METHOD FOR PRODUCING HIGH-VISCOSITY OIL WITH IN-WELL THERMAL ACTIVATION OF BINARY SOLUTION Russian patent published in 2024 - IPC E21B43/24 E21B36/04 C09K8/592 

FIELD: oil and gas industry.

SUBSTANCE: in the method of producing high-viscosity oil with in-well electrical activation of a binary solution, the well is first lined with a casing pipe. The well has a horizontal or inclined section, the casing pipe has first and second exposed zones on the horizontal or inclined section. A lower heat-resistant packer and an additional upper heat-resistant packer are lowered into the well, connected to each other by a perforated injection pipe, heated by a tubular electric heater installed parallel to the perforated injection pipe between the lower heat-resistant packer and the upper heat-resistant packer, the lower tubing string is connected, over which the coaxially perforated fluid extraction pipe is placed. Next, a heat-resistant separation packer is installed that limits the annulus space, a support with a built-in adjustable valve is screwed into the perforated fluid extraction pipe, and a submersible pump is connected. A bypass pipe corresponding to the length of the submersible pump, parallel to the submersible pump, is inserted into the support from above. A tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, from the opposite side of which the upper tubing string is screwed. Before the tee, an internal additional pipe with a sealing element is inserted with an annular gap, at the end of which the tee is attached. The cable of the tubular electric heater is pulled together with the cable of the tubular electric centrifugal pump. Then the annular space between the casing and the upper tubing string is filled with water; in the lower part, the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support. Next, a binary solution is pumped containing, wt.%: ammonium nitrate - 27.8; sodium nitrite - 32.2; water - 40, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe. Next, the binary solution, through the first opened zone or the second opened zone, enters the productive formation and is pressed with light oil with a density of no more than 0.92 g/cm³. Then, the downhole thermal activation of the exothermial chemical reaction of the injected binary solution is started with a tubular electric heater. Heating is stopped when a stable increase in pressure and temperature appears on the installed control devices by turning off the power supply to the tubular electric heater. The resulting heated oil-water emulsion with reaction products flows through the first opened zone into the annulus between the lower column and the initial section of the casing, then it enters through a built-in adjustable valve to receive a submersible pump, then it is pumped to the surface through an additional pipe. When the flow rate decreases, pumping is stopped and the binary solution is reinjected into the productive zone of the formation through the lower column to increase oil fluidity.

EFFECT: enhanced oil recovery, ability to delay the onset of chemical impact on the bottomhole zone without the risk of premature start of the chemical reaction.

2 cl, 2 dwg, 1 tbl, 1 ex