气体钻井最小注气量模型的优化  

Optimized Model for Predicting Minimum Gas Injection Rate in Gas Drilling

作　　者：孙士慧[1] 闫铁[1] 毕雪亮[1] 张东[2] 

机构地区：[1]东北石油大学提高油气采收率重点实验室,黑龙江大庆163318 [2]安东石油技术 (集团)有限公司,北京100102

出　　处：《石油天然气学报》2014年第4期86-90,7,共5页Journal of Oil and Gas Technology

基　　金：国家科技重大专项(2011ZX05021-006);国家自然科学基金项目(51374077)

摘　　要：气体钻井施工中保持合理的气体体积流量对钻井的成功至关重要,为实现气体体积流量的准确预测,根据修正的Tabatabei携液最小动能理论,结合考虑岩屑和侵入流体影响的环空压降计算方法,建立了气体钻井连续携岩、携液的最小注气量模型。其中,Tabatabei携液最小动能理论的修正考虑了温度对表面张力的影响及雷诺数和液滴球形度对曳力系数的影响;由于模型所确定的最小注气量是地面条件下的,因此引入了原油体积系数、天然气体积系数、地层水体积系数来表征温度、压力对油、气、水等流体的影响。模型计算结果分析表明,气体钻井连续携岩、携液需要更大的注气量;注气量的大小与机械钻速、环空截面积、井口回压有关。It was critical important for maintaining an adequate rate of a successful gas drilling operation.To accurately predict the volumetric gas flow,based on verified Tabatabeis minimum kinetic energy theory and in combination with a method for calculating annulus pressure drawdown that considered the influence of rock cuttings and fluid invasion,a numerical model was established for determining the required minimum gas flow rate for continuously carrying cuttings. The effects of temperature on interfacial tension and Reynolds number and sphericity on drag coefficient were taken into account in modifying minimum kinetic energy theory.Because the required minimum flow rate was determined at surface condition,oil volumetric coefficient,gas volumetric coefficient and the volumetric coefficient of formation water were introduced to represent the impact of temperature and pressure on oil,gas and water.Model calculation results show that a higher gas injection rate is required for continuously carrying cuttings and liquid during gas drilling.And the size of required gas injection rate is related with ROP,annulus area and back-pressure on wellhead.

关 键 词：气体钻井 最小动能 最小注气量 携液 携岩 

分 类 号：TE22[石油与天然气工程—油气井工程]