Drilling fluid design and test method for offshore ultra-HTHP wells and new drilling fluid technology abroad

This paper presents the latest definition and classification of HTHP wells in abroad and the distribution of HTHP wells offshore in the world; sets forth the design method for drilling fluid properties for offshore HTHP wells, mainly including density, stability time under high temperature and heat, high temperature resistance, HTHP filtrate loss, anti-contamination capacity, rheological performance at low temperature and inhibition capacity to hydrates; comes up with the idea that the stability time at high temperature and heat, resistance to high temperature and HTHP filtrate loss should be the three key indicators for property design and evaluation of HTHP drilling fluid; has established the evaluation method for stability time at static high temperature and heat of drilling fluid HTHP well and dynamic resistance to high temperature through circulation simulated by ultra-HTHP rheometer Chandler 7600. This paper also provides detailed information on anti-232 ℃ ultra-high temperature chromium-free environment-friendly water-based drilling fluid, anti-220 ℃ ultra-high temperature high density cesium formate drilling fluid, anti-180 ℃ high temperature clay-free reservoir drilling fluid, anti-260 ℃ ultra-high temperature oil-based drilling fluid and anti-315 ℃ extremely high temperature fluorine invert emulsion drilling fluid in abroad. The above technologies are of reference significance to the research on ultra-high temperature or even extremely high temperature drilling fluid technology in China.