Development module of a geothermal reservoir in sedimentary rocks in Taiwan

Abstract

The purpose of this study is to build up a geothermal development module for the geothermal reservoir in sedimentary rocks in Taiwan. The sedimentary geothermal reservoir we targeted is a saline aquifer with a formation temperature above 147? in Taiwan's sedimentary basins. The geothermal gradient of the sedimentary basin in western Taiwan is above 3.5?/100m. This makes the formation temperature higher than 130? at a depth of 3500 meters.
The reservoir simulation method is used in this study. We build up a natural-state geothermal reservoir model and then give a specific well design by considering the well replacement, well completion, production and injection rates, and the total simulation time. The basic design of the geothermal development module is using two horizontal production wells and one horizontal injection well with a horizontal section length longer than 1000 meters. The injection well is placed in the middle between them. The numerical calculation is conducted by the simulator STARS developed by CMG.
The efficiency of the geothermal development module is analyzed based on the running capacity calculation. The spatial distribution of the reservoir pressure, fluid flow, and temperature are analyzed. We use the pressure front to define the effective volume of the geothermal development module with specific well replacement and well completion designs. The injected water front is used to analyze the recirculation efficiency of the geothermal fluid. The cold front is used to define the optimal distance between the injection and production wells within an operation time period.