The Researches about Makeup and Selection Optimization of Shale Gas Production Casing

The mining of Shale gas demands for extreme sealing performance of casing, while the size of make-up torque will determine the initial sealing performance of casing. At present, there are seldom researches how the make-up torque affects casing threads connection strength and sealing performance. Based on the deformation compatibility principle of internal and external casing threads, derived a formula about load distribution of unusual casing thread after clicked, Established three-dimensional computational models of TP-CQ, developed only by Tianjin, and API Buttress Casing, By computational analysis, obtained the best make-up torque of the two casings. Studied the stress and contact pressures distribution while casing threads are under composite loads (inner pressure, outer pressure, tension, bending), Drawn some stress and contact pressures distribution curve for this two casing after a lot of calculation, besides optimized selection of the corresponding depth of the casing.