Degree

Doctor of Philosophy (PhD)

Department

Petroleum Engineering

Document Type

Dissertation

Abstract

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.

Date

8-30-2018

Committee Chair

Rao, Dandina

Available for download on Friday, August 30, 2019

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