Abstract
Firstly, in view of the mechanism of rock damage of hydraulic fracturing for oil reservoir and considering the changes of matrix porosity and micro-cracks volumes for loading on the rock, the tensor damage variable of rock damage are defined by using the changes of matrix porosity and microfracture volumes and the rock damaging deterioration model of hydraulic fracturing is obtained based on damage theory. Secondly, assuming the dynamic evolution of micro- fracture of the process of hydraulic fracturing satisfy with the Logistic fork standard model, the microfracture dynamic evolution model is established based on the damage theory and according to the conservation of energy principle of hydraulic fracturing, the relation among the strain, medium porosity and damage variable of the process of rock damage evolution is determined. Finally, the model of matrix porosity and the evolution of permeability tensor of Micro- fracture for hydraulic fracturing rock is established. Take one well in Ji-Lin oil field as object, the regularity for change of parameters of rock were obtained.
