压力衰减储层直井井壁稳定性研究  

Research on Wellbore Stability of Vertical Wells in Pressure Depleted Reservoirs

作　　者：冯永存[1] 李晓蓉[1] 蔚宝华[1] 邓金根[1] 

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249

出　　处：《长江大学学报（自然科学版）》2011年第10期50-53,277,共4页Journal of Yangtze University(Natural Science Edition)

摘　　要：我国大部分油田已进入开发中后期,很多油田储层孔隙压力出现了严重的衰减。储层压力衰减会影响储层地应力,进而导致钻井安全泥浆密度窗口的改变。研究了储层压力下降对地应力及直井井壁围岩应力的影响,推导了压力衰竭储层直井坍塌压力和破裂压力的预测模型,并进行了实例分析。结果表明,储层压力衰减导致直井坍塌压力和破裂压力的降低,钻遇储层时要及时调整钻井液密度,主要防止储层漏失。该研究结果可为压力衰减储层中直井钻井设计提供参考。Most of the oilfields in our country are in the middle or later period of development.Reservoir pressure in many of these oilfields depletes significantly.The pressure depletion can induce the changes in in-situ stress and further influence the safe density of drilling mud.This paper studies the effects of reservoir pressure depletion on in-situ stress in the formation and stress state on the borehole;then,it derives the prediction model of collapse pressure and fracturing pressure considering pressure depletion;finally,it analyzes a field example.Research result shows that pressure depletion would result in the reduction of collapse pressure and fracturing pressure of the formation.So mud density should be adjusted timely while drilling through depleted reservoir in order to prevent formation leakage.The research provides a reference for vertical well design in depleted reservoirs.

关 键 词：压力衰减 直井 地应力 坍塌压力 破裂压力 井壁稳定 

分 类 号：TE256[石油与天然气工程—油气井工程]