservoir provided by the embodiments of the present invention;

[0035] Figure 7 Schematic diagram of the structure of an electronic device provided by the embodiments of the present invention.

[0036] Description of reference numerals

[0037] 101 - Acquisition module, 102 - Water cut curve generation module, 103 - Water saturation determination module, 104 - Water drive front position determination module, 201 - Processor, 202 - Memory. Detailed implementation manners

[0038] The following details the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for explaining and illustrating the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0039] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0040] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the directions shown in the drawings or in the vertical, perpendicular or gravitational directions for describing the relative positions of the components. In the description of the present invention, it should also be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection; it can be a wired connection, or a wireless connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0041] In the prior art, the reservoir engineering method is often used to calculate the water drive front position of a channel sand reservoir on the assumption that the channel sand body is a homogeneous sand body. Although this method can achieve the water drive front of the channel sand reservoir, it does not consider the situation of different permeability strips, and the obtained results do not conform to the actual sand body situation of the channel sand reservoir.

[0042] Considering the problem that the existing technology does not consider different permeability zones when calculating the water drive front of channel sand reservoirs, resulting in inaccurate calculation results, the present invention proposes a method for determining the water drive front of different permeability zones in channel sand reservoirs. This method can determine the front water saturation by analyzing the water cut curve, and then can determine the water drive front position of different permeability zones and the average water saturation in the two-phase seepage zone before water breakthrough through the corresponding calculation model, providing key technical indicators for oilfield development and supporting the design of water drive development plans. Compared with the existing methods for determining the water drive front position, this method can improve the prediction accuracy of the water drive front position in heterogeneous channel sand reservoirs. In specific implementation, the above method can be executed by an electronic device, which can be a server, a terminal or other devices with processing functions.

[0043] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0044] The present invention considers that the water drive process in channel sand reservoirs is a one-dimensional non-piston rigid water drive process of oil-water two-phase, and the Buckley-Leverett water drive theory can be used for calculation.

[0045] First, the present invention considers that the channel sand body is homogeneous and the permeability is equal along the way. According to Darcy's law, the oil-phase seepage velocity in one-dimensional oil-water two-phase seepage is:

[0046]

[0047] The water-phase seepage velocity is:

[0048]

[0049] Combining Equation (1) and Equation (2), the fractional flow equation (water cut equation) without considering gravity and capillary force is obtained:

[0050]

[0051] In the formula, v ox represents the oil-phase seepage velocity, m / s; v wx represents the water-phase seepage velocity, m / s; f w represents the water cut; k ro represents the oil-phase relative permeability; k rw represents the water-phase relative permeability; μ o represents the formation viscosities of the oil phase and the water phase, mPa·s; μ w represents the water-phase formation viscosity, mPa·s.

[0052] It can be seen from the above formula (3) that when the viscosities of oil and water are known, f w is a function of the relative permeability of oil and water, and the relative permeability is in turn a function of the water saturation S w Therefore, f w is only a function of S w : f w = f w (S w ).

[0053] According to the principle of mass conservation, the difference between the amount of water flowing into and out of the unit volume within Δt is equal to the change in the amount of water in the unit volume within the time Δt.

[0054] Among them, the mass of water flowing into the unit volume within Δt is:

[0055] Q wx ρ w Δt = Qρ w f wx Δt (4)

[0056] The mass of water flowing out of the unit volume within Δt is:

[0057] Q wx+Δx ρ w Δt = Qρ w f wx+Δx Δt (5)

[0058] The change in the amount of water in the unit volume is:

[0059] Δm w = AΔxφρ w (S wt+Δt - S wt ) (6)

[0060] Combining formulas (4) to (6) and arranging them, we get:

[0061] QΔt(f wx - f wx+Δx ) = AΔxφ(S wt+Δt - S wt ) (7)

[0062] Converting formula (7) into differential form:

[0063]

[0064] In the formula, A represents the cross-sectional area, m 2 , for a channel sand reservoir, A = width of the channel sand body × thickness; φ is the porosity; Q is the water injection volume, m 3 / d.

