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

FIELD: oil and gas industry.

SUBSTANCE: invention is applicable for horizontal or inclined multifunctional wells that combine the functions of production and injection. In the method of producing high-viscosity oil with in-well thermal activation of a binary solution, a well is first equipped, then a binary solution is injected 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 said binary solution, through the first exposed zone or the second exposed zone, enters the productive formation and then it is pressed with light oil with a density of no more than 0.92 g/cm³. Next, downhole thermal activation of the exothermial chemical reaction of the injected binary solution is started by the method of simultaneously and separately injecting the said binary solution and the activator - copper sulphate - through a mixing reactor at the ratio, m³: binary solution: activator - copper sulphate = 1:0.02. In this case, an instant exothermal reaction occurs in the mixing reactor with the release of hot gases and vapours, the temperature of which exceeds by more than 60 °C the activation temperature of the previously injected binary solution, injection of the binary solution and the copper sulphate activator ends with the launch of the chemical reaction of the binary solution, which is determined by the increase in pressure and temperature on the installed control devices. Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products. The heat front heats up the highly viscous oil in the reservoir. 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, then pumping is carried out and the cycles are repeated.

EFFECT: increased oil recovery, ability to choose the time from the start of binary solution injection to the start of initiation of a chain exothermial reaction, ability to delay the onset of chemical exposure of the binary solution to the bottomhole zone without the risk of premature initiation of the chemical reaction.

1 cl, 3 dwg, 1 tbl, 1 ex