干热岩储层多簇缝网压裂热流固顺序耦合模型研究

doi:10.13809/j.cnki.cn32-1825/te.2022.06.005

摘要/Abstract

摘要：

针对干热岩储层压裂的热流固耦合模型计算复杂且难以实现大规模多簇缝网压裂模拟的问题，提出了一种干热岩压裂顺序耦合模拟方法，建立了单簇裂缝和多簇缝网的裂缝扩展热流固顺序耦合模型，实现了大规模干热岩多簇缝网压裂的热流固顺序耦合模拟。利用多簇缝网热流固顺序耦合模型讨论了地层温度、干热岩脆性指数、应力场、排量等关键参数对多簇缝网扩展的影响。模拟结果表明：较高的温差、较大的岩石脆性指数以及较大的注入排量能促进缝网的扩展，而较大的应力差不利于缝网的扩展。

关键词: 水力压裂, 干热岩储层, 热流固耦合, 多簇缝网, 数值模拟

Abstract:

In order to solve the problem that thermal-hydro-mechanical coupling model of hot-dry-rock（HDR） reservoir fracturing is complex and it is difficult to achieve large-scale multiple cluster of fracturing network simulation, a sequential coupling simulation method of HDR fracturing is proposed. By establishing a fracture expansion thermodynamic solid sequential coupling model of single cluster fracture and multi-cluster fracture network, the thermal-hydro-mechanical sequential coupling simulation of large-scale HDR fracture network is realized. The influence of brittleness index, stress field displacement and other key parameters on the propagation of fracture network are analyzed in this model. The results showed that high temperature difference, large brittleness index and large injection pumpage could promote the propagation of fracture network, but large stress difference is not conducive to the propagation of fracture network.

Key words: hydraulic fracturing, hot-dry-rock（HDR） reservoir, thermal-fluid-solid coupling, multiple cluster of fracturing network, numerical simulation

中图分类号:

TE319

陈劭颖,王伟,杨清纯,张立松. 干热岩储层多簇缝网压裂热流固顺序耦合模型研究[J]. 油气藏评价与开发, 2022, 12(6): 869-876.

CHEN Shaoying,WANG Wei,YANG Qingchun,ZHANG Lisong. Sequential coupling thermal-hydro-mechanical model for multiple cluster of fracturing network fracturing in dry hot rock reservoir[J]. Petroleum Reservoir Evaluation and Development, 2022, 12(6): 869-876.

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参数名称	参数值	参数名称	参数值
模型尺寸（m）	200×400	压裂液黏度（Pa·s）	0.001
网格基本尺寸（m）	0.5~2.0	射孔长度（m）	16
储层渗透率（10^-3 μm²）	0.000 1	Cohesive单元厚度（m）	0.001
储层孔隙率（%）	10	黏性正则化系数	0.000 1
压裂液密度（kg/m³）	1 000	原位地应力（MPa）	50/65/50
储层弹性模量（GPa）	15	初始孔隙比	0.1
储层泊松比	0.15	压裂液流量（m³/min）	6
损伤强度（MPa）	6/20/20	储层温度（℃）	100
单元损伤位移（m）	0.001	压裂液温度（℃）	10
滤失系数	1×10^-14	注入时间（s）	4 000