Method and device for evaluating injection capacity of reinjection water, equipment and medium

Abstract

The invention relates to a reinjection water injection capacity evaluation method, evaluation device, equipment and medium, in particular to the technical field of oilfield water injection development, based on the fact that a dimensionless water absorption index is reduced along with increase of the reinjection proportion of reinjection water in injected water, quantitative characterization is conducted on the reinjection water through index decreasing, and the reinjection capacity of the reinjection water is evaluated. And the change relation between the water absorption index of the water injection well and the water content of the oil field can be deduced. In addition, according to the relative permeability curve, the change relation of the fluid production index of the production well along with the water content of the oil field can be obtained. And calculating the change relation of the maximum water injection speed and the maximum liquid production speed of the well network unit along with the water content in combination with the water absorption index and the liquid production index tested in the oilfield exploration evaluation stage or the initial development stage, and evaluating the injection capability risks in different water-containing stages by comparing the difference between the two. The evaluation method provided by the invention not only can quantitatively evaluate the yield reduction risk caused by the reduction of the injection capability through a theoretical method, but also can be applied to numerical simulation, and has wide applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield water injection development, and specifically to an evaluation method and evaluation device, equipment and medium for injection capacity of reinjection water, and in particular to an evaluation method and evaluation device, equipment and medium for injection capacity of reinjection water under the condition of produced water reinjection. Background Art

[0002] At present, the composition of produced water from oilfield development varies significantly due to different reservoir conditions and oil properties. Even after water treatment, it usually contains a certain amount of oil droplets and suspended solid particles.

[0003] The results of oilfield development practice and investigation show that in most cases, compared with the injection of clean water, the reinjection of produced water will lead to a decrease in reservoir permeability in the near-wellbore area of ​​the injection well, an increase in the tested skin coefficient, a decrease in injection capacity, and the extent of the decrease in injection capacity is related to the proportion of produced water in the injected water when it is reinjected. Generally, when the injection capacity of the injection well decreases, the required injection volume can be maintained by increasing the injection pressure. However, once the injection pressure reaches the maximum value, the injection volume will also begin to decrease, which may have an adverse effect on the maintenance of reservoir pressure and oil well productivity.

[0004] Therefore, considering and quantitatively characterizing the decline in injection capacity and evaluating the risk of reduced injection capacity in advance can play an important role in optimizing the injection-production well network and production system; however, the current research on the decline in injection capacity caused by the reinjection of produced water is only at the qualitative research stage, and there is no method that can quantitatively characterize it, and there is no corresponding evaluation method for the risk of reduced production caused by it. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide an evaluation method and evaluation device, equipment, and medium for the injection capacity of reinjection water, so as to solve the current defect that the reduction in the injection capacity of reinjection water cannot be quantitatively analyzed and explained, and the risks brought about by the reduction in the injection capacity of reinjection water cannot be predicted.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for evaluating the injection capacity of reinjection water, the method comprising:

[0008] S1. Using the test data of different water injection stages of the water injection well, calculate the water absorption index II and the proportion of produced water injected into the oil field f PWRI The decreasing exponent n in the changing functional relationship;

[0009] S2, combined with the water absorption index II to determine the decline index n, the proportion of produced water injected into the oil field and the proportion of produced water injected into the oil field f PWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of

[0010] S3, combined with dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change;

[0011] S4. Establish dimensionless liquid extraction index J LD With the water content of oil field f w The changing relationship curve;

[0012] S5, combining the oil field water content equation obtained in S4 with the initial liquid production index PI0 of the oil wells actually tested in the oil field, the ratio of production and injection wells m of the well network unit and the production pressure difference ΔP prod , derive and establish the production index PI along with the oil field water content f w The relationship curve of the change and the liquid production rate Q of the well network unit prod With the water content of oil field f w The changing relationship curve;

[0013] S6, combined with the relationship curve of S3 and S5, the predicted liquid production rate Q of the well network unit is obtained prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w The changing relationship between the water injection volume and the reservoir pressure can be determined to determine whether the water injection volume in the oil field can meet the reservoir pressure maintenance requirements at different development stages.

[0014] The evaluation method provided by the present invention is based on the fact that the dimensionless water absorption index decreases as the reinjection ratio of the reinjection water in the injected water increases, and the reinjection water is quantitatively characterized by exponential decline, and then the relationship between the water absorption index of the injection well and the water content of the oil field can be derived. In addition, the relationship between the production well liquid production index and the water content of the oil field can be obtained according to the phase permeability curve. Then, combined with the water absorption index and liquid production index tested in the oil field exploration and evaluation stage or the initial development stage, the relationship between the water injection rate and the liquid production rate of the well network unit and the water content can be calculated, and the injection capacity risk at different water content stages can be evaluated by comparing the difference between the two. The evaluation method provided by the present invention can not only quantitatively evaluate the risk of reduced production caused by reduced injection capacity through theoretical methods, but can also be applied to numerical simulation, and has wide applicability.

