Journal of Southwest Petroleum University(Science & Technology Edition) ›› 2025, Vol. 47 ›› Issue (3): 1-9.DOI: 10.11885/j.issn.1674-5086.2024.09.01.01

• SPECIALIST FORUM •     Next Articles

Researches on and Prospect of ROP Improvement in Deep and Ultra-deep Oil and Gas Drilling

ZHU Xiaohua1,2   

  1. 1. MOE Key Laboratory of Oil and Gas Equipment, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploration, Southwest Petroleum University, Chengdu, Sichuan 610500, China
  • Received:2024-09-01 Published:2025-07-11

Abstract: Increasing ROP, controlling complex downhole conditions, and improving drilling-encounter ratio are the three major challenges in deep and ultra-deep oil and gas drilling. Since the “12th Five-Year Plan” period, China has made significant progress in drilling technologies such as rotary steering, precise pressure control, efficient PDC bits, and drilling tools, and a number of ultra-deep wells of about 8 000 meters have been drilled. This paper focuses on the ROP improvement and summarizes the recent research progress in drillstring dynamics, efficient rock breaking and drilling tools, mainly including the review of the development of drillstring dynamics theory, the evaluation methods of drillstring vibration, buckling, and dynamic friction torque. Focusing on the theory of ductile-brittle critical failure of rock, the selection and optimal design method of drill bit based on ductile-brittle critical failure are deeply analyzed. This paper also systematically introduces a series of drilling tools based on impact accelerated crack growth and vibration drag reduction, and the relevant analysis and evaluation method based on CAE numerical calculation. The comprehensive ROP improving method based on efficient energy transfer and utilization is summarized and analyzed. Finally, suggestions are provided for increasing research efforts on downhole power drilling tools and new rock breaking methods. The research work has a certain reference value for improving the drilling speed of deep hard formation and ultra-deep complex structure wells.

Key words: deep and ultra-deep formation, ROP improvement, drillstring dynamics, ductile-brittle transition, drilling tools for improving ROP

CLC Number: