川西南高压页岩气井固井技术

CEMENTING TECHNOLOGIES OF HIGH PRESSURE SHALE GAS WELL IN SOUTHWEST SICHUAN AREA

川西南页岩气水平井固井存在油基钻井液密度高、黏度大,井眼不规则、套管下入困难,后期压裂对水泥环力学性能要求高等难点。从流体、固井工艺、工具、附件等几方面入手,采用范式旋转黏度计法,优选出QY高密度驱油前置液体系,使用增韧剂配制弹塑性水泥浆体系,水平段使用引鞋"抬头"技术辅助套管下入,并采用旋流刚性扶正器和弹性扶正器交叉使用的方式保证套管居中度,实现螺旋流顶替等技术。经川西南3口页岩气水平井固井试验,施工成功率达100%,水平段固井质量均达到优质,为以后类似井固井提供了参考。

For the density and viscosity of oil- base drilling fluid used in the cementing of horizontal shale gas well in Southwest Sichuan area is high,and borehole is irregular,running casing is difficult and displacement efficiency is low. In order to solve the cementing problems,the QY high- density oil- displacement pad fluid system was optimized by Fan's rotational viscometer method,the elastic- plastic cement slurry system was preparated by adding flexibilizer,and adopting cyclone rigid centralizer and elastic centralizer ensure casing centralization to realize helical flow displacement. The cementing technology has been used successfully in 3 shale gas wells in Southwest Sichuan area,the success ratio was high up 100%,and obtained good cementing quality.