[0015] As a preferred technical solution of the present invention, the water absorption index II varies with the ratio of produced water injected into the oil field to the re-injection of water f PWRI The functional relationship of the change is as follows (1):

[0016]

[0017] In the formula, J ID is the dimensionless water absorption index; II is the water absorption index, m 3 / d / MPa; II0 is the initial water absorption index, m 3 / d / MPa;f PWRI It is the ratio of produced water reinjection to injected water, a decimal; n is the decreasing exponent.

[0018] As a preferred technical solution of the present invention, the dimensionless water absorption index J ID and oilfield water content f w The derivation process of the functional relationship is as follows:

[0019] If the water production of the oil well is Q w , unit is m 3 / d, the oil production of the oil well is Q o , unit is m 3 / d, water injection volume is Q i , unit is m 3 / d, moisture content is f w , the crude oil volume coefficient is B o , the injection-production ratio is IRR, then the injection volume Q i The calculation of is as follows (2):

[0020] Q i =IRR·(Q w +Q o B o ) (2)

[0021] If all produced water is reinjected, the proportion of produced water reinjected in the injected water is as follows (3):

[0022]

[0023] Combining equations (1) and (3) gives the dimensionless water absorption index J ID and oilfield water content f w The functional relationship is as follows (4):

[0024]

[0025] As a preferred technical solution of the present invention, the maximum injection speed Q of the water injection well is established. inj With the water content of oil field f wThe derivation process of the changing functional relationship is as follows:

[0026] Maximum injection rate of water injection well Q inj The calculation formula is as follows (5):

[0027] Q inj =ΔP inj II = ΔP inj ·J ID ·II0 (5)

[0028] Combining equations (4) and (5), we can get the maximum injection rate Q of the injection well: inj With the water content of oil field f w The functional relationship of the change is as follows (6):

[0029]

[0030] As a preferred technical solution of the present invention, the dimensionless liquid extraction index J is established. LD With the water content of oil field f w The derivation process of the changing relationship curve is as follows:

[0031] Using the Corey phase permeability curve expression, as shown in equations (7), (8) and (9):

[0032]

[0033] In the formula, S w is water saturation; S wi is the bound water saturation; S or is the residual oil saturation; K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; K ro (S wi ) is the relative permeability of the oil phase under irreducible water saturation; K rw (S or ) is the relative permeability of water phase at residual oil saturation; S wD is the normalized water saturation; n o is the oil phase index; n w is the water phase index;

[0034] Using the flow rate equation, the water content of the oil field is calculated to be f w As shown in formula (10):

[0035]

[0036] In the formula, μ w is the viscosity of the water phase, in mPa·S; μ0 is the viscosity of the oil phase, in mPa·S;

[0037] When the production pressure difference remains unchanged, the dimensionless liquid production index J is calculated. LD As shown in formula (11):

[0038]

[0039] The oil field water content f obtained by formula (10) w is the x-axis of the curve, and the dimensionless liquid production index J obtained by formula (11) LD As the y-axis of the curve, the dimensionless liquid production index J of the oil well is plotted. LD With the water content of oil field f w The change curve.

[0040] As a preferred technical solution of the present invention, the production index PI is established along with the oil field water content f w The derivation process of the changing relationship curve is as follows:

[0041] The calculation formula of the liquid extraction index PI is as follows (12):

[0042] PI=PI0·J LD (12)

[0043] Where PI0 is the initial oil well production index, m 3 / d / MPa;

[0044] The calculation formula of the liquid production index PI during oil well production is as follows (13):

[0045]

[0046] The oil field water content f obtained by formula (10) w The x-axis of the curve is the production index PI obtained by formula (13) and the y-axis is the production index PI. w The changing relationship curve.

[0047] Then the liquid production rate Q of the well pattern unit prod The calculation formula is as follows (14):

[0048]

[0049] Where m is the ratio of production and injection wells; ΔP prod is the production pressure difference, MPa;

[0050] The oil field water content f obtained by formula (10) w The x-axis of the curve is the liquid extraction speed Q obtained by formula (14): prod As the y-axis, plot the liquid collection speed Q prod With the water content of oil field f w The changing relationship curve.

[0051] As a preferred technical solution of the present invention, the predicted liquid production rate Q of the well pattern unit is obtained by combining equation (6) and equation (14): prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w of the changing relationship.

