阅读说明：本技术 一种适用于低渗透油田水平井区加密调整方法 (Encryption adjusting method suitable for horizontal well region of low-permeability oil field ) 是由 刘性全 冷小勇 孙美凤 祖琳 郑宪宝 吴景峰 宫宝 刘仰东 马玉玲 王利 郭晓娟 于 2019-07-27 设计创作，主要内容包括：本发明公开了一种适用于低渗透油田水平井区加密调整方法,其特征在于,包括计算需加密调整井区的经济极限井距及经济极限有效厚度下限；取所述需加密调整井区的井位图与四个水平井区加密调整模版作对比,选择对应的水平井区加密调整模版；依据所述对应的水平井区加密调整模版部署加密井位；在所述井位图上测量所述加密井位的拟加密井与临井的井距；依据所述需加密调整井区分层砂体图,用周围油水井钻遇砂体厚度预测所述加密井位的拟加密井的厚度；若所述井距大于所述经济极限井距,且所述厚度大于所述经济极限有效厚度,则所述拟加密井为加密井,否则为非加密井；解决现有常规加密调整方法不适用于水平井区的问题。(the invention discloses a method for adjusting encryption of a horizontal well region in a low-permeability oilfield, which is characterized by comprising the steps of calculating the economic limit well spacing and the economic limit effective thickness lower limit of the well region needing to be adjusted by encryption; comparing the well bitmap of the well region needing to be encrypted and adjusted with the encryption adjusting templates of the four horizontal well regions, and selecting the corresponding encryption adjusting template of the horizontal well region; arranging an encryption well position according to the corresponding horizontal well region encryption adjusting template; measuring the well spacing between a to-be-encrypted well and an adjacent well of the encrypted well position on the well pattern; according to the well zone layered sand body diagram needing to be encrypted and adjusted, predicting the thickness of the to-be-encrypted well at the encryption well position by using the thickness of the sand body encountered by the surrounding oil-water well; if the well spacing is larger than the economic limit well spacing and the thickness is larger than the economic limit effective thickness, the well to be encrypted is an encrypted well, otherwise, the well to be encrypted is an unencrypted well; the problem that the conventional encryption adjusting method is not suitable for a horizontal well area is solved.)

1. A method for adjusting encryption of a horizontal well region in a low-permeability oilfield is characterized by comprising the following steps:

Calculating the economic limit well spacing and the economic limit effective thickness lower limit of the well region needing to be encrypted and adjusted;

Comparing the well bitmap of the well region needing to be encrypted and adjusted with the encryption adjusting templates of the four horizontal well regions, and selecting the corresponding encryption adjusting template of the horizontal well region;

arranging an encryption well position according to the corresponding horizontal well region encryption adjusting template;

measuring the well spacing between a to-be-encrypted well and an adjacent well of the encrypted well position on the well pattern;

adjusting the well area layered sand body diagram according to the encryption requirement, and predicting the thickness of the to-be-encrypted well of the encryption well position by using the thickness of the surrounding oil-water well layered sand body;

And if the well spacing is larger than the economic limit well spacing and the thickness is larger than the economic limit effective thickness, the encryption-planned well is an encryption well, otherwise, the encryption-planned well is a non-encryption well.

2. The horizontal well zone encryption adjustment method according to claim 1, wherein:

The four horizontal well area encryption adjusting templates are respectively as follows:

a first template: no well position exists between the injection and production far end of the horizontal well region and the fault;

And (2) template II: horizontal well plane and longitudinal upper reserve loss;

And (3) template III: the injection-production interval is larger than 300m of the conventional injection-production well pattern and exceeds two horizontal well zones of the well spacing of the encrypted wells;

And (4) template IV: the straight well zone fault edge, the well pattern center and the well pattern edge have no well position.

3. The horizontal well zone encryption adjustment method according to claim 2, wherein:

A method of deploying the encrypted well locations according to the template: arranging an encryption well at the edge of the fault by taking a limit encryption well spacing as a boundary;

The method for deploying the encrypted well positions according to the second template comprises the following steps: arranging encryption wells at positions where drilling sections at the heel and toe ends of the two sides of the horizontal well meet a limit encryption well spacing;

And deploying the encrypted well positions according to the template III: the method comprises the steps that an oil-water well is encrypted in a whole row encryption mode in a direction parallel to a horizontal well track at an encryption well spacing position between a vertical well and a horizontal well, and the well spacing of encryption wells in rows is not smaller than a limit economic well spacing;

the method for deploying the encrypted well positions according to the template four comprises the following steps: and deploying the encrypted well according to a conventional vertical well encryption adjusting method.

