Horizontal well deployment economic limit parameter quantitative characterization method

Abstract

The invention provides a horizontal well deployment economic limit parameter quantitative characterization method, which belongs to the field of oil and gas field development engineering, and comprises the following steps: simulating an oil reservoir numerical model to obtain the relationship between the oil layer thickness, the oil saturation or the horizontal well length and the numerical simulation cumulative oil production; establishing a horizontal well yield index, simulating a relation curve of cumulative oil production and the yield index according to a numerical value, and establishing an equation; establishing an equation according to a relation curve between the economic limit cumulative oil production and the oil layer thickness, the oil saturation or the horizontal well length; the economic limit cumulative oil production is used as a fitting target, a target function is established, and horizontal well deployment parameters under the economic limit are obtained. According to the method, on the basis of numerical simulation results of the oil layer thickness, the oil saturation or the horizontal well length, an equation set is established according to the relation between the oil layer thickness, the oil saturation and the horizontal section length and the economic limit cumulative oil production, and accurate calculation of well spacing parameters is achieved.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field development engineering, and in particular relates to a method for quantitatively characterizing economic limit parameters of horizontal well deployment. Background Art

[0002] Horizontal wells are an important means of developing complex reservoirs such as carbonate fracture reservoirs, reservoirs with gas caps or bottom water, thin-layer reservoirs, and low-permeability reservoirs. This method can effectively increase the leakage area of ​​oil and gas layers and increase the production and recovery rate of low-energy oil and gas reservoirs. The layout conditions of horizontal wells are related to the controlled reserves, and their development effect is limited by factors such as the effective thickness of the oil layer in the well layout area, the oil saturation, and the length of the horizontal section. Therefore, determining the lower limit of the oil layer thickness, the lower limit of the oil saturation, and the length of the horizontal well under the economic limit before deploying the horizontal well can achieve economical and efficient development.

[0003] The existing method mainly uses reservoir numerical simulation. When two of the above three parameters (oil layer thickness, oil saturation and horizontal well length) are determined, the third parameter is listed by enumeration to simulate the production of horizontal wells. After the development indicators under the discrete data conditions of different oil layer thickness, different horizontal section length and different oil saturation are obtained through reservoir numerical simulation calculation, the relationship between the three parameters and the cumulative production is established.

[0004] For example, Yin Xiangrong used numerical simulation methods to predict the recoverable reserves and horizontal well production of different horizontal sections in the article "Optimization of Well Parameters of Horizontal Wells in Low Permeability Oil Fields". By comparing the effective limits of recoverable reserves and horizontal well production, the length of the horizontal section reached the corresponding limit, and the length limit of the horizontal section was obtained by conversion method; Cui Chuanzhi established the equation between the initial production capacity of the economic limit of a single well and the actual initial production capacity in the article "Study on the Economic and Technical Limits of Horizontal Wells in Staged Fracturing of Ultra-Low Permeability Reservoirs", and established a chart to obtain the effective thickness and permeability limits corresponding to the economic and effective development of the reservoir, that is, the economic and technical limits of the reservoir. These methods are combined with the economic limit cumulative oil production, and the horizontal well deployment parameters are roughly estimated by checking the chart, but they cannot accurately determine the economic limit horizontal section length, the lower limit of the effective thickness of the oil layer, and the lower limit of the oil saturation of the deployed horizontal well.

[0005] In actual mine development, the methods for determining parameters such as oil layer thickness, oil saturation and horizontal well length often have very limited precision and accuracy, resulting in unsatisfactory horizontal well development results. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for quantitatively characterizing the economic limit parameters of horizontal well deployment. The technical problem to be solved by the present invention is how to accurately determine the horizontal section length, the lower limit of the effective thickness of the oil layer and the lower limit of the oil saturation under the economic limit of deploying the horizontal well, so as to achieve economical and efficient development.

