摘要
在钻井过程中,不同尺寸的井眼揭开地层时,井壁上揭露的裂隙、节理等缺陷不同,实践表明同样地层井眼越小,井壁一般越稳定,这种直观认识缺乏理论支撑,由于井壁裂隙、节理等缺陷不能被精确地刻画,井眼尺寸对井壁稳定的影响也很少用在坍塌压力计算中。针对这一问题,建立了基于Weibull统计强度尺寸效应理论的脆性地层井壁稳定模型,并对不均匀性、井眼尺寸等主要影响因素进行了讨论。结果表明:随着井周围岩均匀性的增加,井眼尺寸对井壁稳定的影响减小;相对于参考标尺的6″井眼,井眼尺寸增加,坍塌压力增加。对实际施工而言,在满足其他工程要求的前提下,对易垮塌地层应尽量采用小的井眼。
During the drilling process,when drilling with different boreholes unlocks the formation,the cracks,joints and other flaws exposed on the borehole wall are different.Experiment shows that generally the smaller the borehole,the more stable the borehole wall is.However,this intuitive understanding is lacking of theoretical support.Since the flaws of the wall such as cracks and joints cannot be accurately described,the influence of wellbore size on well stability is rarely used in the calculation of collapse pressure.To solve this problem,a brittle formation borehole stability model based on Weibull’s statistical strength-size-effect theory was established,and the main influencing factors such as inhomogeneity and borehole size were discussed.The results showed that with the uniformity of the surrounding rock increased,the impact of borehole size on the stability of the borehole wall is reduced;compared to the reference 6?borehole,in which the collapse pressure increases with the borehole size increases.For the actual construction,while meeting the requirements of other projects,use small boreholes as much as possible for the formation that is easy to collapse.
作者
邱康
褚道余
王颖
李乾
熊振宇
李基伟
崔强
QIU Kang;CHU Daoyu;WANG Ying;LI Qian;XIONG Zhenyu;LI Jiwei;CUI Qiang(SINOPEC Offshore Oilfield Services Company,Shanghai 200120,China)
出处
《海洋石油》
CAS
2022年第4期76-79,共4页
Offshore Oil
关键词
尺寸效应
脆性地层
库伦准则
坍塌压力
统计模型
size effect
brittle formation
Coulomb criterion
collapse pressure
statistical model
