CN-121980778-A - Induced dynamic crack numerical characterization method based on dynamic embedded discrete cracks

CN121980778ACN 121980778 ACN121980778 ACN 121980778ACN-121980778-A

Abstract

The invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a dynamic crack numerical characterization method based on dynamic embedded discrete cracks. A dynamic embedded discrete crack numerical value characterization method based on dynamic embedded discrete crack is characterized by comprising the steps of determining a starting position for inducing growth and extension of dynamic crack, generating dynamic embedded discrete crack pieces describing the growth and extension or closing process of the dynamic crack at the moment time by time sequence with the starting position as a starting point, and realizing space splicing on a public boundary of adjacent dynamic embedded discrete crack pieces to keep the whole continuity of the crack so as to form a dynamic embedded discrete crack model covering the whole life cycle of the induced dynamic crack. The invention realizes the effective simulation of the growth extension and closure process of the dynamic cracks induced by water injection in the ultra-low permeability reservoir energy storage permeability-increasing injection process, thereby providing effective technical guidance for the implementation of the ultra-low permeability reservoir energy storage permeability-increasing technology field.

Inventors

LIANG WEIWEI
LIU WENQIANG
HUANG HAI
DANG HAILONG
TANG HOUJUN
XU BO
LIU BIN
LI LUSHENG
ZHANG TIANYANG
ZHANG LIANG

Assignees

西安石油大学

Dates

Publication Date: 20260505
Application Date: 20260109

Claims (8)

1. A dynamic embedded discrete crack numerical value characterization method based on dynamic embedded discrete crack is characterized by comprising the steps of determining a starting position for inducing growth and extension of dynamic crack, generating dynamic embedded discrete crack pieces describing the growth and extension or closing process of the dynamic crack at the moment time by time sequence with the starting position as a starting point, and realizing space splicing on a public boundary of adjacent dynamic embedded discrete crack pieces to keep the whole continuity of the crack so as to form a dynamic embedded discrete crack model covering the whole life cycle of the induced dynamic crack.
2. The dynamic fracture numerical characterization method based on the dynamic embedded discrete fracture of claim 1 is characterized in that the specific process of the initial position for inducing the growth and extension of the dynamic fracture is that if the initial moment does not exist in the injection well, the position of the well bore where the perforation section of the injection well is located is taken as the initial position for inducing the growth and extension of the dynamic fracture, and if the initial moment exists in the injection well, the initial moment is taken as the initial position for inducing the growth and extension of the dynamic fracture when the initial moment is located in the injection well, and the position of the dynamic embedded discrete fracture piece far away from the well bore where the perforation section of the injection well is located.
3. The dynamic-embedded-crack-value-induced characterization method based on the dynamic embedded discrete cracks according to claim 1, wherein the dynamic embedded-crack-value-induced characterization method is characterized in that the dynamic embedded-crack-value-induced characterization method comprises three types, namely a type 1, wherein the crack height and the crack opening degree are kept constant, only the crack length is changed with time, a type 2, wherein the crack height is kept constant, the crack length and the crack opening degree are changed with time, and a type 3, wherein the crack length, the crack height and the crack opening degree are all changed with time.
4. The dynamic-embedded-crack-based induced dynamic crack numerical characterization method according to claim 3, wherein the specific process of implementing spatial stitching on the common boundary of adjacent dynamic-embedded-discrete-crack pieces is as follows: The dynamic embedded discrete fracture pieces of the types 1,2 and 3 grow to extend a next dynamic embedded discrete fracture piece along the vertical boundary of the current dynamic embedded discrete fracture piece at each moment, and the next dynamic embedded discrete fracture piece coincides with the vertical boundary of the current dynamic embedded discrete fracture piece; the type 1, the crack length of the next dynamic embedded discrete crack piece is different from that of the current dynamic embedded discrete crack piece, and the crack opening and the crack height are the same; the type 2, the crack length and the crack opening degree of the next dynamic embedded discrete crack piece are different from those of the current dynamic embedded discrete crack piece, and the crack heights are the same; And 3, the crack length, the crack opening and the crack height of the next dynamic embedded discrete crack piece are different from those of the current dynamic embedded discrete crack piece.
5. The method for characterizing the induced dynamic crack numerical value based on the dynamic embedded discrete crack as recited in claim 1, wherein the generation process of the dynamic embedded discrete crack sheet is that the generation time, the crack type parameter and the crack attribute parameter of the induced dynamic crack at different moments are obtained by combining microseism monitoring interpretation and considering induced dynamic crack numerical value simulation under ground stress or dynamic monitoring interpretation analysis means, so as to generate the dynamic embedded discrete crack sheet at the moment.
6. The method for characterizing the induced dynamic fracture numerical value based on the dynamic embedded discrete fracture according to claim 2, wherein the generating process of the initial time dynamic embedded discrete fracture piece is that the analysis and the interpretation of the original fracture pattern and the attribute parameters of the injection well are carried out by combining microseism monitoring interpretation data, unstable well test interpretation and production dynamic analysis results, so as to generate the initial time dynamic embedded discrete fracture piece for characterizing the initial time injection well original fracture.
7. The method for characterizing a dynamic crack induced numerical value based on a dynamic embedded discrete crack as recited in claim 5, wherein the crack type parameters include a starting position and direction of growth extension or closure of the dynamic crack induced at different times, a crack length, a crack height, a crack opening, a crack inclination angle and a crack azimuth angle, and the crack attribute parameters are crack permeability.
8. The method for characterizing an induced dynamic fracture value based on a dynamic embedded discrete fracture according to claim 7, wherein the fracture permeability comprises a permeability k fci of the dynamic embedded discrete fracture piece along a long side and a permeability k fdi of the dynamic embedded discrete fracture piece along a short side; The specific calculation process of the permeability k fci of the dynamic embedded discrete fracture piece along the long side is as follows: k fci =ξk fc ·ω f 3 /ω fo 3 The specific calculation process of the permeability k fdi of the dynamic embedded discrete fracture piece along the short side is as follows: k fdi =ξk fd ·ω f 3 /ω fo 3 Wherein k fci is the permeability of the dynamic embedded discrete fracture piece along the long side, mu m 2 , ζ is the permeability correction coefficient, no dimension, k fc is the permeability of the dynamic embedded discrete fracture piece along the long side at the starting position, mu m 2 ;ω f is the fracture opening, mu m, omega fo is the fracture opening at the starting position of the dynamic embedded discrete fracture piece, mu m, k fdi is the permeability of the dynamic embedded discrete fracture piece along the short side, mu m 2 ;k fd is the permeability of the dynamic embedded discrete fracture piece along the short side at the starting position, and mu m 2 .