[0065] The water saturation S in the oil-water two-phase zone w is a function of time t and displacement x: S w =S w (x, t). The water saturations at different positions at different times are equal, that is, it can be regarded as the equal saturation surface moving with time. The equation of the equal saturation surface can be expressed as:

[0066] S w (x, t) = C (9)

[0067] where C is a constant.

[0068] The differential equation of Equation (9) is:

[0069]

[0070] After arranging Equation (10), we get:

[0071]

[0072] Substituting Equation (8) into Equation (11), we get:

[0073]

[0074] Changing Equation (11) to integral form:

[0075]

[0076] Taking the derivative of both sides of the equation with respect to S w we get:

[0077]

[0078] According to the material balance relationship, the cumulative injected water volume within a period of time is equal to the increment of water content in the two-phase seepage zone:

[0079]

[0080] Combining and arranging Equation (14) and Equation (15), we get:

[0081]

[0082] Using the method of integration by parts to calculate Equation (16), and substituting the special values (f w ′(S wm ) = 0 and f w (S wm ) = 1), we get:

[0083]

[0084] According to Equation (17), the water saturation at the water drive front can be determined. Since the water saturation S wf remains constant throughout the entire water drive process, after determining the water saturation at the water drive front, it can be substituted into Equation (13) to calculate the position of the water drive front before water breakthrough:

[0085]

[0086] In the formula, x f -x0 represents the distance between the water drive front and the injection well, in m.

[0087] Substitute Equation (18) into Equation (15) to calculate the average water saturation in the two-phase flow zone before water breakthrough:

[0088]

[0089] Further considering the situation where different permeability zones exist, as Figure 1 shown, the amount of water injected into different permeability zones is related to the water saturation S w (x p , t) at the entrances of the high and low permeability zones. Substituting it into Equation (13) gives:

[0090]

[0091] It can be seen from Equation (20) that as the amount of injected water continuously increases, f w ′(S wp ) continuously decreases. From the water cut curve, the corresponding water saturation S wp continuously increases. According to the above formula, the water saturation S p corresponding to the x wp point can be calculated.

[0092] Assume that the permeability of the low permeability zone is k1, with the unit of mD; the permeability of the high permeability zone is k2, with the unit of mD. Consider that the relative permeability curves of the high and low permeability zones are the same. According to Darcy's law, the amount of water injected into the low permeability zone is:

[0093]

[0094] The amount of water injected into the high permeability zone is:

[0095]

[0096] It is known from the numerical simulation results that the pressure gradients of the high and low permeability zones in the water drive direction are equal. Therefore, the ratio of the water injection amounts of the two zones is obtained as:

[0097]

[0098] In the formula, n represents the permeability ratio. To simplify the subsequent calculations, m is used to represent the ratio of the water injection amounts in the high- and low-permeability zones.

[0099] Therefore, the water injection amount into the high-permeability zone (referred to as the high-permeability zone for short) per unit time can be obtained as:

[0100]

[0101] The water injection amount into the low-permeability zone (referred to as the low-permeability zone for short) per unit time is:

[0102]

[0103] Substituting Equation (24) and Equation (25) into Equation (18) respectively, the positions of the water drive fronts in different permeability zones can be obtained:

[0104]

[0105]

[0106] In the formula, t p represents the time when the water drive front reaches the front ends of the high- and low-permeability zones and can be calculated using Equation (18).

[0107] In summary, the specific process of the method for determining the water drive fronts in different permeability zones of a channel sand reservoir according to the embodiments of the present invention is as follows (as Figure 2 shown):

[0108] Step S101: Obtain the basic water drive data of the channel sand reservoir.

[0109] Here, the basic water drive data of the channel sand reservoir includes: the permeability of the channel sand body zone, the relative permeability of oil and water, the viscosities of oil and water, the sandstone porosity, the water injection time, the water injection amount, the positions of the injection well and the production well, the length, width, and thickness of the channel sand body.

