支撑剂回流理论研究

Theoretical Study on Proppant Reflux

压裂是低渗透油藏的重要开发手段,而压裂返排施工关乎压裂成败。通过对压裂过程中的支撑剂进行受力分析,利用牛顿第二定律分析了支撑剂在水平和竖直方向上的运动状态,建立了支撑剂回流模型。利用室内模拟实验,模拟了在单条裂缝中的支撑剂运动,分析了不同返排流量下的支撑剂运动状态,验证了支撑剂回流模型的准确性。通过室内模拟实验和回流模型计算分析了实际压裂过程中支撑剂在裂缝中的运动,得到支撑剂在裂缝中的运动距离相对于裂缝半长很小,为现场施工过程中进行顶替返排提供理论支撑。

Fracturing is an important means of developing low permeability reservoirs; the construction of fracturing fluid flowback is very key step in the fracturing process. In this paper, through analyzing the stress of proppant in the fracturing process, the motion states of proppant in horizontal and vertical directions were analyzed by Newton＇s second law, the proppant backflow model was established. Through indoor simulation experiment, proppant movement in a single crack was simulated, and proppant motion states under different flowback rates were analyzed to verify the accuracy of proppant backflow model. Proppant motion states in the cracks during actual fracturing process were analyzed through indoor simulation experiments and model calculation, it＇s pointed out that proppant movement distance in cracks was very small relative to the fracture half length, which provided theoretical support for the construction of flowback process.