CN112253079B

CN112253079B - Method and device for determining well pattern density of oil reservoir

Info

Publication number: CN112253079B
Application number: CN202011250583.5A
Authority: CN
Inventors: 张家良; 何书梅; 李健; 张津; 张志明; 李辉; 黄芳; 郭志桥; 高淑芳; 李佩敬; 魏朋朋; 庄天琳; 齐双瑜; 成亚斌
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-11-10
Filing date: 2020-11-10
Publication date: 2022-11-01
Anticipated expiration: 2040-11-10
Also published as: CN112253079A

Abstract

The application discloses a method and a device for determining well pattern density of an oil reservoir, and relates to the technical field of oil field development. The host computer may determine a target well pattern density based on an income amount function that may reflect a relationship between a discount value of crude oil sales income and the well pattern density and an expenditure amount function that may reflect a relationship between a discount value of crude oil production expenditure and the well pattern density. The method provided by the application considers the time value of capital in the process of determining the density of the well pattern, so that the accuracy of the well pattern density determined by the method provided by the application is higher compared with the well pattern density determined by the related art.

Description

Method and device for determining well pattern density of oil reservoir

Technical Field

The application relates to the technical field of oil reservoir exploitation, in particular to a method and a device for determining well pattern density of an oil reservoir.

Background

The well pattern density refers to the number of well mouths in a unit area of an oil field, and the well mouth density is directly related to the recovery ratio of an oil reservoir and then is related to the economic benefit of oil field development. Therefore, prior to the development of the reservoir, the well pattern density needs to be determined.

In the related art, the well pattern density is generally determined by using a convergence calculation formula derived from the schelcack geoff formula. However, the related art, the accuracy of the determined pattern density is low.

Disclosure of Invention

The application provides a method and a device for determining the well pattern density of an oil reservoir, which can solve the problem that the accuracy of the well pattern density determined by the related technology is low. The technical scheme is as follows:

in one aspect, a method of determining a pattern density of a reservoir, the method comprising:

determining an income amount function, wherein the income amount function is used for reflecting the relation between the discount value of the crude oil sales income of the oil reservoir and the well pattern density in the mining period;

determining a cost function which is used for reflecting the relation between the oil deposit crude oil exploitation cost discount value and the well pattern density in the exploitation time period;

determining a target pattern density based on the revenue amount function and the expenditure amount function.

Optionally, the determining the revenue amount function includes:

determining a first relation reflecting a relationship between a discount value of a first crude oil sales income of the oil reservoir and the target well pattern density in the production period;

determining a discount value of second crude oil sales revenue for the reservoir over a target production period included in the production period;

determining the revenue amount function based on the first relationship and a discount value of the second crude oil sales revenue;

the first oil displacement mode is different from the second oil displacement mode.

Optionally, the determining the first relation includes:

determining a yield function reflecting a relation between the target annual yield of crude oil obtained by the first drive mode and the well pattern density, wherein the yield function q (S) satisfies:

determining the first relational expression based on the yield function, the unit price of the crude oil, the commodity rate of the crude oil and the benchmark yield, wherein the first relational expression satisfies the following conditions:

wherein N is the geological reserve of the reservoir, D_cAn annual rate of oil production of crude oil obtained by the first flooding pattern, E_dFor the oil displacement efficiency of the first oil displacement mode, K is the effective permeability of an oil layer of the oil reservoir, M is the initial injection-production well ratio, a is the well pattern index, phi is the porosity, S_oIs the saturation of the crude oil, h is the effective thickness of the reservoir, S is the well pattern density, R_TThe crude oil production degree under the initial well pattern density is set, the initial well pattern density is smaller than the target well pattern density, T is the production end time of the production period, V₁Is the discount value of the sales revenue for the first crude oil, P is the unit price of the crude oil, τ is the commodity rate of the crude oil, and i is the benchmark revenue rate.

Optionally, the determining the discount value of the second crude oil sales income of the oil reservoir in the target production period included in the production period comprises:

determining a ratio function of annual enhanced recovery ratio to time period within the target production time period, the ratio function f (t) satisfying:

determining a discount value of sales income of second crude oil of the oil reservoir based on the unit price of the crude oil, the commodity rate of the crude oil, the geological reserve, the enhanced recovery ratio of the crude oil produced by the second oil displacement mode in the target production period, the ratio function and the benchmark profitability, wherein the discount value V of the sales income of the second crude oil is₂Satisfies the following conditions:

wherein, T_ADuration, T, used to perfect the pattern_BAfter the well pattern is completed and before the second oil displacement mode is adopted for mining, the length of time for mining by the first oil displacement mode is adopted, mu is the average number of the annual enhanced recovery ratios of the historical oil deposit, sigma is the standard deviation of the annual enhanced recovery ratios of the historical oil deposit, P is the unit price of the crude oil, tau is the commodity rate of the crude oil, N is the geological reserve, R is the commodity rate of the crude oil, and_pfor the enhanced oil recovery, the enhanced oil recovery is a ratio of a total amount of crude oil obtained in the target production period by using the second oil displacement method to the geological reserve, the annual enhanced oil recovery ratio is an annual enhanced oil recovery in the target production period, τ is the rate of commodity of the crude oil, f (t) is the ratio function, and i is the benchmark yield.

Optionally, the determining a payout amount function includes:

acquiring a second relational expression, wherein the second relational expression is used for reflecting the relation between the discount value of the capital construction investment of the oil reservoir and the target well pattern density in the mining period, and the second relational expression meets the following requirements:

obtaining a third relation formula, wherein the third relation formula is used for reflecting the relation between the conversion value of the operation cost of the oil reservoir and the target well pattern density in the mining period, and the third relation formula meets the following requirements:

acquiring a fourth relational expression, wherein the fourth relational expression is used for reflecting the relation between the comprehensive tax of the oil reservoir and the reduced value of the reserve usage fee and the target well pattern density in the mining period, and the fourth relational expression satisfies the following conditions:

determining the payout amount function based on the second relationship, the third relationship, and the fourth relationship;

wherein, V₃For the reduced value of the capital construction investment, L is the single well capital construction investment, A is the oil-containing area of the oil reservoir, S is the target well pattern density, n is the initial well number, the initial well number is less than the well number corresponding to the target well pattern density, i is the reference yield, V₄For the reduced value of the operating cost, W is the ton oil operating cost, q (S) is a yield function reflecting the relation between the target annual yield of the crude oil obtained by adopting the first oil displacement mode and the well pattern density, D_cThe annual rate of reduction of the oil yield of the crude oil obtained by the first oil displacement mode is adopted, N is the geological reserve, R is_pFor the enhanced oil recovery, the enhanced oil recovery is the ratio of the total amount of crude oil obtained in the target production period by the second oil displacement mode to the geological reserve, f (t) is a ratio function of annual enhanced oil recovery ratio to the period in the target production period, i is the benchmark profitabilityP is unit price of crude oil, Y is value-added tax rate, L₁To become tax rate, L₂Adding tax rate for education and education, Z is reserve usage charge, tau is the rate of said crude oil commodity, T_AFor the moment of well pattern completion, T_BAnd the time when the exploitation is completed by adopting the first oil displacement mode comprises the target exploitation time interval, the annual enhanced oil recovery ratio is the annual enhanced oil recovery ratio in the target exploitation time interval, and the first oil displacement mode is different from the second oil displacement mode.

