Discussion on the Application of Wire-line Coring Drilling Technology in Unconsolidated Salt Strata

Abstract:

Core recovery has always been focused on in geological core drilling, which is also an important evaluation index for core drilling. It is difficult to have good core quality by traditional core drilling method in loose, soft and salt formations, especially in those formations containing soluble salt. By the use of wire-line coring drilling, ideal coring effect can be achieved in complete formation; at the same time, the labor productivity can be greatly improved with labor intensity reduction. For the loose and soft layers, coring drilling is sometimes more difficult than traditional drilling. Taking the case of scientific drilling project in Dabuxungan salt playa, exploration and research were made on how to improve core recovery in the drilled surface layer and loose layer. The practice proved that wire-line core recovery can be largely improved in loose, soft, unconsolidated and salt bearing formations by the improvement of flushing fluid performance, property of core lifter and bit water way. The average core recovery is raised from original 30% up to 96%.