GAS-OIL DEPOSIT DEVELOPMENT METHOD Russian patent published in 2015 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: on a gas-oil deposit containing gas formations with an oil bank containing high-viscosity oil there drilled strictly under each other are horizontal wells. Some part of wells is located above an oil-gas contact zone, and the other portion is located under an oil-gas contact zone. Water is injected to upper horizontal wells, which is lowered in the formation under action of gravity forces down to an oil bank zone. After that, a pause is maintained, during which a provision is made for contact of the pumped water to oil with formation of an oil-water emulsion having increased viscosity, and increase of viscosity on an oil-gas contact reduces conductivity of the system in a vertical plane. Due to this, reliable isolation of the oil bank from a gas cap is achieved in vicinity of the wells being considered. Then, to the same upper wells there pumped is a hydrophobic liquid - it is lowered downwards as well, and being distributed in the formation volume, it creates one more layer above an oil-water emulsion, which prevents movement of this emulsion in an upward direction - to a gas part of the formation. Therefore, pumping of the hydrophobic liquid allows creating a zone non-permeable for the oil-water emulsion, and the latter in its turn prevents penetration of oil into the gas cap. After that, operation of the gas cap through upper wells and that of the oil bank through the lower ones is started.

EFFECT: improving oil production efficiency due to independent parallel sampling of the product of a productive formation, avoiding breakthrough of gas into oil-producing wells and vice versa oil to gas-producing wells.

3 cl, 4 dwg