Drainage Mechanism of Steam with Solvent Coinjection under Steam Assisted Gravity Drainage (SAGD) Process

Abstract

Coinjecting solvent with steam under steam assisted gravity drainage (SAGD) process to reduce the required steam for production has gained importance in recent years. An extensive 2D simulation study to better understand the drainage mechanism of steam with solvent coinjection in the SAGD process shows that the relative condensation times of solvent and steam result in different films of gas solvent, liquid solvent, and water along the fluid interface. There is an optimal solvent type and concentration ratio range for a particular reservoir and operating condition. The solvent stays in or approaches the liquid phase ahead of steam along the fluid interface. Coinjecting the solvent at low concentration ratios can take advantage of the solvent solubility effect without losing too much heat effect from steam. In addition, this study indicates coinjection of suitable solvent mixtures leads to better performance than injection of pure solvent in the field.

Experimental Study on Water-in-Heavy-Oil Droplets Stability and Viscosity Variations in the Dilution Process of Water-in-Heavy-Oil Emulsions by Light Crude Oil

“…Heavy oil emulsions probably contained free water with the high-water fraction of 60%. Therefore, the emulsification occurred again between free water and introduced light crude oil, which increased the viscosity to some extent [59]. The transition was more pronounced during the dilution process with light heavy oil.…”

“…In addition, Sullivan and Kilpatrick [54] compared the heavy oil' solubility in the solvent and the aromatic hydrocarbons. Employed solvents were pure refined oils, fractionated oil, natural gas condensate, and other light oils [55][56][57][58][59]. Results show that asphaltene particles and resin asphaltene would still aggregate on the oil-water interface, forming W/O droplets, or even causing asphaltene precipitation, while heavy oil in aromatic solvents better solvates asphaltene aggregates since its increased resin or aromatic solvent content.…”

Numerical Investigation of Potential Injection Strategies To Reduce Shale Barrier Impacts on SAGD Process

“…A top injector above the shale barrier could be helpful for pushing the trapped oil through the end of the shale barrier. Meanwhile, coinjecting the solvent at a low concentration ratio may remove the flow resistance at the end of shale barrier caused by the additional solvent dilution effect (Li and Mamora 2010).…”

Density and Viscosity of Multicomponent Solvent (n-Pentane + n-Hexane + n-Heptane + cyclo-Hexane + Toluene) and Bitumen Mixtures─Implications for In Situ Bitumen Recovery and Transportation of Diluted Bitumen

“…Among these, SAGD combined with solvent coinjection stands out as a highly promising approach. − This method demonstrates increased oil production by capitalizing on the interactions between the solvent and bitumen. By both thermal and chemical means, the viscosity of the bitumen is lowered, leading to a reduction in the volume of steam required for generating the same quantity of oil achievable through standalone SAGD operations. , …”

“…By both thermal and chemical means, the viscosity of the bitumen is lowered, leading to a reduction in the volume of steam required for generating the same quantity of oil achievable through standalone SAGD operations. 13,14 One of the crucial elements in solvent-assisted recovery processes involves assessing the solvent's ability to impact the thermophysical characteristics of bitumen. Numerous studies have extensively documented a thorough examination of thermophysical characteristics within various bitumen samples and pure solvents including methane, ethane, propane, butane, pentane, and dimethyl ether.…”