承压堵漏技术研究及其应用

钻遇多套压力层系地层时,需要应用承压堵漏技术来提高较低压力地层的破裂及漏失压力,扩大安全密度窗口,以满足正常钻井施工的要求.承压堵漏需要确定合理的粒径级配进行架桥和先期充填以达到承压的目的,之后需要纤维材料和可变形材料在封堵层表面形成一层致密的隔层以达到稳压的目的.将根据SAN-2工程分布理论确定的粒径级配用于承压堵漏...

Study and application of pressure bearing and lost circulation technique

When drilling into the stratum with many pressure systems,the pressure bearing and lost circulation technique can be used to increase the leak pressure and break down pressure gradient,and enlarge the safe density window to satisfy the drilling program.The theory of pressure bearing and lost circulation technique is:firstly,the bridging particles with reasonable particle size-distribution bridge and pack to pressure bearing;secondly,the fiber and deformable materials make up a compact plugged zone on the surface of sealing wall to keep steady pressure.The bridging particle which optimized according to the particle-size distribution SAN-2,and proper fiber and temporary plugging particle is used in the plugging formula.The evaluation experiment shows that the formula can plug artificial fracture with width from 1 to 5 mm and the resistance to pressure is more than 7 MPa.The pressure bearing and lost circulation formula is successfully used in Well Xinheichi 1 in which the open interval is from 2,846 m to 4,771 m and Well Heba 101 in which the open interval is from 5,408 m to 5,705 m.The drilling fluid density is 2.10 g/cm3 to 2.25 g/cm3,which increases the bearing pressure and meets the requirement of cementing.