Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Petroleum Engineering

First Advisor

Zaki Bassiouni


In dipping, water-drive reservoirs, substantial incremental oil can be produced using gravity-assisted gas injection improved recovery processes. These processes include the Double Displacement Process (DDP) and the Second-Contact Water Displacement (SCWD). The efficiency of these processes depends, in part, on phase distribution in the pore space after gas injection which in turn depends on interfacial and surface tensions (IFT) of the phases involved. The research described here-in pertains to experimental work performed to investigate various aspects of the DDP and the SCWD in both homogenous and heterogeneous rock types with dead oil/nitrogen and recombined-oil/methane fluid systems. Additional work was performed with transparent cells in order to visualize mobilization and displacement of residual oil. Measurements of interfacial tension were also performed to predict phase distribution within the pore space. Based on experimental investigation, the DDP and SCWD processes were found to be efficient methods of incremental oil recovery. Transparent cell experiments provided insight into the mechanisms of the DDP and SCWD processes. These experiments support the presumption of film flow of water displacement residual oil. Existing IFT measurement techniques were adapted to provide rapid and convenient measurement at high-pressure and high-temperature conditions. The interfacial and surface tension properties of several fluid systems were investigated under reservoir conditions with different injection gases. The relative convenience of these IFT measurements opens the way to the development of an empirical screening criteria needed in the selection of reservoirs suitable for DDP and SCWD processes.