Method of eliminating zones of loss in well

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry, particularly to methods of eliminating zones of loss in well and can be implemented for isolation of zones of loss of formation at capital repair of producing and pressure wells and also at regulating profile injection capacity of pressure wells and isolation of water floods in producing wells. According to the method of eliminating zones of loss in a well liquid glass is successively pumped into the well with density of 1360-1450 kg/m3, then liquid glass with density of 1100-1200 kg/m3, and silicon-organic reagent ACOR-BN 102 with density of 980-1100 kg/m3, with following fixing in bed water. The composition is used at a following ratio of components, volume %: liquid glass with density of 1360-1450 kg/m3 10-20, liquid glass with density of 1100-1200 kg/m3 10-20, silicon-organic reagent ACOR-BN 102 with density of 980-1100 kg/m3 60-80. Between liquid glass and silicon-organic reagent ACOR-BN 102 a buffer of fresh water is pumped.

EFFECT: eliminating intensive zones of loss in well.

1 tbl

 

The invention relates to the oil industry, in particular to the elimination of the absorption zones in the borehole, and can be used to isolate areas of acquisitions in the overhaul of production and injection wells, as well as in the regulation of the profile of injection wells and isolation of water in producing wells.

Known composition for plugging zones absorption (patent RF №796388, EV 33/138, publ. 10.01.96,, bull. No. 1), including injection into the well of a composition containing a polyamide resin is nylon, or nylon (25-35%) rest of the composition is a concentrated hydrochloric acid (GOST 14261-69). When mixed with fresh and mineralized water this composition coagulates with the formation of a gel-like mass, which then after a time hardens, turning in a solid substance.

A known way to isolate water production and absorption zone (inventor's certificate SU # 1774689, EV 33/138, publ. 15.01.81,, bull. No. 2), including dual injection into the irrigated part of the formation of two streams: one stream - gipan (0,01 - 1,0%), liquid glass (2-6%), water, the second stream is an aqueous solution of hydrochloric acid (0,44 - 4,0%). After mixing flows into the well advanced pumped water solution of the acid (0,44 - 4,0%). Push the mixture into the layer of fresh water for 8-12 hours, and ZAT the m stand for 2-3 days.

The main disadvantages of these methods is the duration keeping well for hardening cement slurry (up to three days). In conditions of intense absorption in the bore b of the insulation screen does not have time to form. In addition, the injected within 8-12 hours of plugging composition dispersed compositions instantly absorbed in the zone of intensive absorption layer.

The closest to the technical nature of the claimed method is a method of isolation of absorbing layers in the borehole (RF patent No. 2211913, EV 33/138, publ. 10.09.2003,, bull. No. 25), including dual injection into the irrigated part of the formation of two streams of organic additives and an aqueous solution of hydrochloric acid, characterized in that the organic additives used product on the basis of saponified still bottoms from the production of synthetic fatty acids containing not less than 30% dry residue, at least 1.7 mEq/l sodium Soaps of synthetic fatty acids and not more than 0.1% of free alkali based on the dry residue and the aqueous solution of hydrochloric acid using 5-10%concentration.

The disadvantage of this method is the heterogeneity and kakovosti precipitate formed, which invariably leads to stratification of the sediment by the intense absorption wells that eventually when the goes to the erosion of the backfill mixture. Kakovosti and the heterogeneity of the resulting sludge is the result of a 5-10%concentration aqueous solution of hydrochloric acid, and suggests that to fully achieve probablecause effect fails, the method will not provide complete isolation of the absorption layer well.

Technical challenge is the way of eliminating the intensive absorption in the borehole, and to improve the ability of plugging mixture. The improvement is achieved by moving the injected components in the stream of produced water in the absorption zone, with stirring, a homogeneous, crystalline, dense precipitate, followed by fixation mineralized water reservoir in the absorption zone is created bridging effect, high adhesiveness of the surface layer of cement mixture to the formation rock is resistant to formation water and high temperatures.