Optionally, the second oil displacement mode is chemical oil displacement; the determining a payout amount function further comprises:

obtaining the conversion value of the chemical flooding cost, wherein the conversion value V of the chemical flooding cost₆Satisfies the following conditions:

said determining said payout amount function based on said second relationship, said third relationship, and said fourth relationship, comprising:

determining the payout amount function based on the second relational expression, the third relational expression, the fourth relational expression and the discount value of the medicine fee;

wherein X is the cost per ton of oil, V_ptThe injection rate of the drug in the T year, T_cThe length of time for injecting the chemical agent.

Optionally, the target well pattern density is a target economic limit well pattern density; determining a target pattern density based on the revenue amount function and the expenditure amount function, comprising:

and determining the target well pattern density when the discount value of the crude oil sales income of the oil deposit of the income amount function is equal to the discount value of the crude oil exploitation expenditure of the oil deposit of the expenditure amount function as the target economic limit well pattern density.

Optionally, the target well pattern density is a target economically reasonable well pattern density; determining a target pattern density based on the revenue amount function and the expenditure amount function, comprising:

determining a derivative function of a target function, wherein the target function is obtained by subtracting the income function from the expenditure function;

and determining the target well pattern density when the derivative function is zero as the target economic and reasonable well pattern density.

In another aspect, there is provided an apparatus for determining a pattern density of a reservoir, the apparatus comprising:

the system comprises a first determination module, a second determination module and a third determination module, wherein the first determination module is used for determining a revenue function, and the revenue function is used for reflecting the relation between the discount value of the crude oil sales revenue of the oil reservoir and the well pattern density in the production period;

the second determination module is used for determining a expenditure function which is used for reflecting the relation between the discount value of the crude oil exploitation expenditure of the oil reservoir and the well pattern density in the exploitation time period;

a third determination module to determine a target pattern density based on the income amount function and the expenditure amount function.

Optionally, the first determining module is configured to:

determining a discount value of second crude oil sales revenue for the reservoir within a target production period included in the production period;

wherein the first oil sales income is determined based on the crude oil obtained by adopting a first oil displacement mode, the second oil sales income is determined based on the crude oil obtained by adopting a second oil displacement mode, and the first oil displacement mode is different from the second oil displacement mode.

Optionally, the first determining module is configured to:

wherein N is the geological reserve of the reservoir, D_cAn annual rate of oil production of crude oil obtained by the first drive mode, E_dFor the oil displacement efficiency of the first oil displacement mode, K is the effective permeability of an oil layer of the oil reservoir, M is the initial injection-production well ratio, a is the well pattern index, phi is the porosity, and S_oIs the saturation of the crude oil, h is the effective thickness of the reservoir, S is the well pattern density, R_TThe crude oil production degree under the initial well pattern density is set, the initial well pattern density is smaller than the target well pattern density, T is the production end time of the production period, V₁And (d) is the reduction value of the sales income of the first crude oil, P is the unit price of the crude oil, tau is the commodity rate of the crude oil, and i is the benchmark yield.

Optionally, the first determining module is configured to:

determining a ratio function of an annual enhanced oil recovery ratio to a time interval within the target production interval, the ratio function f (t) satisfying:

based on the unit price of the crude oil, the commodity rate of the crude oil, the geological reserve, the enhanced recovery ratio of the crude oil produced by the second oil displacement mode in the target production period, theA ratio function and a benchmark profitability, determining a reduction value of a second crude oil sales income of the oil reservoir, the reduction value V of the second crude oil sales income₂Satisfies the following conditions:

Optionally, the second determining module is configured to:

acquiring a fourth relational expression, wherein the fourth relational expression is used for reflecting the relation between the discounted values of the comprehensive taxes and the reserve usage fees of the oil reservoir in the mining period and the target well pattern density, and the fourth relational expression meets the following requirements:

determining the payout amount function based on the second relational expression, the third relational expression and the fourth relational expression;

wherein, V₃For the discount value of the capital construction investment, L is the single well capital construction investment, A is the oil-containing area of the oil reservoir, S is the target well pattern density, n is the initial well number, the initial well number is less than the well number corresponding to the target well pattern density, i is the reference yield, and V is the initial well number₄For the reduced value of the operating cost, W is the tonnage oil operating cost, q (S) is a production function reflecting the relationship between the target annual production of crude oil obtained by the first drive mode and the well pattern density, D_cThe annual rate of reduction of the oil yield of the crude oil obtained by the first oil displacement mode is adopted, N is the geological reserve, R is_pFor the enhanced oil recovery, the enhanced oil recovery is the ratio of the total amount of crude oil obtained in a target exploitation period by adopting the second oil displacement mode to the geological reserve, f (t) is a ratio function of annual enhanced oil recovery ratio to the period in the target exploitation period, i is the benchmark yield, P is the unit price of the crude oil, Y is the value-added tax rate, and L is₁To become the build tax rate, L₂Adding tax rate for education and education, Z is reserve usage charge, tau is the rate of commodity of crude oil, T_AFor the moment of well pattern completion, T_BAnd the time when the first oil displacement mode is adopted for completing the production, the production period comprises the target production period, the annual enhanced oil recovery ratio is the annual enhanced oil recovery ratio in the target production period, and the first oil displacement mode is different from the second oil displacement mode.

Optionally, the second oil displacement mode is chemical oil displacement; the second determining module is further configured to:

Optionally, the target well pattern density is a target economic limit well pattern density; the third determining module is to:

Optionally, the target well pattern density is a target economically reasonable well pattern density; the third determining module is to:

and determining the target well pattern density when the derivative function is zero as the target economic reasonable well pattern density.

