CN-121997636-A - Two-dimensional non-uniform diversion fracture productivity simulation method for tight oil reservoir based on slickwater fracturing

CN121997636ACN 121997636 ACN121997636 ACN 121997636ACN-121997636-A

Abstract

The invention provides a two-dimensional nonuniform flow guiding fracture capacity simulation method of a tight oil reservoir based on slickwater fracturing, which comprises the following steps of S1, obtaining basic parameters of the tight oil reservoir, S2, dispersing hydraulic fracture to obtain a two-dimensional nonuniform flow guiding energy force field of a fracture unit, and S3, passing through a coupling coefficient The method comprises the steps of realizing multi-scale flow coupling of a matrix-fracture system to form a closed seepage control equation set, constructing a full three-dimensional finite element model comprising two-dimensional discrete units of the fracture and a matrix multi-scale grid, carrying out finite element discrete on the coupled seepage control equation set, carrying out iterative solution, and calculating single well productivity, wherein the system comprises a matrix-fracture system, a closed seepage control equation set, a step S4, a step S5, carrying out finite element discrete on the coupled seepage control equation set, and carrying out iterative solution, and a step S6. The method carries out multi-scale coupling on a two-dimensional non-uniform diversion energy field and a matrix low-speed non-Darcy seepage and fracture coefficient variable seepage equation, and carries out strong non-linear solution, thereby realizing full three-dimensional efficient simulation of 'two-dimensional non-uniform diversion capacity characterization of a fracture + matrix non-Darcy seepage + fracture-matrix dynamic coupling'.

Inventors

DENG YAN
ZHANG YUHANG
ZHANG TAO
GUO JIANCHUN
SUN JIAYI
ZHANG QIXIAO
FENG XINYU
WANG QIANG

Assignees

西南石油大学

Dates

Publication Date: 20260508
Application Date: 20251226

Claims (10)

1. A two-dimensional non-uniform diversion fracture productivity simulation method for a tight oil reservoir based on slickwater fracturing is characterized by comprising the following steps: S1, acquiring basic parameters of a tight oil reservoir, wherein the basic parameters comprise matrix parameters, hydraulic fracture parameters, proppant laying parameters and production system parameters; S2, dispersing the hydraulic fracture along the length direction and the height direction, and obtaining a two-dimensional non-uniform fluid conductivity force field of the fracture unit according to the permeability data of the proppant fluid conductivity experimental test Distribution; S3, constructing a low-speed non-Darcy seepage equation and a fracture coefficient seepage equation of a tight oil reservoir matrix through a coupling coefficient Realizing multi-scale flow coupling of a matrix-fracture system to form a closed seepage control equation set, wherein the coupling coefficient Dynamically associating a diversion energy force field; Coupling coefficient Is that Wherein, the D is the distance from the center of the matrix grid to the fracture surface; S4, constructing a full three-dimensional finite element model comprising two-dimensional discrete units of the crack and a matrix multi-scale grid by adopting an embedded discrete crack model or a local grid encryption technology, and realizing efficient spatial discrete of the crack-matrix region; S5, performing finite element dispersion on the coupled seepage control equation set, performing iterative solution, and synchronously obtaining the pressure field distribution of the matrix and the crack; And S6, calculating the single well productivity based on the obtained fracture pressure field and the production system parameters.
2. The capacity simulation method according to claim 1, wherein in step S1, the hydraulic fracture parameters include fracture length Height of crack Initial width of crack The proppant placement parameters include proppant particle size distribution, concentration distribution, permeability after compaction k f (x, z), and fracture effective width distribution w (x, z) in a fracture length x height two-dimensional space.
3. The capacity simulation method according to claim 1, wherein in step S1, the production schedule parameters include a production pressure difference, a bottom hole pressure, and a production time interval.
4. The method according to claim 1, wherein in step S2, the two-dimensional non-uniform conductivity field of the crack unit The method comprises the following steps: wherein, the For each fracture cell flow conductivity, For the proppant permeability within each fracture cell, For each slit cell width.
5. The capacity simulation method according to claim 1, wherein in step S3, the fracture-coefficient-variation percolation equation is: Wherein, the For the fracture pressure to be the same, For the combined compression coefficient of the fracture, Is the fluid flux of the matrix to the fracture.
6. The capacity simulation method according to claim 1, wherein in step S3, the multi-scale flow coupling equation of the matrix-fracture system is: Wherein, the For the fluid flux of the matrix to the fracture, As a result of the coupling coefficient, For the pressure of the substrate, Is fracture pressure.
7. The capacity simulation method according to claim 1, wherein in step S4, comprising: s4.1, performing three-dimensional grid dispersion on the dense reservoir area by adopting an embedded discrete fracture model or a local grid encryption technology; s4.2, explicitly discretizing the crack area into Two-dimensional units, which are in one-to-one correspondence with the crack units in the step S2, each crack unit is associated with a corresponding crack unit ; S4.3, performing multi-scale dispersion on the matrix region, wherein an encryption grid is adopted in the region close to the crack, and a coarse grid is adopted in the region far from the crack, so that multi-scale grid matching is realized; s4.4, establishing interface association of the crack unit and the adjacent matrix unit.
8. The capacity simulation method according to claim 1, wherein the step S5 further comprises: Finite element discretization is carried out by the Galergold method, and iterative solution is carried out on a strong nonlinear system by the Newton-Laporton method.
9. A computer-readable storage medium, comprising: the computer readable storage medium stores a computer program which, when executed by a processor, implements the method of any of claims 1-8.
10. A computer program product comprising a computer program which, when executed by a processor, implements the method of any of claims 1-8.

