Application of the Wire-line Coring Technique to Large-Diameter Deep Drilling

Because of its high efficiency and good coring quality,the wire-line coring technology widely applied to small diameter solid mineral drilling projects.It is,however,little used in large-diameter deep-hole drilling in sedimentary strata.Considering the advantages and disadvantages of wire-line core drilling and oil drilling technology,this paper proposes the idea of increasing the gap between hole and drill tools and using the oil drilling technique with large pump capacity and high return speed,and the wire-line coring two-in-one technology.From production test at a 2630m depth salt mine(geothermal) exploration hole in the Yewu sag basin of Henan Province,this paper analyzes the main problems during the test following the idea aforementioned,and then proposes detailed measures to solve them.The test proves that the wire-line coring technology used in large-diameter drilling is feasible,and exhibits its merits such as low cost,safety and reliability.Meanwhile,increasing the pump capacity and enlarging the gap between hole and drill tools can avoid the drilling cuttings crushing repeatedly,thus the drilling efficiency can be highly improved.