[0110] Step S102: Generate a water cut curve based on the relative permeability of oil and water and the viscosities of oil and water.

[0111] Here, since, when the viscosities of oil and water are known, according to Equation (3), f w is a function of the relative permeability of oil and water, therefore, the water cut can be calculated using the obtained relative permeability data of oil and water and the viscosities of oil and water, and a water cut curve can be plotted.

[0112] Step S103: Determine the water saturation at the water drive front based on the water cut curve.

[0113] Here, since f w is only a function of S w : f w = fw (S w ), and according to Equation (17), it can be known that the derivative of the water cut f w and the irreducible water saturation S wc , as well as the water cut at the water flood front S wf also form a certain functional relationship. Therefore, by analyzing the water cut curve and performing derivative analysis, the water cut at the water flood front can be determined.

[0114] Step S104: Based on the water cut at the water flood front and the amount of water injected into different permeability zones per unit time, determine the water flood front positions of different permeability zones.

[0115] Specifically, after determining the water cut at the water flood front through Step S103, according to the obtained basic water flood data of the channel sand reservoir, the water flood front position of the low permeability zone can be directly calculated using Equation (26) above, and the water flood front position of the high permeability zone can be calculated using Equation (27) above.

[0116] Furthermore, in a possible implementation manner, in Step S102, a tangent to the water cut curve can be made starting from the irreducible water saturation, and the water saturation corresponding to the tangent point in the water cut curve can be determined as the water cut at the water flood front.

[0117] For example, as Figure 3 shown, for a given water cut curve, the water saturation value S wf of the water flood front can be determined by the graphical method. In Figure 3 , a tangent to the water cut curve is made starting from the irreducible water saturation S wc , and the water saturation corresponding to the tangent point is the water cut at the water flood front S wf . At the same time, it can be seen that: S wf remains unchanged throughout the entire water flooding process.

[0118] Furthermore, in a possible implementation manner, the method may further include Step S105: Based on the water cut at the water flood front, determine the average water cut in the two-phase flow zone before water breakthrough.

[0119] For example, according to the water cut at the water flood front determined in Step S103, the average water cut in the two-phase flow zone before water breakthrough can be directly calculated using Equation (19) above.

[0120] For another example, the value of the average water cut can also be determined by the graphical method according to Equation (19). As Figure 3 shown, a tangent to the water cut curve is made starting from the irreducible water saturation S wc , and the tangent intersects the straight line f wThe water saturation corresponding to the intersection point of =1 is the average water saturation in the two-phase seepage zone before water breakthrough.

[0121] To better understand the above exemplary embodiments of the present invention, the following further illustrates them with specific examples.

[0122] Taking the TH channel sand reservoir as an example, a water injection well and a production well are designed at both ends of a certain channel sand body in the TH channel sand reservoir. The path length of the channel sand body is 100 m. There are two "parallel" strips with equal widths (both widths are 5 m) in this section of the channel sand body. The permeability of the high-permeability strip is 20 md, and the permeability of the low-permeability strip is 10 mD. The average thickness of the sand body is 2 m, and the width is 10 m. The water injection volume of the water injection well is 5 m 3 / d, and the viscosities of formation oil and water are 1.26 mPa·s and 0.8 mPa·s respectively. The sandstone porosity is 0.12, and the oil-water relative permeabilities of the two strips with different permeabilities are the same. The data are shown in Table 1.

[0123] Table 1 Oil-water relative permeability data

[0124]

[0125]

[0126] According to the steps described in the embodiments of the present invention, first, using Equation (3), draw the water cut curve of a certain section of the channel sand body in the TH channel sand reservoir based on the relative permeability data, as Figure 4 shown.

[0127] Then, according to Equation (17), starting from the irreducible water saturation S wc =0.33, draw a tangent line to the water cut curve, and respectively determine that the water saturation at the water drive front is S wf =0.605 and the average water saturation in the two-phase seepage zone before water breakthrough is

[0128] Finally, calculate the water drive front positions of the strips with different permeabilities according to Equations (26) and (27) respectively. The relationship between the water drive front positions of the strips with different permeabilities and the water injection time obtained by the final calculation is as Figure 5 shown.