[0007] In order to solve the above technical problems, the present invention provides a method for quantitatively characterizing economic limit parameters of horizontal well deployment, comprising the following steps:

[0008] Step S1: simulating the reservoir numerical model to obtain the relationship between the reserve parameters and the cumulative oil production of the numerical simulation;

[0009] Step S2: Establishing the horizontal well production index using the reserve parameters, establishing a numerical simulation cumulative oil production and production index relationship curve based on the relationship between the reserve parameters and the numerical simulation cumulative oil production, and establishing an equation; establishing an equation based on the relationship curve between the economic limit cumulative oil production and the reserve parameters;

[0010] Step S3: Using the two equations and the production index in step S2, taking the economic limit cumulative oil production as the fitting target, establishing the objective function, and obtaining the horizontal well deployment parameters under the economic limit.

[0011] Furthermore, reserve parameters include oil layer thickness, oil saturation and horizontal well length.

[0012] Furthermore, in step S1, the numerical model of the reservoir is simulated, two parameters of the oil layer thickness, oil saturation and horizontal well length are fixed, and the remaining parameters are changed to simulate the cumulative oil production of the horizontal well, and the relationship between the oil layer thickness, oil saturation and horizontal well length and the numerically simulated cumulative oil production is obtained.

[0013] Furthermore, it is characterized in that, in the step S2, the calculation formula of the yield index is as follows:

[0014] Z=L×h×So (1)

[0015] In the formula,

[0016] Z------production index, m·m;

[0017] L------horizontal section length, m;

[0018] h------Oil layer thickness, m;

[0019] So----oil saturation, f.

[0020] f stands for decimal, which is a standard unit in the petroleum industry.

[0021] Furthermore, in step S2, according to the numerical simulation of the relationship curve between cumulative oil production and production index, the following equation is established:

[0022] Np1=1.5412e 0.0009Z (2)

[0023] Where, Np1 is the cumulative oil production in numerical simulation, 10 4 t.

[0024] Furthermore, in step S2, according to the relationship curve between the economic limit cumulative oil production and the horizontal well length, the following equation is established:

[0025] Np2=0.0012L+1.6365 (3)

[0026] Where, Np2 is the economic limit cumulative oil production, 10 4 t.

[0027] Furthermore, in step S3, the following objective function is established:

[0028]

[0029] Where N is the total number of samples, k is the sample number, and J is the objective function.

[0030] Furthermore, in step S3, the Marqudt algorithm is used to establish an objective function with the economic limit cumulative production as the fitting target, and the horizontal well deployment parameters under the precise economic limit are obtained by minimizing the objective function.

[0031] Furthermore, in step S2, according to the relationship between the oil layer thickness, oil saturation or horizontal well length and the numerically simulated cumulative oil production, a relationship curve between the numerically simulated cumulative oil production and the production index is established through Excel.

[0032] Furthermore, in step S2, the drilling cost and production management cost are taken into consideration, and under the condition of setting different variable parameters (oil layer thickness, oil saturation or horizontal section length), the corresponding horizontal well economic limit cumulative oil production parameters are queried, and a relationship curve between the economic limit cumulative oil production and the oil layer thickness, oil saturation or horizontal well length is established through Excel.

[0033] The actual local situation, drilling costs and production management costs are explained as follows: The economic limit cumulative oil production of a single well refers to the sales revenue of the economic limit cumulative oil production of a single well, which is used to make up for the investment, costs and various taxes required for the development of oil and gas fields, that is, the cumulative production of oil and gas wells when the net cash flow of a single well is zero. Therefore, it is necessary to consider the impact of factors such as oil prices, various taxes, drilling investment, surface investment, annual operating costs of a single well, time and discount rate.

[0034] The reservoir numerical model is based on the reservoir numerical simulation software used in oil field research. It is obtained by establishing reservoir numerical simulation according to actual reservoir geology, production parameters and conditions.

