小直径电潜泵排水采气技术的研究与应用

Research and application of drain and gas production technique with minor diameter electric submersible pump

气藏进入开发中后期后,由于井筒积液的影响,目前采用的分离器等井下设备及常规电潜泵排水采气技术无法满足小直径套管完井气井生产的需要,造成气藏报废压力过高。对现有的电潜泵和分离器等井下设备进行了分析,并结合井下气水分离技术,研制了新型的小直径旋流分离器;通过分析气水分离系统的压力与流量的协调关系,采用节点分析方法,设计了气水分离的系统参数,并完善了配套工艺。利用小直径电潜泵排水采气技术成功地将107mm×98mm机组下入生产层下部,使太7井的报废压力从4.5MPa降至2.5MPa以下,至2007年12月底,该井累积产气量为160.74×104m3,累积产水量为35514m3,正常生产380d。现场应用证实,小直径电潜泵排水采气技术降低了气藏的报废压力,形成了一套提高气井产量和气藏最终采收率的新技术。

When the gas reservoirs development has been al middle-tate stage,because of liquid loading,the current downhole equipments such as separator and the conventional technique of drain and gas production by electric submersible pump are not suitable for the production of gas wells which were completed with minor diameter casing. Thus the abandoned pressure of the gas reservoirs is much higher. Based on the analysis of downhole equipment such as electric submersible pump and separator,combined with technique of down-hole gas/water separation,a magical minor-diameter cyclone separator was invented. The coordinate relationship of pressure and rate of flow in gas/water separating system was studied. By means of node analytic method,the operating parameters were optimized and the matching technology was developed. The technique of drain and gas production by minor-diameter electric submersible pump has been applied and Φ107mm × Φ98mm assembly was installed to the bottom of running depth in the reservoir successfully,and the abandoned pressure of well Tai7 decreased from 4. 5MPa to 2. 5MPa. By the end of December,2007,cumulative gas production was 160. 74 × 104 m3 and cumulative water production was 35 514m3 of this well. The normal production time is 380d. The field application proves that it is a new favorable technology to enhance gas production of the gas wells and ultimate recovery efficiency of the gas reservoirs with the abandoned pressure decline.