4. the horizontal well zone encryption adjustment method according to claim 1, wherein:

the theoretical formula for calculating the economic limit well spacing and the economic limit effective thickness is as follows:

economic limit well pattern density:

initial economic limit daily oil production of a single well:

Economic ultimate well spacing:

Economic limit effective thickness lower limit:

in the formula: i is_D、I_Baverage well drilling investment, surface construction investment, 10⁴yuan/kou; r-investment loan interest rate, decimal; t-development evaluation age, a; the beta-oil well coefficient, namely the ratio of the total number of oil-water wells to the number of oil wells, has no dimension; tau is_o-time to oil recovery, decimal; d_o-crude oil commodity rate, decimal fraction; p_o-crude oil sales price, $/bbl; o-crude cost, unit/t; s-tax, Yuan/t; n-crude oil geological reserves, 10⁴t；A_ooil-bearing area, km²；E_R-recovery factor, fractional; d_c-annual integrated decline rate, decimal, of the oil field; w_iThe reserve production degree, decimal, J of recoverable crude oil within the development evaluation period_oOil recovery intensity, h-adjustable thickness.

5. the horizontal well zone encryption adjustment method according to claim 1, wherein:

the method for selecting the corresponding horizontal well region encryption adjustment template comprises the following steps: and selecting the horizontal well region encryption adjusting template consistent with the well position distribution of the well position diagram.

6. The horizontal well zone encryption adjustment method according to claim 1, wherein:

the well spacing measuring method comprises the following steps: the straight-line distance between the two points is determined with a ruler tool on the software displaying the well map.

7. The horizontal well zone encryption adjustment method according to claim 1, wherein:

The method for predicting the thickness of a well to be encrypted at the encryption well location is: the thickness of the layered sand body of the encryption well is the same as that of the surrounding oil-water well, the layered sand body of the surrounding oil-water well is arranged on the layered sand body diagram, and the sum of the thicknesses of the layered sand bodies is the thickness of the encryption well.

Technical Field

The invention relates to the technical field of oilfield development, in particular to a method for adjusting encryption of a horizontal well region of a low-permeability oilfield.

background

the development of the horizontal well effectively promotes the effective utilization of a low-permeability reservoir, a certain block is a typical straight and flat combined development well pattern, the comprehensive water content of the block is 67.3 percent, the development stage of the medium and high water content is entered, the injection and production system of part of well regions is incomplete, a water-drive blank region exists, the residual oil is locally enriched, and the overall production degree of the block is low and is only 12.88 percent.

at present, aiming at the situation, a method of encryption adjustment is usually adopted, and the conventional encryption method for the vertical well area is not suitable for a horizontal well area well pattern; secondly, due to the fact that the longitudinal cross-layer drilling of the horizontal well of the low-permeability oil field meets the perforation, reserves of partial sections are lost, and the reserves of the conventional straight well zone encryption method cannot be used, the encryption adjustment of the horizontal well zone in the prior art is not applicable, and an effective technical method is not formed in the encryption adjustment of the horizontal well zone.

disclosure of Invention

in view of the above, the invention provides a method for adjusting encryption of a horizontal well region in a low-permeability oilfield, which solves the problem that the conventional encryption adjusting method is not suitable for the horizontal well region.

In order to achieve the above object, the encryption adjusting method for the horizontal well region in the low permeability oilfield is characterized by comprising the following steps:

Calculating the economic limit well spacing and the economic limit effective thickness lower limit of the well region needing to be encrypted and adjusted;

Comparing the well bitmap of the well region needing to be encrypted and adjusted with the encryption adjusting templates of the four horizontal well regions, and selecting the corresponding encryption adjusting template of the horizontal well region;

arranging an encryption well position according to the corresponding horizontal well region encryption adjusting template;

measuring the well spacing between a to-be-encrypted well and an adjacent well of the encrypted well position on the well pattern;

adjusting the well area layered sand body diagram according to the encryption requirement, and predicting the thickness of the to-be-encrypted well of the encryption well position by using the thickness of the surrounding oil-water well layered sand body;

And if the well spacing is larger than the economic limit well spacing and the thickness is larger than the economic limit effective thickness, the encryption-planned well is an encryption well, otherwise, the encryption-planned well is a non-encryption well.

preferably, the four horizontal well encryption adjusting templates are respectively:

a first template: no well position exists between the injection and production far end of the horizontal well region and the fault;

And (2) template II: horizontal well plane and longitudinal upper reserve loss;

and (3) template III: the injection-production interval is larger than 300m of the conventional injection-production well pattern and exceeds two horizontal well zones of the well spacing of the encrypted wells;

and (4) template IV: the straight well zone fault edge, the well pattern center and the well pattern edge have no well position.

