力学温度和化学耦合作用下泥页岩地层井壁失稳研究  

EFFECTS OF TEMPERATURE, CHEMICAL AND PERCOLATION ON WELLBORE INSTABILITY IN SHALE

作　　者：王炳印[1] 邓金根[2] 宋念友 

机构地区：[1]中国石化集团国际石油勘探开发有限公司 [2]石油大学石油天然气工程学院 [3]长庆石油天然气设备制造有限公司

出　　处：《钻采工艺》2006年第6期1-4,141,共4页Drilling & Production Technology

基　　金：全国优秀博士论文基金项目;编号:200349。

摘　　要：为减少泥页岩地层,特别是高温-高压泥页岩地层的井眼失稳问题,将泥页岩地层视为孔隙介质,在综合考虑岩石特性、井眼周围三维地应力、化学及热效应等因素对泥页岩地层井眼稳定的影响的情况下建立了井眼周围有效应力计算模式,通过有限差分法进行求解。结合地层失效准则,得到了温度、渗流以及岩石特性对坍塌压力和破裂压力的影响规律。研究的结果表明对低渗透率的泥页岩来说,热效应以及化学反应在确定钻井液密度窗口时起到重要作用。计算结果对实际钻井有理论上的指导意义。Wellbore instability is regarded as a major problem in oil and gas drilling operations, especially in high temperature and high pressure shale formation. Many factor, such as rock properties, 3D stresses, chemical shale/fluid interactions and thermal effects, should be considered in the wellbore stability analysis in order to reduce wellbore instability problems. The shale formation is considered as pore medium. A comprehensive study of wellbore stability in shale formations that takes into account the 3D stresses around the wellbore as well as chemical and thermal effects is presented. The effective stresses calculation mode of shale formation in oil well is set up, combining with the failure criteria of formation, the wellbore instability mechanism is analyzed. Results form this study indicate that for low permeability shales, thermal effect and chemical interactions between the shale and water-based fluids play an important role in determining the mud-weight-window. The calculation results can guide drilling practices.

关 键 词：井壁失稳 孔隙压力 溶质浓度 地层破坏比 地层破裂压力 

分 类 号：TE21[石油与天然气工程—油气井工程]