超临界二氧化碳喷射压裂井筒流体相态控制  

Phase control of wellbore fluid during supercritical CO_2 jet fracturing

作　　者：程宇雄[1] 李根生[1] 王海柱[1] 沈忠厚[1] 蔡承政[1] 

机构地区：[1]中国石油大学油气资源与探测国家重点实验室,北京102249

出　　处：《石油学报》2014年第6期1182-1187,共6页Acta Petrolei Sinica

基　　金：国家自然科学基金创新研究群体项目(No.51221003)和国家自然科学基金重大国际(地区)合作项目(No.51210006)资助

摘　　要：为了探索超临界CO2喷射压裂的井筒流体相态控制方法,建立了超临界CO2喷射压裂井筒流动模型,进行了实例计算和分析,并以异常低地温梯度的地层为例研究井筒流体的相态控制问题。结果表明:超临界CO2喷射压裂过程中,随着井深增加,井筒压力逐渐增高,井筒温度先增高后在接近压裂层位处开始降低;井筒压力很容易达到CO2流体的临界压力,井筒温度的控制是超临界CO2喷射压裂相态控制的关键;如果地温梯度过低,压裂层位井筒中的CO2流体将达不到临界温度,影响超临界CO2喷射压裂作业的正常进行,此时提高注入CO2流体的温度,可有效促进压裂层位的CO2成为超临界态。该研究可为超临界CO2喷射压裂技术的流体相态控制提供一定的借鉴。This study investigated the method for phase control of wellbore fluid during supercritical CO2 jet fracturing.A wellbore flow model of supercritical CO2 jet fracturing was built and then used for example calculation and analysis.Moreover,the phase control issue was investigated in an example formation at a subnormal geothermal gradient.During supercritical CO2 jet fracturing,wellbore pressure increases with increasing well depth,while wellbore temperature first increases and then decreases near the target zone.Wellbore pressure easily reaches the critical pressure,and the control of wellbore temperature appears to be the key factor for phase control of supercritical CO2 jet fracturing.When the geothermal gradient is significantly low,CO2 fluid in the wellbore of the target zone can not reach the critical temperature,thus affecting the process of supercritical CO2 jet fracturing.In this case,increasing the temperature of CO2 fluid injected into the wellbore will effectively promote CO2 fluid to enter the supercritical state.This study provides a reference for phase control of wellbore fluid during supercritical CO2 jet fracturing.

关 键 词：超临界流体 CO2 喷射压裂 井筒 相态控制 传热 

分 类 号：TE377[石油与天然气工程—油气田开发工程]