ROP Improvement Technology for High-Pressure Terrestrial Tight Abrasive Formations in the Yuanba Gas Field

Drilling footage and service life of cone bits were short and the comprehensive benefits were low in the Yuanba Gas Field,due to the fact that the Ziliujing and Xujiahe Formations in deep onshore regions are tight, hard and highly abrasive. Based on practical drilling situations, high-efficiency drill bits were selected through the analysis of the formations’ drillability and rock breaking principles. Appropriate dynamic drilling tools were selected according to the matching principle of drill bits and drilling tools.Then, field tests were conducted on the following three drill bits and tools combinations, including imported impregnated diamond bits and high-speed turbines, impregnated diamond bits and screws, and cones and PDC. Drill bits were selected on the basis of specific energy for unit footage consumption, and the three combinations were economically evaluated using breakeven analysis. Based on field test results, adoption was recommended for the homemade impregnated diamond bit and high-speed screw drilling for high-pressure and highly abrasive tight formations, and the impregnated diamond bit and high-speed turbo drilling for Zhenzhuchong Formation with high gravel content, and the cone and PDC drilling for high-pressure tight formations with more interbeds of sandstones and mudstones. Studies showed that the application of homemade impregnated diamond drill bit and high-speed screw drilling gave the best economic benefit contributions, followed by cone and PDC drilling followed by the imported impregnated diamond drill bit and high-speed turbo drilling.