Doctor of Philosophy (PhD)
In this study we investigate displacement mechanism for oil recovered using Gas- Assisted Gravity Drainage (GAGD) method. For a typical oil recovery under gravity drainage, the recovery proﬁle can be characterized by an initial bulk ﬂow which occurs rapidly and a later ﬁlm ﬂow that extends for a longer duration. It is the latter period where ﬁlm spreading, the ability of oil to spread above water in the presence of gas, is identiﬁed as the displacement mechanism responsible for recovering the remaining oil in gravity drainage process. Literature survey indicates that mathematical models for gravity drainage do not account for ﬁlm spreading mechanism adequately. To address this knowledge gap in the literature, we would conduct experiments and simulation of mathematical model. The experiments aim to understand the role of ﬁlm spreading in gravity drainage recovery. This is achieved by using spreading and non-spreading oils in sand packs, where the sand is either water-wet, oil-wet or fractional-wet. We would then evaluate the existing models to account for the observations obtained from these experiments. The experimental results show that oil recovery is higher in spreading ﬂuid system in water-wet sands. In oil-wet sands recovery from non-spreading ﬂuid system is higher than that of spreading ﬂuid. For fractional-wet sands, the recovery trend is similar to that of oil-wet experiments in that the non-spreading ﬂuid produces more oil than spreading ﬂuid system. We explain the results in terms of pore scale mechanism and investigate the role of gravity, capillary and viscous forces during gravity drainage experiment. Curve ﬁtting of the experimental data with gravity drainage models show that the model which incorporates ﬁlm ﬂow mechanism in its formulations is able to match most of the experimental data.
Dzulkarnain, Iskandar, "Investigation of Flow Mechanisms in Gas-Assisted Gravity Drainage Process" (2018). LSU Doctoral Dissertations. 4699.