Using T2well for simulating coupled wellbore-reservoir simulations

Abstract

Geothermal modelling plays a crucial role in the successful development of geothermal fields. It aids in the planning of resource utilization, as well as the assessment and management of geothermal fluid production to achieve
optimal performance. An important application of a wellbore/reservoir model is conducting future scenario simulations to make accurate forecasts using a wellcalibrated reservoir model. To accurately simulate the future
performance of geothermal wells, it is crucial to understand the coupling requirements to effectively integrate wellbore and reservoir simulators. T2Well is a simulator for nonisothermal and multiphase fluid flow that can model tightly coupled wellbore-reservoir flow. T2Well extends the capabilities of the numerical reservoir simulator TOUGH2 by integrating a wellbore sub-domain into the numerical grid, allowing it to compute flow in both the wellbore and the reservoir concurrently and efficiently. However, it appears that there are no published examples where T2WELL has been applied to a full-scale convective 3D geothermal model.
This paper presents a 3D coupled wellbore-reservoir model developed following geothermal reservoir modelling best practices. We utilized T2Well with a pure water equation of state, EOS1, to fulfil the necessary model setup requirements for a hot, convective geothermal system with reservoir temperatures ranging from 250°C to 270°C. The initial conditions for the fully coupled wellbore-reservoir simulation are based on the results of the natural state simulation of a synthetic geothermal field. The model was then used to simulate transient, late transient, and pseudosteady state production phases for a geothermal well over a one year period.