CARBONATE BED HYDROFRAC Russian patent published in 2015 - IPC E21B43/27 

FIELD: oil-and-gas industry.

SUBSTANCE: proposed process comprises lowering of flow string in hydrofrac zone and sealing of well annulus by packer. Rock is subjected to hydrofracturing to produce cracks by forcing gasified fluid via said flow string with the fracture propping. After sealing of casing string-borehole annuity packer is used to cool bottom hole zone by nitrogen gas with temperature of minus 40 to minus 45 degrees Centigrade. Then, hydrofrac is performed by injection of the mix of hydrochloric acid and nitrogen in amount sufficient for production of hydrochloric acid foam with foam content of 57% at well bottom. Then, 220°C superheated steam is forced via said flow string to hydrofracture. Note here that volume of said steam is selected to equal or to exceed that of forced hydrochloric acid foam and that of flow string. Now, the well is operated.

EFFECT: higher efficiency of fracturing.

1 dwg