压裂井支撑剂回流预测研究
Prediction method of proppant flowback in fractured wells
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摘要: 新疆油田准东、石西和陆梁油田部分油井在压裂后出现支撑剂回流现象,影响了油井的正常生产,降低了压裂效果。针对压裂井支撑剂回流问题,开展了支撑剂回流预测研究,建立了支撑剂回流预测模型,以便在压裂设计阶段预测支撑剂回流趋势、采取适当的控制措施。在建立模型时,考虑了地层力学性质、地层流体、人工裂缝和支撑剂的影响。裂缝导流能力和地层渗透率决定了产出液在裂缝和基质之间的分配关系;在建立裂缝临界流量模型时,首先推导出理论临界流速,然后考虑缝宽、闭合应力和支撑剂的影响对其进行修正。现场实例计算表明,模型的预测结果与现场生产实际相符合。Abstract: Some wells experience proppant flowback after fracture treatment in Xinjiang Oilfield. Loss of proppant from the fractures limits fracture conductivity and impairs the effectiveness of fracture treatment. This paper develops a new prediction model of proppant flowback. Using this new model, the trend of proppant flowing into wellbore from fractures can be predicted and proper treatment can be taken during treatment. While developing the new model the authors took rock mechanics, reservoir fluid, hydraulic fracture and proppant into consideration. Fracture conductivity and formation permeability determine the percentage of the total flow produced through the fracture. When developing frac-ture critical rate model, the authors firstly deduced theoretic critical flow rate, and then corrected the critical rate considering fracture width, closure stress and proppant. The application of the model to fractured wells implies the results of model are in accordance with production.