摘要
涠州12-1北油田涠二段泥页岩地层层理发育、水敏性强，虽然采用了油基钻井液钻进，但井壁垮塌等井下复杂情况仍频繁发生。该油田涠二段地层岩石力学试验结果表明，涠二段泥页岩强度具有显著的各向异性，其受到的最大主应力方向与层理面法向之间的夹角为30°～70°，岩心易发生沿层理面的剪切滑移破坏，强度远低于最大主应力方向与层理面法向平行时的最大强度，这是造成定向井井壁失稳的主要原因。结合岩石力学试验结果，将层理性泥页岩视为横观各向同性材料，建立了合理钻井液密度的确定方法，确定了定向井坍塌压力随井眼轨迹的分布规律。利用定向井坍塌压力随井眼轨迹的分布规律，对该油田的定向井钻井液密度和井眼轨迹进行了优化，成功解决了涠二段地层的并壁失稳问题。
Shale formations behave remarkable stratification and high water sensitvity in Weier section, Weizhou 12-1 Block. Even with oil based drilling fluids, wellbore still sloughs frequently during drilling in shale formations. Rock mechanics tests and analysis show that the main reason for borehole collapse is the anisotropic of shale formation. The angle between the direction of maximum main stress and the direction normal to stratification face ranges 30°- 70°, and rock core is prone to shear failure. The strength is far below the maximum strength when the direction of maximum main stress is parallel to the direction normal to stratification face. This is the main reason for wellbore collapse. Based on the experimental results, the methods to determine drilling fluid density and collapse pressure along well were developed assuming stratificatified shale as isotropic medium. Using the informa tion of collapse pressure along well, drilling fluid density and well trajectory were optimized and the wellbore col lapse problem was solved successfully.
出处
《石油钻探技术》
CAS
北大核心
2010年第1期56-59,共4页
Petroleum Drilling Techniques
基金
全国优秀博士学位论文作者专项资金资助项目(编号:200349)资助
关键词
泥岩
页岩
岩石力学
定向井
坍塌层
井眼轨迹
涠州12-1北油田
mudstone
shale
rock mechanics
directional well
slough formation
hole trajectory
Weizhou 12-1 North Oilfield
