Application and understanding of packer-type liner tieback technology in Nanpu Oilfield

The burial depth of buried hills in Nanpu Oilfield is deep, the reservoir temperature is high, and the formation pressure coefficients are between 0.99 and 1.01, so overflow or fluid loss may occur even there is a slight change in drilling fluid density. For this end, a special packer-type liner tie-back technology has been developed, whose tie-back device includes the tie-back plug with top packer, blind sub, vortex sub and float collar; the liner is set when the packer is setting, using anti-back slips, which prevents upward movement of casing retraction caused by the difference between cement slurry and drilling fluid density during cementing. This technology procedure is tieback, setting, and cementing, which can effectively prevent lost circulation. Field practice shows that this pipe string used in this packer-type liner tie-back technology is rational in structure, easy to use, good sealing reliable of the tie-back device and resistant to high temperature, specially solve the liner tie-back problem in Nanpu Oilfield, where has co-existence of overflow and leakage, and has been successfully used in the oilfield.