CN-121993182-A - Oil reservoir balanced displacement degree evaluation method and device

CN121993182ACN 121993182 ACN121993182 ACN 121993182ACN-121993182-A

Abstract

The invention provides an oil reservoir balanced displacement degree evaluation method and device, and the method comprises the steps of selecting a typical injection well group, calculating an oil reservoir balanced displacement index of the typical injection well group, wherein the oil reservoir balanced displacement index refers to a vector product of a cumulative percentage of the number of wells and a dimensionless cumulative extraction degree ratio, the cumulative percentage of the number of wells is a ratio of the cumulative number of wells to the total number of wells, the dimensionless cumulative extraction degree ratio is a ratio of the cumulative extraction degree to the total cumulative extraction degree, carrying out production dynamic analysis according to the oil reservoir balanced displacement index of the typical injection well group, determining an evaluation index, and carrying out balanced displacement effect quantitative evaluation on each current production well according to the evaluation index. By utilizing the scheme of the invention, the evaluation accuracy of oil reservoir balanced displacement can be improved, and a more accurate adjustment decision basis is provided for oil field development.

Inventors

YANG ZHANWEI
ZHANG ZHAOCHEN
ZHANG HAIBO
WANG AIXIA
ZHAI WENHAN
KONG DEYU
HU QINGHE
LIU JIAN
FAN XINGSHENG
QIAN LINLIN
BAI YUFEI
WANG LEI
PENG YONGCHENG
TANG YIMING

Assignees

中国石油集团长城钻探工程有限公司
中国石油天然气集团有限公司

Dates

Publication Date: 20260508
Application Date: 20241104

Claims (10)

1. An evaluation method for oil reservoir balanced displacement degree, which is characterized by comprising the following steps: Selecting a typical injection well group; Calculating an oil reservoir balanced displacement index of the typical injection and production well group, wherein the oil reservoir balanced displacement index is a vector product of a cumulative percentage of well numbers and a dimensionless cumulative production degree ratio, the cumulative percentage of well numbers is a ratio of cumulative well numbers to total well numbers, and the dimensionless cumulative production degree ratio is a ratio of cumulative production degrees to total cumulative production degrees; Carrying out production dynamic analysis according to the oil reservoir balanced displacement index of the typical injection well group, and determining an evaluation index; And quantitatively evaluating the balanced displacement effect of each current production well according to the evaluation index.
2. The method for evaluating the oil reservoir balanced displacement degree according to claim 1, wherein the selecting a typical injection well group comprises: and selecting a plurality of normal production oil wells in the oil field injection and production well group, and selecting injection and production wells with long and stable injection and production relation time to form a typical injection and production well group.
3. The reservoir equalized displacement level evaluation method according to claim 1, wherein the equalized displacement index G of the typical injection and production well group is calculated according to the following formula: Wherein, the In the formula, N is the total number of oil extraction wells, x j is the cumulative percentage of the number of the j th well, y j is the dimensionless cumulative extraction degree ratio of the j th well, Q oi is the cumulative oil yield of the i th well, and N is the oil reservoir geological reserve.
4. The method for evaluating the oil reservoir balanced displacement degree according to claim 1, wherein the step of performing production dynamic analysis according to the oil reservoir balanced displacement index of the typical injection and production well group, and the step of determining the evaluation index comprises the steps of: And formulating an oil reservoir balanced displacement index and a dimensionless accumulated extraction degree evaluation index according to the balanced displacement index of the typical injection and production well group.
5. The oil reservoir balanced displacement degree evaluation method according to claim 3, wherein the oil reservoir balanced displacement index and dimensionless cumulative extraction degree evaluation index comprises: if the equalized displacement index of the typical injection and production well group is less than 0.1, representing absolute equalization of displacement; If the balanced displacement index of the typical injection well group is 0.1-0.3, representing that the displacement is relatively balanced; If the balanced displacement index of the typical injection well group is 0.3-0.5, the displacement difference is larger; If the equalized displacement index of the typical injection and production well group is greater than 0.5, a significant difference in displacement is indicated.
6. The method for evaluating the oil reservoir balanced displacement degree according to any one of claims 1 to 5, wherein the quantitative evaluation of the balanced displacement effect of each current production well according to the evaluation index comprises: selecting the production wells to be evaluated currently, and arranging the production wells in descending order according to the extraction degree; respectively counting the extraction degree and geological reserves of each production well on the plane and in the longitudinal direction; respectively calculating balanced displacement indexes on the oil reservoir plane and in the longitudinal direction at the current time according to the extraction degree and the geological reserves; And quantitatively evaluating the balanced displacement effect of the production well according to the balanced displacement indexes and the evaluation indexes in the oil reservoir plane and the longitudinal direction of the current time.
7. An oil reservoir equalization displacement degree evaluation device, characterized in that the device comprises: The screening module is used for selecting a typical injection well group; The calculation module is used for calculating an oil reservoir balanced displacement index of the typical injection and production well group, wherein the oil reservoir balanced displacement index is a vector product of a cumulative percentage of well number and a dimensionless cumulative production degree ratio, the cumulative percentage of well number is a ratio of cumulative well number to total well number, and the dimensionless cumulative production degree ratio is a ratio of cumulative production degree to total cumulative production degree; the evaluation index determining module is used for carrying out production dynamic analysis according to the oil reservoir balanced displacement index of the typical injection well group to determine an evaluation index; And the evaluation module is used for quantitatively evaluating the balanced displacement effect of each current production well according to the evaluation index.
8. The reservoir equalization displacement degree evaluation device according to claim 7, wherein: The screening module is particularly used for selecting a plurality of normal production wells in the oilfield injection well group, and selecting injection well groups with long and stable injection well relation time to form a typical injection well group.
9. The reservoir equalization displacement degree evaluation device according to claim 7, wherein: The evaluation index determining module is specifically configured to formulate an oil reservoir balanced displacement index and a dimensionless accumulated extraction degree evaluation index according to the balanced displacement index of the typical injection and production well group.
10. The reservoir equalization displacement degree evaluation device according to any one of claims 7 to 9, wherein the evaluation module comprises: the sequencing unit is used for selecting the production wells to be evaluated currently and sequencing the production wells in descending order according to the extraction degree; The statistics unit is used for respectively counting the extraction degree and the geological reserves of each production well on the plane and in the longitudinal direction; The calculation unit is used for calculating balanced displacement indexes on the oil reservoir plane and in the longitudinal direction at the current time according to the extraction degree and the geological reserves; And the evaluation unit is used for quantitatively evaluating the balanced displacement effect of the production well according to the balanced displacement indexes and the evaluation indexes in the oil reservoir plane and the longitudinal direction of the current time.

