A Fully-Coupled Implicit Transient Two-Phase Wellbore Simulator

Abstract

Boreholes under operation conditions typify a highly non-linear and complexly coupled thermo-hydraulic-chemical (THC) system. Multiple parameters, such as temperature, pressure, specific heat, enthalpy, viscosity, flow regime, heat transfer, degassing, steam quality, salinity and solubility are inter connected. Production and injection often entail several engineering challenges and operational problems within the boreholes but also up and down stream (reservoir-power plant-reservoir), which can be very diverse in their character. Finding solutions or working on process optimization prerequisite a profound understanding and a reliable tool to quantify these processes. Compared to reservoirs, the processes in boreholes are highly dynamic and fluctuating. Most existing simulators provide either only steady state solutions or are based on a just weakly coupled numerical scheme. We develop a new tool solving for the aforementioned parameters in a fully-coupled, implicit, and transient manner, which is a prerequisite to realistically model dynamic borehole conditions. Herein, we present the current state of the development of the simulator for multicomponent non-isothermal two-phase flow. To demonstrate the capabilities of the code, validation results and synthetic test cases for compressible single-phase flow as well as two-phase drift-flux are shown. Applications of such a tool are manifold. It can be used for exploration in early stages of the reservoir development, to constrain the static formation temperature (SFT) from logging data measured under dynamic production/injection conditions. What-if-calculations support the design and dimensioning of future power plants. Optimization of production and injections scenarios are more reliable when they are based on solid quantifications of thermo-hydraulic borehole processes. Furthermore, borehole simulation can also be the basis for managing the complex handling of co-produced noncondensable gases or preventing scaling formation and steel corrosion

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