METHOD OF OIL POOL DEVELOPMENT Russian patent published in 2002 - IPC

FIELD: oil producing industry. SUBSTANCE: invention deals with methods of development of oil pools with nonuniform porous-fractures, fractured-porous and fractured reservoirs where increasing of oil recovery is realized by creation of flexible filtration conditions in formations and periodic change of direction of filtration. Claimed method includes maintenance of flexible conditions of formation operation by use of cyclic injection of displacement agent into injection wells and periodic operation of groups of operating wells with their shutoff for period of time determined by data of well hydrodynamic researches. According to invention, results of well hydrodynamic researches are additionally analyzed and volumes of fractures in drainage zones of producing and injection wells are determined. Direction of increased reservoir fractures is determined. Producing wells are formed in cells with injection wells in cell center and divided into two groups. The first group includes producing wells located at a distance of not above half the distance between wells from injection axis passing through injection well along direction of increased reservoir fractures. The second group includes all remaining producing wells. Operation of producing and injection wells in each cell is carried out by cycles. In each cycle during the first period with shutoff producing wells, injected into injection wells is fringe of viscoelastic composition in voluem equalling that of fractures in zone of injection wells. During the cycle second period, the first group of producing wells is put into operation, and injected simultaneously into injection wells is displacement agent fringe in volume equalling total volume of fractures in zones of injection and all producing wells. Operation of producing wells of the first group is continued for time for which volume of fluid is withdrawn equalling the volume of fractures in drainage zone of the first group producing wells. During the third period of cycle, injection of displacement agent to injection wells and operation of producing wells of the first group are discontinued. The second group of producing wells is put into operation for period of time during which producing wells of the second group withdraw fluid volume equalling total volume of fractures in zones of injection and producing wells of the second group. Cycles of periodic operation producing wells groups are repeated until economic criteria of operation cessation are obtained. EFFECT: increased efficiency of claimed method due to consideration of nonuniformity in permeability of fractures system in different directions, and increased oil recovery ratio. 3 cl, 1 dwg