In yet another aspect, an apparatus for determining a pattern density of a reservoir is provided, the apparatus comprising: a processor, a memory and a computer program stored on the memory and executable on the processor, the processor when executing the computer program implementing the method of determining a pattern density of a reservoir as described in the above aspect.

In yet another aspect, a computer-readable storage medium having instructions stored therein, which when run on a computer, cause the computer to perform a method of determining a pattern density of a reservoir as described in the above aspect is provided.

In a further aspect, there is provided a computer program product comprising instructions which, when run on the computer, cause the computer to perform the method of determining a pattern density of a reservoir of the above aspect.

The beneficial effect that technical scheme that this application provided brought includes at least:

the upper computer can determine the target well pattern density based on an income function and an expenditure function, the income function can reflect the relation between the discount value of the sales income of the crude oil and the well pattern density, and the income function can reflect the relation between the discount value of the exploitation expenditure of the crude oil and the well pattern density. In other words, the method provided by the application considers the time value of capital in the process of determining the well pattern density, so that the accuracy of the well pattern density determined by the method provided by the application is higher compared with the well pattern density determined by the related art.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flow chart of a method for determining a pattern density of a reservoir provided by an embodiment of the present application;

FIG. 2 is a flow chart of another method for determining a pattern density of a reservoir provided in an embodiment of the present application;

FIG. 3 is a flowchart of a method for determining a first relationship according to an embodiment of the present application;

FIG. 4 is a flow chart of a method for determining a reduction in sales revenue of a second crude oil from a reservoir over a target production period as provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of raw data for enhanced annual oil recovery and a fitted curve based on the raw data;

FIG. 6 is a schematic illustration of a determination of a target economic limit pattern density provided by an embodiment of the present application;

FIG. 7 is a schematic illustration of a determination of a target economically reasonable pattern density provided by an embodiment of the present application;

FIG. 8 is a block diagram of an apparatus for determining a pattern density of a reservoir according to an embodiment of the present disclosure;

fig. 9 is a block diagram of another apparatus for determining a pattern density of an oil reservoir according to an embodiment of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, the following detailed description of the embodiments of the present application will be made with reference to the accompanying drawings.

The embodiment of the application provides a method for determining the well pattern density of an oil reservoir, and the method can be applied to an upper computer. Referring to fig. 1, the method may include:

step 101, a revenue amount function is determined.

The revenue function may be used to reflect the trade-off value of the oil deposit's crude oil sales revenue versus well pattern density over the production interval. Wherein the production period may be a period from the beginning of production from the reservoir to the end of production.

Step 102, determining a payout amount function.

The pay function may be used to reflect the relationship of the outage value of the oil recovery pay of the reservoir to the well pattern density over the recovery period. The production expenditure of crude oil may include, among others: capital investment, operating cost and comprehensive tax. For example, the production expenditures for crude oil may include: capital investment, operating costs, and comprehensive taxes.

And 103, determining the target well pattern density based on the income amount function and the expenditure amount function.

After the income amount function and the expenditure amount function are determined, the upper computer can determine the target well pattern density based on the income amount function and the expenditure amount function. A target well spacing may then be determined based on the target pattern density, and the reservoir may be produced based on the target well spacing. The well pattern density of the exploited oil reservoir is the target well pattern density, and the well spacing of the exploited oil reservoir is the target well spacing.

In summary, the embodiments of the present application provide a method for determining a well pattern density of an oil reservoir, in which an upper computer may determine a target well pattern density based on an income function and an expenditure function, the income function may reflect a relationship between a discount value of a sales income of crude oil and the well pattern density, and the income function may reflect a relationship between a discount value of an exploitation expenditure of crude oil and the well pattern density. In other words, the method provided by the embodiment of the application considers the time value of capital in the process of determining the well pattern density, so that the accuracy of determining the well pattern density by the method provided by the embodiment of the application is higher compared with the well pattern density determined by the related art.

The method for determining the well pattern density can be applied to a primary oil extraction scene, a secondary oil extraction scene or an oil extraction scene in a two-three combined development mode. The two-three combined development mode can refer to: in the high water content development stage of an oil reservoir, the layer system well network of secondary development and tertiary oil recovery is integrally optimized and deployed, fine water injection development is performed in the early stage (namely, a first oil displacement mode is adopted for exploitation), the water drive recovery rate is improved, tertiary oil recovery is switched to in the selected time (namely, a second oil displacement mode is adopted for exploitation), the synergistic fusion effect of the advantages of the integrity of the secondary development well network and the technical advantages of the tertiary oil recovery for improving the oil displacement efficiency is exerted, meanwhile, benefit evaluation and project management of the whole life cycle are implemented, and the optimized development mode of the development level and the overall benefit of the oil field is realized. That is, the two-three combined development mode may be a development mode in which, after the oil reservoir enters the high water content development stage, an injection-production well pattern (hereinafter, referred to as a well pattern) of the oil field is completed, and then the oil reservoir is developed by sequentially adopting the first oil displacement mode and the second oil displacement mode to improve the recovery ratio of the oil reservoir.

The first oil displacement mode is different from the second oil displacement mode, for example, the first oil displacement mode is water displacement (abbreviated as water flooding), and the second oil displacement mode is chemical displacement (abbreviated as chemical flooding).

The method for determining the well pattern density of the oil reservoir is exemplarily described by taking the method as an example for application to an oil extraction scene in a two-three combined development mode, wherein the first oil displacement mode is water displacement and the second oil displacement mode is chemical displacement. Referring to fig. 2, the method may include:

step 201, determining a first relational expression.

The first relationship may be used to reflect a discount value of a first crude oil sales revenue of the reservoir versus a target well pattern density over the production time period. The production period may refer to the period from the beginning of production from the reservoir (from the construction of the pattern) until the end of the evaluation period (which may also be referred to as the economic evaluation period) of the reservoir. The economic evaluation period is typically 15 years.

In this embodiment of the application, referring to fig. 3, the process of determining the first relation by the upper computer may include:

step 2011 determines the yield function.

The production function may be used to reflect a target annual production of crude oil versus well pattern density for the first drive mode (water flooding in this example).

The target annual yield of the crude oil obtained by adopting the first oil displacement mode can be as follows: and under the two-three combined development mode, after the well pattern of the oil field where the oil reservoir is located is completed based on the target well pattern density, the annual output of the first year of water-drive oil production. The well pattern of the oil field where the oil reservoir is located can be completed before secondary development.

