Research Into Safe Drilling Technology In Formations Abnormal Pressure In Da'an Area

It has complicated geologic structures with low permeability and high pressure in the upper formations and low fracture pressure coefficient in the lower formations in the Da'an area in Jilin Province. The area has well-developed fault fissures and serious mud loss problems. While no technical casing running in the hole,drilling operations are very difficult. In the paper,some drilling accidents such as well blowouts,borehole collapses and lost circulation can be effectively prevented by using anti-suction bypass valves,optimizing well bore structures,improving amphoteric ion compound drilling fluids as well as using some cementing techniques such as early strength low weight cement slurry and dual density cement slurry and a set of safe drilling technology suitable for the formations with abnormal pressure in Da'an area have been developed. It has made the drilling operations more scientific and reasonable and has improved the drilling speed and drilling economics. At the same time,it has reduced the accidents and drilling costs,providing strong theoretical and technical support for drilling operations. It will be of significance in improving operation safety in Da'an area.