石油钻采工艺2025，Vol.47Issue(6)：729-738,10.DOI:10.13639/j.odpt.202508020
干热岩储层超临界CO2压裂缝内动态流动传热特性研究
Study on transient flow and heat transfer characteristics of CO2 fracturing in hot dry rock reservoirs
摘要
Abstract
Supercritical CO2 fracturing offers advantages such as reduced initiation pressure and the formation of complex fracture networks,making it one of the effective methods for hot dry rock reservoir stimulation.Addressing the challenges of unclear fluid flow and heat transfer characteristics within fractures during supercritical CO2 fracturing in high-temperature hard rocks,and the difficulty in predicting CO2 phase behavior,a coupled flow-heat transfer model for supercritical CO2 fracturing in geothermal reservoirs was established.This model reveals the influence patterns of pump column and reservoir parameters on the flow and heat transfer characteristics within the fractures.The study indicates that CO2 rapidly transitions to a supercritical state within the first 1-5 m of the fracture entrance.Its density and viscosity decrease by approximately 50%at a fracture length of 25 m before stabilizing.Parameter sensitivity analysis indicates that injection flow rate,rock strength,and injection temperature significantly influence the fracturing effectiveness.Increasing the injection flow rate from 0.04 m3/s to 0.1 m3/s raised the injection pressure by only 0.2 MPa(an increase of 0.66%),while extending the fracture length by 78 m(an increase of 73.2%).Simultaneously,CO2 demonstrated superior fracture generation capability in high-strength reservoirs.Increasing the rock elastic modulus from 40 GPa to 60 GPa resulted in a 15 m increase in fracture length(an increase of 8.44%).Injection temperature was increased from 0℃to 30℃,resulting in a 12 m increase in fracture length(an increase of 6.87%).The reservoir temperature had less than a 2%impact on injection pressure and fracture length,rendering it negligible.These findings provide theoretical support for designing supercritical CO2 fracturing process parameters and offer significant guidance for advancing the efficient development of geothermal resources in hot dry rocks.关键词
干热岩/裂缝扩展/超临界CO2/压裂/流动传热特性/耦合模型Key words
hot dry rock/fracture propagation/supercritical CO2/fracturing/flow-heat transfer characteristics/coupled model分类
能源科技引用本文复制引用
DANG Donghong,NAN Weitong,FAN Baichen,WANG Haizhu,WANG Bin,HUANG Zhongwei,FANG Yuze,Alexey Cheremisin..干热岩储层超临界CO2压裂缝内动态流动传热特性研究[J].石油钻采工艺,2025,47(6):729-738,10.基金项目
国家自然科学基金双碳专项项目"页岩油储层超临界CO2聚能压裂与封存基础研究"(编号:52341401) （编号:52341401）
国家自然科学基金国际(地区)合作与交流项目"非纯CO2压裂干热岩裂缝扩展机理及造储方法研究"(编号:W2412078) （地区）
中国石油大学(北京)科研基金项目"页岩复杂缝网内微细支撑剂铺置与压嵌规律研究"(编号:2462022BJRC002)、"CO2注气井筒流动特性与智能控制方法研究"(编号:2462024YJRC019). （北京）
