基于功图的油井动液面计算模型及应用

针对油井动液面实时监测困难和基于地面功图推算误差大的问题,以油井地面示功图为条件,运用一维带阻尼波动方程求解泵功图;并研究了泵功图曲线各点的曲率计算模型、固定阀和游动阀开闭点确定方法以及泵功图上下冲程载荷差的计算方法。结合井筒及环空流体压力分布计算相关式,建立了基于泵功图计算动液面深度的数学模型。经51口油井的计算分析,计算动液面深度与实测动液面深度的最大相对误差为14.84%,最小相对误差为0.48%,平均相对误差为3.61%;相对误差在10%以内的有48口,占计算总井次的94.1%。研究结果表明所建立的计算模型具有较高的精度,能够实现了油井动液面的实时、准确计量,提高了油井生产分析的及时性,有利于油田数字化和信息化建设。

The Study and Application of Dynamic Liquid Level Calculation Model based on Dynamometer Card of Oil Wells

For the difficulty of the well dynamic liquid level real-time monitoring and the problem of the great error that the figure calculated based on the ground dynamometer card, to take the ground dynamometer card as the condition, use the one dimensional volatility equation with damping to get the pump indicator diagrams, and studied the curvature calculation model of the pump dynamometer card curve at every point, the determination method of the opening and closing point of fixed valve and traveling valve, the calculation method of up and down load difference of pump dynamometer card, combining with wellbore and annulus fluid pressure distribution calculation related type, established the mathematical model that calculate the dynamic liquid level depth based on pump dynamometer card; by the calculation analysis of 51 wells, the maximum relative error between the calculated dynamic liquid level depth and the measured liquid level depth is 14.84%, the minimum relative error is 0.48%, the average relative error is 3.61%; there are 48 wells that the relative error is within 10%, account for 94.1% of the total calculated wells.The results show that the established calculation model has higher precision, could realize the real-time, accurate measurement of the dynamic liquid level of oil wells, improve the timeliness of the production analysis of oil wells, be helpful for the digitization and information construction of oilfield.