| abstract |
A method of extracting petroleum from oil reservoirs which comprises blocking highly permeable regions of the petroleum formation by separately injecting at least one acidic formulation comprising water-soluble Al (III) salts and a formulation comprising urea or urea derivatives into the reservoir to increase oil yield , wherein the formulations mix together only in the deposit and the mixture forms highly viscous gels under the influence of the reservoir temperature. In particular, the process can be used in the final stage of reservoir development, in production dilution and, in particular, after steam flooding of the reservoirs. |