In the embodiment of the application, the upper computer can acquire the relationship between the newly increased recoverable reserve and the well pattern density in the two-three combined development mode and the relationship between the newly increased recoverable reserve and the initial annual output in the two-three combined development mode. The upper computer may then determine the production function based on a relationship between the newly added recoverable reserve and the pattern density, and a relationship between the newly added recoverable reserve and the initial annual production.

In the process of oil reservoir exploitation by adopting the two-three combined exploitation mode, water-drive oil exploitation is usually performed first, then chemical-drive oil exploitation is performed, and the water-drive oil exploitation time is about 1 to 2 years, so that the initial annual yield of the crude oil obtained at the initial exploitation stage in the two-three combined exploitation mode is the target annual yield of the crude oil obtained by water drive in the two-three combined exploitation mode. That is, the target annual yield is equal to the initial annual yield.

Optionally, the upper computer may respond to input operations of a worker to obtain a relationship between the newly increased recoverable reserves and the well pattern density in the two-three combined development mode and a relationship between the newly increased recoverable reserves and the initial annual output in the two-three combined development mode.

The relation between the newly-increased recoverable reserve and the well pattern density can be determined based on the relation between the final recovery ratio of oil reservoir water-drive oil recovery and the well pattern density.

In the embodiment of the application, the relationship between the ultimate recovery rate of reservoir water-flooding oil recovery and the well pattern density can satisfy the following formula (1).

In the formula (1), E_RFor ultimate recovery of oil deposits, E_dIn order to adopt the oil displacement efficiency of the first oil displacement mode for mining, K is the effective permeability of an oil layer of an oil deposit, M is the initial injection-production well ratio, a is the well pattern index of an oil field where the oil deposit is located, phi is the porosity of the oil layer, and S_oIs the saturation of the crude oil, h is the effective thickness of the oil reservoir, and S is the well pattern density.

The newly increased recoverable reserve in the two-three combined development mode is equal to the sum of the first newly increased recoverable reserve of the water-drive oil recovery and the second newly increased recoverable reserve of the chemical-drive oil recovery after the oil recovery is started in the two-three combined development mode. And the first newly-increased recovery reserve is the product of the geological reserve of the oil reservoir and the water flooding enhanced recovery ratio which is the difference between the final recovery ratio of the water flooding of the oil reservoir and the recovery degree of the crude oil before the development by adopting the two-three combined development mode (namely under the initial well pattern density). The second newly increased production reserve is the product of the geological reserve of the reservoir and the enhanced recovery from chemical flooding. Wherein the initial pattern density is less than the target pattern density.

Based on the relationship between the newly increased recoverable reserve and the well pattern density in the two-three combined development mode, the following formula (2) can be satisfied.

In the formula (2), Δ N_pFor newly-increased recoverable reserves, N is the geological reserve of the reservoir, Δ E_RIn order to achieve the enhancement of the recovery factor,

well pattern parameter, R, for injection and production of the field in which the reservoir is located_pEnhanced recovery for the chemical flooding, i.e., enhanced recovery of crude oil produced by a second flooding mode (i.e., chemical flooding) within the target production interval, R_TIs the extent of crude oil production at the initial pattern density. Wherein, the target mining period may refer to: the period from the beginning of exploiting the oil reservoir by adopting the two-three combined exploitation mode to the end of exploiting the oil reservoir. I.e. the production interval includes the target production interval.

In the later period of the production in the two-three combined development mode, the annual oil production of the water-drive oil production is gradually reduced year by year, namely the annual oil production is reduced along with the increase of the production time, for example, the annual oil production can be exponentially reduced along with the increase of the production time. For example, in the later stages of reservoir production, the annual rate of oil production in water-flooding is D_cThen, the relationship between the newly added recoverable reserve and the initial annual output (i.e., the target annual output) in the two-three combined development mode may satisfy the following formula (3).

Formula (3) is₀For initial annual production, T is the production period for the reservoir.

And obtaining the relationship between the newly increased recoverable reserves and the well pattern density in the two-three combined development mode, namely the formula (2), and obtaining the relationship between the newly increased recoverable reserves and the initial annual output in the two-three combined development mode, namely the formula (3). And (4) determining a yield function for reflecting the target annual yield and the well pattern density of the crude oil obtained by water flooding oil extraction by the upper computer based on the formula (2) and the formula (3). The yield function determined by the upper computer can be shown in the following formula (4).

Step 2012, determining a first relational expression based on the production function, the unit price of the crude oil, the commodity rate of the crude oil and the benchmark yield.

The upper computer can also obtain the unit price of crude oil, the commodity rate of crude oil and the benchmark yield, and after the yield function is determined, the upper computer can determine the first relational expression based on the yield function, the unit price of crude oil, the commodity rate of crude oil and the benchmark yield.

Wherein the first relationship may be used to reflect a relationship between a reduced value of sales revenue of the first crude oil from the reservoir over a production period and the target well pattern density. The first oil sales revenue is determined based on the crude oil produced using the first drive mode (i.e., water flooding).

Optionally, the upper computer may respond to an operation in which the worker inputs the unit price of the crude oil, the commodity rate of the crude oil, and the benchmark yield, and acquire the unit price of the crude oil, the commodity rate of the crude oil, and the benchmark yield.

In the embodiment of the application, the upper computer determines an initial relational expression reflecting the relation between the reduced value of the first crude oil sales income of the oil reservoir and the target well pattern density in the production period based on the production function, the crude oil unit price, the crude oil commodity rate and the benchmark profitability, and the initial relational expression can be shown as the following formula (5).

In the formula (5), V₁Sales and harvest of first crude oil in production periodThe fold-off value, P is the unit price of crude oil, tau is the commodity rate of crude oil, q_tI is the base profitability for the oil production in the t year of the production period. Wherein t is a positive integer.

Optionally, the upper computer simplifies the initial relation to obtain a first relation shown in formula (6). Because the first relational expression is a simplified relational expression, the target well pattern density is determined by adopting the first relational expression, the calculation complexity of an upper computer can be effectively reduced, and the efficiency of determining the target well pattern density can be improved.

Step 202, determining a reduced value of sales revenue of the second crude oil from the reservoir during a target production interval included in the production interval.

Before the upper computer determines the target well pattern density, the second crude oil sales income discount value of the oil deposit in the target exploitation time period can be determined. Wherein the second oil sales revenue may be determined based on the crude oil obtained using the second drive mode (i.e., chemical flooding).

