煤层气同心管气举排水工艺技术研究

Study of Air-lift Dewatering Technology Using Concentric Pipe

在煤层气抽采过程需要不断排出煤层水以降低煤储层压力,使吸附的甲烷气达到解吸压力之下而解吸,在这个过程中需要不断地排出煤层水以维持较低的煤层压力。目前主要采用抽油机、电潜泵、螺杆泵等油田的开采设备和技术,存在煤粉卡泵、杆管柱磨损、调节工作制度困难等问题,因而研制了煤层气同心管气举排水工艺系统。通过室内试验,表明该系统将排水通道、动力气通道和采气通道分离开来,有效地解决了常规举升方式存在的问题,可以满足沉没度10m以内、排量60m3/d以内变化的要求,为煤层气井的低成本抽采提供了新的排采方式。

In the process of CBM development, it is necessary to dewater the coal seam to reduce the pressure of coal reservoir until it is below the desorption pressure of the absorbed methane. In the process, it is necessary to dewater continuously the coal seam in order to maintain a comparatively low seam pressure. Currently, the technology and equipment for dewatering mainly consists of those used in oilfield, and they are： pumping unit, submerged electric pmnp, screw pump, etc. The existing problems are jamming of pump due to coal fines, corrosion of pipe string, adjustment work system. Therefore, an air-lift dewatering technological system using concentric pipe string was studied. The indoor lab tests have shown that the system separates the dewa- tering channel, the power gas and the gas extraction channel, which effectively solved the existing problems with conventional airlift method. It can meet the requirements that the submerged depth should be within 10m, and displacement within 60m^3/d. It provides the CBM wells with a new dewatering method at a low extraction cost.