摘要
非常规油气资源开发过程中,通过水力压裂形成复杂裂缝网络是实现高效开发的关键技术之一,压裂过程中储层压力场的变化对裂缝扩展具有重要影响。本文基于扩展有限元理论,建立耦合损伤-滤失-应力的水力压裂裂缝动态扩展模型,研究储层压力分布对同步压裂和顺序压裂过程中裂缝动态扩展、起裂压力和延伸压力影响,对比了不同储层压力增量条件下水力裂缝偏转程度和压力变化情况。研究结果表明:(1)压裂液滤失诱发的局部孔隙压力增加会引起储层压力场发生变化,使得水力裂缝在延伸过程中的偏转程度增加,同时水力裂缝的延伸压力和起裂压力也会增加,算例显示裂缝的起裂压力和延伸压力将分别增加27.49%和27.58%;(2)对比同步压裂和顺序压裂下裂缝扩展动态,发现采用顺序压裂时裂缝偏转程度更大,且裂缝延伸压力更高。研究成果可为致密砂岩储层的有效开发提供理论依据和技术支持。
In the process of unconventional oil and gas resources development,the formation of complex fracture networks through hydraulic fracturing is one of the key technologies to achieve efficient development.The change of reservoir pressure field during fracturing has an important influence on fracture propagation.Based on the extended finite element theory,a dynamic fracture prediction model based on coupled damage-filtration-stress is established in this paper.The influence of reservoir pressure distribution on fracture dynamic propagation,fracture initiation pressure and extension pressure is studied for simultaneous fracturing and sequential fracturing.The degree of hydraulic fracture deflection and pressure changes are analyzed under different reservoir pressure increment conditions.The research results show that the increase of local reservoir pressure induced by fracturing fluid leak-off will changes the reservoir pressure field,which increase the deflection of hydraulic fractures during the extension process.At the same time,the extension pressure and initiation pressure of hydraulic fractures will increase.The calculated case shows that the initiation pressure and extension pressure of the crack will increase by 27.49%and 27.58%,respectively.Comparing the fracture propagation performance of synchronous fracturing and sequential fracturing,it is found that the deflection of the fracture is larger and the extension pressure of the crack is higher for sequential fracturing.The research results can provide theoretical basis and technical support for the effective development of tight sandstone reservoirs.
作者
肖元相
兰正凯
史华
代东每
李树生
XIAO Yuanxiang;LAN Zhengkai;SHI Hua;DAI Dongmei;LI Shusheng(Research Institute of Oil and Gas Technology,Changqing Oilfield Company,Xi an 710018,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;Nanjing Tracy Energy Technology Co.,Ltd.,Nanjing 210019,China;The Fifth Gas Production Plant,Changqing Oilfield Company,Xi an 710018,China)
出处
《中国矿业》
2021年第4期140-145,共6页
China Mining Magazine
基金
国家科技重大专项课题“致密气高效开采增产工艺技术”项目资助(编号:2016ZX05047006)
中国石油天然气股份有限公司科技攻关“长庆油田5000万吨持续高效稳产关键技术研究与应用”项目资助(编号:2016E0506)。
关键词
水力压裂
孔隙压力
裂缝偏转
压裂方式
数值模拟
hydraulic fracturing
reservoir pressure
fracture deflection
fracturing pattern
numerical simulation
