Relationship between foam stability and the generated electrokinetic signals during fawag processes

Abstract

The natural pressure in hydrocarbon reservoirs is only sufficient in producing small amount of hydrocarbon at the end of the depletion stage. Therefore, in order to enhance or increase the hydrocarbon recovery, water or other fluids are injected into the formation to extract the hydrocarbon from the pore space. This common practice is known as Improved or Enhanced Oil Recovery (IOR or EOR). Foam is purposely used in some of the EOR displacement processes in order to control the mobility ratio, hence improving the volumetric sweep efficiency. The efficiency of a foam displacement process in EOR depends largely on the stability of the foam films. In laboratory, foam stability is usually measured through physical observation of the foam bubble in a glass tube. Unfortunately, this direct observation is not possible in the reservoir. Therefore, indirect measurement such as the measurement of electrokinetic signal would be a better alternative. This study aims to determine the correlation between the foam stability and the associated electrokinetic potential signals which resulted from the flowing fluid in Foam Assisted Water Alternate Gas (FAWAG) process. The investigation includes sample preparation, sample analysis, displacing fluid formation, rheological properties test, foam stability test and electrokinetic signal measurement by using NI Data Acquisition System (NIDAS). It is expected that the variations of foam bubble stability will change the pattern of the electrokinetic signals. The research findings could lead to a new approach in monitoring a FAWAG process. Application in the real field could benefit the oil and gas industry in term of making the EOR process more efficient and more economic.