[0052] In a second aspect, the present invention provides a device for evaluating the injection capacity of reinjection water, the device comprising:

[0053] The module for determining the decreasing index n is used to calculate the water absorption index II and the proportion of produced water injected into the oil field by using the test data of different injection stages of the water injection well. PWRI The decreasing exponent n in the changing functional relationship;

[0054] Dimensionless water absorption index J ID and oilfield water content f w The function relationship acquisition module is used to determine the water absorption index II of the decline index n and the proportion of produced water reinjection f of the oil field injected water PWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of

[0055] Maximum injection rate of water injection well Q inj With the water content of oil field f w The module for obtaining the functional relationship of the change is used to combine the dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change;

[0056] Dimensionless fluid extraction index J LD With the water content of oil field f w The relationship curve acquisition module is used to establish the dimensionless liquid extraction index J LD With the water content of oil field f w The relationship curve of

[0057] The production index PI changes with the water content of the oil field w The module for acquiring the relationship curve of changes is used to derive and establish the relationship between the production index PI and the oil field water content f according to the oil field water content equation and the initial production index PI0 of the oil well actually tested in the oil field. w The changing relationship curve;

[0058] Well pattern unit liquid production speed Q prodWith the water content of oil field f w The variable function relationship acquisition module is used to combine the production index PI and the oil field water content f w Functional relationship, production-injection well ratio m and production pressure difference ΔP prod , establish the well pattern unit liquid production rate Q prod With the water content of oil field f w Functional relationships of change;

[0059] Liquid collection speed Q prod and the maximum injection rate Q of the injection well inj The function relationship acquisition module is used to obtain the maximum injection rate Q of the injection well. inj With the water content of oil field f w The function relationship of the change acquisition module and the liquid production speed Q of the well network unit prod With the water content of oil field f w The curve relationship of the changing relationship curve acquisition module is used to obtain the predicted liquid production rate Q of the well network unit. prod and the maximum injection rate Q of the injection well inj The functional relationship between the oil field water injection volume and the reservoir pressure maintenance demand can be determined in different development stages.

[0060] In a third aspect, the present invention provides an electronic device, the electronic device comprising:

[0061] at least one processor; and a memory communicatively coupled to the at least one processor;

[0062] The memory stores a computer program executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for evaluating the injection capacity of reinjection water described in the first aspect.

[0063] In a fourth aspect, the present invention provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, the method for evaluating the injection capacity of reinjection water described in the first aspect is implemented.

[0064] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0065] The method provided by the present invention can predict the change of the water absorption index of produced water reinjected into the oil field, and further can quantify the influence of the change of the water absorption index on the pressure maintenance and production capacity of the reservoir, which is of great significance to the design of oil field development plan or the optimization of oil reservoir production system, and helps to realize the reasonable and efficient injection and use of oil field reinjection water, while ensuring the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1is a flow chart of a method for evaluating the injection capacity of reinjection water provided by an embodiment of the present invention;

[0067] Figure 2 is a schematic diagram of an evaluation device for reinjection water injection capability provided by an embodiment of the present invention;

[0068] Figure 3 is a schematic diagram of an electronic device provided by an embodiment of the present invention;

[0069] Figure 4 is a relationship diagram of the decreasing water absorption index obtained in Example 1 of the present invention and the ratio of produced water to injected water;

[0070] Figure 5 is a relationship diagram of the dimensionless water absorption index obtained in Example 1 of the present invention and the relationship curve of the oil field water content;

[0071] Figure 6 is a relationship diagram of the oil-water relative permeability curve obtained in Example 1 of the present invention;

[0072] Figure 7 is a relationship diagram of the dimensionless liquid production index obtained in Example 1 of the present invention and the relationship curve of the oil field water content;

[0073] Figure 8 It is a relationship diagram of the prediction curve between the liquid production rate of the well network unit and the maximum water injection rate obtained in Example 1 of the present invention.

[0074] In the figure: 10 - electronic device, 11 - processor, 12 - ROM, 13 - RAM, 14 - bus, 15 - I / O interface, 16 - input unit, 17 - output unit, 18 - storage unit, 19 - communication unit.

