METHOD FOR OIL PRODUCTION FROM FORMATION WITH ABNORMALLY LOW FORMATION PRESSURE Russian patent published in 2013 - IPC E21B43/12 

FIELD: oil and gas industry.

SUBSTANCE: method provides for extraction of formation liquid by means of a bottom-hole pump from vertical production wells drilled so that a sump is formed. A cavity is created in lower part of a productive formation in each vertical production well. In addition, flat directional production wells are drilled, thus attaching the face of each flat directional well to the cavity of the corresponding production vertical well, and mouths of flat directional production wells are interconnected with atmosphere. Diameter of vertical production wells is larger than diameter of flat directional wells. Mouths of flat directional wells are located for example near mouths of neighbouring vertical production wells. Creation of the cavity is performed for example by water jet washing-out of rock by means of a special adapter with a side water jet nozzle, and filling of the cavity with filler is performed for example by gravel alluviation.

EFFECT: improving oil extraction from formations with high average number of permeable intervals and abnormally low formation pressure owing to enlarging the formation drainage zone and activation of formation liquid runoff by increasing the forces contributing to displacement of formation liquid.

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