套管放气油井环空多相流动计算方法研究

Research on the method to calculate the multi-phase flow in the annulus of gas venting wells

为了研究套管放气油井环空多相流的流动形式,以泰勒气泡在粘滞流体中的上升流速作为主要依据,建立不同原油粘度下套管环空放气流动的截面含气体积分数计算模型和压降计算模型。模型适用于泡状流和段塞流,不适用于过渡流、环空流和雾状流。据计算模型编制了套管放气井环空流动计算软件,用该计算软件计算输出环空压力分布,将计算得到的参考点压力与实测的参考点压力对比40井次。结果表明,建立的计算模型正确、可靠,可为套管环空放气工艺提供多相流计算手段,也可为套管环空压降计算、压力估算和沉没度估算提供依据。

To study the form of the annular multi-phase flow in gas venting wells,the calculation model of gas-bearing concentration and pressure drop concerning the section of casing annular degassing flow under different viscosities of crude oil was established mainly based on the rising flowrate of Talor bubbles in viscous fluid. The model is suitable for bubbly flow and slug flow,but not for transitional flow,annular flow and mist flow. According to the model,the software to calculate the annular flow in the casing degassing well was programmed. The software was used to work out the output annular pressure distribution and then the reference-point pressure obtained by calculation was compared with the actually measured reference-point pressure. The results show that the model can provide the multi-phase calculation method for the casing annular degassing technique and also provide the basis for the calculation of casing annular pressure drop and evaluation of submergence depth.