Semester of Graduation

Spring 2019

Degree

Master of Science in Petroleum Engineering (MSPE)

Department

Craft & Hawkins Department of Petroleum Engineering

Document Type

Thesis

Abstract

Utilizing the power of nature to solve engineering problems has been a time-honored tradition, for example, using the sunlight as a heat and light source. From this principle, the visionary idea of Gas Assisted Gravity Drainage (GAGD) came. The GAGD process utilizes the natural segregation phenomenon of fluids with different densities in order to produce oil efficiently and economically. Waterflooding processes typically do not recover more than 40% of the original oil in place (OOIP), leaving a vast amount of oil behind. A practical and well-planned enhanced oil recovery (EOR) method is needed. However, to plan a successful project, the knowledge of reservoir characteristics and physics that govern these characteristics is required.

Wettability and spreading are critical properties of fluid flow in a porous medium and the recovery of oil. The objective of this work is to study the role that rock-fluid (wettability) and fluid-fluid (spreading) interactions play on GAGD performance. For this purpose, an experimental study has been conducted using sandpacks containing oil-wet sand ratios of 0, 12.5, 25, 62.5, and 100% with different spreading conditions (Decane as non-spreading oil and Soltrol as spreading oil). This core-scale study also described the pore-scale mechanisms to evaluate a reservoir-scale problem.

The results, regarding the recovered oil percent, are as follows: The highest recovery occurred in both complete water-wet sand with the spreading system and complete oil-wet with the non-spreading system. The lowest recovery occurred in both complete water-wet sand with the non-spreading system and complete oil-wet with the spreading system. The second highest recovery was in 12.5% fractional-wet with spreading oil (Soltrol).

The second lowest recovery was in 12.5% fractional-wet with non-spreading oil (Decane). Similar oil recoveries were obtained in 25% fractional-wet and 12.5% fractional-wet, either in spreading conditions or non-spreading conditions. Finally, oil recovery in 62.5% fractional-wet sand in both spreading and the non-spreading system was alike.

The element of innovation in this work is the evaluation of GAGD process in fractional-wettability systems and will help to plan more successful GAGD projects and is considered a step forward in understanding wettability and spreading phenomena and their influence on GAGD performance.

Committee Chair

Rao, Dandina

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