注水泥固井顶替的极限偏心度计算  

Calculation of Ultimate Eccentricity in Eccentric Annulus During Cementing Operation

作　　者：侯婷 李晓 李明忠 王瑞和[3] 王成文[3] 

机构地区：[1]胜利石油工程有限公司钻井工艺研究院,山东东营257017 [2]中石化华北石油工程有限公司井下作业分公司工艺研究所,河南郑州450042 [3]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《应用基础与工程科学学报》2015年第4期815-822,共8页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51174226);国家科技重大专项:断块油田特高含水期提高水驱采收率技术(2011ZX05011-003);"低渗油气田完井关键技术"(2011ZX05022-006)及"胜利油田薄互层低渗透油田开发示范工程"(2011ZX05051)资助

摘　　要：固井水泥浆顶替钻井液时,当套管偏心达到某一临界值后,注水泥顶替效率很难得到改善.为确定这一偏心度临界值,在环空间隙内水泥浆顶替钻井液速度分布的基础上,参考水泥浆开始顶替各间隙处钻井液时的压力梯度条件,建立了偏心环空极限最窄间隙以及极限偏心度模型;给出了偏心环空窄间隙处钻井液零滞留时,水泥浆与钻井液性能参数之间所满足的定量关系.对模型分析并揭示了如下规律:井斜角愈大,偏心环空所允许的极限偏心度愈小;提高水泥浆的屈服应力,降低钻井液的屈服应力,增加钻井液与水泥浆的密度差可以使允许的极限偏心度更大.偏心环空极限最窄间隙以及极限偏心度模型,可根据环空套管偏心实际情况,为水泥浆和钻井液调整性能参数提供理论依据;也可用于指导大斜度井和水平井下套管时扶正器的安放设计.In the process of cementing displacement,displacement efficiency is not improved effectively when casing eccentricity exceeds a critical value. Considering the pressure gradient condition that drilling mud can be displaced by cement slurry in every annular gap,the ultimate eccentricity model was established based on displacement velocity distribution in the narrowest annular gap. Furthermore,aiming at no drilling mud left,quantitative condition about fluid properties of cement slurry and drilling mud was got. The model was analyzed and conclusions were got： As deviation angle increases,the ultimate eccentricity allowed decreases; Ultimate eccentricity allowed increases by increment of cement slurry yield stress,decrement of drilling mud yield stress and increment of density difference between cement slurry and drilling mud.The ultimate eccentricity mode can offer theoretical foundation for the adjustment of fluid properties according to practical situation about casing eccentricity,and can also guild casing centralizers spacing design in highly deviated well and horizontal well.

关 键 词：固井 偏心环空 速度分布 极限偏心度 极限最窄间隙 定量计算 

分 类 号：TE256[石油与天然气工程—油气井工程]