TWO TECHNICAL MEASURES FOR DIAMOND WIRELINE CORE DRILLING INTO BAD FORMATIONS

Two technical measures for diamond wireline core drilling into bad formations are introduced in this paper to solve two outstanding problems. The first one is that when drilling into the formations which collapse easy, leak water out, or sensitive to water, the diamond drill bits whose outer diameters are enlarged, are used in order to enlarge the ring-shaped interstice in hole, and decrease the resistance to drilling. The second one is to set elementary directed drilling holes, to improve the stability of the drilling tools at movement condition, and to use the wedgy pipe in order to set the bent hole right.