METHOD FOR SEALING ANNULAR SPACES OF WELL CASING STRINGS IN CONDITIONS OF DISTRIBUTION OF LOW-TEMPERATURE ROCKS Russian patent published in 2023 - IPC E21B33/14 E21B47/05 

FIELD: geological exploration and subsequent development of mineral deposits.

SUBSTANCE: invention is intended for oil and gas deposits in the conditions of distribution of low-temperature rocks. To implement the method of sealing the annular spaces of casing strings in the conditions of the distribution of low-temperature rocks (LP), geophysical work is carried out, including seismic, electrical exploration, thermometry, the interpretation of which determines the structure of the section of the LP, including the position of the roof and bottom of gas hydrate rocks (GHP). Wells are drilled with the installation of casing and lift strings to the design depth. Drilling under the conductor is carried out to a depth that provides overlapping of the OP thickness by at least 20-40 m with the deepening of the conductor's shoe into stable rocks. A heat-insulated direction is installed in the near-mouth zone of the well overlapping the interval of permafrost rocks (PFR). Seasonal cooling devices (SCA) are installed around the wellhead; the well is equipped with a thermometric fibre-optic cable, which is lowered behind the casing strings and behind the production string. In the annular space behind the direction, conductor and production cemented casing in the intervals of OP, thermobaric conditions are first created in the cement ring for its setting, and then freezing and hydration in the wellhead zone and at depth.

EFFECT: increased tightness of the rocks surrounding the well by providing the conditions for hydration of the channels with potential gas filtration to the mouth in the annulus.

7 cl, 1 dwg