Description

Oil reservoir balanced displacement degree evaluation method and device Technical Field The invention relates to the technical field of oil field development, in particular to a method and a device for evaluating oil reservoir balanced displacement degree. Background The oil reservoir balanced displacement is an oilfield development technology, and aims to effectively weaken interlayer interference phenomenon and realize interlayer balanced displacement through reasonable layer system division and layered injection and production. In oil reservoir development, the whole oil reservoir and the internal displacement of an injection and production well group are unbalanced due to the influence of factors such as the difference of the permeability level of the reservoir layer, the heterogeneity, the injection and production relation, the well pattern well spacing and the like. With the deep development of oil fields, the oil-water relationship is complex, the property of the fluid is changed, and the distribution of the residual oil is dispersed, so that the balanced displacement of the oil reservoir becomes extremely difficult. At present, an effective evaluation method for oil reservoir balanced displacement is not formed, the traditional water-flooding reservoir development effect evaluation method comprises a water-flooding characteristic curve, a Tong Shi plate and other methods, and various evaluation indexes are provided, wherein the evaluation indexes comprise development indexes such as natural progressive rate, water storage rate, water content, oil extraction speed and the like, and the indexes are often too isolated by referring to the comprehensive average level of each index of an oil reservoir, so that the overall balanced displacement degree of the oil reservoir in well groups, among well groups and among well groups can not be comprehensively evaluated. Although means such as fine reservoir descriptions, numerical simulation, macroscopic and microscopic experimental methods can be used in combination, the evaluation accuracy of balanced displacement is not high due to lack of special countermeasures for balanced displacement of the reservoir. Disclosure of Invention The invention provides a method and a device for evaluating the oil reservoir balanced displacement degree, which are used for improving the evaluation accuracy of oil reservoir balanced displacement and providing more accurate adjustment decision basis for oil field development. Therefore, the invention provides the following technical scheme: a method for evaluating the degree of balanced displacement of an oil reservoir, the method comprising: Selecting a typical injection well group; Calculating an oil reservoir balanced displacement index of the typical injection and production well group, wherein the oil reservoir balanced displacement index is a vector product of a cumulative percentage of well numbers and a dimensionless cumulative production degree ratio, the cumulative percentage of well numbers is a ratio of cumulative well numbers to total well numbers, and the dimensionless cumulative production degree ratio is a ratio of cumulative production degrees to total cumulative production degrees; Carrying out production dynamic analysis according to the oil reservoir balanced displacement index of the typical injection well group, and determining an evaluation index; And quantitatively evaluating the balanced displacement effect of each current production well according to the evaluation index. Optionally, selecting the typical injection well group comprises selecting a plurality of normal production wells in the oilfield injection well group, and selecting injection well groups with long and stable injection and production relation time to form the typical injection well group. Optionally, the equalized displacement index G for the typical injection and production well group is calculated according to the following formula: Wherein: In the formula, N is the total number of oil extraction wells, x j is the cumulative percentage of the number of the j th well, y j is the dimensionless cumulative extraction degree ratio of the j th well, Q oi is the cumulative oil yield of the i th well, and N is the oil reservoir geological reserve. Optionally, the production dynamic analysis is carried out according to the oil reservoir balanced displacement index of the typical injection well group, and the determining the evaluation index comprises the step of formulating the oil reservoir balanced displacement index and the dimensionless accumulated extraction degree evaluation index according to the oil reservoir balanced displacement index of the typical injection well group. Optionally, the oil reservoir balanced displacement index and dimensionless accumulated production degree evaluation index includes: if the equalized displacement index of the typical injection and production well group is less than 0.1, representing absolute equaliz