Optimization design of gas sand deflector for reverse circulation drilling

Abstract

Abstract Gas reverse circulation drilling which has a wide application prospect in complex strata of deep and ultra-deep wells can effectively improve drilling speed, protect the environment, reduce costs, and reduce downhole accidents, but its string structure is different from that of conventional drilling. In this paper, the design of integral and splitter head-in to side-out rotary sand deflecting device consists of rotating inner tube and non-rotating outer deflecting chamber, so that it can be effectively connected to the double-wall drill pipe system to ensure the normal sand deflecting of the gas reverse circulation drilling system. At the same time, the test well was verified and analyzed, and the sand-carrying efficiency was close to 92.53%. After drilling, there was no sand-settling at the bottom of the well. The average carrying rock diameter is about 10-15mm, and the maximum can be up to 30-40mm, indicating that the top-injection side-exit gas sand guide can be used for gas reverse-circulation drilling.