Heat Transfer between Fluid Flow and Fractured Rocks

Abstract

Heat transfer between fluid flow and fractured rocks is governed by a very complex mechanism. The challenge of modeling this heat transfer process results from the complex geometry of rock fracture networks, variation of rock and fluid properties with temperature, and uncertainty of the flow and heat transfer types. As the heat transfer models are based on the fracture models and fluid flow models, there can be several approaches to model the heat transfer between fluid and fractured rocks. This study starts with a review of the fracture and flow models on which the heat transfer models are based. To clearly present the models, the rock fracture models are grouped into two categories: Fracture Continuum Models (FCM) and Discrete Fracture Models (DFM). A new heat transfer model based on stochastic DFM, GEOFRAC, is then introduced. A thermal drawdown equation for a geothermal reservoir is derived based on the simulation results of the new heat transfer model.