Enhanced Oil Recovery Using Micellar Polymer Flooding
Micellar polymer is injected into the oil reservoir to reduce the viscous and tacky crude oil's surface tension, thus releasing the oil globules from their grip on the reservoir rock.
There are can be up to five stages in micellar polymer flooding:
This first stage consists of injecting a solution of fresh water into the reservoir, flushing out the reservoir brine. This brine contains sodium, calcium and magnesium ions and, being contaminates, if not removed would impede the action of the micellar surfactant.
2. Micellar Polymer Injection
Micellar is prepared in the form of a slug that can contain numerous chemicals such as the polymer surfactant, sub-surfactant, brine, alcohol and a hydrocarbon in the form of oil. The slug is injected into the reservoir through a specially drilled injection well, spreading slowly through the rock.
3. Surfactant Mobility Enhancement
This is achieved by the injection of a viscosifier; solution of fresh water and polymer which effectively spreads the surfactant mixture through the reservoir rock to achieve maximum coverage.
4. Water Buffer
Fresh water is injected again, but this time it remains in the reservoir, preventing contamination of the slug chemicals from any surviving reservoir brine ions, by acting as a buffer between them.
5. Drive Water
In this the final stage, pressurized water is pumped down the injection well into the reservoir rock. Here it gathers up the now less viscous crude oil, and sweeping it off the rock, forces it towards the production wellhead from where it flows up the production well to the platform.