An Implicit Simulation Framework for Well Acidizing Process in Carbonate Reservoirs

Abstract

This thesis elaborates on a newly developed Fully Implicit simulation model that captures the full coupling of reaction kinetics and fluid dynamics during carbonate matrix acidizing at an extensive (field) scale. The framework describes the physical processes at reservoir scale, by accounting for upscaled pore-scale-based quantities for reaction rates and reservoir flow properties (e.g. permeability and porosity). The coupled Darcy-Stokes system of equation, as represented in a unified Brinkman formulation, is incorporated in the model to account for free flow (wormholes) and flow trough porous media. The model is built to investigate the subsurface behavior of the specifc (Dissolvine Stimwell) acid developed by AkzoNobel Co. Dissolvine Stimwell includes chelating agents which have, under specific conditions, significant advantages over conventional acids. Generally, carbonate acidizing treatment experiments are conducted at the core scale. However, in Salt Lake City Utah a carbonate acidizing experiment was carried out at unprecedented scale. The corresponding results are compared with the developed model to validate the dependency of the wormhole formation with the injection rate. In addition, the reduction in the skin factor is briefly addressed. Apart from the FIM simulation development of this thesis work for coupled reactive transport equation with Brinkman formula for flow, its other valuable contribution lies on the validation with experimental results at the unprecedented scale.