Abstract:

At present,the gas for carrying cuttings in gas drilling system is commonly burnt or exhausted directly,which causes pollution of environment and waste of energy.A ground system was designed to separate drilling cuttings from gas in gas drilling.The system is composed of two-stage series-wound cyclone separators and two filters(one is spare).The high-cost drilling gas purified by this system can be recovered and recycled.The granularity and mass concentration of cuttings at inlet of cyclone separator were obtained on the basis of the concentration of the drilling cuttings at wellhead.The simulation test in laboratory indicated that the separation efficiency of cyclone separator could be above 99.5%,and drilling cuttings bigger than 10 μm in diameter could be removed absolutely.The field tests indicated that the system operated steadily and reliably.The diameters of drilling cuttings at the filter outlet were smaller than 5 μm,and the mass concentration was less than 0.05 mg/m³,which could meet the requirement of compressors.

Key words: gas drilling, gas recovery, cyclone separator, separation system, separation rate

摘要：

气体钻井现有工艺都将环空返回到地面的携岩气体直接排放或放燃,既污染环境又浪费能源。根据气体钻井的特点,设计了由两级串联的旋风分离器与两台过滤器(一台备用)组成的气体钻井地面分离系统,对成本较高的气体钻井介质(氮气或天然气)进行回收和循环利用。通过对井口钻屑的采样分析和浓度计算,得到了旋风分离器入口钻屑的粒度分布和质量浓度范围。对旋风分离器进行的室内模拟试验结果表明,旋风分离器的分离效率稳定在99.5%以上,能够完全除净粒径大于10μm的粉尘颗粒。钻井现场试验结果显示,整个分离系统工作稳定,过滤器出口气体中钻屑的最大粒径小于5μm,质量浓度小于0.05mg/m³,已达到进入压缩机的要求。

关键词: 气体钻井, 气体回收, 旋风分离器, 分离系统, 分离效率