煤层气田开采后期地面集输增压方式优化

Optimization of on-ground gathering transportation and pressure-improving modes in later developing period of CBM Field

沁水盆地南部是我国煤层气开发试验最早的地区之一,整体地质条件较好,开发条件佳。气田投产第5个年头产量达到峰值后开始逐渐递减,目前大部分生产井已进入开发生产后期。随排采时间增长,气井压力不断下降,产气量递减速率快,仅依靠单井和管网自身压力难以完成整个气田的集输过程,稳产形势严峻。结合气田开发后期面临的一系列问题,为增加气田全生命周期集输工艺的灵活性,对气田管网的压力系统进行优化。通过改变集输系统的压力级制,优选增压设备,有效降低了井口回压,单井产量显著提高,延长了气田的开采寿命,实现了老区高效开发。

Southern Qinshui Basin is one of the earliest coal-bed methane developing area in our country which has great geological and developmental conditions. Average daily gas production reached its peak value at the fifth year,then start to decline. Now most of the production wells have entered the later developing period. As time went by,pressure of the gas well declined continuously,and the production decline rate increased persistently. It was hard to complete the field gathering process only relying on the pressure of gas wells and pipe network themselves,keeping stable production had become a serious challenge. Facing series problems in the later stage of the gas field development,optimized the gathering system to increase the full life-cycle gathering process flexibility of the gas field. By changing the pressure levels of the gathering system,optimizing the supercharging equipment,which effectively reduced the wellhead backpressure. Now the production of gas wells has improved significantly,the life of gas field was prolonged,even the old field has obtained its better economic recovery.