Browsing by Author "Zhang, Yushuo"

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    Co-Injection of Non-Condensable Gas and Foam in SAGD using a Modified Well Configuration
    (2023-12-19) Zhang, Yushuo; Maini, Brij B.; Chen, Zhangxing; Sarma, Hemanta Kumar; Achari, Gopal; Rao, Dandina Nagaraja
    The purpose of this project is to evaluate the performance of a non-condensable gas (NCG) foam as an additive to the steam assisted gravity drainage (SAGD) process using the conventional as well as modified well configurations. Both laboratory experiments and numerical simulations were used in the study. For safety reasons, nitrogen gas was used in the laboratory experiments to form the foam. However, in numerical simulations, methane is used as the gas component of the foam. The purpose of foam in this process is to reduce the heat loss and to decrease the residual oil saturation. Modified well configurations are designed to enhance steam efficiencies in the target zones. SAGD experiments were conducted in linear sand-packs to evaluate the effects of NCG and Foamed NCG as steam additives on the oil recovery performance. The value of residual oil saturations under NCG or foamed NCG conditions were determined through history matching of these experiments with numerical simulation. Several different foaming agents were evaluated for their effectiveness in reducing the residual oil saturation and achieving high recovery factor. The best performing foaming agent NC160 was then evaluated in a linear physical model for its foam flow characteristics. The results of these tests were also history-matched with a thermal reservoir simulator to determine the foam flow characteristics that can be applied to field scale simulations. A numerical simulation study of Long Lake Pad 16 found that steam only SAGD operation in 10 years had a cumulative Steam Oil Ratio (cSOR) of 6.23 and the total oil production of 79,193 m3. However, the best performing case of foam assisted SAGD, using three horizontal wells configuration, reduced the cSOR to 3.94 and increased the total oil production to 85,068 m3. As expected, a foam insulation layer formed above steam chamber, which resulted in superior performance regarding steam efficiency. This field scale simulation study was based on the foam flow parameters determined through history matching of the lab-scale physical model tests.
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    Co-Injection of Non-Condensable Gas and Foam in SAGD using a Modified Well Configuration - A Simulation Study
    (2018-08-29) Zhang, Yushuo; Maini, B. B.; Sumon, Kazi Z.; Dong, Mingzhe; Sarma, Helmanta Kumar
    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.