| abstract |
The permeability of subterranean oil-bearing formations is controlled by injection of an organic polysilicate ester. The ester may be derived from simple, monohydroxylic alcohols such as methanol, ethanol, propanol or butanol, from diols such as ethylene glycol, from polyols such as glycerol and alkylene oxide polymerization products and from other organic compounds containing functional hydroxy groups, for example, partial ethers and esters of glycols and polyols. The polysilicates are injected into a formation through injection wells, suitably in an amount from 10 to 100% of the pore volume of the zone to be treated. In the formation, the polysilicate esters form gels which selectively decrease the permeability of the high permeability regions of the formation, to divert the flow of flooding liquid used in flooding operations to the less permeable regions of the formation. |