Horizontal well drilling techniques in subsalt oil zones

In order to increase reserves and production, the horizontal well drilling technique is chosen to be applied to the development of the subsalt oil and gas zones in Yinmai-7 condensate field well in Tarim Oilfield. The vertical distance between the oil and gas zone and the upper gypsum bed is only 30 m, so the sidetracking whipstocking and most building sections (between 0 and 70°) can only be carried out in the gypsum bed. As a result, the difficulty and risk in construction gets higher. The difficulties are analyzed and the optimal design of the casing program, the well profile, and the drilling fluid is conducted. Drilling bits and rigs are optimized. Systematic technical measures are undertaken including well control, safe tripping of intermediate casing. So the safe and smooth construction is guaranteed. Four horizontal wells have so far been fulfilled in the block. Yingmai 7-H11 well is under construction. The oil and gas production is satisfying after the horizontal well is put into operation.