Degree

Doctor of Engineering (DEng)

Department

Petroleum Engineering

Document Type

Dissertation

Abstract

In the domain of upstream Petroleum Engineering, the dynamics of co-current and counter-current multiphase flows present huge challenges, significantly impacting the efficiency of associated processes. This study investigates two specific applications concerning these flow behaviors, involving both laboratory experiments and transient computer simulations. This work investigates two distinct well control and production enhancement processes, involving multiphase flow dynamics: the bullheading kill procedure and liquid-assisted gas lift (LAGL).

The first topic (Topic 1) explores the bullheading process, a type of well control methods, by challenging the traditional understanding that gas removal efficiency increases monotonically with injection pump flow rate. Through 1D transient multiphase flow simulations using OLGA software and validation via small-scale visualization experiments, the study demonstrates that gas removal efficiency exhibits non-linear trends with increasing injection rates. The findings highlight the role of co-current and counter-current gas-liquid interactions, identifying transitions between annular, slug, and bubbly flow regimes. The results of this work provide insights for optimizing bullheading operations under varying flow conditions.

The second topic (Topic 2) examines the LAGL process, a co-injection enhancement of conventional gas lift where liquid is injected alongside gas to improve unloading efficiency. Dynamic transient simulations across different well depths and a wide range of gas and liquid injection rates reveal that co-current injection can reduce the maximum injection pressure, but only within an optimal operational window. This window corresponds to specific flow regimes where pressure reductions and effective liquid unloading coincide. The study presents contour maps of injection pressure and liquid holdup, serving as practical tools for field design and operation of LAGL systems.

Date

8-26-2025

Committee Chair

Kam, Seung I.

Download

Share

COinS