METHOD FOR COMPLEX THERMAL STABILIZATION OF PERMAFROST ROCKS IN THE IMPACT ZONES OF PRODUCING WELLS OF NEOCOMIAN-JURASSIC DEPOSITS Russian patent published in 2022 - IPC E21B36/00 

FIELD: mining industry.

SUBSTANCE: invention relates to the field of design, construction and operation of producing wells (PW) and can be used in the operation of Neocomian-Jurassic deposit PWs with a high temperature of the extracted fluid. The method for complex thermal stabilization of permafrost rocks (PMR) includes drilling at least one permafrost-parametric well before the construction of the PW. During drilling, the depth of the PMR bottom is visually determined as the boundary between the frozen and thawed soil zone. Also, during drilling, thermometry is carried out in the trunk of a permafrost-parametric well, according to which the phase characteristic of the soil ΔT in the inter-well space is calculated as the difference between the temperature of the soil in the inter-well space and the temperature of the beginning of its freezing at a certain depth. Then the curve of the dependence of the phase characteristics of the soil in the inter-well space on the depth of the permafrost-parametric well is constructed. At the intersection of the curve of the phase characteristic of the soil with a zero isotherm (ΔT = 0), the depth of the PMR bottom is determined, which is compared with the result of the depth of the PMR bottom determined visually by the condition of the soil. The largest of the compared results of determining the depth of the bottom of the PMR is used in the construction of the PW in the PMR interval, during which the PW trunk is drilled and a double-walled heat-insulated direction (HID) is lowered into it, between the walls of which there is a screen-vacuum insulation (SVI) or polyurethane foam insulation (PUF), a conductor, an intermediate column and an operational column. Moreover, the descent of the HID is carried out to a depth that provides thermal insulation of the upper horizons of the PMR. Then the annular space of the HID is cemented, as well as the inter-tube space of the TN and the conductor, the inter-tube space of the conductor and the intermediate column, the inter-tube space of the intermediate column and the operational column. In this case, cementing in the PMR interval is carried out with a grouting solution with a thermal conductivity coefficient of cement stone ≤ 0.25 W/(m⋅K). Then, a double-walled tubing string is lowered to the depth of the bottom of the PMR, between the walls of which the SVI is located. In addition, the thermal stabilization of the soils at the base of the facilities for the arrangement of the PW cluster site is carried out by installing seasonal cooling devices (SCD) filled with refrigerant into the ground and having an above-ground condenser part and an underground evaporative part installed in the soils at the base of the facilities for the arrangement of the PW cluster site. Also, if necessary, the thermal stabilization of the soils of the estuary zone of the PW is carried out by installing in it a cooling system filled with refrigerant and having an above-ground condenser part and an underground evaporative part installed in the soil of the estuary zone of the PW site.

EFFECT: minimization of the thermal effect of the PW of Neocomian-Jurassic deposits with a high temperature of the extracted fluid.

1 cl, 4 dwg