METHOD OF PRODUCING BITUMINOUS CARBONATE RESERVOIRS USING CYCLIC STEAM AND AN AQUATHERMOLYSIS CATALYST INJECTION Russian patent published in 2020 - IPC E21B43/24 E21B43/22 C09K8/592 E21B47/06 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to methods of developing deposits of heavy oil and natural bitumen. In the method of development of bituminous carbonate reservoirs in an inclined-directed well with a production string with diameter of not less than 168 mm, a pipe string with plugged ends and end holes made at the end section are lowered for pumping of the working agent into the interval of slotted perforation of the productive formation. Pipe of oil aquathermolysis is injected through pipe holes, containing, wt%: organic oil-soluble nickel salt 20–50; mixture of aliphatic and aromatic hydrocarbons 50–80, by means of cementing unit using pumps at rate of pumping into productive formation 1–5 m³/h. Volume of pumping is calculated by formulas depending on presence or absence of data on dimensions of steam chamber. Through the pipe holes there is pumped organic solvent, consisting of a mixture of aliphatic and aromatic hydrocarbons, with possibility of washing out residues of previously injected catalyst from well shaft and its delivery to oil-saturated zone of formation, volume of solvent injection is calculated by formula V_p=1.5⋅(h_TS⋅(π⋅R_TS²)+(h_UPH-h_TS)⋅(π⋅R_PS²)), where h_TS is the length of the tubing string (TS) through which the catalyst is pumped, m; R_TS – radius of the tubing string section, from which the catalyst was pumped, m; h_UPH is the well length from UPH – upper perforation holes, m; R_PS is the radius of the production string. Further, the well is closed for a period of not less than two days. Steam is injected at temperature of 200 °C to 350 °C, with formation pressure of 3.0 MPa to 15.0 MPa, the productive formation is heated, brought to temperature of 200 °C to 300 °C and continued pumping of steam for not less than five days with possibility of aquathermolysis reactions in productive formation. Well is stopped for 5 days to 14 days; liquid product is extracted from the well.

EFFECT: possibility of underground refining of oil in order to increase efficiency of oil recovery of carbonate reservoirs, irreversible reduction of viscosity of heavy oil and natural bitumen, reduction of fraction of heavy fractions and increase of fraction of light fractions of heavy oil and natural bitumen.

3 cl, 6 dwg, 4 ex