Polyacrylamide-polyalkeneoxide mobility control process
In secondary and tertiary oil recovery, mobility control of aqueous solutions of polyelectrolyte (e.g. partially hydrolyzed polyacrylamides) can be increased by the addition of a non-polyelectrolyte (e.g. polyalkeneoxide). Most generally, any water-soluble polyelectrolyte and any water-soluble agent which increases viscosity may be used in this solution. The polyacrylamides should have a molecular weight of 3 to 6 million, be hydrolyzed no more than 10 to 30 percent, and be used in the range from 0.02 to about 0.2 weight percent of the thickened water solution. Polymerized ethylene oxide (Polyox) is the preferred form of the polyalkeneoxides. A molecular weight of 1 x 10/sup 6/ to about 6 x 10/sup 6/ and a solution concentration of 0.02 to about 0.2 weight percent give the best results for mobility control. The solvent water may contain as much as 300,000 ppM of dissolved solids. Oil filled Berea sandstone cores were initially flooded with water. The following mobility control tests with thickened water indicated that a synergistic improvement in oil production occurred for the 0.5 to 0.8 pore volume injection. Since the polyacrylamide is the depletable component, the injection can include nearly 100 percent polyacrylamide at the leading edge and gradually increases the percentage of polyalkeneoxide as the displacement slug progresses.
- Assignee:
- TIC; EDB-77-143854
- Patent Number(s):
- US 3684014
- OSTI ID:
- 7301272
- Country of Publication:
- United States
- Language:
- English
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