Stuck Releasing Technology for Differential Pressure Sticking in Offshore Wells with Complex Trajectories

Most of the offshore adjustment wells in the eastern parts of South China Sea are horizontal wells that are prone to differential pressure sticking during drilling operations. In case of sticking, it is difficult to unstuck because forces for stuck releasing cannot be transferred effectively. To improve the success rate of stuck releasing, this paper analyzes the causes of the differential pressure sticking from the aspects of formation properties, the borehole trajectory, the drilling fluid performance and the operation process of well A in the offshore Lufeng 13-1 oilfield while running ϕ177.8 mm casing. The guidelines and techniques of stuck releasing through mechanical releasing, soaking solution and seawater washing were adopted and their application effects were evaluated in this paper, and it was finally stuck releasing successfully. Stuck releasing technology for differential pressure sticking of well A in the Lufeng 13-1 oilfield can provide good construction experience and reference for wells with similar conditions.