In an embodiment of the present application, referring to fig. 4, the process of determining, by the upper computer, the discount value of the second crude oil sales income of the reservoir in the target mining period may include:

2021, determining a ratio function of the annual enhanced oil recovery ratio to the time period within the target production time period.

The upper computer can obtain the annual oil increment of the chemical flooding oil recovery of the historical oil deposit and the geological reserve of the historical oil deposit, and the historical oil deposit is an exploited oil deposit. Then, for each annual oil increment in the annual oil increment, the upper computer can determine the quotient of the annual oil increment and the geological reserve as the annual enhanced oil recovery ratio to obtain the annual enhanced oil recovery ratio. The upper computer may then fit the plurality of annual enhanced oil recovery rates to obtain a ratio function of annual enhanced oil recovery rate to time within the target production interval. The ratio function may satisfy the following formula (7).

In the formula (7), T_AThe length of time it takes to complete the well pattern may also be referred to as the well pattern completion period. T is a unit of_BThe length of time it takes to recover oil in the first drive mode (i.e., water flooding) after the well pattern is completed and before recovery in the second drive mode (i.e., chemical flooding) may also be referred to as a pre-water flooding period. μ is the average of the multiple annual enhanced recovery ratios of the historical reservoir and σ is the standard deviation of the multiple annual enhanced recovery ratios of the historical reservoir. As can be seen from equation (7), the chemical flooding oil recovery can satisfy the skewed distribution between the annual enhanced oil recovery ratio and the time period.

For example, fig. 5 shows raw data for an annual enhanced oil recovery ratio and a schematic of a fitted curve fitted based on the raw data. As can be seen from fig. 5, the fitted-in annual enhanced recovery ratio can satisfy the skewed distribution as the production time increases.

2022, determining the discount value of the sales income of the second crude oil of the oil reservoir based on the unit price of the crude oil, the commodity rate of the crude oil, the geological reserve, the enhanced recovery ratio of the crude oil obtained by the second oil displacement mode in the target mining period, the ratio function and the benchmark profitability.

After the upper computer determines the ratio function, the reduced value of the second crude oil sales income of the oil reservoir can be determined based on the unit price of the crude oil, the commodity rate of the crude oil, the geological reserve, the enhanced recovery ratio of the crude oil obtained by the second oil displacement mode in the target mining period, the ratio function and the benchmark profitability.

Wherein the discount value V of the sales income of the second crude oil₂The following formula (8) can be satisfied.

Step 203, determining a revenue amount function based on the first relational expression and the discount value of the sales revenue of the second crude oil.

After determining the first relational expression and the discount value of the second crude oil sales income, the upper computer can add the first relational expression and the discount value of the second crude oil sales income to obtain an income amount function. Wherein the revenue function may be used to reflect a relationship between a discount value of crude oil sales revenue of the reservoir and well pattern density over the production time period. The revenue amount function may satisfy the following formula (9).

V₀₁＝V₁+V₂Formula (9)

In the formula (9), V₀₁The reduced value of the sales income of the crude oil in the mining period.

And step 204, acquiring a second relational expression.

The staff can input the second relational expression, correspondingly, the upper computer can respond to the operation that the staff input the second relational expression, and the second relational expression is obtained. The second relational expression can be used for reflecting the relation between the discount value of the capital construction investment of the oil reservoir and the well pattern density in the mining period. This second relational expression can be expressed as the following expression (10).

In the formula (10), V₃And (3) taking the conversion value of the capital construction investment, wherein L is the single well capital construction investment, A is the oil-containing area of the oil reservoir, S is the target well pattern density, and n is the initial well number (namely the well number before encryption). The initial well number is less than the well number corresponding to the target well pattern density.

Optionally, after the upper computer obtains the second relational expression, the second relational expression may be simplified. Therefore, the calculation complexity of the follow-up upper computer for determining the density of the target well pattern can be reduced, and the efficiency of determining the density of the target well pattern can be improved.

The simplified second relational expression may be as shown in formula (11).

Step 205, obtain the third relation.

The staff can input the third relational expression, and correspondingly, the upper computer can respond to the operation of inputting the third relational expression by the staff to acquire the third relational expression. Wherein the third relational expression can be used for reflecting the relation between the reduced value of the operation cost of the oil deposit and the target well pattern density in the mining period. This third relational expression can be expressed as the following formula (12).

In the formula (12), V₄And W is the reduction value of the operation cost of the oil reservoir, and W is the ton oil operation cost.

Optionally, after the upper computer obtains the third relational expression, the third relational expression may be simplified. Therefore, the calculation complexity of determining the target well pattern density by the follow-up upper computer can be reduced, and the efficiency of determining the target well pattern density can be improved.

The simplified second relational expression may be as shown in formula (13).

And step 206, acquiring a fourth relational expression.

The staff can input the fourth relational expression, and correspondingly, the upper computer can respond to the operation of the staff for inputting the fourth relational expression and obtain the fourth relational expression. The fourth relational expression can be used for reflecting the relation between the comprehensive tax of the oil deposit and the reduced value of the reserve usage fee and the target well pattern density in the mining period. The fourth relational expression V₅May be as shown in the following equation (14).

Formula (II)(14) In, V₅For the reduced value of the combined tax and reserve usage charge, Y is the value-added tax rate, L₁To become tax rate, L₂Tax rates are added for education and education, and Z is the reserve usage charge.

Optionally, after the upper computer obtains the fourth relational expression, the fourth relational expression may be simplified. Therefore, the calculation complexity of determining the target well pattern density by the follow-up upper computer can be reduced, and the efficiency of determining the target well pattern density can be improved.

The simplified second relational expression may be as shown in equation (15).

And step 207, obtaining the reduced value of the chemical flooding cost.

The upper computer can obtain the reduced value V of the chemical flooding chemical cost₆The following formula (16) can be satisfied.

In the formula (16), X represents the ton oil cost of the medicament, V_ptThe injection rate of the drug in the T year, T_cThe length of time for injecting the chemical agent.

Step 208, determining a function of the payout amount based on the second relational expression, the third relational expression, the fourth relational expression and the reduced value of the medicine fee.

After determining the second relational expression, the third relational expression, the fourth relational expression and the discount value of the medicine fee, the upper computer adds the second relational expression, the third relational expression, the fourth relational expression and the discount value of the medicine fee to obtain a payment amount function. Based on this, it may be determined that the payoff function may be used to reflect the contribution to the oil recovery payoff of the reservoir over the recovery period versus the well pattern density. The oil recovery expenditures may include capital investments, operating costs, comprehensive taxes, and drug charges as described above.

