Geochemical Modeling of Polymer EOR for High-Temperature and High-Salinity Carbonate Rocks

Abstract

The global energy demand is on a continual upsurge, where the oil and gas (O&G) industry has positioned itself as an energy supplier essential to the energy-mix for satisfying this global need. However, regulation constraints and exploration complexity have been increasing on a yearly basis, requiring the industry to maximize oil recovery from the existing fields. Enhanced Oil Recovery (EOR) techniques, encompassing chemical, solvent, and thermal methods, have shown great potential to increase oil recovery from reservoirs that were produced by conventional primary and secondary recovery methods. Specifically, Chemical Enhanced Oil Recovery (cEOR) techniques have the capacity to change rock and fluid interactions at a reasonable technical and economic cost, rendering them a promising category of oil recovery. Polymer flooding is among the most prevalent cEOR techniques that has proven its value through the improvement of macroscopic sweep efficiency. Understanding the effects such as diffusion, polymer adsorption, and geochemical interactions between polymer, brine, and rock phases is imperative for appropriately selecting a suitable polymer. Therefore, the main objective of this research is to propose a mechanistic model that captures the physicochemical aspects of polymer flow in porous media through a geochemical perspective using a coupled reservoir flow and geochemical numerical simulator (i.e., in-house developed MRST-IPhreeqc simulator) for applications in carbonate rocks. In this research, we developed a mechanistic model using MRST reservoir flow and the IPhreeqc geochemical simulator. The MRST polymer module was modified to model key parameters such as polymer viscosity, adsorption, IPV, RRF, hydrolysis, and shear effects. We also integrated the Surface Complexation Modeling from IPhreeqc to model Indiana limestone carbonate rocks and introduced a polymer specie of ATBS sulfonated polymer for interaction within the MRST simulator for Low Salinity Polymer flooding paradigm. The adsorption equilibrium is captured through thermodynamic reactions and flow equations. The updated simulator was validated against experimental tests for carbonate rocks using SAV10 by Thomas et al. (2020) and Sebastian (2023). The results demonstrate the simulator's effectiveness in modeling the main mechanism of Low Salinity Polymer flooding. This work offers insights into geochemical, reservoir flow, and adsorption in polymer flooding. The integration of geochemical factors is crucial for optimizing polymer flooding in the Middle East's harsh carbonate reservoir conditions, enhancing regional oil recovery.

Date of Award	21 Dec 2023
Original language	American English
Supervisor	Emad Al Shalabi (Supervisor)