DECREASING GAS MOBILITY TO ACHIEVE BETTER SWEEP EFFICIENCY IN FAWAG PROCESS

The alternation of slugs of gas and water injection i.e. Water Alternating Gas
(WAG) has been a common practice to obtain better mobility ratio and improve sweep
efficiency 161.Eventually, WAG can suffer from viscous instability and gravity
overriding and therefore has not always been a successful method on controlling gas
mobility. Therefore, foams are then introduced to WAG for mobility control in
enhanced oil recovery operations. This paper aims to prove it by lowering gas mobility
better sweep efficiency can be achieved resulting in better oil recovery. Experiments on
different gas mobility ratio will be conducted using the same core properties for each
experiment and kept to reservoir conditions. The alteration of gas mobility is done by
using sodium dodecyl sulphate (a type of surfactant) as a mobility control agent.
Furthermore, the optimum concentration of surfactant is obtained for optimal oil
recovery. This is done by varying the concentration of surfactant. To determine the
outcome of this project, fluid collection of each experiment is observed for volume of
oil accumulated. Simulation of the project is also conducted to make a comparison the
experiment data in order to have a precise and accurate data thus making a solid
conclusion. The methodology of the paper is included to show the organized process
that is being followed and approximate duration of the project can be determined. In a
nutshell, the experiments will lead to a conclusion whereby decreasing gas mobility
better sweep efficiency can be achieved in a foam assisted water alternating gas
(FA WAG) process.