[0075] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0076] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0077] This embodiment provides a method for evaluating the injection capacity of reinjection water, the flow chart of which is as follows: Figure 1 As shown, the evaluation method includes:

[0078] S1. Using the test data of different water injection stages of the water injection well, calculate the water absorption index II and the proportion of produced water injected into the oil field f PWRI The decreasing exponent n in the changing functional relationship;

[0079] S2, combined with the water absorption index II to determine the decline index n, the proportion of produced water injected into the oil field and the proportion of produced water injected into the oil field f PWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of

[0080] S3, combined with dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change;

[0081] S4. Establish dimensionless liquid extraction index J LD With the water content of oil field f w The changing relationship curve;

[0082] S5, combining the oil field water content equation obtained in S4 with the initial liquid production index PI0 of the oil wells actually tested in the oil field, the ratio of production and injection wells m of the well network unit and the production pressure difference ΔP prod , derive and establish the production index PI along with the oil field water content f w The relationship curve of the change and the liquid production rate Q of the well network unit prod With the water content of oil field f w The changing relationship curve;

[0083] S6, combined with the relationship curve of S3 and S5, the predicted liquid production rate Q of the well network unit is obtained prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w The changing relationship between the water injection volume and the reservoir pressure can be determined to determine whether the water injection volume in the oil field can meet the reservoir pressure maintenance requirements at different development stages.

[0084] In the present invention, a preliminary prediction can be made for an oil field that has not yet been produced by analogy with the development data of similar oil fields, and then a further accurate prediction can be made based on actual production data.

[0085] Specifically, the water absorption index II varies with the ratio of produced water injected into the oil field to the re-injection of water. PWRI The functional relationship of the change is as follows (1):

[0086]

[0087] In the formula, J ID is the dimensionless water absorption index; II is the water absorption index, m 3 / d / MPa; II0 is the initial water absorption index, m 3 / d / MPa;f PWRI It is the ratio of produced water reinjection to injected water, a decimal; n is the decreasing exponent.

[0088] Specifically, the dimensionless water absorption index J ID and oilfield water content f w The process of establishing the functional relationship is as follows:

[0089] If the water production of the oil well is Q w , the oil production of the oil well is Q o , the water injection volume is Q i , the moisture content is f w , the crude oil volume coefficient is B o , the injection-production ratio is IRR, then the injection volume Q i The calculation of is as follows (2):

[0090] Q i =IRR·(Q w +Q o B o ) (2)

[0091] If all produced water is reinjected, the proportion of produced water reinjected in the injected water is as follows (3):

[0092]

[0093] Combining equations (1) and (3) gives the dimensionless water absorption index J: ID and oilfield water content f w The functional relationship is as follows (4):

[0094]

[0095] Specifically, the maximum injection rate Q of the water injection well is established. inj With the water content of oil field f w The process of changing the functional relationship is as follows:

[0096] Maximum injection rate of water injection well Q inj The calculation formula is as follows (5):

[0097] Q inj =ΔP inj II = ΔP inj ·J ID ·II0 (5)

[0098] In the formula, Q inj is the maximum injection rate of the injection well, in m 3 / d;ΔP inj is the maximum water injection pressure difference, in MPa;

[0099] Combining equations (4) and (5), we can get the maximum injection rate Q of the injection well: inj With the water content of oil field f w The functional relationship of the change is as follows (6):

[0100]

[0101] Specifically, the dimensionless liquid extraction index J is established. LD With the water content of oil field f w The process of the changing relationship curve is as follows:

[0102] Using the Corey phase permeability curve expression, as shown in equations (7), (8) and (9):

[0103]

[0104] In the formula, S w is water saturation; S wi is the bound water saturation; S or is the residual oil saturation; K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; K ro (S wi ) is the relative permeability of the oil phase under irreducible water saturation; K rw (S or ) is the relative permeability of water phase at residual oil saturation; S wD is the normalized water saturation; n o is the oil phase index; n w is the water phase index.

[0105] Using the partial flow equation, calculate the oil field water content f w As shown in formula (10):

[0106]

[0107] In the formula, μ w is the viscosity of the water phase, in mPa·S; μ0 is the viscosity of the oil phase, in mPa·S;

[0108] Calculate the dimensionless liquid production index J when the production pressure difference remains unchanged LD As shown in formula (11):

[0109]

[0110] The oil field water content f obtained by formula (10) w is the x-axis of the curve, and the dimensionless liquid production index J obtained by formula (11) LD As the y-axis of the curve, the dimensionless liquid production index J of the oil well is plotted. LDWith the water content of oil field f w The change curve.

[0111] Specifically, the production index PI is established according to the oil field water content f w The derivation process of the changing relationship curve is as follows:

[0112] The calculation formula of the liquid extraction index PI is as follows (12):

[0113] PI=PI0·J LD (12)

[0114] Where PI0 is the initial oil well production index, m 3 / d / MPa;

[0115] The calculation formula of the liquid production index PI during oil well production is as follows (13):

[0116]

[0117] The oil field water content f obtained by formula (10) w The x-axis of the curve is the production index PI obtained by formula (13) and the y-axis is the production index PI. w The changing relationship curve.

