STATUS QUO AND FACED CHALLENGES OF DEEP WELL DRILLING TECHNIQUES OF PETROCHINA

The drilling technique of deep well and ultradeep well is a symbol of a national drilling technique standard. The American and European’s drilling technique of deep well is always in the lead of the world. Recently, the penetration rate of deep well, drilling cycle and bit consumed per well etc. of Petrochina obtains the great progress, at the same time, it also has great development on the deep well drilling unit. Compared with the advanced level in world, Petrochina still has the very big margin in the complicated deep well drilling level. In recent years Petrochina suffered the world hard nut to crack in complicated deep well drilling process in Quele and Dina Tarimu, Yumen Kulongshan, the east of Sichuan and Xinjiang Huoerguosi etc. The outstanding expression is prevention deviation and quick drilling in hill foot high dip angle structure and over thrust body, and inaccurate identification of geologic strata in Tarimu Quele which causes sticking due to borehole shrinkage, and narrow safe mud density window that leads to differential sticking problem in Dina, and prevention malignant lost circulation in Sichuan, and complex in-situ stress, formation fractured and abnormal pressure etc. in south edge of Xinjiang. This study presents the appropriate solution for these problems, and shows off the ways drilling the same kind geologic strata.