Co-Injection of Non-Condensable Gas and Foam in SAGD using a Modified Well Configuration - A Simulation Study
Date
2018-08-29
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Abstract
The objective of this research is to examine the feasibility of foam co-injection with steam in SAGD using modified well configurations using numerical simulation. The foam used in this project is a composition of water, non-condensable gas (NCG) and surfactant. The application of foam in this study is for achieving the gas mobility reduction and decreasing the residual oil saturation. The use of foam forms a more stable insulating layer below the top of formation, which results in lowered overburden heat loss and cSOR. To place the foam directly below the overburden rock, vertical steam injectors are implemented in this study. Simulation runs are created using CMG STARS (Thermal and Advanced Process Simulator) using Long Lake Pad 16 as the target location. These simulation results demonstrated substantial improvement in cSOR by co-injecting foam with steam using the vertical injectors. Non-flowing boundary condition was used in all simulations. The producer operational constraint is a combination of maximum live steam rate and minimum bottom hole pressure (BHP). The base case forecasts production from January 2017 to January 2027 in steam only SAGD operation. The base case showed approximately 75,000 m3 oil production in 10 years, with a cumulative Steam Oil Ratio (cSOR) of 6.19. The simulation results show that injecting the foam improved both cumulative oil production and cSOR. As expected, foam reduces the gas mobility and stabilizes the insulating blanket formed by high gas saturation at the top of the steam chamber. Injection of foam also increases the trapped gas saturation and reduces the residual oil saturation. The optimized simulation case with three vertical wells enabled the cSOR to be as low as 4.3 at 3,500 kPa operation pressure. However, the maximum allowed operating pressure at Long Lake is 2,600 kPa. The optimized case under lowered pressure of 2,500 kPa uses four injection-wells configuration, which gave cSOR of 4.25.
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Keywords
Foam, SAGD, NCG, Thermal Recovery
Citation
Zhang, Y. (2018). Co-Injection of Non-Condensable Gas and Foam in SAGD using a Modified Well Configuration - A Simulation Study (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32894