摘要
Abstract
Deep carbonate gas reservoirs are dedicated to 59%of natural-gas resources in Sichuan Basin.Widely affected by water in-vasion,the developed reservoirs feature high temperature and pressure,sulfur occurrence and complex wellbore conditions in addition to deep burial depth,leading to difficulties in their air lift,like shortage of design methods and tools in poor performance.Thus,covering air lift in deep wells with high pressure and drainage gas recovery without any workover,a series of new technologies of drainage gas recovery have been created for these deep sour gas wells after plenty of technical breakthroughs and practices on the design optimiza-tion,prepared high-pressure lift valve and drainage gas recovery.Results show that(i)consulted the design of conventional air lift and introduced the liquid absorption index,a method of air lift is built for deep wells with high pressure based on coupled formation-bore-hole flow.It may increase top valves in the depth of setting,reduce both lift and laying-out valves by 60%,and eliminate interference between valves;(ii)with the nitrogen-charged pressure of 35 MPa and the resistance to external pressure of 90 MPa,a high-pressure and corrosion-resistant lift valve is manufactured by valve optimization,which meets the requirements of combined acidizing and air lift together with long-term downhole operation at the well depth less than or equal to 6,000 m;and(iii)one gas lift packer with one-way injection channel as the core is planned to construct one-way process channel,and then the other packer with self-sealing and sus-pension as the core is also mapped out for this channel reconstruction.And the developed preset,isolated and span-separated drainage gas recovery tools meet technical demands of water drainage when permanent packers are used in different stages of completed wells,and drainage gas recovery without workover comes true.These air lift technologies have been applied to more than 300 deep sour gas wells in Sichuan-Chongqing area,whose the depth excesses 6,000 m and the maximum displacement of 650 m3/d,respectively.They can solve problems on the drainage gas recovery in deep sour wells with high pressure in this area.关键词
含硫深井/气举/设计方法/排水采气工具/高压气举阀Key words
Deep sour gas well/Air lift/Design method/Drainage gas recovery tool/High-pressure lift valve