[0118] Furthermore, the liquid production rate Q of a well network unit is prod The calculation formula is as follows (14):

[0119]

[0120] Where m is the ratio of production and injection wells; ΔP prod is the production pressure difference, MPa.

[0121] The oil field water content f obtained by formula (10) w is the x-axis of the curve, and the liquid extraction speed Q obtained by formula (14) prod As the y-axis, plot the liquid collection speed Q prod With the water content of oil field f w The changing relationship curve.

[0122] Specifically, according to equations (6) and (14), the predicted liquid production rate Q of the well pattern unit is obtained: prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w The change relationship is as follows: w is the x-axis, the liquid collection speed Q prod and the maximum injection rate Q of the injection well inj As the y-axis, plot the liquid collection speed Q prod and the maximum injection rate Q of the injection wellinj At the same time, as the oil field water content f w The changing relationship between the water injection volume and the pressure of the reservoir can be determined in different development stages to determine whether the water injection volume can meet the reservoir pressure maintenance requirements.

[0123] Specifically, if the water content f in any oil field is w In this case, the predicted water injection rate of the well network unit is greater than the liquid production rate, indicating that at different stages of oilfield development, the water injection capacity can meet the pressure supply demand of the oil wells, and the corresponding injection capacity of the reinjection water is low risk.

[0124] Specifically, if the water content in the oil field is f w and low oilfield water content f w Under the condition of high oilfield water content f, the water injection rate of the well pattern unit is predicted to be greater than the liquid production rate. w Under this condition, the predicted water injection rate of the well network unit is lower than the liquid production rate, which means that the water injection capacity cannot meet the pressure supply demand of the oil wells in the high water content stage, and the corresponding injection capacity of the reinjection water is medium risk. w During this stage, adjustment measures such as unblocking injection wells or increasing the number of injection wells may be required.

[0125] Specifically, if the water content f in any oil field is w In this case, the water injection rate predicted by the well network unit is lower than the liquid production rate, indicating that the water injection capacity cannot meet the pressure supply demand of the oil wells at different development stages when there is no sufficient edge and bottom water or other energy supplement in the oil field. The corresponding injection capacity of the reinjection water is at high risk, and adjustment measures such as increasing the number of water injection wells are needed.

[0126] In the present invention, the high oil field water content f w It means the water content is greater than 60%, the water content of oil fields is f w Refers to the water content of 20-60%, low oil field water content f w It means moisture content <20%.

[0127] Furthermore, this embodiment provides a device for evaluating the injection capacity of reinjection water, such as Figure 2 As shown, the evaluation device comprises:

[0128] The module for determining the decreasing index n is used to calculate the water absorption index II and the proportion of produced water injected into the oil field by using the test data of different injection stages of the water injection well. PWRI The decreasing exponent n in the changing functional relationship;

[0129] Dimensionless water absorption index J ID and oilfield water content f w The function relationship acquisition module is used to determine the water absorption index II of the decline index n and the proportion of produced water reinjection f of the oil field injected waterPWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of

[0130] Maximum injection rate of water injection well Q inj With the water content of oil field f w The module for obtaining the functional relationship of the change is used to combine the dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change;

[0131] Dimensionless fluid extraction index J LD With the water content of oil field f w The relationship curve acquisition module is used to establish the dimensionless liquid extraction index J LD With the water content of oil field f w The relationship curve of

[0132] The production index PI changes with the water content of the oil field w The module for acquiring the relationship curve of changes is used to derive and establish the relationship between the production index PI and the oil field water content f according to the oil field water content equation and the initial production index PI0 of the oil well actually tested in the oil field. w The changing relationship curve;

[0133] Well pattern unit liquid production speed Q prod With the water content of oil field f w The variable function relationship acquisition module is used to combine the production index PI and the oil field water content f w Functional relationship, production-injection well ratio m and production pressure difference ΔP prod , establish the well pattern unit liquid production rate Q prod With the water content of oil field f w Functional relationships of change;

[0134] Liquid collection speed Q prod and the maximum injection rate Q of the injection well inj The function relationship acquisition module is used to obtain the maximum injection rate Q of the injection well. inj With the water content of oil field f w The function relationship of the change acquisition module and the well network unit liquid production speed Q prod With the water content of oil field f w The function relationship acquisition module of the change obtains the predicted liquid production rate Q of the well network unit prod and the maximum injection rate Q of the injection well injThe functional relationship between the oil field water injection volume and the reservoir pressure maintenance demand can be determined in different development stages.

[0135] Furthermore, regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0136] Further, the present invention provides an electronic device, which is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0137] like Figure 3 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The I / O interface 15 is also connected to the bus 14.

[0138] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0139] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a method for evaluating the injection capability of reinjection water.

