寄生管充气钻井环空多相流流动特性研究

针对寄生管充气钻井技术的特征,选用Hasan多相流计算模型,确定了井筒环空的流型和压降计算方法,给出了编程求解的计算流程。利用新疆某充气欠平衡井的数据进行计算,对井筒压力、流型变化、含气体积分数随注气量、钻井液排量、井口回压的变化规律进行了研究。在寄生管充气钻井的过程中,井筒环空压力随注气量的增大而减小,随钻井液排量的增大而增大,随井口回压的增大而增大。井筒环空中的含气体积分数随注气量的增大而增大,随钻井液排量的增大而减小,随井口回压的增大而减小。井筒环空中的流型转换点随注气量的增大而下移,随钻井液排量的增大而上移,随井口回压的增大而上移。

A study of the flow characteristics of the annular multiphase flow in parasitic pipe-based aerated drilling

In light of the technological features of parasitic pipe-based aerated drilling and selecting the Hasan multiphase flow calculation model,the flow pattern of wellbore annulus and the method to calculate the pressure drop were determined and the calculation scheme for programming to find the solution was offered.Using the data obtained from an aerated underbalanced well in Xinjiang,the calculation was performed and a study was conducted to deal with the change law of wellbore pressure,flow pattern,gas fraction with the variation of injection rate,drilling fluid discharge and wellhead back pressure.In the drilling process,the wellbore annular pressure decreased with the increase of gas injection rate,increased with the increase of both the drilling fluid discharge and the wellhead back pressure.The gas fraction in wellbore annulus increased with the increase of gas injection rate,decreased with the increase of both the drilling fluid discharge and the wellhead back pressure.The reversal point for the flow pattern in wellbore annulus moved downward with the increase of gas injection rate,moved upward with the increase of both the drilling fluid discharge and the wellhead back pressure.