RU2422628C1 - Control method of water flooding of non-homogeneous reservoir beds of deposits of minefields by means of cross-linked polymer systems with filler - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: control method of water flooding of non-homogeneous reservoir beds of deposits of minefields by means of cross-linked polymer systems with filler involves pumping of mixture in cycles with hold intervals in number of up to 12 cycles; at that, first, polyacrylimide with stitcher is pumped in portions in each cycle. Chrome acetate is used as stitcher, and then filler is pumped, and 0.7% (by weight) solution of calcium carbonate is used as filler; quantity of calcium carbonate is increased in each next cycle by 0.01 wt %.

EFFECT: reducing the number of by-effects of use of cross-linked polymer systems, uniform distribution of mixture, owing to which water flooding of the well remains controllable and reversible; elimination of blockage of well channels; simplification of cleaning of sludges from the well.

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Description

The invention relates to the mining industry and can be used to increase the return of deposits developed using water flooding.

Numerous geophysical, hydrodynamic, indicator and other field studies indicate that one of the important factors affecting the efficiency of oil field development using water flooding is the geological heterogeneity of the productive section. Even with a slight heterogeneity of the reservoir in terms of power or area (vertical and zonal heterogeneity), the presence of relatively low viscosity oil, interlayers with increased permeability in the section are produced at an accelerated pace. In this case, as a rule, less permeable layers are being developed at a slower pace or not at all involved in the development.

Methods of mathematical and physical modeling, as well as extensive field studies, have made it possible to increase the efficiency of reservoir development during water flooding using rims of water-insulating reagents pumped into injection wells.

A known method of developing an oil deposit (patent RU No. 2205946), which includes injecting into the formation an aqueous suspension based on polyacrylamide, bentonite clay and a chromium compound and an aqueous suspension based on wood flour, condensed sulphite-alcohol stillage and potassium dichromate.

A known method for the development of heterogeneous oil reservoirs (patent RU No. 2313665), including flooding, cyclic injection into the reservoir of components of a polymer dispersed system containing polyacrylamide, clay powder, a chromium compound and water, characterized in that the modified bentonite clay powder is used as the clay powder; 4-6% suspension of modified bentonite clay powder in a 0.04-0.12% aqueous solution of polyacrylamide, push it into the reservoir with a buffer volume of water and incubated for 1-3 hours, then 1-6% suspension of modified bentonite clay powder is subsequently pumped. in water containing 0.005-0.015% chromium compound, at a pressure of 10-40% higher than the water injection pressure, and a mixture of 0.07-0.25% aqueous solution of polyacrylamide and 0.033-0.1% solution of chromium compound at water injection pressure.

A known method of regulating the development of oil fields (patent RU No. 2346151), including the injection of a gelling composition based on a polysaccharide, a compound of a polyvalent metal, water and technological exposure for gelation, guar gum is used as a polysaccharide, zinc oxide in the presence of chromium acetate is used as the specified compound in mineralized water, according to one embodiment, and as said compound, magnesium oxide in the presence of chromium acetate in both fresh and mineralized water according to another option, and exposure is carried out from 3 to 5 days, with a ratio of components, wt.%: guar gum 0.2-0.5, zinc oxide 0.03-0.05 and chromium acetate 0.02-0.1 or oxide magnesium 0.02-0.04 and chromium acetate 0.01-0.12, water - the rest in options, respectively.

There is a method of aligning the injection profile in injection and limiting water inflow in producing wells (patent RU No. 2169258), which includes injecting into the formation an insulating composition based on polymers, a crosslinker and water, using a dispersion of water of carboxymethyl cellulose, polyacrylamide and a crosslinking agent in the ratio of components , wt.%: carboxymethyl cellulose 0.1-3.0, polyacrylamide 0.005-0.5, a crosslinker 0.01-0.2, water - the rest, while the insulating composition is pushed into the formation at a distance to gel The clear exception is the effect of depression on the gel to a safe level. Moreover, at high injectivity of the well, the insulating composition additionally contains filler in an amount of 0.5-10.0 wt.%.

The closest analogue is a method for regulating the development of a heterogeneous oil reservoir (patent RU No. 2279540), which involves injecting into an injection well an aqueous solution containing PAA polyacrylamide with a crosslinker, and an aqueous solution containing a surfactant surfactant and calcium chloride, and then injecting an aqueous a solution containing surfactant and calcium chloride, and injection of a displacing agent - water. As an aqueous solution containing PAA with a crosslinker, use an aqueous solution of the composition,%: PAA 0.1-0.5, crosslinker - chromium acetate 0.01-0.05, water - the rest, and as an aqueous solution containing surfactant and calcium chloride, an aqueous solution of the composition,%: nonionic surfactant 1.0 - 5.0, calcium chloride 1.5-3.5, water - the rest.

The disadvantage is that the clay present in the formation under the influence of calcium chloride swells, which leads to blockage of channels and cracks in the well.

The aim of the invention is to reduce the number of side effects of the use of crosslinked polymer systems.

The goal is achieved due to the fact that 0.7% calcium carbonate solution is used as a filler. In this case, the system is injected into the well in portions. In the first portion, polyacrylamide is pumped with a crosslinker, which is used as chromium acetate, in the second - 0.7% calcium carbonate solution. Then, with an interval of exposure, up to 12 cycles of pumping the mixture are carried out in the same order, but with an increase in the amount of calcium carbonate by 0.01% in each cycle.

As a result, a uniform distribution of the mixture is achieved, so that the water cut of the well remains adjustable and reversible. Blocking of the borehole channels is eliminated, and well cleaning from sludge is simplified.

The implementation of the invention

Before pumping the mixture determine the injectivity of the well. Next, the polyacrylamide is mixed with chromium acetate in the injection device, after which the mixture is fed into the well. Next, 0.7% calcium carbonate solution is pumped into the well. After exposure, injection cycles are again carried out in the same order, but with an increase in the amount of calcium carbonate by 0.01% in each cycle.

Example

Injection volumes and composition of the mixture for injectivity of the well 200 m ³ / day.

No. p / p Parameter Value one The volume of injection, m ³ : - 1-6 cycles 638.7 - 7-9 cycles 299.1 - 10 cycle 25.0 2 The concentration of polymer in the composition, wt.%: - 1-6 cycles 0.250 - 7-9 cycles 0.364 - 10 cycle 0.700 3 The concentration of the crosslinker, wt.%: - 1-6 cycles 0,025 - 7-9 cycles 0,036 - 10 cycle 0,050 four The concentration of calcium carbonate, wt.%: - 1 cycle 0.7 - 7 cycle 0.76 - 10 cycle 0.79 5 The total volume of injection, m ³ 962.8 6 Composition download time, days from 10

Claims (1)

A method for controlling flooding of heterogeneous reservoir beds of deposits using crosslinked polymer systems with a filler, which consists in pumping the mixture in cycles at a shutter speed of up to 12 cycles, with polyacrylamide with a crosslinker first being pumped in portions in each cycle, using chromium acetate, and then the filler, which is used as a 0.7% solution of calcium carbonate, in each subsequent cycle, the amount of calcium carbonate is increased by 0.01%.