压裂液返排过程中支撑剂回流规律研究

Study on proppant backflow during flowback of fracturing fluid

油井压裂结束后,均有压裂后返排过程。返排过程中支撑剂回流是评价压裂效果的重要因素,因此有必要对其进行研究。考虑压裂返排过程中缝宽的动态变化,根据质量守恒定律和伯努利方程,考虑返排过程压裂液的滤失,得到缝内任意垂直截面的流速计算模型;对回流过程中支撑剂进行力学分析,得到支撑剂发生回流的临界条件,进而提出控制支撑剂回流的合理返排方案。根据建立的支撑剂返排模型,对吉林油田嫩平1井进行压裂液返排设计,制定出合理的控制支撑剂回流的返排施工方案。

After oil wells fracturing,process of fracturing fluid flowback always exists,and the back flow of proppant during this process is a major factor in evaluating fracturing performance,so it is necessary to study the relative problem.According to the mass conservation law and Bernoulli’s equation,a calculation model of flow velocity at any vertical section inside the fracture is established with considering the dynamic variation of the fracture width and filtration of fracturing fluid during flowback.The critical condition of proppant backflow is after mechanic analyzing of proppant during the process of back flow,and then a reasonable system backflow plan of controlling the proppant backflow is proposed.According to the established model,a reasonable flowback procedure which can control the back flow of proppant in terms of Well Nenping 1 Jilin oilfield is designed.