[0140] In some embodiments, the method for assessing the injection capability of reinjection water may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for assessing the injection capability of reinjection water described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform the method for assessing the injection capability of reinjection water by any other appropriate means (e.g., by means of firmware).

[0141] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0142] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0143] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0144] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0145] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0146] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0147] The server provided in this embodiment includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the above-mentioned method for evaluating the injection capacity of reinjection water when executing the program.

[0148] Unless otherwise specifically stated, terms such as processing, computing, calculating, determining, displaying, etc. may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which operate and convert data represented as physical (e.g., electronic) quantities within registers or memories of a processing system into other data similarly represented as physical quantities within memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0149] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments of the present invention may all be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on the specific application and the design constraints imposed on the entire system. A skilled person may implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection disclosed in the present invention.

[0150] The steps of the method or algorithm illustrated in conjunction with the embodiments of the present invention can be directly embodied as hardware, a software module executed by a processor, or a combination thereof. The software module can be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. The ASIC can be located in a user terminal. Of course, the processor and the storage medium can also be present in a user terminal as discrete components.

[0151] For software implementation, the techniques described in the present invention can be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described in the present application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is coupled to the processor in a communication manner via various means, which are well known in the art.

[0152] Furthermore, in order to illustrate the recognition effect that can be achieved by the evaluation method for reinjection water injection capability provided by the present invention, an actual example is used for illustration, as follows:

[0153] Example 1

[0154] This embodiment provides an evaluation process for the injection capacity of reinjection water for a specific oil field, which is as follows:

[0155] Take the K oilfield in the Albert Lake area of ​​the East African Rift Basin as an example. The reservoir of this oilfield is fan delta sediments with good reservoir properties and an average porosity of about 23%; the permeability is generally 200-500mD, and the crude oil viscosity is 3.5cp. The development plan is designed to start water injection from the time the oilfield is put into production, and the design target injection-production ratio is 1 to maintain a reasonable formation pressure. In the early stage of the oilfield, lake water is mainly injected. When the oil wells start to produce produced water, lake water + produced water are mixed and then reinjected. As the development progresses, the proportion of produced water reinjection to injected water will become higher and higher. Since the water quality of produced water is worse than that of lake water, it is expected to have a certain impact on the injection capacity. The K oilfield adopts a well network of edge water injection + internal point water injection, especially the internal reverse nine-point well network, which has high requirements on the injection capacity of the water injection wells. Therefore, predicting the changes in injection capacity can identify the risk of insufficient injection capacity in advance, which is of great significance to reservoir management. By using the method proposed in the present invention, the injection-production well of the oil reservoir is taken as an example to illustrate how to perform injection capacity reduction and risk analysis under the condition of produced water reinjection.

[0156] Since K oilfield is a new oilfield with no production data, three representative wells with different water absorption index declines were selected as high, medium and low solutions by analogy with the actual development data of B oilfield. According to formula (1), the decreasing index n of high, medium and low solutions was determined to be 0.36, 0.7 and 1.2 respectively. That is, corresponding to the three examples, the water absorption index II and the produced water reinjection ratio f of injected water were calculated. PWRI The relationship is as Figure 4 shown.

[0157] Depend on Figure 4 It can be seen that as the produced water reinjection ratio increases to 100%, the water absorption index of the representative high, medium and low schemes decreases by 30%, 50% and 70% respectively.

[0158] According to formula (4), the dimensionless water absorption index J of K oil field can be calculated: ID and oilfield water content f w The relationship curve, such as Figure 5 shown.

[0159] Combined dimensionless water absorption index J ID and oilfield water content f w Functional relationship, the initial water absorption index II0 of the actual test water injection well in the oil field (the value is 225m 3 / d / MPa) and the maximum injection pressure difference ΔP inj (value is 7.6MPa), establish the maximum injection rate Q of the injection well inj With the water content of oil field f w For details, see Figure 8 The maximum injection rate Q of the injection well inj There are three curves for high, medium and low scenarios.

[0160] in accordance with Figure 6 The oil-water relative permeability curve of the K oil field shown in the figure can be combined with formulas (10) and (11) to calculate the dimensionless liquid production index J of the K oil field: LD and oilfield water content f w The relationship curve, such as Figure 7 shown.

[0161] According to formula (14) and the actual test results of oil field, the initial oil production index PI0 (120m 3 / d / MPa) ratio of production and injection wells m (value is 3), production pressure difference ΔP prod (value is 3.5MPa), and the fluid production rate Q of the well network unit is obtained prod With the water content of oil field f w The changing relationship curve, such as Figure 8 Liquid collection speed curve in .

