CN-121997784-A - Method for evaluating potential of seepage field in high water content period

CN121997784ACN 121997784 ACN121997784 ACN 121997784ACN-121997784-A

Abstract

The invention belongs to the technical field of oil and gas field development, in particular relates to a method for evaluating potential of a seepage field in a high water-cut period, and aims to solve the problems that the existing evaluation method is not complete in attribute parameter and inaccurate in evaluation of potential of the seepage field. The method comprises the steps of collecting parameters of a high-water-content oil field, screening to obtain a space-time attribute representation parameter for potential use of a seepage field, analyzing seepage characteristics of the high-water-content oil field according to a method for simulating the seepage field through a streamline, calculating an influence coefficient of the movable seepage potential by combining the space-time attribute representation parameter for potential use of the seepage field, and obtaining the movable seepage potential of the high-water-content oil field in a development stage according to each influence coefficient, namely an evaluation result. The method solves the problems of incomplete attribute parameters and inaccurate evaluation results of the existing seepage field potential utilization evaluation method.

Inventors

ZHANG JIN
GUO YIBING
MA WENHUA
ZONG JIE
WEI PENGPENG
ZHANG ZHIMING
CAO GUOMING
ZHANG HUIQING
FENG GUOJUN
WANG RUI

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. A method for evaluating potential of a seepage field in a high water-cut period, which is characterized by comprising the following steps: Acquiring parameters of a high-water-content oil field and screening to obtain a space-time attribute representation parameter for potential use of a seepage field, wherein the space-time attribute representation parameter for potential use of the seepage field comprises injection well spacing, permeability, injection well pressure difference, effective thickness, surface flux, saturation, uniform surface strength, non-uniformity, use balance and use uniformity; Analyzing seepage characteristics of the high-water-content oil field according to a method for simulating a seepage field by a streamline, and calculating an influence coefficient of the movable seepage potential by combining with a space-time attribute characterization parameter of the potential of the seepage field, wherein the influence coefficient comprises a driving and control capacity coefficient, a potential coefficient, a weak-unused reserve grade, a channeling channel average grade difference, a channeling channel volume ratio, formation pressure and a benefit dynamic coefficient; and according to each influence coefficient, obtaining the movable seepage potential of the high-water-content oil field in the development stage, namely an evaluation result.
2. The method for evaluating potential of a seepage field in a high water content period according to claim 1, wherein the average surface strength is calculated by the following steps: where ω is the average surface intensity, i.e., the average surface intensity, A max is the maximum cross-sectional area traversed by the streamline, Q is the surface flux, Q is the individual streamline flow across the cross-section, The number of the streamline strips.
3. The method for evaluating potential of a seepage field in a high water content period according to claim 2, wherein the method for calculating the potential balance is as follows: Wherein V gql is the usage balance, subscript g represents the balance, subscript ql represents the fluid flow, u is the number of wells around any 1 well or the number of wells, m, i, j are serial numbers, natural numbers 1, 2, 3 are taken, and a is the cross-sectional area through which the streamline passes.
4. A method for evaluating potential of a high water cut seepage field according to claim 3, wherein the method for calculating the potential uniformity comprises: Wherein V bql is the usage uniformity, subscript b represents uniformity, subscript ql represents fluid flow, and n is the total number of streamlines.
5. The method for evaluating potential of a seepage field in a high water content period according to claim 4, wherein the driving and controlling capacity coefficient is calculated by the following steps: or C a = ω Wherein C a is a driving capacity coefficient, K is reservoir permeability, H is reservoir effective thickness, deltaP is a production pressure difference, mu w is formation water viscosity, L is an injection and production well distance, and r w is a well bore radius.
6. The method for potential use evaluation of a high water-cut seepage field according to claim 5, wherein the potential use coefficient is calculated by: Wherein C p is the potential coefficient of use, S o is the saturation of oil content, and S or is the saturation of residual oil content.
7. The method for potential use evaluation of a high water cut seepage field according to claim 6, wherein the calculation method of the weak-unused reserves and the weak-unused reserves grade is as follows: N ne ＝(AHφΔS o ) ne U ne ＝(KHφΔS o ) ne Where N ne is the weak-unused reserve, U ne is the weak-unused reserve grade, Φ is the porosity, ΔS o is the difference in saturation of the mobile oil and the residual oil.
8. The method for evaluating potential of a high-water-cut seepage field according to claim 7, wherein the calculation method of the average level difference of the channeling is as follows: Or C K ＝V bql Wherein C K is the average level difference of the crossflow channel, K C is the permeability of the crossflow channel, Is the average permeability of the reservoir.
9. The method for evaluating potential of a seepage field in a high water content period according to claim 8, wherein the calculation method of the volume ratio of the channeling channel is as follows: Or C V ＝V bql Wherein C V is the volume ratio of the cross-flow channel, l is the number of small layers, V C is the volume of the cross-flow channel, and V is the volume of the single-layer pore.
10. The method for evaluating potential of a seepage field in a high water content period according to claim 9, wherein the benefit dynamic coefficient is calculated by the following steps: Wherein, C e is the benefit power coefficient, V gql is the utilization balance, deltaN r is the limit oil recovery, P is the oil price, and IN is the input cost.

