FIELD: oil and gas industry.
SUBSTANCE: invention relates to methods of treating wells or an underground oil-and-gas bearing formation. Method of treating well or underground oil and gas bearing formation to increase extraction of hydrocarbons from formation includes: introducing either a water-soluble acrylamide polymer and a metal-free organic cross-linking agent or an acrylamide polymer to be cross-linked into the injected liquid, entering the wellbore or formation, wherein the acrylamide polymer and the cross-linking agent or the cross-linkable acrylamide polymer form a fluid cross-linked polymer in the presence of injected fluid flowing in the formation, and the fluid cross-linked polymer pushes hydrocarbons from the formation, while the fluid cross-linked polymer continues to flow through the formation, the cross-linking agent includes a polymeric polyamine, which or (i) is a product of a polymerisation reaction of a mixture consisting of at least one monomer of formula II or III or a salt thereof, or (ii) consists of at least one structural unit of formulas IIA, IIIA, IIIB or IVA, wherein formulas II, III, IIA, IIIA, IIIB and IVA have given corresponding structures, and the cross-linkable acrylamide polymer includes a product of a mixture polymerisation reaction, consisting of at least one acrylamide monomer and at least one monomer of formula II or III or a salt thereof. Method for improving coverage efficiency of underground oil-and-gas bearing bed with flooding fluid for increasing hydrocarbon extraction from formation includes: introducing either a water-soluble acrylamide polymer and a metal-free organic cross-linking agent or an acrylamide polymer to be cross-linked into the injected liquid, entering the borehole or formation, to produce cross-linked polymer in the high permeability zone existing inside the formation, stopping production of hydrocarbons from the treated formation for a period of time, sufficient to increase viscosity of cross-linked polymer in high permeability zone, such that cross-linked polymer remains fixed inside high permeability zone, to direct liquid flow into formation zones not covered by displacement, after step of suspension introduction of pumped liquid into treated formation for water flooding of formation, providing mobility to hydrocarbons and formation of a flooding liquid, and extraction of a flooding liquid containing mobile hydrocarbons from the well in form of the produced liquid, wherein the cross-linking agent contains a polymeric polyamine, which or (i) is a polymerisation product of a mixture consisting of at least one monomer of formula II or III or a salt thereof, or (ii) consists of at least one structural unit of formulas IIA, IIIA, IIIB or IVA, wherein formulas II, III, IIA, IIIA, IIIB and IVA have reduced structures, and the cross-linkable acrylamide polymer includes a polymerisation product of a mixture consisting of at least one acrylamide monomer and at least one monomer of formula II or III or a salt thereof.
EFFECT: technical result is the increase in the treatment efficiency.
37 cl, 4 dwg, 6 tbl, 7 ex