The deduction function is determined based on the discount value of the cost of the chemicals, namely the economic benefit brought by tertiary oil recovery in the two-three combined development mode is fully considered by the method provided by the embodiment of the application, so that the accuracy of the well pattern density determined by the method provided by the embodiment of the application is higher in the two-three combined development mode.

In the embodiment of the present application, the upper computer may determine the amount function based on the simplified second relational expression, that is, the formula (11), the simplified third relational expression, that is, the formula (13), the simplified fourth relational expression, the formula (15), and the reduced value of the cost of medicine. The determined payout amount function may satisfy the following equation (17).

V₀₂＝V₃+V₄+V₅+V₆Formula (17)

In the formula (17), V₀₂The reduced value of the oil exploitation expenditure of the oil reservoir.

Step 209 determines a target pattern density based on the revenue amount function and the expenditure amount function.

In an embodiment of the present application, after the upper computer determines the income amount function and the expenditure amount function, an objective function may be determined, and a target pattern density may be determined based on the objective function.

The objective function may be a function obtained by subtracting the income amount function and the expenditure amount function. The subtraction of the income amount function and the expenditure amount function may refer to: the expression to the left of the equal sign of the income amount function is subtracted from the expression to the left of the equal sign of the expenditure amount function, and the expression to the right of the equal sign of the income amount function is subtracted from the expression to the right of the equal sign of the expenditure amount function.

For example, if the income amount function determined by the upper computer is the above formula (9) and the expenditure amount function is the above formula (17), the upper computer may determine the objective function based on the income amount function and the expenditure amount function as shown in the formula (18).

V＝V₁+V₂-V₃-V₄-V₅-V₆Formula (18)

In an embodiment of the present application, the target pattern density may include: a target economic limit pattern density and a target economic reasonable pattern density. The target economic limit pattern density may refer to: the density of the well pattern when the oil field is not lost or profitable is the target density of the well pattern when the discount value of the crude oil sales income of the oil deposit is equal to the discount value of the crude oil exploitation expenditure of the oil deposit. The target economically reasonable pattern density may refer to: the target pattern density at which the oil field profitability is highest.

Based on this, for the target economic ultimate well pattern density, the upper computer may determine the target well pattern density when the profit is zero in the target function (i.e., the above equation 18), that is, the target well pattern density when the discount value of the crude oil sales income of the oil reservoir of the income amount function is equal to the discount value of the crude oil production expenditure of the oil reservoir of the expenditure amount function, and determine the target well pattern density as the target economic ultimate well pattern density.

For a target economically reasonable well pattern density, the upper computer first determines a derivative function of the objective function with respect to the well pattern density. The derivative function may be as shown in equation (19). And then, the upper computer can determine the target well pattern density when the derivative function is zero, and determine the target well pattern density as the target reasonable well pattern density.

In the formula (19), the first and second groups,

in this application embodiment, the host computer can determine the target well spacing based on the well pattern density after determining the well pattern density. The reservoir may then be mined based on the target well spacing. The well pattern density of the mined oil reservoir is the target well pattern density, and the well spacing is the target well spacing.

For example, in a two-three combined development mode, the upper computer is assumedThe parameters of the reservoir obtained are shown in table 1. As can be seen from Table 1, the geological reserve N of this reservoir is 1470X 10⁴Ton (t), oil-containing area A of 11.62 square kilometers (Km)²) The effective permeability K is 1269.2X 10^-3Micron square (mum)²) The effective thickness h of the oil layer is 7.9 meters (m), the operation cost W per ton of oil is 630 yuan per ton, the unit price P of crude oil is 2205 yuan per ton, and the well pattern perfection period T is_A2 years, leading water flooding period T_BFor 1 year.

TABLE 1

The upper computer brings the parameters shown in table 1 to the right of the equal sign of the above formula (18), and makes the left of the equal sign 0, so as to determine the target economic limit well pattern density, as shown in fig. 6, which is 308 ports per square kilometer (ports/Km)²). Based on this, the target economic limit well spacing may be determined to be 57m.

Wherein y1 in fig. 6 satisfies:

the C is₃Satisfies the following conditions:

y2 satisfies: y is₂＝C₂×(A×S-n)。

The upper computer substitutes the parameters shown in the table 1 into the right side of the equal sign of the formula (19) and makes the left side of the equal sign be 0, so that the target economic reasonable well pattern density can be determined, as shown in fig. 7, the target economic limit well pattern density is 44 ports/Km². Based on this, a target economically reasonable well spacing of 150.8m can be determined.

Wherein y3 in fig. 7 satisfies:

y4 satisfies: y is₄＝C₂×A×S²。

Optionally, the sequence of the steps of the method for determining the well pattern density of the oil reservoir provided by the embodiment of the application may be appropriately adjusted, and the steps may be correspondingly increased or decreased according to the situation. For example, steps 201 to 203 may be performed after steps 204 to 208, or may be performed simultaneously with steps 204 to 208. Step 207 can be deleted as appropriate, for example, the method provided by the present application is applied to a primary oil recovery scenario or a secondary oil recovery scenario, and steps 204 to 206 can also be deleted as appropriate, for example, the second relational expression, the third relational expression, and the fourth relational expression are stored in the upper computer in advance. Those skilled in the art can easily conceive of various methods within the technical scope of the present disclosure, and therefore, the detailed description is omitted.

In the foregoing embodiment, the second relational expression, the third relational expression and the fourth relational expression are described by taking an example of inputting the input result of the worker into an upper computer, and in actual implementation, the second relational expression, the third relational expression and the fourth relational expression may be obtained in other manners, for example, determined by the upper computer according to a preset rule, or obtained by fitting preset parameters, which is not limited in the embodiment of the present application.

In summary, the embodiment of the present application provides a method for determining a well pattern density of an oil reservoir, in which an upper computer may determine a target well pattern density based on an income value function and an expense value function, the income value function may reflect a relationship between a discount value of crude oil sales income and the well pattern density, and the income value function may reflect a relationship between a discount value of crude oil production expense and the well pattern density. In other words, the method provided by the embodiment of the application considers the time value of capital in the process of determining the well pattern density, so that the accuracy of determining the well pattern density by the method provided by the embodiment of the application is higher compared with the well pattern density determined by the related art.