Preferably, the method of deploying the encrypted well locations according to the template: arranging an encryption well at the edge of the fault by taking a limit encryption well spacing as a boundary;

The method for deploying the encrypted well positions according to the second template comprises the following steps: arranging encryption wells at positions where drilling sections at the heel and toe ends of the two sides of the horizontal well meet a limit encryption well spacing;

And deploying the encrypted well positions according to the template III: the method comprises the steps that an oil-water well is encrypted in a whole row encryption mode in a direction parallel to a horizontal well track at an encryption well spacing position between a vertical well and a horizontal well, and the well spacing of encryption wells in rows is not smaller than a limit economic well spacing;

The method for deploying the encrypted well positions according to the template four comprises the following steps: and deploying the encrypted well according to a conventional vertical well encryption adjusting method.

Preferably, the theoretical formula for calculating the economic limit well spacing and the economic limit effective thickness is as follows:

economic limit well pattern density:

initial economic limit daily oil production of a single well:

Economic ultimate well spacing:

economic limit effective thickness lower limit:

in the formula: i is_D、I_Baverage well drilling investment, surface construction investment, 10⁴Yuan/kou; r-investment loan interest rate, decimal; t-development evaluation age, a; the beta-oil well coefficient, namely the ratio of the total number of oil-water wells to the number of oil wells, has no dimension; tau is_o-time to oil recovery, decimal; d_o-crude oil commodity rate, decimal fraction; p_o-crude oil sales price, $/bbl; o-crude cost, unit/t; s-tax, Yuan/t; n-crude oil geological reserves, 10⁴t；A_ooil-bearing area, km²；E_R-recovery factor, fractional; d_c-annual integrated decline rate, decimal, of the oil field; w_ithe reserve production degree, decimal, J of recoverable crude oil within the development evaluation period_oOil recovery intensity, h-adjustable thickness.

preferably, the method for selecting the corresponding horizontal well encryption adjustment template is as follows: and selecting the horizontal well region encryption adjusting template consistent with the well position distribution of the well position diagram.

Preferably, the well spacing measuring method comprises the following steps: the straight-line distance between the two points is determined with a ruler tool on the software displaying the well map.

Preferably, the method of predicting the thickness of a well to be encrypted at the encryption well location is: the thickness of the layered sand body of the encryption well is the same as that of the surrounding oil-water well, the layered sand body of the surrounding oil-water well is arranged on the layered sand body diagram, and the sum of the thicknesses of the layered sand bodies is the thickness of the encryption well.

the invention has the following beneficial effects:

Aiming at the characteristics of a vertical well pattern of a horizontal well zone, combining the characteristics of the horizontal well pattern and the characteristics of layered drilling, being different from a conventional vertical well encryption mode, breaking through well position limitation, carrying out encryption deployment on the part of an un-drilled section at the toe end of a horizontal well, and aiming at the characteristics of layered drilling of the horizontal well, meeting the economic limit on the encryption well position deployment at the near ends of two sides of a well track of the horizontal well, rapidly determining the well position of an encryption well, preferably carrying out selective perforation on the un-drilled section of the horizontal well meeting a low water-flooded zone, and fully utilizing the reserve of the horizontal well zone.

Meanwhile, the four horizontal well zone encryption adjusting templates form a set of horizontal well zone encryption adjusting technology suitable for the low-permeability oil field, the encryption adjusting well position of the horizontal well zone is effectively and quickly determined, and reference is provided for the subsequent encryption adjustment of the horizontal well zone of the oil field of the same type.

drawings

the above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a template;

FIG. 1A is a schematic diagram of a template-encryption adjustment template;

FIG. 1B is a schematic diagram of deployment of an encrypted wellsite according to FIG. 1A;

FIG. 2 is a schematic view of a template II;

FIG. 2A is a schematic diagram of a template two encryption adjustment template;

FIG. 2B is a schematic diagram of deployment of an encrypted wellsite according to FIG. 2A;

FIG. 3 is a schematic diagram of a template;

FIG. 3A is a schematic diagram of a template triple encryption adjustment template;

FIG. 3B is a schematic diagram of deployment of an encrypted wellsite according to FIG. 3A;

FIG. 4 is a schematic view of a template four;

FIG. 4A is a schematic diagram of a template quad-encryption adjustment template;

FIG. 4B is a schematic diagram of deployment of an encrypted well site according to FIG. 4A;

FIG. 5 is an illustration of the diagram in FIGS. 1A-4B;

FIG. 6 is an encrypted adjusted well map of an exemplary embodiment of a 66-Ping 21 well region;

FIG. 7 is an example of a state 62-Ping 61 well encryption adjustment well map.

Detailed Description

the present invention will be described below based on examples, but it should be noted that the present invention is not limited to these examples. In the following detailed description of the present invention, certain specific details are set forth. However, the present invention may be fully understood by those skilled in the art for those parts not described in detail.