[0035] The present invention provides a method for quantitatively characterizing the economic limit parameters of horizontal well deployment. The method utilizes numerical simulation combined with the production equation of horizontal well layout reserve parameters (oil layer thickness, oil saturation, and horizontal section length) to achieve accurate quantitative characterization of oil layer thickness, oil saturation lower limit, and horizontal section length under the economic limit. Although the prior art is also based on the results of three-parameter numerical simulation, its determination process is to establish a plate to look up the value and make an approximate estimate. On the basis of the prior art, the present invention establishes a group of equations based on the relationship between the oil layer thickness, oil saturation, and horizontal section length and the cumulative oil production of numerical simulation, as well as the relationship between the oil layer thickness, oil saturation, and horizontal section length and the cumulative oil production of the economic limit, thereby achieving accurate calculation of the well layout parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 (a) is a 3D schematic diagram of the reservoir numerical model, where O-1 well is a horizontal well to be deployed. The marked gas zone represents the gas layer, the marked oil zone represents the oil layer, and the marked bottom water represents the water layer. Figure 1 (b) is a schematic diagram of the cross-section of the reservoir numerical model, in which O-1 well is a horizontal well to be deployed. The part marked with gas zone represents the gas layer, the part marked with oil zone represents the oil layer, and the part marked with bottom water represents the water layer;

[0037] Figure 2 The relationship diagram between the cumulative oil production and the production index Z of the numerical simulation of the quantitative characterization method of the economic limit parameters of horizontal well deployment in the present invention is shown in FIG. 1 , where R represents the variance, R represents the variance, and R represents the production index Z. 2 represents standard deviation, R>0.9 and R 2 When it is >0.81, it means the correlation is good;

[0038] Figure 3 This is a relationship diagram between the horizontal section length and the economic limit cumulative oil production of a method for quantitatively characterizing the economic limit parameters of horizontal well deployment in the present invention, where R represents the variance, R 2 represents standard deviation, R>0.9 and R 2 When >0.81, it means the correlation is good.

[0039] Figure 4 The present invention is a flowchart of a method for quantitatively characterizing economic limit parameters of horizontal well deployment. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In order to better understand the purpose, structure and function of the present invention, a quantitative characterization method for economic limit parameters of horizontal well deployment of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0045] Embodiment 1:

[0046] like Figure 4 As shown, a method for quantitatively characterizing economic limit parameters of horizontal well deployment according to the present invention comprises the following steps:

[0047] Step S1: simulating the reservoir numerical model to obtain the relationship between the oil layer thickness, oil saturation or horizontal well length and the numerical simulation cumulative oil production;

[0048] Step S2: using the oil layer thickness, oil saturation and horizontal well length, establishing a horizontal well production index, and establishing a set of equations based on the numerical simulation relationship curve between cumulative oil production and production index, and the relationship curve between economic limit cumulative oil production and oil layer thickness, oil saturation or horizontal well length;

[0049] Step S3: Using the equation group and production index in step S2, taking the economic limit cumulative oil production as the fitting target, establishing the objective function, and obtaining the horizontal well deployment parameters under the economic limit.

[0050] Embodiment 2:

[0051] like Figure 4 As shown, a method for quantitatively characterizing economic limit parameters of horizontal well deployment according to the present invention comprises the following steps:

[0052] Step S1: simulating the reservoir numerical model to obtain the relationship between the oil layer thickness, oil saturation or horizontal well length and the numerical simulation cumulative oil production;

[0053] Step S2: using the oil layer thickness, oil saturation and horizontal well length, establishing a horizontal well production index, and establishing a set of equations based on the numerical simulation relationship curve between cumulative oil production and production index, and the relationship curve between economic limit cumulative oil production and oil layer thickness, oil saturation or horizontal well length;

[0054] Step S3: Using the equation group and production index in step S2, taking the economic limit cumulative oil production as the fitting target, establishing the objective function, and obtaining the horizontal well deployment parameters under the economic limit.

[0055] The difference between this embodiment and the first embodiment is that:

[0056] In the step S1, the reservoir numerical model is simulated, two parameters among the oil layer thickness, oil saturation and horizontal well length are fixed, and the remaining parameters are changed to simulate the cumulative oil production of the horizontal well, and the relationship between the oil layer thickness, oil saturation and horizontal well length and the cumulative oil production calculated by numerical simulation is obtained;

[0057] In step S2, the calculation formula of the yield index is as follows:

[0058] Z=L×h×So (1)

[0059] In the formula,

[0060] Z------production index, m·m;

[0061] L------horizontal section length, m;

[0062] h------Oil layer thickness, m;

[0063] So----oil saturation, f.

