盐间非砂岩地层支撑裂缝长期导流能力实验研究

Experimental study on the long-term flow conductivity of the hydraulic fracture in the non-sandstone reservoir between salt formations

盐间非砂岩地层是强度较低、塑性变形量大、流变性强的储层,如果支撑剂选择不当,支撑剂嵌入将很严重,支撑裂缝的长期导流能力将损失巨大.运用FCES-100裂缝导流仪,模拟盐间非砂岩地层的温度与闭合应力条件,采用3种支撑剂、2种铺砂浓度,进行了盐间非砂岩地层岩石的支撑裂缝长期导流能力实验.发现:盐间非砂岩地层的支撑剂嵌入问题较严重,有必要使用高铺砂浓度、优质以及大粒径的支撑剂,以获得更高的支撑裂缝长期导流能力.根据实验结果回归出了在70℃、20MPa闭合压力情况下,支撑裂缝导流能力随时间变化的关系式,可以用其来预测盐间非砂岩地层中支撑裂缝导流能力的衰减趋势,对现场压裂有一定指导意义.

The non-sandstone reservoir between salt formations has lower strength,greater plastic deformation and strong rheology,so the long-term flow conductivity of the hydraulic fracture in this reservoir will greatly decrease if suitable proppant is not chosen.The long-term flow conductivity of the fracture in the non-sandstone cores is studied by simulation experiments FCES-100 fracture flow conductometer.In the experiments,the temperature and the closing stress in this type of reservoir are simulated,and three types of proppant of two concentrations are used.It is shown that there is serious proppant embedding in this type of reservoir.So the proppant of larger particle size and higher concentration should be used for increasing the long-term flow conductivity of the hydraulic fractures.The relationship between the flow conductivity and time at 70 ℃ and 20 MPa is obtained by the regression of experimental data,which can be used for the prediction of the decreasing tendency of the flow conductivity of the propped fractures in this type of reservoir and can provide guidance for field fracturing operation.