A horizontal well zone encryption adjusting method suitable for a low permeability oilfield comprises the following steps:

(1) Determining the economic limit well spacing and the economic limit effective thickness lower limit of a well zone needing to be encrypted and adjusted by applying a theoretical formula according to the basic parameters (oil field basic data) of the oil field;

(2) according to a well pattern (oil field basic data) of a well region needing to be encrypted and adjusted, comparing four horizontal well region encryption adjustment templates shown in figures 1A-4A in the attached drawings, selecting a corresponding template, then determining an encryption well position according to a deployment encryption well position schematic diagram and an encryption well deployment method of the corresponding template shown in figures 1B-4B in the attached drawings, and after determining the well position, measuring the well distance between a to-be-encrypted well and an adjacent well on the well pattern (the well distance measured on the well pattern is the prior art, and a straight line distance between two points can be determined by a straight line tool on software for displaying the well pattern);

according to the well zone layered sand body diagram (the oil field basic data, the layered sand body thickness is on the surrounding oil-water well layered sand body diagram), because the thickness of the surrounding oil-water well layered sand body is the same as that of the to-be-encrypted well, the sum of the thicknesses of the surrounding oil-water well layered sand bodies is the predicted to-be-encrypted well thickness;

(3) comparing the well spacing and the thickness parameter of the quasi-encrypted well obtained in the step (2) with the economic limit well spacing and the economic limit effective thickness obtained by theoretical calculation in the step (1), if the numerical values of the well spacing and the thickness parameter are both larger than or equal to the theoretical numerical value calculated in the step (1), the well is in accordance with the economic limit, the well position can be determined as an encrypted well, the quasi-encrypted well smaller than the theoretical numerical value in the step (1) is not in accordance with the condition, the well is a non-encrypted well, and the well is discarded.

Specifically, the step (1) is to determine the economic limit well spacing and the economic limit effective thickness lower limit of the well zone needing to be encrypted and adjusted by applying a theoretical formula according to the basic parameters (oil field basic data) of the oil field; the applied formulas are (wherein the economic limit well pattern density formula and the single-well initial limit daily oil yield formula are used for solving the economic limit well spacing and the economic limit effective thickness lower limit in the following steps):

In the formula: i is_D、I_BAverage well drilling investment, surface construction investment, 10⁴yuan/kou; r-investment loan interest rate, decimal; t-development evaluation age, a; the beta-oil well coefficient, namely the ratio of the total number of oil-water wells to the number of oil wells, has no dimension; tau is_o-time to oil recovery, decimal; d_o-crude oil commodity rate, decimal fraction; p_o-crude oil sales price, $/bbl; o-crude cost, unit/t; s-fee taxN, m/t; n-crude oil geological reserves, 10⁴t；A_oOil-bearing area, km²；E_R-recovery factor, fractional; d_c-annual integrated decline rate, decimal, of the oil field; w_ithe reserve production degree, decimal, J of recoverable crude oil within the development evaluation period_oOil recovery intensity, h-adjustable thickness.

specifically, the four horizontal well zone encryption adjustment templates (i.e., the well pattern of the existing basic well pattern is compared with the following four templates, and if any template is met, the well position of the encryption well is quickly determined according to the template):

Firstly, a well position-free area between a far end and a fault is injected and produced in a horizontal well area, and an encryption well is deployed on the edge of the fault by taking a limit encryption well spacing as a boundary. (this part of the empty area is poor for water drive due to its location at the injection and production far end, and the outer fault is blocked, forming a remaining oil rich zone). (as shown in FIGS. 1A and 1B).

secondly, the reserve loss on the horizontal well plane and the longitudinal direction is caused, and the encrypted wells are arranged at the positions where the drilling meeting sections at the heel and toe ends of the two sides of the horizontal well meet the requirement of one limit encrypted well spacing. (because of the drilling specificity of the horizontal well reservoir, the distance between the heel end and the toe end of a part of horizontal well is greater than one encryption limit well distance, no water drive control exists at the position, and the residual oil is enriched). (as shown in fig. 2A and 2B).

and thirdly, the horizontal well area with the injection-production interval larger than 300m of the conventional injection-production well pattern and the well distance exceeding two encryption well areas encrypts the oil-water well in a whole row encryption mode in a direction parallel to the well track of the horizontal well at an encryption well distance position between the vertical well and the horizontal well, wherein the well distance of the encryption well among rows is not smaller than one limit economic well distance. (as shown in fig. 3A and 3B).

Fourthly, arranging the encrypted wells according to the conventional encryption adjusting method of the vertical wells in the areas without the well positions at the edges of the fault, the well pattern center and the well pattern edge of the vertical well area. (see FIG. 4A and FIG. 4B)