[0064] f stands for decimal, which is a standard unit in the petroleum industry.

[0065] According to the numerical simulation of the relationship curve between cumulative oil production and production index, the equation is established as follows:

[0066] Np1=1.5412e 0.0009Z (2)

[0067] Where, Np1 is the cumulative oil production in numerical simulation, 10 4 t;

[0068] According to the relationship curve between economic limit cumulative oil production and horizontal well length, the equation is established as follows:

[0069] Np2=0.0012L+1.6365 (3)

[0070] Where:

[0071] Np2----Economic limit cumulative oil production, 10 4 t.

[0072] In step S3, the Marqudt algorithm is used to establish an objective function with the economic limit cumulative production as the fitting target, and the oil layer thickness is automatically adjusted. By minimizing the objective function, the oil layer thickness is solved and the horizontal well deployment parameters under the accurate economic limit are obtained;

[0073] The following objective function is established by equation (1), equation (2) and equation (3):

[0074]

[0075] Where N is the total number of samples, k is the sample number, and J is the objective function.

[0076] Since Np1(L,h,So) is a nonlinear function, the Marqudt algorithm is used to minimize the above objective function and solve the unknown parameters:

[0077]

[0078] J m is the minimum value of the objective function J.

[0079] The present invention provides a method for quantitatively characterizing the economic limit parameters of horizontal well deployment. The method utilizes numerical simulation combined with the production equation of three factors (oil layer thickness, oil saturation and horizontal section length) of horizontal well deployment to achieve accurate quantitative characterization of oil layer thickness, oil saturation lower limit and horizontal section length under the economic limit. Although the prior art is also based on the results of three-parameter numerical simulation, its determination process is an approximate estimate by establishing a plate to check the value. On the basis of the prior art, the present invention establishes a group of equations based on the relationship between the oil layer thickness, oil saturation and horizontal section length and the cumulative oil production calculated by numerical simulation, as well as the relationship between the economic limit cumulative oil production and the oil layer thickness, oil saturation and horizontal section length, thereby achieving accurate calculation of the well deployment parameters.

[0080] Embodiment 3:

[0081] This example takes a certain exploration area as the research object, collects and organizes the basic data of the reservoir, and establishes a reservoir numerical simulation, such as Figure 1 As shown;

[0082] Step S1: Determine that the original oil saturation of the oil layer in the area is 0.85, the length of the horizontal well is 1000m, and simulate the cumulative oil production of the horizontal well to the abandonment pressure (4Mpa at the bottom of the well) under the conditions of oil layer thickness (1m, 2m, 3m...) through the reservoir numerical model to obtain the relationship between different oil layer thicknesses and the numerically simulated cumulative oil production;

[0083] Step S2: Establish a yield index, the calculation formula of which is as follows:

[0084] Z=L×h×So (1)

[0085] In the formula: Z------production index, m·m; L------horizontal section length, m; h------oil layer thickness, m; So----oil saturation, f;

[0086] like Figure 2 As shown in the figure, after determining the oil saturation of the oil layer and the length of the horizontal section of the horizontal well, the cumulative oil production of the horizontal well before the abandonment pressure is simulated by enumerating different oil layer thicknesses, and the relationship between the numerical simulation cumulative oil production and the production index is established. The established equation is as follows:

[0087] Np1=1.5412e0.0009Z (2)

[0088] Where, Np1 is the cumulative oil production calculated by numerical simulation, 10 4 t;

[0089] like Figure 3 As shown in the figure, combined with the local actual situation, drilling cost and production management cost, the relationship between the horizontal well length (100m, 200m, 300m...) and the economic limit cumulative oil production is statistically analyzed, and the equation is established as follows:

[0090] Np2=0.0012L+1.6365(3)

[0091] Where, Np2 is the economic limit cumulative oil production, 10 4 t.

