Monitoring Foam Stability in Foam Assisted Water Alternate Gas (FAWAG) Processes Using Electrokinetic Signals

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 streaming potential signals which resulted from the flowing fluid in foam assisted water alternate gas (FAWAG) process. The experimental work will be conducted at the Reservoir and Drilling Engineering Laboratories at the Faculty of Petroleum and Renewable Energy Engineering (FPREE), UTM. The investigation includes sample preparation, sample analysis, displacing fluid formation, rheological properties test and electrokinetic signal measurement by using NI Data Acquisition System (NIDAS). It is expected that the burst of the foam bubble 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.

A Review of CCUS in the Context of Foams, Regulatory Frameworks and Monitoring

“…Foam-assisted water-alternating gas (FAWAG) is another WAG-inspired EOR technique. FAWAG may be considered an immiscible WAG injection method and may improve sweep efficiency, reduce the GOR, and maximize recovery [148,149]. Modifying injected water characteristics, such as its salinity, may also improve recovery by altering wettability and suppressing crude oil snap-off and microdissection formation [150].…”

Measurement of Streaming Potential in Downhole Application: An Insight for Enhanced Oil Recovery Monitoring

“…Streaming potential measurement has been a promising reservoir monitoring technique, but many studies have been focused on the water flooding brine-saturated porous media and the recent analysis of streaming potential at varying brine salinity [7,12,13]. Limited studies have been conducted to measure streaming potential in monitoring EOR processes, such as water alternate gas (WAG) and foam assisted water alternate gas (FAWAG) by Anuar et al and Omar et al [52,53,54,55]. Basically WAG is a process where intermittent slugs of gas and water are injected into the reservoir.…”

“…In addition, foam improves gas mobility control by delaying the early gas breakthroughs. Omar et al (2013) has measured the streaming potential resulted from the flowing fluid in FAWAG process to be correlated with the foam stability [53]. The principle is similar with the water flooding to monitor the process, but it provides indirect measurement of foam stability in order to monitor the efficiency of the EOR process.…”

“…Since foamability and stability are the key factors for enhancing the recovery [58], measuring streaming potential could aid in monitoring the foam stability from the surface. Using the same principle from Kostoglou et al (2010) [59], their research was based on theory that the FAWAG process flowing in the porous medium could produce an electric current, where electrokinetic signal pattern varied with the changes of foam stability [53]. In 2014, Omar et al found that the increase in surfactant concentration, sodium dodecyl sulphate (SDS) has decreased the voltage (electrokinetic potential) and decreased as shown in Fig.…”

CO2-Foam Monitoring using Resistivity and Pressure Measurements

“…Foam monitoring has been restricted to electrokinetic (streaming potential) measurements (Omar et al, 2013). Wo et al (2012) ran foam experiments on unsaturated soil samples and investigated the possibility of using electrical measurements for foam monitoring.…”