Description

Induced dynamic crack numerical characterization method based on dynamic embedded discrete cracks Technical Field The invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a dynamic crack numerical characterization method based on dynamic embedded discrete cracks. Background The technology mainly adopts the principle that the dual mechanisms of fracturing and water injection are combined, and the large-displacement and large-liquid-amount injection is adopted in a short period, so that water injection induced dynamic cracks are generated near the bottom of an injection well and a high-pressure area distributed along the dynamic cracks is formed, and the purpose of increasing the yield of the oil well is achieved through the effects of flushing, imbibition exchange and well opening displacement. Meanwhile, the domestic long-term water injection development practice of the ultra-low permeability reservoir also shows that the water injection induced dynamic fracture has a new geological property in the water injection development of the ultra-low permeability reservoir, on one hand, the water injection induced dynamic fracture is easy to form water channeling and water flooding channels between injection and production wells, invalid circulation of injected water is emphasized, meanwhile, the water injection induced dynamic fracture is generated to exacerbate the reservoir plane and vertical heterogeneity, a residual oil enrichment area is formed in the reservoir, the reservoir development effect is reduced, on the other hand, the water injection induced dynamic fracture is generated in the energy storage and permeation injection process of the ultra-low permeability reservoir, which is a forward effect, the seepage capability of the ultra-low permeability reservoir is effectively improved, the pressure wave and volume in the energy storage and permeation injection process are increased, the generation condition of a dynamic fracture system is greatly improved, meanwhile, the smoldering well seepage promotes effective replacement of oil and water in the reservoir, and the single well yield and the stage recovery rate are greatly improved. Therefore, how to accurately represent and simulate the dynamic change characteristics of the water injection induced dynamic cracks in the ultra-low permeability reservoir, effectively utilize the advantages brought by the generation of the water injection induced dynamic cracks, avoid the defects brought by the generation of the water injection induced dynamic cracks, become the key point and the difficult point of the research on the oil reservoir development effect by the ultra-low permeability reservoir energy storage and permeation enhancement technology, and currently aim at the research on the water injection induced dynamic cracks, mainly based on the equivalent numerical representation method of the traditional static cracks, such as local grid encryption and discrete crack models, but the traditional numerical representation method cannot dynamically represent the types and the attribute parameters of the induced dynamic cracks, and has stronger limitation, so that the research on the numerical representation method of the induced dynamic cracks based on the dynamic embedded discrete cracks is needed to be explored. Disclosure of Invention The invention aims at solving the problems and provides a dynamic crack numerical characterization method based on dynamic embedded discrete cracks. The technical scheme of the invention is as follows: the dynamic embedded discrete crack numerical characterization method based on the dynamic embedded discrete crack comprises the steps of determining a starting position for inducing the growth and extension of the dynamic crack, generating dynamic embedded discrete crack pieces describing the growth and extension or closing process of the dynamic crack at the moment time by time sequence with the starting position as a starting point, and realizing space splicing on the public boundary of adjacent dynamic embedded discrete crack pieces to keep the whole continuity of the crack so as to form a dynamic embedded discrete crack model covering the whole life cycle of the induced dynamic crack. The specific process of the initial position for inducing the growth and extension of the dynamic cracks comprises the steps of taking the shaft position of the perforation section of the injection well as the initial position for inducing the growth and extension of the dynamic cracks if the initial position of the injection well does not have the original cracks, and taking the shaft position of the perforation section of the injection well, which is far away from the initial position of the injection well, as the initial position for inducing the growth and extension of the dynamic cracks if the initial position of the injection well has the original cracks. The dynamic embedded discre