METHOD OF WELL CASING Russian patent published in 2002 - IPC

FIELD: deep well drilling, particularly, methods of casing of oil-gas, geothermal, injection wells and other special wells, injection and producing wells on underground gas storage objects. SUBSTANCE: in method of well casing which includes successive injection to annular space of nonsolidifying isolating material with higher plugging and colmatage effect and solidifying plugging material forming solid rings with required strength characteristics fixing casing string, distance between fixing solid rings is determined by the following expression L = , where E is pipe material modulus of elasticity, MPa; J is moment of inertia of casing string section, m⁴; Kk is coefficient considering influence of annular space nonsolidifying material on casing string stability; σ_cr is critical stress, MPa; F is cross-section area of casing string, sq. m. At temperature from 70 to 180 C nonsolidifying isolating material is used in the form of highly structurized gel-like suspension of thermopas and polygorskite clay with regulators of structural-mechanical, adhesive properties and density. Said material possesses high plugging ability and colmatage effect at the following amounts of components, mas. pts: water, 100; polygorskite clay, 5-17; thermopas, 5-15; chrysolite-asbestos, 6-15; granulated blast-furnace slag, 10-20; weighing compound, 20-120. At temperature from 150 to 300 C, nonsolidifying isolating material is used in the form of highly structurized neutralized slime of electroplating with regulators of structural-mechanical, adhesive properties and density. Said material possesses high plugging ability and colmatage effect at the following amounts of ingredients, mas. pts: water, 100; slime of electroplating (in terms of dry matter), 8-50; chrysolite-asbestos, 8-18; γ- belite-diatomaceous earth cement, 15-30; copper sulfate, 0.5-15; hematite, 10-120. At temperatures from 80 to 250 C, nonsolidifying isolating material is prepared from hydrocarbon-base fluid with regulator of structural-mechanical properties and density. Said material features high plugging ability and colmatage effect with the following amounts of components, mas. pts: diesel fuel, 100; bitumen, 1.5-12.5; cresol, 0.3-2.0; bentonite and powder, 10-30; rubber crumb, 10-20; barite, 20-120. EFFECT: increased service life and ecologic reliability of well casing under conditions of thermomechanical loads and deformation of casing string at temperatures from 70 to 300 C. 4 cl, 1 dwg, 1 tbl