Research and Field Application of the Axial-Torsional Coupled Percussion Drilling Technology

Enhancing the rate of penetration (ROP) is one of the goals pursued by the oil and gas drilling industry. It has been proved that percussion drilling is a feasible method to increase drilling efficiency. However, single percussion drilling technology (axial percussion or torsional percussion) cannot cater to the current needs. This paper proposed a new technology/tool called the axial-torsional coupled percussion drilling, which can use the advantages of the percussion drilling in a better way. Mechanical structure and working principle of this tool were first introduced in detail and the theoretical analysis of the impact force and the impact frequency were then conducted. It was found that both the axial impact force and the torsional impact force are in direct proportion to the fluid density and are in direct proportion to the square of the pump rate. Both the axial impact frequency and the torsional impact frequency are in direct proportion to the pump rate and are in direct proportion to the square root of the fluid density. Subsequently, a laboratory experiment was conducted to verify the above theoretical results. The tools were applied to the oil field in Xin Jiang province, China. Field application results indicate that the penetration rate of the test well is averagely 1.6–3.3 times as fast as that of the adjacent well.