The embodiment of the application provides a device for determining the well pattern density of an oil reservoir, and the device can be arranged in an upper computer. Referring to fig. 8, the apparatus may include:

a first determining module 301 for determining a revenue amount function reflecting a relationship between a reduction value of a sales revenue of the crude oil from the reservoir and a well pattern density over the production period.

A second determining module 302 for determining a cost function reflecting a relationship between a turnover value of a crude oil extraction cost of the reservoir during the extracted time period and a well pattern density.

A third determining module 303, configured to determine a target well pattern density based on the income amount function and the expenditure amount function.

Optionally, the first determining module 301 may be configured to:

determining a first relational expression which is used for reflecting the relation between the discount value of the first crude oil sales income of the oil deposit and the target well pattern density in the production period; determining a discount value of second crude oil sales income of the oil reservoir in a target exploitation period included in the exploitation period; determining a revenue amount function based on the first relationship and the discount value of the second crude oil sales revenue;

Optionally, the first determining module 301 may be configured to:

determining a yield function, wherein the yield function is used for reflecting the relation between the target annual yield of the crude oil obtained by adopting a first oil displacement mode and the well pattern density, and the yield function q (S) meets the following conditions:

determining a first relational expression based on the yield function, the unit price of the crude oil, the commodity rate of the crude oil and the benchmark yield, wherein the first relational expression satisfies the following conditions:

wherein N is the geological reserve of the reservoir, D_cAn annual rate of oil production of crude oil by the first drive mode, E_dThe oil displacement efficiency of the first oil displacement mode, K is the effective permeability of an oil layer of an oil reservoir, M is the initial injection-production well ratio, a is the well pattern index, phi is the porosity, S_oIs the saturation of the crude oil, h is the effective thickness of the oil reservoir, S is the well pattern density, R_TThe initial well pattern density is less than the target well pattern density, T is the end time of the production in the production period, V₁The first base oil sales revenue is discounted, P is base oil unit price, τ is base oil commodity rate, and i is base profitability.

Optionally, the first determining module 301 may be configured to:

determining a ratio function of annual enhanced recovery ratio to time interval within the target production interval, the ratio function f (t) satisfying:

determining the discount value of the sales income of the second crude oil of the oil deposit and the discount value V of the sales income of the second crude oil based on the unit price, the commodity rate, the geological reserve and the enhanced recovery rate, the ratio function and the benchmark profitability of the crude oil obtained by the second oil displacement mode in the target mining period₂Satisfies the following conditions:

wherein, T_ADuration, T, used to perfect the pattern_BIn order to ensure that the time used for the exploitation in the first oil displacement mode is long after the well pattern is completed and before the exploitation in the second oil displacement mode is adopted, mu is the average of the annual enhanced recovery ratio of the historical oil reservoir,sigma is the standard deviation of the annual enhanced oil recovery ratio of the historical oil reservoir, P is the unit price of crude oil, tau is the commodity rate of crude oil, N is the geological reserve, R_pIn order to improve the recovery efficiency, the improved recovery efficiency is the ratio of the total amount of crude oil obtained in the target exploitation time interval by adopting a second oil displacement mode to the geological reserve, the annual improved recovery efficiency is the annual improved recovery efficiency in the target exploitation time interval, tau is the commodity rate of the crude oil, f (t) is a ratio function, and i is the benchmark yield.

Optionally, the second determining module 302 may be configured to:

acquiring a second relational expression, wherein the second relational expression is used for reflecting the relation between the reduced value of the capital construction investment of the oil reservoir and the target well pattern density in the mining period, and the second relational expression meets the following requirements:

acquiring a third relation, wherein the third relation is used for reflecting the relation between the breakdown value of the operation cost of the oil reservoir in the mining period and the target well pattern density, and the third relation meets the following requirements:

acquiring a fourth relational expression, wherein the fourth relational expression is used for reflecting the relation between the comprehensive tax of the oil deposit and the conversion value of the reserve usage charge and the target well pattern density in the mining period, and the fourth relational expression meets the following requirements:

determining a payout amount function based on the second relational expression, the third relational expression and the fourth relational expression;

wherein, V₃The method is characterized in that the method is a conversion value of capital construction investment, L is single-well capital construction investment, A is the oil-containing area of an oil reservoir, S is target well pattern density, n is initial well number, the initial well number is smaller than the well number corresponding to the target well pattern density, and i is reference incomeRate, V₄For the reduced value of the operation cost, W is the ton oil operation cost, q (S) is a yield function for reflecting the relation between the target annual yield of the crude oil obtained by adopting the first oil displacement mode and the well pattern density, D_cThe annual rate of oil production of crude oil obtained by adopting a first oil displacement mode, N is geological reserve, R_pIn order to improve the recovery ratio, the improved recovery ratio is the ratio of the total amount of crude oil obtained in a target exploitation time interval by adopting a second oil displacement mode to the geological reserve, f (t) is a ratio function of annual improved recovery ratio and time interval in the target exploitation time interval, i is a reference yield, P is the unit price of the crude oil, Y is an incremental tax rate, and L is₁To become the build tax rate, L₂Adding tax rate for education and education, Z is reserve usage charge, tau is the rate of said crude oil commodity, T_ADuration, T, used to perfect the pattern_BThe method is characterized in that after a well network is completed and before the well network is exploited by adopting a second oil displacement mode, the exploitation time period comprises a target exploitation time period, the annual enhanced oil recovery ratio is the annual enhanced oil recovery ratio in the target exploitation time period, and the first oil displacement mode is different from the second oil displacement mode.

Optionally, the second oil displacement manner is chemical oil displacement, and the second determining module 302 may be further configured to:

obtaining the conversion value of chemical oil displacement and V₆Satisfies the following conditions:

determining a function of the payout amount based on the second relational expression, the third relational expression, the fourth relational expression and the discount value of the medicine fee;

Optionally, the target pattern density is a target economic limit pattern density. The third determining module 303 may be configured to:

Optionally, the target pattern density is a target economically reasonable pattern density. The third determining module 303 may be configured to:

determining a derivative function of an objective function, wherein the objective function is a function obtained by subtracting an income amount function from a spending amount function;

In summary, the present application provides an apparatus for determining a well pattern density of an oil reservoir, which may determine a target well pattern density based on an income function and an expenditure function, wherein the income function may reflect a relationship between a discount value of a sales income of crude oil and the well pattern density, and the income function may reflect a relationship between a discount value of a production expenditure of crude oil and the well pattern density. That is, the device takes into account the time value of the capital in determining the pattern density, and therefore the device determines the pattern density with a higher accuracy than the pattern density determined in the related art.

