海上高含蜡油田井筒清蜡周期预测图版建立及应用

渤海部分高含蜡油井投产后面临比较严重的井筒结蜡问题，现场作业人员一般根据生产经验确定清蜡周期，导致准确度低、清蜡作业成功率有限。根据海上油井生产管柱特征，以Ramey温度场计算数学模型为基础，结合井筒结蜡速率模型计算得到了井筒结蜡剖面，推导建立了电潜泵井清蜡周期预测方法，并进一步绘制了某油田A区块清蜡周期和清蜡深度预测图版。结果表明，清蜡周期随产液量的下降呈幂函数形式变短，随含水率增加呈指数函数形式增加。根据清蜡周期预测图版，预测3口井的清蜡周期分别为11 d、15 d、46 d，实际清蜡周期分别为8 d、12 d、39 d，预测结果与实际基本吻合。该方法同样适用于陆地油田自喷井确定清蜡周期和清蜡深度，对高含蜡电潜泵井、自喷井及时制定清防蜡措施具有借鉴意义。

Establishment and application of paraffin removal cycle prediction chart in offshore highly waxy oil fields

Some highly waxy oil wells in Bohai Sea were facing serious well paraffin deposition after putting into operation. Field workers used to determine paraffin removal cycles based on production experience, which led to low accuracy and limited success rate of paraffin removal operation. According to the characteristics of offshore oil well production strings and based on Ramey temperature field calculation mathematical model and wax deposition profile calculated by well wax deposition rate model, a prediction method for wax removal cycle of ESP wells is deduced and established, and a prediction chart for wax removal cycle and wax removal depth of block A in an oilfield is further drawn. The results show that the wax removal cycle decreases in power function form with the decrease of liquid yield and increases in exponential function form with the increase of water content. According to the prediction chart of wax removal cycle, the predicted wax removal cycles of three wells are 11 d, 15 d and 46 d respectively, and the actual wax removal cycles are 8 d, 12 d and 39 d respectively. The predicted results are basically consistent with the actual ones. This method can also be used to quickly and accurately determine the period and depth of paraffin removal in gushers in land oilfields. It has important guiding significance for timely formulation of paraffin removal and prevention measures in highly wax ESP wells and gushers.