RU2521236C1 - Method of bottomhole support in sand wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method of bottomhole support in the formation with unstable rocks includes generation of a filter by preparation and injection of the polymer composition to the bottomhole zone. Before and after these operations a solution is injected which makes 10-30% by volume of the polymer composition. Thereafter the well is blown by a flow of gas and withhold for the composition reacting and curing. At that a mixture of silicone resin and solution Chimeco-P is used as the polymer composition in quantity of 95.0-98 wt %: hardener AGM-9 - 5-.0-2.0 wt % representing aminopropyltriethoxysilane. A mixture of xylol or a mixture of rectification residues KORE in quantity of 0.0-100 wt % and aromatic solvent Nefras A in quantity of 100.0-0.0 wt % is used as the solvent.

EFFECT: increased efficiency of the method.

1 dwg, 1 tbl

Description

The invention relates to the gas industry and can be used for fastening the bottom-hole zone of sand-producing gas wells, including used for underground gas storage.

There is a method of fixing the bottom-hole zone of sand-producing wells by first injecting a polymer composition based on a mixture of urea-formaldehyde and acetone-formaldehyde resins, and then a solution of hydrochloric acid [1 - analogue].

The disadvantages of this method are the complexity of operations associated with the rapid hardening of the composition, multi-stage process, as well as the use of corrosive hydrochloric acid.

A known composition for fixing the bottom-hole zone of the formation during sand control, including the injection of a solution of the following composition: bottoms of furfuryl alcohol, concentrated technical hydrochloric acid, acetone, 25% aqueous ammonia solution, water [2 - analogue].

The disadvantages of this method are the use of a multicomponent composition, low strength characteristics and insufficient gas permeability of the fixed sandstone.

Closest to the alleged invention in technical essence is a method of attaching the bottomhole formation zone with a composition containing resin, ammonium chloride and sodium nitrite [3 - prototype].

A disadvantage of the above composition for attaching a weakly cemented formation is that the coating formed during its use significantly reduces the permeability of the reservoir, and also that the stone formed during fastening of sand has low strength characteristics.

The aim of this invention is to develop a technologically advanced method of fastening the bottom-hole zone of gas wells while maintaining reservoir properties of the formation.

The technical result of the invention is to increase the efficiency of the method by improving the strength and filtration-capacitive characteristics of sandstone, bonded by the claimed composition and preventing the formation of sand plugs and the removal of sand into the wellbore.

SUMMARY OF THE INVENTION

A method for fixing the bottom-hole zone of the formation with unstable rocks is proposed, including creating a filter by preparing and pumping a cured polymer composition into the bottom-hole zone, which consists in the fact that a solvent is pumped before and after the specified composition, the volume of which is 10-30% vol. from the polymer composition, after which the well is purged with a gas stream and held to react and cure the composition, and a mixture of organosilicon resin and solvent — Himeko-P and hardener AGM-9, which is aminopropyltriethoxysilane, is used as the curing polymer composition, in the following ratio of components, wt.%:

Sand-strengthening composition

Himeko-P 95.0-98.0 Hardener AGM-9 5.0-2.0,

as a solvent, xylene or aromatic solvents, the following component composition, wt.%:

Distillation distillation residues

KORE 0.0-100.0

Aromatic solvent

Nefras A 100.0-0.0

For research were used:

1. The sand-strengthening composition according to TU 2458-105-54651030-2012 is a mixture of an organosilicon polymer and a solvent.

The organosilicon resin is a solution of polymethylphenylsiloxane resin modified with polyester in xylene, and the solvent is o-xylene TU 2458-105-54651030-2012 rev. No 1 on October 12, 2012

2. The hardener AGM-9 according to TU 6-02-724-77 is an aminopropyltriethoxysilane.

The quantitative ratios are selected based on the fact that the use of a hardener of more than 5.0% is impractical, and with less than 2.0%, the efficiency of curing the sand-strengthening composition is reduced.

An experimental study of the composition was carried out on a HP-CFS high-pressure filtration unit. The installation diagram is shown in Figure 1.

In laboratory conditions at room temperature, this composition was tested to assess the effect of its injection on the filtration-capacitive properties of the porous medium of the bottomhole zone of a gas well.

The reservoir model was a bulk model with a length of 22.4 cm and an inner diameter of 4.71 cm ² . To obtain a given permeability of the porous medium, a quartz sand fraction ground for a certain time was used.

After packing the model with sand, it was saturated with water and the coefficient of water permeability was determined. The solvent was pumped into the model, then the polymer composition and again the solvent, after which the model was purged with air for 24-48 hours to completely cure the composition. After purging, the model was again saturated with water and the final value of the phase permeability coefficient for water was determined. The permeability recovery coefficient was calculated from the obtained values of the permeability coefficient before and after processing.

At the final stage, the presence or absence of sand removal at an overpressure of up to 5.0 MPa was determined.

The results are presented in table 1.

Table 1 The influence of the composition on the recovery coefficient of permeability and sand removal Experience number one 2 3 four 5 prototype The composition, wt.% Himeko-P 95 96.5 98 97.5 - AGM-9 5 3,5 2 2,5 - Carbamide resin - - - - 80 Ammonium chloride - - - - 3.0 Sodium nitrite - - - - 2.0 The solvent,% wt. KORE - fifty one hundred - - Nefras one hundred fifty - - - Xylene - - - one hundred - The amount of solvent,% vol. from the composition Before 10 twenty twenty thirty - After twenty 10 twenty thirty - The amount of composition, V then 2 2 2 2 0.5 Permeability to water, microns ² Before processing 0.4421 0.5281 0.5867 0.5346 3,180 After processing 0.5084 0.5559 0.5867 0.5880 2,012 Permeability recovery coefficient, β 1.15 1.05 1,0 1,1 0.63 The degree of compression, MPa 3.6 3,5 3.4 3.4 - Sand removal no no no no no

As follows from the table, the proposed composition prevents the removal of sand, while not reducing the permeability of the porous medium by gas, while the composition of the prototype prevents the removal of sand, but significantly reduces the permeability of the porous medium by gas.

Information sources

1. RF patent No. 2387806, E21B 33/138, Method for fastening the bottom-hole zone of sand-producing wells, No. 2009112473/03; published on April 27, 2010. - analogue.

2. RF patent №2138616, E21B 33/138, Composition for fastening the bottom-hole formation zone, No. 97118822/03; published on 09/27/1999. - analogue.

3. RF patent 2352764, E21B 33/138, Method for fastening the bottom-hole formation zone, No. 2007119854/03; published on April 20, 2009. - prototype.

Claims (1)

The method of fastening the bottom-hole zone of the formation with unstable rocks, including creating a filter by preparing and injecting a cured polymer composition into the bottom-hole zone, characterized in that a solvent is pumped before and after said composition, the volume of which is 10-30% vol. from the polymer composition, after which the well is blown with a gas stream and held to react and cure the composition, and a mixture of organosilicon resin and solvent - Himeko-P and hardener AGM-9, which is aminopropyltriethoxysilane, is used as the curing polymer composition, in the following ratio of components, wt.%:
Sand-strengthening composition
Himeko-P 95.0-98.0 Hardener AGM-9 5.0-2.0
as a solvent, xylene or a mixture of aromatic solvents, the following component composition, wt.%:
Distillation distillation residues
KORE 0,0-100
Aromatic solvent
Nefras A 100.0-0.0

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