[0162] According to step S6, the initial liquid production index PI0 is 120m 3 / d / MPa, initial water absorption index II0 is 225m 3 / d / MPa, production pressure difference ΔP prod 3.5MPa, maximum injection pressure difference ΔP inj The production rate Q of the internal reverse nine-spot well pattern unit in K oilfield is 7.6 MPa and the ratio of production and injection wells in the internal reverse nine-spot well pattern unit is 3. prod and the maximum injection rate Q of the injection well inj At the same time, the prediction curve of the change of water content is as follows: Figure 8 shown.

[0163] Depend on Figure 8 It can be seen that in medium and low oil fields, the water content f w In the stage, the maximum water injection rate is greater than the liquid production rate, and the water content of the high oil field f w In the stage, the maximum water injection rate of the medium and low schemes is gradually lower than the liquid production rate, indicating that the injection capacity is at medium risk, which means that acid removal measures or additional water injection wells may be required in the high water content stage. Taking the low scheme as an example, when the water content is 90%, the maximum water injection rate is 587m 3 / d, the liquid collection speed is 1000m 3 / d, the liquid production will have to be gradually reduced due to the low injection capacity, affecting the production ratio by about 41%.

[0164] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0165] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0166] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for evaluating the injection capacity of reinjection water, characterized in that: The evaluation methods include: S1. Using the test data of different water injection stages of the water injection well, calculate the water absorption index II and the proportion of produced water injected into the oil field f PWRI The decreasing exponent n in the changing functional relationship; S2, combined with the water absorption index II to determine the decline index n, the proportion of produced water injected into the oil field and the proportion of produced water injected into the oil field f PWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of S3, combined with dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change; S4. Establish dimensionless liquid extraction index J LD With the water content of oil field f w The changing relationship curve; S5, combining the oil field water content equation obtained in S4 with the initial liquid production index PI0 of the oil wells actually tested in the oil field, the ratio of production and injection wells m of the well network unit and the production pressure difference ΔP prod , derive and establish the production index PI along with the oil field water content f w The relationship curve of the change and the liquid production rate Q of the well network unit prod With the water content of oil field f w The changing relationship curve; S6, combined with the relationship curve of S3 and S5, the predicted liquid production rate Q of the well network unit is obtained prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w The changing relationship between the water injection volume and the reservoir pressure can be determined to determine whether the water injection volume in the oil field can meet the reservoir pressure maintenance requirements at different development stages.

2. The method for evaluating the injection capacity of reinjection water according to claim 1, characterized in that: The water absorption index II varies with the ratio of produced water injected into the oil field to the re-injection of water. PWRI The functional relationship of the change is as follows (1): In the formula, J ID is the dimensionless water absorption index; II is the water absorption index, the unit is m 3 / d / MPa; II0 is the initial water absorption index, unit is m 3 / d / MPa;f PWRI is the ratio of produced water reinjection to injected water; n is the decreasing exponent.

3. The method for evaluating the injection capacity of reinjection water according to claim 2, characterized in that: The dimensionless water absorption index J ID and oilfield water content f w The derivation process of the functional relationship is as follows: If the water production of the oil well is Q w , unit is m 3 / d, the oil production of the oil well is Q o , unit is m 3 / d, water injection volume is Q i , unit is m 3 / d, moisture content is f w , the crude oil volume coefficient is B o , the injection-production ratio is IRR, then the water injection volume Q i The calculation of is as follows (2): Q i =IRR·(Q w +Q o B o ) (2) If all produced water is reinjected, the proportion of produced water reinjected in the injected water is as follows (3): Combining equations (1) and (3) gives the dimensionless water absorption index J ID and oilfield water content f w The functional relationship is as follows (4):

4. The method for evaluating the injection capacity of reinjection water according to claim 3, characterized in that: The maximum injection speed Q of the water injection well is established inj With the water content of oil field f w The derivation process of the changing functional relationship is as follows: Maximum injection rate of water injection well Q inj The calculation formula is as follows (5): Q inj =ΔP inj ·II=ΔP inj ·J ID ·II0 (5) In the formula, Q inj is the maximum injection rate of the injection well, in m 3 / d; ΔP inj is the maximum water injection pressure difference, in MPa; Combining equations (4) and (5), we can get the maximum injection rate Q of the injection well: inj With the water content of oil field f w The functional relationship of the change is as follows (6):

