基于热力学模型的油井井筒析蜡规律

Research on patterns of wax precipitation in wellbore based on thermodynamic model

安永生 周大可 欧阳铁兵 杨玉贵 郑磊 杨巨顺1

中国石油大学（北京）石油工程教育部重点实验室，北京 102249 中国石油天然气管道工程有限公司，河北 廊坊 065000 中海油研究总院，北京 100028）

MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China China Petroleum Pipeline Engineering Corporation, CNPC, Langfang 065000, China CNOOC Research Institute, Beijing 100028, China)

含蜡原油的开采通常受井筒结蜡问题的影响，预测生产过程中井筒析蜡深度和析蜡量对油井清防蜡作业具有重要意义。基于预测蜡析出的热力学模型，结合井筒多相流理论，提出了井筒析蜡量的计算方法。结果表明，井筒析蜡量分布受油井产量、原油含蜡率、含水率和油管内径等因素的综合影响。产量和含蜡率的增大使井筒析蜡量增加，但高产量条件下受井筒温度增加的影响，析蜡区域显著减小；油管内径对井筒析蜡的影响较小；油井进入中后期高含水阶段时，析蜡量明显降低。在实际生产过程中，可以通过调整油井生产参数减少井筒中的析蜡问题。该方法可为高含蜡油井的清防蜡作业提供理论依据，实现高含蜡原油的正常开采。

The exploitation of waxy crude oil is usually affected by the problem of wax deposition in wellbore, and it is important to predict wax appearance point and wax precipitation rate during production process. The purpose of this study is to calculate the amount of solid phase wax in the tubing on the basis of thermodynamic model and multiphase flow theory. The result shows that the amount of the wax precipitation is associated with yield, water content, internal tubing radius and wax content of the crude oil. Wax precipitation will be more serious with the increase of yield and wax content of crude oil, while the wax precipitation region decreases with the increases of yield and wellbore temperature. Tubing radius has less effect on wax precipitation. When the well is at high water?鄄cut stage, the wax precipitation is obviously reduced. Actually, wax precipitation in wellbore can be slowed down by adjusting production parameters. This method can guide wax prevention and ensure the success of the production.

10.6056/dkyqt201905022