APPLICATION OF QPL-Y HIGH STRENGTH BOREHOLE PLUGGING AGENT IN ANTILEAKAGE AND LOSS CIRCULATION CONTROL WHILE DRILLING

Severe lost circulation were encountered frequently in adjustment well drilling. They are characterized by an abundance of lost circulation intervals and corresponding changing of fissures with pressure surges. When QPL-Y agent is used, the shattered lost circulation zones were firmly bound and sealed and enhanced formation strength to pressure were obtained by formation of hydrolyzed calcium aluminate and hydrolyzed calcium sulfate and formation of spatial lattice structure with active fibers, swelling bentonite, asphalt particles and some polymers that aggregate and solidify at high temperature and pressure when they are penetrate in the lost zones. The rig-site application of 6 wells provided a 100% success ratio.