[0092] The actual local situation, drilling costs and production management costs are explained as follows: The economic limit cumulative oil production of a single well refers to the sales revenue of the economic limit cumulative oil production of a single well, which is used to make up for the investment, costs and various taxes required for the development of oil and gas fields, that is, the cumulative production of oil and gas wells when the net cash flow of a single well is zero. Therefore, it is necessary to consider the impact of factors such as oil prices, various taxes, drilling investment, surface investment, annual operating costs of a single well, time and discount rate.

[0093] Combining the above formula (1), equation (2) and equation (3) to form a system of equations;

[0094] Use the Marqudt algorithm to solve the above equations:

[0095] Based on the above equations, the following objective function is established:

[0096]

[0097] Where J is the objective function.

[0098] Taking the economic limit cumulative production as the fitting target, the oil layer thickness is automatically adjusted to minimize the objective function, thereby solving the oil layer thickness.

[0099]

[0100] J m is the minimum value of the objective function J.

[0101] Finally, when the horizontal section length L is 1000m, the original oil saturation So of the oil layer is 0.85, and the economic limit cumulative oil production of the 1000m horizontal well is 36314 tons, the calculated lower limit of the oil layer thickness is 3.31m.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A quantitative characterization method for economic limit parameters of horizontal well deployment, characterized in that: The following steps are involved: Step S1: simulating the reservoir numerical model to obtain the relationship between the reserve parameters and the cumulative oil production of the numerical simulation; Step S2: Establishing the horizontal well production index using the reserve parameters, establishing a numerical simulation cumulative oil production and production index relationship curve based on the relationship between the reserve parameters and the numerical simulation cumulative oil production, and establishing an equation; establishing an equation based on the relationship curve between the economic limit cumulative oil production and the reserve parameters; Step S3: Using the two equations and the production index in step S2, taking the economic limit cumulative oil production as the fitting target, establishing the objective function, and obtaining the horizontal well deployment parameters under the economic limit.

2. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 1 is characterized in that: Reserve parameters include oil layer thickness, oil saturation and horizontal well length.

3. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 2 is characterized in that: In step S1, the reservoir numerical model is simulated, two parameters among the oil layer thickness, oil saturation and horizontal well length are fixed, and the remaining parameters are changed to simulate the cumulative oil production of the horizontal well, and the relationship between the oil layer thickness, oil saturation and horizontal well length and the numerically simulated cumulative oil production is obtained.

4. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 3 is characterized in that: In step S2, the calculation formula of the yield index is as follows: Z=L×h×So (1) In the formula, Z------production index, m·m; L------horizontal section length, m; h------Oil layer thickness, m; So----oil saturation, f.

5. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 4 is characterized in that: In step S2, according to the numerical simulation of the relationship curve between cumulative oil production and production index, the following equation is established: Np1=1.5412e 0.0009Z (2) Where, Np1 is the cumulative oil production in numerical simulation, 10 4 t.

6. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 5, characterized in that: In step S2, according to the relationship curve between the economic limit cumulative oil production and the horizontal well length, the following equation is established: Np2=0.0012L+1.6365 (3) Where, Np2 is the economic limit cumulative oil production, 10 4 t.

7. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 6, characterized in that: In step S3, the following objective function is established: Where N is the total number of samples, k is the sample number, and J is the objective function.

8. The method for quantitatively characterizing the economic limit parameters of horizontal well deployment according to claim 1, characterized in that: In step S3, the Marqudt algorithm is used to establish an objective function with the economic limit cumulative production as the fitting target, and the accurate horizontal well deployment parameters under the economic limit are obtained by minimizing the objective function.

9. The method for quantitatively characterizing economic limit parameters of horizontal well deployment according to claim 1, characterized in that: In step S2, according to the relationship between the oil layer thickness, oil saturation or horizontal well length and the numerically simulated cumulative oil production, a relationship curve between the numerically simulated cumulative oil production and the production index is established through Excel.

10. The method for quantitatively characterizing economic limit parameters of horizontal well deployment according to claim 1, characterized in that: In step S2, the drilling cost and production management cost are taken into consideration to establish a relationship curve between the economic limit cumulative oil production and the oil layer thickness, oil saturation or horizontal well length.

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