Fracture characterisation in carbonate reservoirs for geothermal production

Abstract

Subsurface energy projects carry high risk due to the lack of data available to accurately model reservoir characteristics. There is a need for high level analysis to extrapolate subsurface data from a single point (i.e. a well). The focus of this study will be on fracture characterisation in a carbonate reservoir located within the Geneva Basin for the purposes of geothermal exploration. The goal is to use fracture characterisation techniques in the form of an OBI analysis and the use of a fracture growth model with a focus on geomechanics to predict the possible fracture growth patterns. This work will allow for a better understanding of fluid flow and permeability throughout the reservoir. As well as explore the benefits and limitations of this approach. The case study is a fractured carbonate reservoir made up of limestone and marlstone packages. To calculate the paleo stress environment, the fracture data is used to back calculate the possible magnitude of the stress field during fracture formation. This choice was made after careful consideration and comparison of the fracture data with the fault data. The output of this modelling will be a DFN with multiple layers controlled by the fracture density. This model can hopefully be used in the future for dynamic simulation to understand the impacts of these assumptions and validate with production data from the well.