GROUTING MIXTURE USING A MAGNETIC GRANULAR POLYMER COMPOSITION WITH THE POSSIBILITY OF SELF-HEALING CEMENT STONE FOR CASING STRINGS ATTACHMENT AND REPAIR AND INSULATION WORKS Russian patent published in 2021 - IPC E21B33/138 C04B14/02 C04B28/04 C09K8/46 C09K8/467 H01F1/04 C08L7/00 

FIELD: wells construction.

SUBSTANCE: invention relates to the construction of wells and can be used in the oil and gas industry and mining, in particular when cementing casing strings at the construction stage and repair and insulation works at the stage of well operation, if necessary, providing sufficiently low values of the cement stone permeability behind the production casing. The grouting granular mixture includes oil-well portland cement PCT-I-G, a magnetoactive additive, a crosslinking agent and an insulating agent. In this case, the magnetoactive additive consists of a polymer matrix, which is used as a natural or synthetic rubber, selected from butyl rubber or silicone rubber and a magnetic filler, which is used as magnetic powders with a particle size in the range of 1-100 microns in the form of iron-neodymium magnetic powders boron (NdFeB) or magnetite (Fe₃O₄), or powdered iron (Fe), or iron-cobalt, or iron-nickel. A polymer selected from natural or synthetic rubber selected from butyl rubber or silicone rubber is used as a crosslinking agent, and an insulating agent is used as an insulating agent including a lyophilic fragment and a hydrophilic fragment. Wherein the lyophilic fragment is selected from the group consisting of butyl rubber or natural rubber, or silicone rubber, or polyurethane polymer, or styrene block copolymer, and the hydrophilic fragment contains crystal-forming inorganic materials with a particle size of up to 100 microns and a density of up to 4 g/cm³, with working temperature -5 to + 200°С, selected from calcium oxide or calcium aluminate, or silicon oxide, or calcium carbonate, or sodium silicate, or potassium silicate, or calcium silicate. In this case, inorganic materials are treated with an organic solution with the possibility of microencapsulation, so that the particles do not begin to react ahead of time with the mixing water of the cement slurry. The organic solution is selected from the group consisting of an organosilicon hydrophobizator selected from a gas condensate liquid GCL 136-41 or an organosilicon liquid GCL 136-157 m, or an organic solution of polybutyl acrylate, or its copolymer with styrene with a styrene content in the solution of not more than 50 wt%, or a thermoplastic - a polyolefin obtained by copolymerizing ethylene and vinyl acetate monomer - Hanwha material. In this case, the content of the magnetic filler is 1-75 parts by weight, portland cement PCT-GI - 100 parts by weight, a crosslinking agent - 1-10 parts by weight, an insulating agent - 1-10 parts by weight, a polymer matrix - 100 parts by weight In this case, the granules of the grouting mixture have the following characteristics - the density of the magnetic polymer is 1.4-2.5 g/cm³, the elasticity is 0.5-30 MPa, the residual magnetization is 1-30 g.wt.⋅cm³/g with an operating temperature from -50 to +200 °C.

EFFECT: invention increases the efficiency of self-healing cement stone, reducing cracks, increasing elasticity, increasing adhesion to the casing.

1 cl, 1 dwg, 3 tbl, 12 ex