Numerical simulation of fracture temperature field distribution during oil and gas reservoir hydraulic fracturing based on unsteady wellbore temperature field model

Abstract

In the hydraulic fracturing oil and gas reservoir, the temperature variation of the fracturing fluid has a great impact on its flow and rheology, affecting the sand-carrying capacity and friction resistance of the fracturing fluid, and also affecting the settling speed of proppant in the fracture, thus changing the sand setting profile and sand laying concentration, and finally affecting the geometry of the fracture. Based on the energy balance and continuity equations, a numerical model for the distribution of wellbore temperature field in an extended-reach well is developed, and a variation law for the wellbore and reservoir temperature fields during fracturing also is formulated. A 3D mathematical model of the temperature distribution in hydraulic fracture and near-fracture formations has been developed based on heat transfer theory and finite-difference methods, taking into account the temperature gradients of fracture length and height according to the energy balance principle and fracture fluid continuity equations. The sensitivity factors of the temperature field are clarified, the wellbore temperature field and the fracture matrix temperature field model are coupled, and the influence rule of the temperature field change of the construction layer on the fracture shape while fracturing is revealed, which provides a theoretical basis for the hydraulic fracturing design optimization.