METHOD OF REDUCING WATER INFLUX TO MULTILATERAL WELLS Russian patent published in 2016 - IPC E21B43/27 E21B43/22 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and can be used in developing multiple-zone or layer of oil deposit with predominantly pore type by multi-branch horizontal wells. Method of reducing water influx to multi-hole wells involves selection of productive multi-hole horizontal well, each shaft of which utilises separate oil-saturated layer, pumping of working agent in it and start of well production. Laboratory tests on core of each of interlayers, during which are migration of fine clay particles from pores under action of working agent and blockage of pore channels, defined by reduction of phase permeability collector of water is not less than 1.5 times. As working fluid for injection of water with overall mineral content of salts of not more than 5 g/l and density of not more than 1,080 kg/m³ - low-salted water and/or water with pH of more than 8.0 d. units - alkaline water. In selected producer influx of water from each of interlayers, pumping of low-salt and/or alkaline water is carried out separately in each of layers in selected production well, and nearest located at a distance of not more than 600 m, injection well. In each layer of pumping is performed simultaneously in production and injection wells, values of initial flow rate of low-salt and/or alkaline water for each interlayer is determined proportional to concentration of fine clay particles at core during laboratory studies, but in sum over all interlayers not less than flow rate in injection well waste or brine water to pumping of working agent. Pumping of low-salt and/or alkaline water in each layer is performed during time proportional to water cut of each shaft of production well, but not less than five days after injection in each layer. Production well is brought into operation at same conditions as before pumping and injection well is transformed for pumping waste or brine water with flow rate to injection of working agent. Injection cycles of low-salt and/or alkaline water is repeated as watering of production well at 10-30 % relative to water cut after previous cycle of injection and recovery of working agent. Volume of low-salt and/or alkaline water in each subsequent cycle is increased.

EFFECT: higher efficiency of isolation of water inflow to multi-hole horizontal wells and increasing oil recovery factor of deposit.

1 cl, 1 dwg, 4 ex