An Efficient and Accurate Approach for Studying the Heat Extraction from Multiple Recharge and Discharge Wells

Abstract

In order to understand the thermal recovery Behavior of an engineered geothermal system (EGS), this paper develops a model in which fluid circulates in a single, planar hydraulic fracture with a constant hydraulic aperture via multiple recharging and discharging wells. The coupled equations for heat convection in the fracture plane and heat transfer into the rock are provided for steady and irrotational fluid flow conditions. By using velocity potentials and streamline functions, the temperature along a streamline is found to be only a function of the potential. By utilizing the Laplace transformation, the analytical solutions in the Laplace space for the temperature field are found, which are numerically inverted for timedomain results. Several examples with different arrangements of injection and production wells are investigated and the comparison with other published results is provided. The semi-analytical results demonstrate that the proposed model provides an efficient and accurate approach for predicting the temperatures of a multi-well reservoir system.

Numerical Investigation on the Influence of Areal Flow on EGS Thermal Exploitation Based on the 3-D T-H Single Fracture Model

“…Gringarten and Sauty [28] used theoretical research methods to study the thermal energy extraction of geothermal systems with uniform regional flow, but Schulz [21] found that this calculation method is too cumbersome and inefficient. Rodemann [29], Heuer [30], and Wu et al [31] studied dual wells and multi-well systems, but they did not consider the effects of regional flows. Wu et al [32] used a theoretical research method to establish a two-dimensional semi-analytical model, they studied the influence of regional flow on geothermal system thermal mining, and studied well location optimization in the presence of regional flow in EGS reservoirs, but its application model is simple, it can't better reflect the real complex reservoir situation.…”

An Approximate Solution for Predicting the Heat Extraction and Preventing Heat Loss from a Closed-Loop Geothermal Reservoir

“…In addition to extracting heat from the reservoir by fluid circulation, the closed-loop system can prevent contaminants in fluids from leaking into the reservoir. As the output performance, including temperature 2 Geofluids and thermal power, of a geothermal reservoir is affected by many factors such as number and location of wells and fractures, flow rates, and velocity and direction of areal flow [6,7], an efficient mathematical model is required for studying the relationship between reservoir performance and these parameters depending on specific system configuration.…”