Description

Method for evaluating potential of seepage field in high water content period Technical Field The invention belongs to the technical field of oil and gas field development, and particularly relates to a method for evaluating potential of a seepage field in a high water-cut period. Background Seepage field is the reservoir space and migration channel of oil and natural gas, and is the comprehensive expression of the existence and change of fluid in underground porous medium. The common methods for evaluating the seepage capability or the potential of the seepage field at home and abroad are mainly three types, namely a weight analysis method, a fuzzy comprehensive evaluation method and a physical experiment model method. These methods typically choose as the basis for evaluation the parameters of properties such as porosity, permeability, mobile fluid saturation, effective thickness, initiation pressure gradient (only hypotonic/tight reservoir). When the reservoir enters the high water-cut development stage, the existing evaluation method is no longer applicable. On one hand, the development stage of high water content is generally accompanied with the generation of channeling channels such as large pore channels, cracks and fissures, the original pore structure size and distribution of a reservoir are greatly changed, so that the attribute parameters of the existing evaluation method are inaccurate and incomplete, on the other hand, the seepage field of the development stage of high water content is generally close to solidification, and the influence of the factors on the actual movable seepage potential is not considered in the existing method, so that the evaluation result is inaccurate and inapplicable. Therefore, there is a need to propose a method for evaluating the potential of a seepage field for high water-bearing reservoir development. Disclosure of Invention In order to solve the above-mentioned problems in the prior art, that is, to solve the problems that the existing method has incomplete attribute parameters and inaccurate evaluation of potential use of the seepage field under the influence of the generation of the channeling and the general approach of the solidification of the seepage field after the reservoir enters the development stage of the high water content period, the first aspect of the present invention proposes a potential use evaluation method of the seepage field in the high water content period, which comprises: Acquiring parameters of a high-water-content oil field and screening to obtain a space-time attribute representation parameter for potential use of a seepage field, wherein the space-time attribute representation parameter for potential use of the seepage field comprises injection well spacing, permeability, injection well pressure difference, effective thickness, surface flux, saturation, uniform surface strength, non-uniformity, use balance and use uniformity; Analyzing seepage characteristics of the high-water-content oil field according to a method for simulating a seepage field by a streamline, and calculating an influence coefficient of the movable seepage potential by combining with a space-time attribute characterization parameter of the potential of the seepage field, wherein the influence coefficient comprises a driving and control capacity coefficient, a potential coefficient, a weak-unused reserve grade, a channeling channel average grade difference, a channeling channel volume ratio, formation pressure and a benefit dynamic coefficient; and according to each influence coefficient, obtaining the movable seepage potential of the high-water-content oil field in the development stage, namely an evaluation result. In some preferred embodiments, the area-averaged intensity is calculated by: where ω is the average surface intensity, i.e., the average surface intensity, A max is the maximum cross-sectional area traversed by the streamline, Q is the surface flux, Q is the individual streamline flow across the cross-section, The number of the streamline strips. In some preferred embodiments, the method for calculating the usage balance is: Wherein V gql is the usage balance, subscript g represents the balance, subscript ql represents the fluid flow, u is the number of wells around any 1 well or the number of wells, m, i, j are serial numbers, natural numbers 1, 2, 3 are taken, and a is the cross-sectional area through which the streamline passes. In some preferred embodiments, the uniformity of the usage is calculated by: Wherein V bql is the usage uniformity, subscript b represents uniformity, subscript ql represents fluid flow, and n is the total number of streamlines. In some preferred embodiments, the driving capability coefficient is calculated by the following method: or C a = ω Wherein C a is a driving capacity coefficient, K is reservoir permeability, H is reservoir effective thickness, deltaP is a production pressure difference, mu w is formation water visc