It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the apparatus and the modules described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

Fig. 9 is a block diagram of a device for determining a well pattern density of an oil reservoir according to an embodiment of the present disclosure, and referring to fig. 9, the device 400 may include: a processor 401, a memory 402 and a computer program stored on the memory 402 and operable on the processor 401, the processor 401 when executing the computer program may implement the method for determining a well pattern density of a reservoir as provided by the above method embodiments, for example, the method shown in fig. 1 or fig. 2.

Embodiments of the present application also provide a computer-readable storage medium having instructions stored therein, which when run on a computer, cause the computer to perform a method for determining a well pattern density of a reservoir, such as the method shown in fig. 1 or fig. 2, as provided by the above method embodiments.

Embodiments of the present application also provide a computer program product comprising instructions, which when run on a computer, cause the computer to perform a method for determining a well pattern density of a reservoir, such as the method shown in fig. 1 or fig. 2, provided by the above method embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, and the program may be stored in a computer-readable storage medium, where the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk.

The above description is only exemplary of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements and the like that are made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of determining a pattern density of a reservoir, the method comprising:

determining a pay function for reflecting a relationship between a discount value of a crude oil exploitation pay of the oil reservoir and the well pattern density within the exploitation period;

determining a target pattern density based on the income amount function and the expenditure amount function;

the determining a revenue amount function includes:

determining a first relation reflecting a discount value of a first crude oil sales revenue of the reservoir over the production period versus the target well pattern density;

determining the revenue amount function based on the first relationship and the discount value of the second crude oil sales revenue;

the first oil displacement mode is different from the second oil displacement mode;

the determining a first relation comprises:

wherein N is the geological reserve of the reservoir, D_cAn annual rate of oil production of crude oil obtained by the first flooding pattern, E_dFor the oil displacement efficiency of the first oil displacement mode, K is the effective permeability of an oil layer of the oil reservoir, M is the initial injection-production well ratio, a is the well pattern index, phi is the porosity, and S_oIs the saturation of the crude oil, h is the effective thickness of the reservoir, S is the well pattern density, R_TIs the production degree of crude oil under the initial well pattern density, the initial well pattern density is less than the target well pattern density, T is the production ending time of the production period, V₁The discount value of the sales income of the first crude oil, P is the unit price of the crude oil, tau is the commodity rate of the crude oil, and i is the benchmark yield;

the determining a discount value of sales revenue of the second crude oil for the reservoir over a target production period included in the production period comprises:

wherein, T_ADuration, T, used to perfect the pattern_BAfter the well pattern is completed and before the second oil displacement mode is adopted for exploitation, the duration of exploitation of the first oil displacement mode is adopted, mu is the average number of the annual enhanced recovery ratios of the historical oil deposit, sigma is the standard deviation of the annual enhanced recovery ratios of the historical oil deposit, P is the unit price of the crude oil, tau is the commodity rate of the crude oil, N is the geological reserve, R is the unit price of the crude oil, and_pfor the enhanced oil recovery, the enhanced oil recovery is a ratio of a total amount of the crude oil obtained in the target production period by using the second oil displacement mode to the geological reserve, the annual enhanced oil recovery ratio is an annual enhanced oil recovery in the target production period, τ is the rate of commodity of the crude oil, f (t) is the ratio function, and i is the benchmark yield.

2. The method of claim 1, wherein determining the payout function comprises:

wherein, V₃For the reduced value of the capital construction investment, L is the single well capital construction investment, A is the oil-containing area of the oil reservoir, S is the target well pattern density, n is the initial well number, the initial well number is less than the well number corresponding to the target well pattern density, i is the reference yield, V₄For the reduced value of the operating cost, W is the ton oil operating cost, q (S) is a yield function reflecting the relation between the target annual yield of the crude oil obtained by adopting the first oil displacement mode and the well pattern density, D_cThe annual rate of reduction of the oil yield of the crude oil obtained by the first oil displacement mode is adopted, N is the geological reserve, R is_pFor the enhanced oil recovery, the enhanced oil recovery is the ratio of the total amount of crude oil obtained in a target exploitation period by adopting the second oil displacement mode to the geological reserve, f (t) is a ratio function of annual enhanced oil recovery ratio to the period in the target exploitation period, i is the benchmark yield, P is the unit price of the crude oil, Y is the value-added tax rate, and L is₁To become tax rate, L₂Adding tax rate for education and education, Z is reserve usage charge, tau is the rate of said crude oil commodity, T_AFor the moment of well pattern completion, T_BAnd the time when the exploitation is completed by adopting the first oil displacement mode comprises the target exploitation time interval, the annual enhanced oil recovery ratio is the annual enhanced oil recovery ratio in the target exploitation time interval, and the first oil displacement mode is different from the second oil displacement mode.

3. The method of claim 2, wherein the second flooding regime is chemical flooding; the determining a payout amount function further comprises:

4. The method of any of claims 1 to 3, wherein the target pattern density is a target economic limit pattern density; determining a target pattern density based on the revenue amount function and the expenditure amount function, comprising:

5. The method of claim 1, wherein the target pattern density is a target economically reasonable pattern density; determining a target pattern density based on the revenue amount function and the expenditure amount function, comprising:

6. An apparatus for determining a pattern density of a reservoir, the apparatus comprising:

a first determining module for determining an income amount function for reflecting a relation between a discount value of crude oil sales income of the oil reservoir and well pattern density in a production period;

the second determination module is used for determining a payout function which is used for reflecting the relation between the discount value of the crude oil exploitation payout of the oil reservoir and the well pattern density in the exploitation time interval;

a third determination module for determining a target pattern density based on the income amount function and the expenditure amount function;

the first determination module is to:

the determining a first relation comprises:

wherein N is the geological reserve of the reservoir, D_cAn annual rate of oil production of crude oil obtained by the first drive mode, E_dFor the oil displacement efficiency of the first oil displacement mode, K is the effective permeability of an oil layer of the oil reservoir, M is the initial injection-production well ratio, a is the well pattern index, phi is the porosity, S_oIs the saturation of the crude oil, h is the effective thickness of the reservoir, S is the well pattern density, R_TThe crude oil production degree under the initial well pattern density is set, the initial well pattern density is smaller than the target well pattern density, T is the production end time of the production period, V₁Is the reduction value of the sales income of the first crude oil, P is the unit price of the crude oil, tau is the commodity rate of the crude oil, i is the benchmark incomeThe benefit rate;