气体钻井分离设备液体排料临界流速的影响因素分析

现行气体钻井存在污染环境、浪费能源等问题。为了回收钻井介质氮气或者天然气，设计了气体分离设备和液体排料方案；为了使气体钻井地面分离设备液体排料系统能够连续工作，必须要保证排料速度大于排料，临界流速。运用R．Durand临界流速计算公式分析得出，在设备结构确定以后，排料临界流速随着井口钻屑粒径、排料流体体积分数的增加而增加。通过对井口钻屑粒径影响因素的分析和排料流体体积分数的计算，将排料临界流速与钻井工况参数进行了关联，得出排料，临界流速随着注气量、钻井速度、分离器分离效率的增加而增加；随着井深、岩层硬度和孔隙率的增加而减小。

Effect of Condition Parameters of Gas Drilling on Critical Flow Rate of Material Discharge

At present, pollution the environment and energy waste existed in gas drilling system. In order to collect nitrogen or gas used in drilling, a liquid material discharge system was designed. Only when the flow rate of material discharge was higher than critical flow rate, could the system work continuously. According to R. Durand formula, critical flow rate increased with the increase of the granularity of wellhead drilling cuttings and the volume concentration of liquid discharged when the structure of equipments were determined. Based on the analysis of influencing factors of the granularity of wellhead drilling cuttings and the calculation of the volume concentration, the critical flow rate and parameters of drilling condition were correlated. Critical flow rate increased with the increase of the gas injection rate, drilling speed, efficiency of cyclone and decreased with the increase of well depth, the rigidity of the rock formation, and porosity rate.