[0129] It can be seen that the water drive front in the high-permeability strip advances faster, and the water breakthrough time of the production well is about 12 days after water injection.

[0130] In addition, the implementation environment of this embodiment includes at least one terminal and a server, and this method is executed on the terminal or the server respectively. The terminal and the server can be communicatively connected to achieve the interactive transmission of information.

[0131] Among them, the terminal can be any kind of electronic product that can interact with users through one or more ways such as keyboard, touchpad, touch screen, voice interaction, etc., such as PC (Personal Computer), PPC (Pocket Personal Computer), tablet computer, etc.

[0132] The server can be a single server, a server cluster composed of multiple servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms.

[0133] As Figure 6 As shown, the embodiment of the present invention also provides a device for determining the water drive front of different permeability strips in a channel sand reservoir. The device includes: an acquisition module 101, a water cut curve generation module 102, a water saturation determination module 103, and a water drive front position determination module 104.

[0134] The acquisition module 101 is used to acquire the basic data of water drive in the channel sand reservoir. Among them, the basic data of water drive in the channel sand reservoir includes: the permeability of the channel sand body strip, the relative permeability of oil and water, the viscosity of oil and water, the porosity of the sandstone, the injection time, the injection volume, the positions of the injection well and the production well, the length, width, and thickness of the channel sand body.

[0135] The water cut curve generation module 102 is used to generate a water cut curve based on the relative permeability of oil and water and the viscosity of oil and water.

[0136] The water saturation determination module 103 is used to determine the water saturation at the water drive front based on the water cut curve.

[0137] The water drive front position determination module 104 is used to determine the water drive front position of different permeability strips based on the water saturation at the water drive front and the water volume injected into different permeability strips per unit time.

[0138] It should be noted that when the above-mentioned provided device realizes its functions, only the above-mentioned division of each functional module is used for illustration. In actual applications, the above-mentioned functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device provided in the above embodiment and the method provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0139] As Figure 7As shown in the figure, an embodiment of the present invention further provides an electronic device, which includes a processor 201 and a memory 202. At least one computer program is stored in the memory, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors, so that the processor implements the method for determining the water drive front of different permeability zones in the river channel sand reservoir in the above embodiment.

[0140] Of course, the electronic device may also have components such as a wired or wireless network interface, a keyboard, and an input / output interface for input and output. The electronic device may also include other components for implementing the functions of the device, which will not be elaborated here.

[0141] An embodiment of the present invention further provides a computer-readable storage medium, in which at least one program code is stored. The program code is loaded and executed by a processor, so that a computer implements the method for determining the water drive front of different permeability zones in the river channel sand reservoir in the above embodiment.

[0142] Optionally, the computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a Compact Disc Read-Only Memory (CD-ROM), a magnetic tape, a floppy disk, and an optical disc data storage device, etc. Those skilled in the art can understand that all or part of the steps in implementing the method of the above embodiment can be completed by instructing relevant hardware through a program. The program is stored in a storage medium, including several instructions to enable a single-chip microcomputer, a chip, or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: USB flash drives, mobile hard disks, Read-Only Memories (ROMs), Random Access Memories (RAMs), magnetic disks, or optical discs and other various media that can store program codes.

[0143] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0144] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0145] In addition, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

Claims

1. A method for determining the water drive front of different permeability zones in a channel sand reservoir, characterized in that, The method includes: Obtaining the basic waterflooding data of the channel sand reservoir, where the basic waterflooding data of the channel sand reservoir includes: the permeability of the channel sand body strip, the relative permeability of oil and water, the viscosities of oil and water, the sandstone porosity, the water injection time, the water injection volume, the positions of the injection well and the production well, the length, width and thickness of the channel sand body; Generating a water cut curve based on the relative permeability of oil and water and the viscosities of oil and water; Determining the waterflood front water saturation based on the water cut curve; Determining the waterflood front positions of different permeability strips based on the waterflood front water saturation and the water volume injected into different permeability strips per unit time.

