METHOD FOR ISOLATION OF WATER FLOW IN OPEN HORIZONTAL SECTION PRODUCING WELLS Russian patent published in 2016 - IPC E21B43/32 E21B33/138 

FIELD: oil industry.

SUBSTANCE: invention relates to oil and gas industry, particularly to operation and repair of wells and isolation of brine water influx in horizontal wells. Water flow isolation technique in uncased horizontal borehole section of a production well drilled in a carbonate reservoir includes extracting the pump equipment from the well, drilling below the main borehole of the well an additional borehole with a horizontal section along the water inflowing formation, lowering to the additional hole a tubing string by axial displacement from the face to the head with simultaneous supply of a water isolating material to the tubing string. Prior to lowering the tubing string an interval of the water inflow along the horizontal section in the main borehole is determined with further isolation of these intervals through the additional borehole by successive pumping polyaluminium chloride solution and polyacrylamide solution prepared on the formation water of the Devonian horizon and the lower part of the wall of the additional horizontal hole. Pumping of polyacrylamide solution is performed after pressing the polyaluminium chloride solution into the water-bearing stratum and holding it for gelling during one day. Pumping of polyacrylamide is performed on the side in the intervals of face and cutting of the additional horizontal hole, then the tubing string is removed from the additional hole. Prior to lowering the pump equipment a packer is installed equipped with a jointing assembly for connection of the tubing string to it, the well is put into operation with the bottom-hole pressure in the main borehole of 3.2-4.1 MPa, herewith the polyacrylamide solution additional pumping is carried out automatically from the vertical borehole filled with the polyacrylamide solution as it is filtered to the main hole of the horizontal well.

EFFECT: technical result of the invention is higher quality of water isolation treatment, the possibility of evaluating effectiveness of performed water isolation treatment during operation of the producing well, higher technological effectiveness of water isolation treatment at negative temperatures, reduced negative effect of chemical reagents on collector properties of the bottomhole zone of the producing well, increase of oil resources withdrawal from the productive formation.

1 cl, 4 dwg