Description

Two-dimensional non-uniform diversion fracture productivity simulation method for tight oil reservoir based on slickwater fracturing Technical Field The invention belongs to the technical field of petroleum and natural gas engineering, and particularly relates to a two-dimensional non-uniform diversion fracture productivity simulation method for a compact oil reservoir based on slickwater fracturing. Background The dense oil reservoir has the characteristics of low pores and low permeability, and effective development is realized through hydraulic fracturing fracture. In the existing mainstream large-displacement slickwater multistage or combined particle size sand fracturing technology, due to lower viscosity of slickwater, proppants are easy to subside and move unevenly, so that the proppants in the two-dimensional space of the length (x direction) and the height (z direction) have obvious differences in particle size, concentration and compaction state, proppants with large particle size and high concentration are generally piled at the bottom of the crack, proppants with small particle size and low concentration are arranged at the top of the crack, and partial areas are even free of proppants. The proppant is unevenly paved, so that the fracture conductivity shows strong two-dimensional non-uniformity, meanwhile, seepage of a compact oil reservoir matrix accords with a low-speed non-Darcy law, multi-scale flux coupling exists between the fracture and the matrix, and a strong non-uniform multi-scale coupling partial differential equation set of a fracture coefficient two-dimensional seepage equation and a matrix low-speed non-Darcy equation is needed to be solved in productivity calculation. However, the conventional oil reservoir simulator generally simplifies the fracture conductivity into a constant or one-dimensional distribution, and cannot characterize the two-dimensional non-uniformity. Disclosure of Invention The invention aims to overcome the defects of the prior art, solve the problems of accurate representation of two-dimensional nonuniform conductivity of cracks and efficient solution of a multi-scale coupled seepage equation set of a matrix-crack system in a compact oil reservoir after slickwater fracturing, and realize accurate simulation of productivity. In order to achieve the above purpose, the invention adopts the following technical scheme: a two-dimensional non-uniform diversion fracture productivity simulation method for a tight oil reservoir based on slickwater fracturing comprises the following steps: S1, acquiring basic parameters of a tight oil reservoir, wherein the basic parameters comprise matrix parameters, hydraulic fracture parameters, proppant laying parameters and production system parameters; S2, dispersing the hydraulic fracture along the length direction and the height direction, and obtaining a two-dimensional non-uniform fluid conductivity force field of the fracture unit according to the permeability data of the proppant fluid conductivity experimental test Distribution; S3, constructing a low-speed non-Darcy seepage equation and a fracture coefficient seepage equation of a tight oil reservoir matrix through a coupling coefficient Realizing multi-scale flow coupling of a matrix-fracture system to form a closed seepage control equation set, wherein the coupling coefficientDynamically associating a diversion energy force field; S4, constructing a full three-dimensional finite element model comprising two-dimensional discrete units of the crack and a matrix multi-scale grid by adopting an embedded discrete crack model or a local grid encryption technology, and realizing efficient spatial discrete of the crack-matrix region; S5, performing finite element dispersion on the coupled seepage control equation set, performing iterative solution, and synchronously obtaining the pressure field distribution of the matrix and the crack; And S6, calculating the single well productivity based on the obtained fracture pressure field and the production system parameters. Further, in step S1, the hydraulic fracture parameters include fracture lengthHeight of crackInitial width of crackThe proppant placement parameters include proppant particle size distribution, concentration distribution, permeability after compaction k f (x, z), and fracture effective width distribution w (x, z) in a fracture length x height two-dimensional space. Further, in step S1, the production system parameters include a production pressure difference, a bottom hole flow pressure, and a production time interval. Further, in step S2, the two-dimensional heterogeneous energy-guiding force field of the fracture unitThe method comprises the following steps: wherein, the For each fracture cell flow conductivity,For the proppant permeability within each fracture cell,For each slit cell width. Further, in step S3, the fracture coefficient seepage equation is: Wherein, the For the fracture pressure to be the same,F