Drilling fluid technology for deep subsurface Tako-1 well

The drilling process of deep-earth Tako-1 well is confronted with a series of extreme conditions such as ultra-high temperature, ultra-high pressure and ultra-high salt. These complex conditions bring great challenges to drilling fluid technology. As the "blood" in drilling process, the performance of drilling fluid is directly related to the success or failure of drilling. This paper systematically introduced the technology of 10,000 meters deep drilling fluid. On the basis of revealing the mechanism of ultra-high temperature and high salt resistance of the key treatment agent of drilling fluid and the mechanism of the plugging material improving the pressure bearing capacity of the fracture-cavity lose layer, through the development of new materials, the construction of new systems and the development of new software, It has formed three key core technologies, which are temperature resistant 240℃ salt-water resistant drilling fluid, temperature resistant 240℃ salt-oil based drilling fluid and malignant fracture- cavity leakage and plugging. It has successfully solved the problems such as the deterioration of drilling fluid's high temperature performance, wellbore instability, friction reduction, malignant leakage and formation pollution, and has been successfully applied in the deep-ground Tako-1 well. It provides key technical support for the successful drilling of the deep subsurface Tako-1 well to 10,910 meters.