乌兹别克复杂水平井固井工艺技术

1-G井、350井是乌兹别克斯坦的第一批水平井,表层套管尺寸大,技术套管裸眼段长,地层异常高温,盐膏层段长,油气层"上喷下漏"导致固井难度极大.经过研究摸索,(4)508 mm表层套管、(4)339.7 mm技术套管采用了插入法固井,采取两凝水泥、稀释钻井液、大排量注替等措施较好地解决了长裸眼大环空内的水泥浆窜槽问题.(4)244.5 mm尾管固井,选用厚壁套管、悬挂简单可靠的外台阶式尾管悬挂器,使用欠饱和盐水水泥浆,采取稀释钻井液、增加水泥浆的接触时间、大排量紊流顶替等措施,达到了封隔地层防止长段膏岩层蠕动之目的.(4)139.7mm完井套管固井,采用管外封隔器带分级箍加盲板的复合结构,使用不渗透水泥浆体系,较好地解决了高渗透油气层的封固问题.350井完井固井工具出现问题后,成功地实施了反向注水泥固井技术.

Cementing technology of complex horizontal wells in Uzbekistan

Well 1-G and Well 350 are the first horizontal wells in Uzbekistan. Complex well bore conditions of oversized surface casing, long open hole in intermediate string, abnormal temperature, long salt-gypsum layer and blowout upper and lost circulation bottom in oil/gas formation make it difficult to operate suc-cessful cementing. Based on investigation and study on above characteristics, measures taken are as follows: (1) Stab-in cementing was used in cementing the 508 mm surface casing and the 339.7 mm intermediate string, incorporated with using two-stage cement slurry, diluting drilling fluid and displacing with high-duty circulation, cement slurry channeling in large annular of long open hole was successfully solved.(2) In the process of the 244.5 mm liner completion, thick wall casing and out-step type extension hanger were employed, under-saturated salt water cement slurry was used, and measures such as diluting drilling fluid, prolonging the touch time of the slurry and displacing with high-duty circulation were taken to cement the formation and to prevent long gypsum layer from creeping deformation. (3) During the 139.7mm casing cementing, compound tool which includes external packer, stage collar and blind rams and nonfiltration cement slurry were used to successfully deal with cementing problem of high permeability formation. After cementing tools appeared failed, reverse circulation cementing technology was applied successfully.