2. The method for determining the water drive front of different permeability zones in a channel sand reservoir according to claim 1, characterized in that The determining the waterflood front water saturation based on the water cut curve includes: Making a tangent line to the water cut curve starting from the irreducible water saturation, and determining the water saturation corresponding to the tangent point in the water cut curve as the waterflood front water saturation.

3. The method for determining the water drive front of different permeability zones in a channel sand reservoir according to claim 1, characterized in that The calculation formula for the waterflood front positions of different permeability strips is: where x f1 -x p is the water flooding front position of the low permeability strip, x f2 -x p is the water flooding front position of the high permeability strip, f w is the water cut, S wf is the water saturation at the water flooding front, A1 is the cross-sectional area of the low permeability strip, A2 is the cross-sectional area of the high permeability strip, φ is the porosity, t p is the time when the water flooding front reaches the front ends of the high and low permeability strips, Q1 is the water volume injected into the low permeability strip per unit time, and Q2 is the water volume injected into the high permeability strip per unit time.

4. The method for determining the water drive front of different permeability zones in a channel sand reservoir according to claim 3, characterized in that The calculation formula for the water volume injected into different permeability strips per unit time is: Where Q1 is the water volume injected into the low-permeability strip per unit time, Q2 is the water volume injected into the high-permeability strip per unit time, m is the ratio of the water volumes injected into the high- and low-permeability strips, and Q is the cumulative water injection volume.

5. The method for determining the water drive front of different permeability zones in a river channel sand reservoir according to claim 1, characterized in that The method further includes: Determining the average water saturation in the two-phase flow zone before water breakthrough based on the waterflood front water saturation.

6. The method for determining the water drive front of different permeability zones in a channel sand reservoir according to claim 5, characterized in that, The calculation formula for the average water saturation in the two-phase flow zone before water breakthrough is: Among them, is the average water saturation in the two-phase seepage zone before water breakthrough, f w is the water cut, S wf is the water saturation at the water drive front, S wc is the irreducible water saturation.

7. The method for determining the water drive front of different permeability zones in a channel sand reservoir according to claim 5, characterized in that, The determining the average water saturation in the two-phase flow zone before water breakthrough based on the waterflood front water saturation includes: Taking the irreducible water saturation as the starting point, draw a tangent line to the water cut curve, and determine the average water saturation in the two-phase flow zone before water breakthrough as the water saturation corresponding to the intersection point of the tangent line and the straight line f w = 1 in the water cut curve.

8. A device for determining the water drive front of different permeability zones in a channel sand reservoir, characterized in that, The device includes: an acquisition module, a water cut curve generation module, a water saturation determination module, and a waterflood front position determination module; The acquisition module is used to obtain the basic waterflooding data of the channel sand reservoir, where the basic waterflooding data of the channel sand reservoir includes: the permeability of the channel sand body strip, the relative permeability of oil and water, the viscosities of oil and water, the sandstone porosity, the water injection time, the water injection volume, the positions of the injection well and the production well, the length, width and thickness of the channel sand body; The water cut curve generation module is used to generate a water cut curve based on the relative permeability of oil and water and the viscosities of oil and water; The water saturation determination module is used to determine the waterflood front water saturation based on the water cut curve; The waterflood front position determination module is used to determine the waterflood front positions of different permeability strips based on the waterflood front water saturation and the water volume injected into different permeability strips per unit time.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory, and at least one computer program is stored in the memory. The at least one computer program is loaded and executed by one or more of the above processors so that the processor executes the method for determining the waterflood front of different permeability strips in the channel sand reservoir according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one program code, and the program code is loaded and executed by a processor so that the computer executes the method for determining the waterflood front of different permeability strips in the channel sand reservoir according to any one of claims 1 to 7.

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