Single Phase Microemulsions Applied to Oil Sands
- P. Sharma (University of Houston) | K. Kostarelos (University of Houston) | X. Xiong (University of Houston)
- Document ID
- Society of Petroleum Engineers
- SPE Western Regional Meeting, 22-26 April, Garden Grove, California, USA
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Petroleum Engineers
- 5 Reservoir Desciption & Dynamics, 2 Well completion, 5.8 Unconventional and Complex Reservoirs, 5.2 Fluid Characterization, 2.5.2 Fracturing Materials (Fluids, Proppant), 2.4 Hydraulic Fracturing, 5.2.1 Phase Behavior and PVT Measurements, 5.8.5 Oil Sand, Oil Shale, Bitumen
- Enhanced Oil Recovery, Oil Sands, Micromeulsion, Surfactant, Heavy Oil
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Extra–heavy oil sands deposits represent a significant part of the oil resources available all around the world. Current recovery techniques such as open pit mining, SAG-D, etc., are not very efficient and have been debated for their possible adverse effect on environment. We propose a method of oil recovery that has the potential of being a "game changer" for such resources: using cyclic injection of surfactant solutions forming single–phase microemulsion (m.e.) without mobilizing the oil. This type of m.e. has several advantages: it is less viscous than the extra heavy oil/bitumen; when the surfactant is injected, the m.e. can finger through the tar to a production well, where it will contain a high mass of heavy oil and can be transported without addition of diluent. This approach would use two parallel horizontal wells as an injector/producer pair so that injected surfactant solution would create viscous fingers/flow paths through the oil sands. The m.e. formed during the process would be produced in the second well. After transportation, the surfactant will need to be recovered from the m.e. and recycled for re-injection.
Phase behavior experiments such as surfactant screening, salinity scans and aqueous stability were conducted focusing on forming single phase m.e. Previous work aimed at single phase m.e. used coal tar as a model oil for phase behavior studies and flow experiments that yielded promising results. As a result of the previous work, new phase behavior studies were conducted using bitumen extracted from oil sands obtained from Alberta, Canada that are presented in this paper. Three flow experiments were conducted using a surfactant formulation selected based on the results of the phase behavior experiments to recover bitumen from the oil sands.
For bitumen, single phase m.e. was achieved with a mixture of internal olefin sulfonate and alcoxy sulfate (1:1) surfactants with alkali (sodium carbonate), with bitumen solubilization of the order of 300,000 ppm. The three flow experiments were conducted to explore two different flow schemes, to compare a synthetic oil sand (bitumen from oil sands mixed with OK-75 sand) with an actual oil sand, and to investigate the effects of two experimental setups. The recoveries from these flow experiments were lower than expected, only achieving a bitumen solubilization of the order of 10,000 ppm. The analyses of the results and possible reasons for lower recovery are discussed in the paper.
Surfactant solubilization method using single phase m.e., could provide an environment-friendly alternative to current recovery methods. It would also eliminate the need of adding solvents for transportation. While improved surfactant formulations could yield better recovery, the economic feasibility of the process will depend upon the final step—recovery of the surfactant from the produced m.e. Work is currently being conducted on several potential surfactant recovery processes.
|File Size||1 MB||Number of Pages||13|