提高定向井第二界面胶结质量的钻固一体化技术

Integrated Drilling and Cementing Fluid Technique to Improve Second Interface Bonding Quality in Directional Wells

定向井由于其井眼轨迹复杂、套管不易居中,导致固井顶替效率低、泥饼清除困难。而顶替不干净的钻井液和未清除的井壁泥饼与水泥浆不相溶是固井第二界面胶结质量差的主要原因。钻固一体化技术的实质是在钻井液中引入一种可固化的潜活性胶凝材料,在井壁形成可固化的泥饼,固井时通过补充潜活性材料和加入激活剂可将其转换做为固井液,有效解决了钻井液与固井液不相溶的难题。该技术在两口定向井成功应用,有效提高了油层段的第二界面胶结质量,有效防止了各种流体层间窜流的可能性。

The complicate wellpath and eccentric casing string in directional well resulted in low mud displacement efficiency and the difficult in removing mud cake. The mud cake and drilling fluids incompatible with cement are the main reason for poor second interface quality. Integrated drilling and cementing technique can make solidifiable mud cake on wellbore. During cementing operation, through adding active agents, mud cake can be solidified along with cement slurry, which effectively solves the inoompatible problem between conventional cement slurry and mud. The applications in two complex directional wells show that the technique can effectively improve second interface bonding and prevent oil, gas and water migration among pay zones.