5. The method for evaluating the injection capacity of reinjection water according to claim 4, characterized in that: The dimensionless liquid production index J is established LD With the water content of oil field f w The derivation process of the changing relationship curve is as follows: Using the Corey phase permeability curve expression, as shown in equations (7), (8) and (9): In the formula, S w is water saturation; S wi is the bound water saturation; S or is the residual oil saturation; K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; K ro (S wi ) is the relative permeability of the oil phase under irreducible water saturation; K rw (S or ) is the relative permeability of water phase at residual oil saturation; S wD is the normalized water saturation; n o is the oil phase index; n w is the water phase index; Using the flow rate equation, the water content of the oil field is calculated to be f w As shown in formula (10): In the formula, μ w is the viscosity of the water phase, in mPa·S; μ0 is the viscosity of the oil phase, in mPa·S; When the production pressure difference remains unchanged, the dimensionless liquid production index J is calculated. LD As shown in formula (11): The oil field water content f obtained by formula (10) w is the x-axis of the curve, and the dimensionless liquid production index J obtained by formula (11) LD As the y-axis of the curve, the dimensionless liquid production index J of the oil well is plotted. LD With the water content of oil field f w The change curve.

6. The method for evaluating the injection capacity of reinjection water according to claim 5, characterized in that: The establishment of the production index PI along with the oil field water content f w The derivation process of the changing relationship curve is as follows: The calculation formula of the liquid extraction index PI is as follows (12): PI=PI0 J LD (12) Where PI0 is the initial oil well production index, m 3 / d / MPa; The calculation formula of the liquid production index PI during oil well production is as follows (13): The oil field water content f obtained by formula (10) w The x-axis of the curve is the production index PI obtained by formula (13) and the y-axis is the production index PI. w The changing relationship curve; Then the liquid production rate Q of the well pattern unit prod The calculation formula is as follows (14): Where m is the ratio of production and injection wells; ΔP prod is the production pressure difference, MPa; The oil field water content f obtained by formula (10) w The x-axis of the curve is the liquid extraction speed Q obtained by formula (14): prod As the y-axis, plot the liquid collection speed Q prod With the water content of oil field f w The changing relationship curve.

7. The method for evaluating the injection capacity of reinjection water according to claim 1, characterized in that: Combining equations (6) and (14) to obtain the predicted liquid production rate Q of the well pattern unit prod and the maximum injection rate Q of the injection well inj At the same time, as the oil field water content f w of the changing relationship.

8. A device for evaluating the injection capacity of reinjection water, characterized in that: The evaluation device comprises: The module for determining the decreasing index n is used to calculate the water absorption index II and the proportion of produced water injected into the oil field by using the test data of different injection stages of the water injection well. PWRI The decreasing exponent n in the changing functional relationship; Dimensionless water absorption index J ID and oilfield water content f w The function relationship acquisition module is used to determine the water absorption index II of the decline index n and the proportion of produced water reinjection f of the oil field injected water PWRI Dimensionless water absorption index J ID and oilfield water content f w Functional relationship of Maximum injection rate of water injection well Q inj With the water content of oil field f w The module for obtaining the functional relationship of the change is used to combine the dimensionless water absorption index J ID and oilfield water content f w Functional relationship, initial water absorption index II0 and maximum water injection pressure difference ΔP of actual test water injection wells in oil fields inj , establish the maximum injection rate Q of the injection well inj With the water content of oil field f w Functional relationships of change; Dimensionless fluid extraction index J LD With the water content of oil field f w The relationship curve acquisition module is used to establish the dimensionless liquid extraction index J LD With the water content of oil field f w The relationship curve of The production index PI changes with the water content of the oil field w The module for acquiring the relationship curve of changes is used to derive and establish the relationship between the production index PI and the oil field water content f according to the oil field water content equation and the initial production index PI0 of the oil well actually tested in the oil field. w The changing relationship curve; Well pattern unit liquid production speed Q prod With the water content of oil field f w The variable function relationship acquisition module is used to combine the production index PI and the oil field water content f w Functional relationship, production-injection well ratio m and production pressure difference ΔP prod , establish the well pattern unit liquid production rate Q prod With the water content of oil field f w Functional relationships of change; Liquid collection speed Q prod and the maximum injection rate Q of the injection well inj The function relationship acquisition module is used to obtain the maximum injection rate Q of the injection well. inj With the water content of oil field f w The function relationship of the change acquisition module and the liquid production speed Q of the well network unit prod With the water content of oil field f w The curve relationship of the changing relationship curve acquisition module is used to obtain the predicted liquid production rate Q of the well network unit. prod and the maximum injection rate Q of the injection well inj The functional relationship between the oil field water injection volume and the reservoir pressure maintenance demand can be determined in different development stages.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively coupled to the at least one processor; The memory stores a computer program executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for evaluating the injection capacity of reinjection water according to any one of claims 1 to 7.

10. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, the method for evaluating the injection capacity of reinjection water according to any one of claims 1 to 7 is implemented.

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