Research on High Temperature and High Density White Oil Based Drilling Fluid and Its Application in Well 201H7-6

As the depth and horizontal length of shale gas development wells increase, the requirement for the temperature resistance and the ability of the drilling fluids to stabilize the shale formation becomes higher. A new type of high temperature and high density white oil based drilling fluid system has been developed in laboratory. Research shows that the drilling fluid system has good rheological property, low filtration loss, strong anti-debris pollution capability and good plugging performance at high temperature and high density. The system has been successfully applied in the 201H7-6 well. Application results show that the drilling fluid rheology, high temperature and high pressure fluid loss and demulsification voltage meet the field requirements. The drilling fluid performance is stable in drilling an 1800 m horizontal section, and no stuck or shale swelling and wellbore collapsing are induced. It is the first well drilled successfully with domestic white oil-based drilling fluid in Zigong Region. It also sets several new records including the deepest well, the shortest drilling cycle, and the fastest drilling speed in that region, which provides valuable experience for the future drilling activities.