MPD Technology Applied In Shale Gas Wells Of Sichuan Wei Yuan

During the drilling process, a series of complex drilling problems will be caused by narrow drilling fluid windows. When the drilling fluid density is small, the formation pressure is unable to be balanced, it may cause the well kick and blowout,causing a major accident, when the drilling fluid density is bigger, fluid column pressure is greater than formation pressure and leakages the formation, make the drilling fluid permeate into the formation, causing serious pollution on the environment. MPD is a new drilling technology which can solve a lot of problems during drilling process like spray, leakage, sticking,provides new ideas and solutions.According to the WeiYuan area shale gas geology research, thick shale formationgs and in some areas exist abnormal high pressure,combined with these characteristics, we analysis and several different application modes of pressure control drilling technology, to keep the bottom hole pressure in equilibrium, ensure wellbore safety as the general principle, and put forward the concrete scheme of the control pressure drilling technology,and carried on the experiment.According to Wei Yuan shale gas well geology survey, the overall scheme and MPD equipments get researched. In addition, MPD technology is developed suitable for Sichuan Wei Yuan shale gas wells to solve practical drilling problems.In the process of theoretical analysis, finding the dual-gradient drilling technology can maintain dual density drilling fluid in the annulus system to control the bottom hole pressure,pressurized mud cap drilling technology can solve the serious fluid leakage, applying to the land and sea loss.The block reservoir formation of this article block pressure is high, poor stability, using oil-base drilling fluid and the horizontal well construction, it is easy to cause leakage phenomenon, for bottom hole in atmospheric pressure control technology.In the process of field drilling, it has sidewall quickly problem, frequently overflowing and losting circulation, drilling fluid loss situation. We use MPD to close wellhead, applying back pressure and cooperating with the cementing job. Adopted the pressure control and loop into mud plugging drilling fluid to make plug success.