METHOD OF DEVELOPING OIL-AND-GAS POOLS Russian patent published in 2010 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to gas-and-oil producing industry, particularly to methods of oil recovery from oil rims located immediately below the gas cap with using water blocks to control gas breakthroughs. The method involves creation of a block between oil and gas zones of a rim by water injection and oil sampling from the oil zone of the rim through the producing wells. According to the invention, in rim development, in a trigger collector with clay minerals, water injection for creation of said block between the oil and gas zones is performed above the level of a gas-oil interface. And water injection is preceded with tests to determine a dependence of layer rock permeability on water mineralisation and a maximise water mineralisation whereat layer rock permeability is not lower than in local water filtration, and minimise water mineralisation whereat permeability decreases at least in 5 times in comparison with that in local water filtration. It is followed with water injection with reducing injected water mineralisation from the maximum whereat there is no swelling of clay minerals, to the minimum providing swelling of clay minerals - size reduction of pore channels within a zone close to a bore with a high pressure gradient.

EFFECT: improved gas isolation of the water block, increased gas-free oil production rates and oil recovery rates from oil-and-gas fields.

3 cl, 4 ex, 3 tbl