Application of Innovative High-Temperature High-Density Oil-Based Drilling Fluid Technology in the Efficient Exploration and Development of Ultra-Deep Natural Gas Resources in West China

Abstract

Abstract Tarim Basin is the biggest oil and gas bearing basin in China. The ultra-deep formations in the Tian Mountain Front Block in North Border of Tarim Basin is characterized by ultra-high temperature, abnormal high pressure, ultra-thick composite salt-gypsum formation, high-pressured brine layer, and high collapse stress formations are widely distributed, so it will bring great challenge to drilling engineering. To solve significant non-productive time (NPT) and low rate of penetration (ROP) encountered in dealing with borehole instability, stuck pipe, and high pressured brine influx in the process of drilling operation of the salt-gypsum formations and fractured pay zones, high-temperature high-density oil-based drilling fluid (HDOBM) has been recommended. The high-density drilling fluid system has excellent comprehensive properties, and it could solve the contradiction between safety drilling of ultra-deep wells and formation complexity. Until now HDOBM has been used in the drilling engineering of above 60 wells in this block. But HDOBM technology is faced with great technical problems to be solved. After many years of technical researches and spread, the existing problems in OBM, including exorbitant price, environmental pollution and high cost caused by downhole losses, have been solved, and a complete set of matching techniques are developed. HDOBM technology has provided a strong technical support for efficient exploration and development of upper-deep oil and gas resources in Tarim Basin, and it has brought great economic and social benefits.