Canadian researchers work to update EOR methods

Oil companies have used enhanced oil recovery for decades, but researchers continue trying to refine and update EOR methods. Some are trying to reduce the environmental impact of existing EOR methods.

The Petroleum Technology Research Center (PTRC) in Regina, Sask., is working to develop a process they call solvent vapor extraction (SVX) to boost recovery of heavy oil reserves.

The overall research project is called Joint Implementation of Vapor Extraction. In the 3-year, $40 million JIVE initiative, PTRC researchers coordinate laboratory studies, physical modeling, and simulations with three vapor extraction pilot projects in the Lloydminister area straddling Alberta and Saskatchewan.

Husky Energy Inc. has a pilot in Edam field, and Nexen Inc. has a pilot in Luseland field, both in Saskatchewan. Canadian Natural Resources Ltd. has a pilot in Primrose field in Alberta.

Researchers are hopeful SVX processes could boost recovery rates from partially depleted heavy oil reservoirs having thinner pay zones, wormholes, and bottom water. Wormholes develop underground when sand is pumped along with oil.

The use of solvent vapor could reduce water use and carbon dioxide emissions compared with steam injection. CO2 emissions would be reduced because the use of SVX eliminates natural gas from being burned for steam injection. SVX processes do not require thermal energy.

The vapor extraction process involves injecting a gaseous hydrocarbon solvent (propane, butane, methane, or CO2) in to the reservoir where it is displaced into the oil, making the oil less viscous so that it drains into a lower horizontal well.

PTRC researchers say success hinges upon a quick uptake of the solvent into the heavy oil and upon 90% of the solvent being recovered. So far, lab researchers have recovered solvent but very little oil. In other cases, they have recovered oil but not solvent.