RU2352764C2 - Method of binding bottomhole zone of formation - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of binding bottomhole zone of formation of unstable rock consists in creating filter by means of pumping composition into zone at amount of 0.5 of porous volume of bound rock containing % wt: carbamide resin 80.0, sal ammonia 1.0-3.0, sodium nitrite 1.0-3.0, water- the rest, in forcing hydrophobic liquid with one porous volume, in conditioning for reaction and hardening within 24 hours.

EFFECT: simplification of process of formation bottomhole zone binding with synthetic resins without significant reduction of their collecting properties.

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Description

The invention relates to the oil and gas industry and can be used during repair and restoration work for fastening the bottom-hole zone of sand-producing wells.

A known method of preventing the removal of sand and reducing water inflow into production wells, including the injection into weakly cemented sections of the formation of a hot supersaturated solution of calcium chloride with a density of at least 1500 kg / m ³ (RU 2164589, class E21B 43/08, 21.02.00).

The disadvantage of this method is the limited scope of its application - reservoir temperatures should not exceed 30 ° C, the reservoir should have low water saturation.

A known method of dealing with sand in oil and gas wells, including the injection into the well of a water-cured hydrophobic polyurethane prepolymer in an organic solvent (RU 2285791, CL EV 43/22, 11/21/05).

The disadvantage of this method is the need for the use of toxic solvents (lower ketones) for the preparation of a prepolymer solution, as well as for washing the pump units, strapping the mouth, tanks, pipes, etc. after preparing and pumping it into the reservoir.

The closest analogue to the proposed method is a method of attaching a bottomhole formation zone, including creating a filter by pumping a curable polymer composition into the bottomhole zone. Urea, phenolic, epoxy and other resins are used as a curable polymer (SU 1461868, CL ЕВВ 33/138, 11.28.86).

The disadvantage of this method is the multicomponent composition of the polymer and the multistage process, including injection of the polymer composition, curing, water washing of the cured composition to dissolve and remove soluble salt, injection of a multicomponent heat-generating foam-forming composition.

The aim of the invention is to simplify the technology of fastening the bottom-hole formation zone with synthetic resins without significantly reducing its reservoir properties.

This goal is achieved by the fact that in the method of fixing the bottom-hole formation zone, including creating a filter by pumping a curable polymer composition into the bottom-hole zone, an aqueous solution of urea resin, ammonium chloride and sodium nitrite in the following ratio, wt.%:

Carbamide resin - 80.0 Ammonium chloride - 1.0-3.0 Sodium nitrite - 1.0-3.0 Water - the rest,

which is pumped into the bottom-hole zone of the well in an amount of 0.5 pore volume of the fixed rock, squeezed with one pore volume of a hydrophobic liquid (salable oil, kerosene, diesel fuel, etc.) and the reaction is carried out and cured for 24 hours.

The essence of this method consists in partially filling the intergranular space of the fixed rock with a cured resin solution due to its smearing with a hydrophobic, squeezing liquid. In addition, during the reaction of ammonium chloride and sodium nitrite under reservoir conditions, nitrogen is released, which ensures the formation of a porous structure in the hardening mass and improves the strengthening properties of the composition by increasing the adhesive strength of the polymer film with mineral grains.

As the urea resin used resin brand KFZH according to GOST 14231-88. Ammonium chloride - NH ₄ Cl according to GOST 2210-73, sodium nitrite - NaNO ₂ according to GOST 19906-74.

To confirm the possibility of using the proposed method in laboratory conditions, tests were conducted on a bulk model of an oil reservoir. The reservoir model was a metal core holder with a diameter of 26 mm and a length of 100 mm filled with disintegrated sand.

After the core was saturated with water, its permeability was measured, 0.5 first volume of polymer composition was injected, one pore volume of hydrophobic liquid was held for 24 hours for reaction and curing, and then core permeability and sand removal were determined again at an overpressure of 10 MPa created by the high pressure pump GILSON 305.

The results of measurements of permeability and sand removal are presented in the table.

No. p / p The polymer composition, wt.% Temperature ° C The permeability of the core, microns ² Sand removal Core Condition Resin NaNO ₂ NH ₄ C1 Water before processing after processing one. 80.0 1,0 3.0 16,0 25 3,748 2,342 no fastened 2. 80.0 2.0 3.0 15.0 40 3,180 2,012 no fastened 3. 80.0 3.0 2.0 15.0 60 3,252 1,913 no fastened four. 80.0 3.0 1,0 16,0 85 3,846 2,645 no fastened

As can be seen from the above data, the use of the proposed method of fixing the rocks of the bottom-hole formation zone allows to strengthen the rock and prevent sand removal while reducing the initial permeability by 35-40%. In addition, the proposed method is quite simple to implement. For its implementation, scarce, expensive reagents and special equipment are not required.

Claims (1)

The method of fastening the bottom-hole zone of the formation with unstable rocks, including creating a filter by pumping a curable polymer composition into the bottom-hole zone, characterized in that an aqueous solution of urea resin, ammonium chloride and sodium nitrite in the following ratio, wt.%:
urea resin 80.0 ammonium chloride 1.0-3.0 sodium nitrite 1.0-3.0 water rest,
which is pumped into the bottom-hole zone of the well in an amount of 0.5 pore volume of the fixed rock, squeezed by one pore volume of hydrophobic fluid, and soak for reaction and curing during the day.