Well pattern optimization method based on CO2 incomplete miscible displacement characteristics

Patent metadata

Field	Value
Publication number	US-12566906-B2
Application number	US-202519066395-A
Country	US
Kind code	B2
Filing date	Feb 28, 2025
Priority date	Mar 1, 2024
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A well pattern optimization method based on CO2 incomplete miscible displacement characteristics is provided, including: obtaining fluid component data of formation crude oil, and establishing a fluid component model based on the fluid component data; establishing a three-dimensional reservoir model based on the fluid component model, and setting reservoir parameters for the three-dimensional reservoir model; performing simulation operation on the three-dimensional reservoir model with set reservoir parameters under different CO2 flooding well pattern modes, and obtaining simulation operation results; and performing analysis of fronts and production parameter comparison on the simulation operation results, and obtaining an optimal CO2 flooding well pattern mode.

First claim

What is claimed is:

1 . A well pattern optimization method implemented by a simulation software based on CO 2 incomplete miscible displacement characteristics, comprising:
obtaining fluid component data of formation crude oil by performing high-temperature and high-pressure PVT experiments comprising constant composition expansion experiments, multi-stage degassing experiments, and gas injection expansion experiments, and establishing a fluid component model based on the fluid component data; establishing a three-dimensional reservoir model based on the fluid component model, and setting reservoir parameters for the three-dimensional reservoir model; performing simulation operation on the three-dimensional reservoir model with set reservoir parameters under different CO 2 flooding well pattern modes, wherein each CO 2 flooding well pattern mode is based on a production system comprising one injection well and at least one production well operating with a fixed CO 2 injection volume, a fixed injection pressure, and a fixed production pressure, and obtaining simulation operation results; and performing analysis of fronts and production parameter comparison on the simulation operation results, and obtaining an optimal CO 2 flooding well pattern mode;
wherein the fronts comprise: a miscible pressure front, a component front, and a phase front, wherein the miscible pressure front is a position with a formation pressure between injection and production wells equaling a minimum miscible pressure of CO 2 and crude oil,
the component front is a position closest to an injection well swept by a zero mole fraction of a CO 2 component between the injection and production wells during a displacement process, and
the phase front is a position closest to a production well swept by a zero oil-gas interfacial tension between the injection and production wells during the displacement process;
wherein performing the analysis of the fronts on the simulation operation results comprises:
analyzing different field maps of the simulation operation results under different CO 2 flooding well pattern modes, and obtaining migration laws of the miscible pressure front, the component front, and the phase front;
based on the migration laws of the miscible pressure front, the component front, and the phase front, judging retreat speeds of the miscible pressure front, CO 2 sweep efficiencies, and miscibility degrees under different CO 2 flooding well pattern modes; and
obtaining front analysis results based on the retreat speeds of the miscible pressure front, the CO 2 sweep efficiencies, and the miscibility degrees;
wherein performing the production parameter comparison on the simulation operation results comprises:
analyzing oil production, gas production, and gas injection curves in the simulation operation results under different CO 2 flooding well pattern modes, comparing reservoir recovery rates, cumulative oil production, oil exchange ratios, and storage ratios under different CO 2 flooding well pattern modes, and obtaining production parameter comparison results;
wherein obtaining the optimal CO 2 flooding well pattern mode comprises:
combining the front analysis results and the production parameter comparison results for analysis and selection, and obtaining the optimal CO 2 flooding well pattern mode,

wherein the method is implemented in connection with the CO 2 flooding production system during CO 2 injection development operations of a reservoir.

2 . The well pattern optimization method based on the CO 2 incomplete miscible displacement characteristics according to claim 1 , wherein obtaining the fluid component data of the formation crude oil comprises:
analyzing the formation crude oil using the high-temperature and the high-pressure PVT experiments to obtain the fluid component data.

3 . The well pattern optimization method based on the CO 2 incomplete miscible displacement characteristics according to claim 1 , wherein establishing the fluid component model based on the fluid component data comprises:
fitting the fluid component data and experimental result data from the high-temperature and high-pressure PVT experiments, and outputting the fluid component model when a fitting effect is greater than a preset value.

4 . The well pattern optimization method based on the CO 2 incomplete miscible displacement characteristics according to claim 1 , wherein the reservoir parameters comprise: a reservoir depth, a reservoir temperature, a reservoir pressure, a reservoir porosity, reservoir permeability, reservoir oil saturation, a temperature gradient, a pressure coefficient, and a reservoir saturation pressure.

Assignees

• Univ China Petroleum Beijing

Inventors

• Chen Hao
• Liu Xiliang
• Li Borui
• Cheng Weiming
• Tian Xiaofeng
• Tan Xianhong
• Zhang Lijun
• Li Yang
• Yang Renfeng
• Zuo Mingsheng
• Yang Baoxi
• Zhang Ruwei
• Li Qiuting
• Lin Zhizhen

Classifications

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• E21B43/30

  Specific pattern of wells, e.g. optimising the spacing of wells · CPC title

• E21B43/164 Primary

  Injecting CO2 or carbonated water (in combination with organic material C09K8/594) · CPC title

• E21B2200/20

  Computer models or simulations, e.g. for reservoirs under production, drill bits · CPC title

• E21B43/00

  Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells (applicable only to water E03B) · CPC title