DEVELOPMENT METHOD OF HIGH-VISCOUS OIL DEPOSIT Russian patent published in 2011 - IPC E21B43/24 

FIELD: oil and gas industry.

SUBSTANCE: method involves construction of production horizontal well in the area of bottom of productive formation, injection horizontal well above production horizontal well, pumping of heat carrier to injection well and extraction of products of formation from production well. Injection horizontal well is located above production horizontal well at the distance of not less than 5 m. Warming of bottom-hole zone of both horizontal wells is performed till hydrodynamic connection is created between wells and oxidation temperature of high-viscous oil is reached in the area of injection well. After oil viscosity is decreased to fluidity in the area of horizontal section of horizontal production well, heated products are extracted and pressure drop zone is created between the area of horizontal section of production well and area of horizontal section of injection well. In parallel, when oil oxidation temperature is reached, oxygen or oxygen-containing mixture is pumped to injection horizontal well in order to perform initiation of in-situ combustion. After ignition the pumping of oxygen or oxygen-containing mixture is alternated with pumping of hot water or superheated steam in proportions which do not stop in-situ combustion. During propagation of combustion front and development of zones of productive formation, pumping of oxygen or oxygen-containing mixture to injection horizontal well is increased by 2 and more times depending on distance of combustion front from injection horizontal well. Vertical wells around horizontal wells at the distance of up to 250 m from horizontal wells are transferred to category of governing ones and used for heat carrier pumping together with horizontal wells or for extraction of products at initiation of combustion in injection well. When temperature increases in one of governing wells over allowable one, it is transferred for injection of non-flammable agent till temperature is reached. In parallel, from vertical wells located after the front of in-situ combustion on the side of injection well, combustion gases are extracted so that pressure is maintained at the level of formation pressure in order to provide uniform propagation of combustion front around horizontal shaft of injection horizontal well.

EFFECT: improving oil recovery, efficiency of displacement process of high-viscous oils and bitumens, including by enlarging the coverage of formation with the agent acting owing to subsequent performance of the whole formation thus maintaining high permeability with possibility of controlling and monitoring the combustion front.

1 ex, 2 dwg