水力裂缝导流能力计算方法

Calculation method of hydraulic support fracture conductivity

为了得到更准确的水力支撑裂缝导流能力计算方法,考虑在应力作用下支撑剂发生应力溶解、扩散、沉积、弹性嵌入、蠕变等对支撑裂缝导流能力的影响,分析4类裂缝渗透率与有效应力之间的关系式,其中Nelson模型比较准确,误差仅为1.41%;建立支撑裂缝初始渗透率计算表达式,通过引入裂缝渗透率伤害系数建立考虑应力影响的支撑裂缝渗透率计算表达式;利用建立的支撑裂缝渗透率表达式,分析裂缝宽度、支撑剂半径和有效应力对支撑裂缝渗透率的影响。研究结果表明,裂缝宽度和有效应力越大,裂缝渗透率越低,支撑剂半径越大,裂缝渗透率越大。

In order to obtain a more accurate calculation method of hydraulic fracture conductivity,the effect of proppant stress dissolution,diffusion,deposition,elastic embedding,creep and other effects were considered on the conductivity of propped fractures under stress.The relationship between permeability and effective stress of four types of fractures was analyzed,among which Nelson model is more accurate with an error of only 1.41%.The expression of initial permeability of supporting fracture was established.By introducing the damage coefficient of fracture permeability,the calculation expression of fracture permeability considering the influence of stress was established.The influence of fracture width,radius of proppant and effective stress on the rate of proppant fracture permeability was analyzed.The results show that the larger the fracture width and effective stress,the lower the fracture permeability is,the larger the radius of proppant,and the greater the fracture permeability is.