METHOD FOR COMBINED PRODUCTION OF OIL OF MULTI-LAYER DEPOSITS Russian patent published in 2021 - IPC E21B43/14 E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and can be used for successive production of oil from all horizons of multilayer deposit. Disclosed is a method for combined production of oil of multi-layer deposits, including injection of nitrogen through injection well, associated petroleum gas (APG) obtained during separation of extracted oil in form of a mixture of nitrogen and hydrocarbon gases dissolved in produced oil, also injecting formation water obtained during separation of oil, in absorbing well and in overlying water-bearing horizons, without channels of migration with productive oil formations, oil inflow is provided in the mode of open flowing through the full cross-section of the production string during the entire period of oil production. At that, five process exploratory wells are used: two producers; two injection and one absorbing, with the help of which oil is extracted from the first overlying horizon by natural gushing and forced flowing due to stabilization and maintenance of current reservoir pressure at the level of the initial one. After oil field production providing for oil production from the first upper horizon is introduced into production, work is carried out to increase production volumes of all assumed underlying deposits of multilayer deposit of stratigraphic section, for which on each underlying oil-bearing horizon there are drilled two exploration wells, of which - one of them, a pressure well, is used for pumping nitrogen into a new underlying horizon, and through the bottomhole zone of the second exploratory well - from this new productive formation to the overlying oil horizon, from which oil production is carried out already operating infrastructure of the first oil horizon. At that, lower parts of casing string are used as artificial channels of migration for receipt of production of underlying oil floors from the second, third, fourth and fifth horizons in overlying horizons: first, second, third and fourth, respectively, wherein the first overlying horizon is used for general oil production. Cement bridges are put on upper parts of casing strings, which are used as artificial migration channels.

EFFECT: proposed invention allows achieving oil recovery factor to level of 95-99%, and also ensuring reduction of prime cost of oil production and due to reduction of labor intensity of works and provision of multiple growth of labor productivity during oil production.

4 cl, 1 dwg