A New Insight into the Steam-Chemical Co-Injection Processes for Heavy Oil Recovery Purposes
Creators: name: Ahmadi, Mohammadali
Publisher: name: Schulich School of Engineering
Year: 2022
Subjects: subject: Engineering--Petroleum
subject: Engineering--Chemical

description: The primary method for bitumen production across the world is still the in-situ steam-based technology. Some drawbacks are associated with steam-driven bitumen recovery methods such as cyclic steam stimulation (CSS), steam flooding, and steam-assisted gravity drainage (SAGD). These cons include the high greenhouse gas footprint, low heavy oil/bitumen recovery, and difficulty stopping operation in emergency conditions. There exists a need for an improved method for recovering residual oils after applying steam injection. One of the potential technologies for doing this is chemical-assisted bitumen recovery, especially surfactant additives. However, the main question is how to achieve the optimized surfactant formulation for this purpose. To answer this question, we need to understand how hydrocarbons and surfactants interact and how we can improve these interactions. This thesis focuses on the theoretical study using molecular dynamics (MD) simulation on interactions between hydrocarbon phase and surfactant additives under broad thermodynamic conditions, especially in-situ thermal processes. In this study, we use different molecular configurations to evaluate the molecular behavior of surfactants in various conditions. We employ interfacial configuration between different surfactants and asphaltenes since asphaltene is the heaviest fraction of oil sands/bitumen, the leading cause of these oil resources' high viscosity value. Our results reveal that anionic surfactants could interact efficiently with Archipelago and Island asphaltenes under wide ranges of temperature close to in-situ thermal conditions. Also, we perform molecular-scale modeling of anionic surfactant-asphaltene interactions to assess the effects of surfactant head-tail connector and asphaltene’s heteroatoms on interactions between anionic surfactant and asphaltenes. According to our result, benzene ring on anionic surfactant could improve the interaction between surfactants and asphaltenes. Likewise, heteroatom inside asphaltene molecules could also enhance these interactions; however, the number of heteroatoms and their positions play significant roles in intermolecular interactions. In the next phase, we use the Saturate-Aromatic-Resin-Asphaltene (SARA) analysis of a real Athabasca oil sample to create a bitumen droplet at the interface with the steam phase and perform MD simulation at thermal thermodynamic conditions. Our results reveal that adding surfactants to the system could increase the interfacial thickness and decrease the interfacial tension between steam and bitumen droplets meaningfully. Finally, we employ a quartz channel with bitumen-surfactant-steam inside to examine the interactions of such a system through porous media. Our results reveal that resin architecture could affect the oil detachment process from rock surface by changing interaction energies between the steam phase, bitumen, and hydrophobic quartz surface.