?????????????????????????

蛇曲井是不同于常规水平井的一种新型复杂结构井，其水平段在纵向上存在较大起伏，不能用常规水平井的压降模型计算其压降。文章对蛇曲井微元段的两相分层流动进行了分析，根据连续性方程和动量方程, 建立了蛇曲井水平段两相分层流动的压力梯度模型，在定产量和定井底流压两种工作制度下，给出了蛇曲井的水平段在两相分层流时的压降计算方法。应用文章所建模型和水平井的水平段压降计算模型分别计算了某蛇曲井水平段在气水两相分层流动时的压降，结果表明蛇曲井水平段的井筒压降不能用常规水平井水平段的压降模型计算，蛇曲井水平段的井筒压降不能忽略。

Pressure Gradient Model of Two-phase Flow in Horizontal Section of Snake-bending Wells

The snake bending well is a new complicated well, which is different from the conventional wells. Its horizontal section is rugged longitudinally. So, the pressure fall can’t be calculated with the pressure fall model of conventional horizontal wells. The article analyzes the two-phase layering flow for the mini element section of the snake bending well. Based on the continuity equation and the momentum equation, the pressure gradient model of two phase layering flow for the horizontal section of snake bending well is established. The calculating methods of pressure fall are proposed for two phase layering flow in the horizontal section of the snake bending well under the two working systems of constant production and constant bottom hole pressure. The pressure fall of layering flow with gas water two phases in the horizontal section of some snake bending well is calculated separately using the model established in the article and the calculating model of pressure fall for the horizontal section of the horizontal well. The results show the pressure fall of the horizontal section of snake bending well can’t be calculated with the pressure fall model of the horizontal sections of conventional horizontal wells. The pressure fall of the horizontal section of snake bending well can’t be omitted.