DEVELOPMENT METHOD OF OIL FRINGE IN CARBONATE RESERVOIR OF COMPLEX STRUCTURE Russian patent published in 2014 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: method involves drilling of injection and horizontal production wells, arrangement of maintenance of formation pressure by water pumping, according to water flooding and gassing of products of production wells - drilling of side horizontal shafts at different levels within oil-saturated thickness as per analysis results of recovery of reserves and hydrodynamic simulation, as well as periodic operation of production wells. According to the invention, based on 3D observation well testing there determined is anisotropy of a productive reservoir in three-dimensional space - the main permeability directions. Both injection and production wells are constructed in the form of horizontal ones. With that, horizontal shafts of production wells are made in middle part of the oil-saturated thickness, and horizontal shafts of injection wells near gas and oil contact (GOC). Injection and production horizontal shafts are arranged parallel to each other as per a mixed single-row pattern so that distance between production shafts in a row can correspond to position of injection shafts in adjacent rows. Injection wells are operated in a periodic mode so that production wells stand idle during water pumping periods and accumulation of elastic energy margin occurs in the formation. Production wells are put into operation during downtime of injection wells. Duration of production and injection periods is chosen at the interval of 1-3 months based on the fact that formation pressure on GOC level in the area of production wells can exceed initial formation pressure by a depression value at operation of production wells plus 3-5 atm, and its reduction beyond the production periods can correspond to achievement of the initial formation pressure level.

EFFECT: improving development efficiency of underlaying oil fringes in carbonate reservoirs of complex structure owing to reducing gas and water breakthrough along the crack system.

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