New in the proposed method, the elimination of the absorption zones in the well is that when successive injection into the absorption zone of the reservoir organosilicon reagent ACRE-bn 102 and liquid glass for greater penetration into permeable reservoir rock and deceleration time of gelation, well consistently pumped liquid glass density 1360-1450 kg/m3, liquid glass density 1100-1200 kg/m3and Kremnica the practical reagent ACRE-bn 102 with density 980-1100 kg/m 3and then consolidate in formation water. For better implementation of the method components are used in the following ratio, volume. %:

liquid glass density 1360-1450 kg/m310-20;

liquid glass density 1100-1200 kg/m310-20;

- organosilicon reagent AKOR-bn 102 density 980-1100 kg/m360-80, and between the liquid glass and silicone reagent AKOR-bn 102 fetch buffer of fresh water.

The inventive method was tested in laboratory conditions. During these tests we used the following components:

- of sodium silicate (glass liquid sodium), silicate module 2,9-4,0, density 1360-1450 kg/m3the viscosity at 20° $ 250-400 MPa·C, the freezing temperature of minus 10°corresponds to GOST 13078-81;

sodium silicate (glass sodium liquid) density 1100-1200 kg/m3received by dissolving in fresh water;

- organosilicon reagent AKOR-bn 102 is a liquid from yellow-brown to dark brown color with a freezing point below minus 50°S, with a dynamic viscosity of 1-30 MPa·C, density 980-1100 kg/m3at 20°corresponds to GOST 3900-85.

In laboratory tests determined the percentage and concentration of liquid glass and reagent AKOR-bn 102 for instant and complete coagulasepositive, recommended for the proposed method. The optimal number of organosilicon reagent AKOR-bn 102 were selected on the basis of education maximum number of sediment with viscosities that do not generate technological difficulties when they are pumping into the well through the tubing. The concentration and amount of liquid glass was chosen taking into account the full coagulation organosilicon reagent AKOR-bn 102 in predetermined proportions proposed cement mixture.

For comparison of water properties of cement mixture according to the claimed method and the prototype was tested on models of the formation. The results of model tests are given in the table.

In the process of modeling ways to eliminate zones of the absorption layer in the well when the composition is injected on the basis of liquid glass is stable relative to the reservoir and desalinated water plugging mass having a high hydrophilic and adhesive properties. Plugging mass penetrates and coats the absorption zone of the formation.

For better penetration and containment response of structure in the absorption zone of the reservoir is pumped liquid glass density 1100-1200 kg/m3that also permeates and envelops the area of the absorption layer, forming a relatively stable formation and desalinated water plugging mass.

<> But by itself, the liquid glass of any density has an amorphous, rather than crystalline structure that is her fault and therefore to give a crystalline structure in the absorption zone of the reservoir wells, pumped organosilicon reagent AKOR-bn 102.

Before download organosilicon reagent AKOR-bn 102, in order to avoid coagulation upon contact with liquid glass or mineral water, pumped buffer of fresh water, the amount is minimal, it serves only to separate the injected components in the tubing.

The results of model tests of the backfill mixture
№p/pDensity kg/m3Sootnesenie of mixture components, vol. %Number of formed sludge, %Insulation coefficient, %
Liquid glassLiquid glassAKOR-bn 102
According to the claimed method
1136020

100

dense


100
200 20
110060
2145015

100

dense


100
110015
98070
3140010

100

dense


100
100010
100080
Prototype
EMKOHCl
410151019,5

dense
72
103010#x0200A;
510151528

dense
74,1
103015

Download the organosilicon reagent AKOR-bn 102 hydrolyzed in the reservoir, mixing with previously uploaded liquid glass density 1360-1450 kg/m3and 1100-1200 kg/m3.THE result of mixing of liquid glass and reagent AKOR-bn 102 is instantaneous coagulation of the components of the cement mixture throughout the volume of the reservoir.

The resulting cement mixture has good adhesive properties, the amount is 100% of the volume of the injected components, with formation of a continuous crystalline structure in the rock formation.

Determining the strength and adhesive properties of cement mixtures, simulated mechanical stirrer vortex flows of fresh and saline water at a temperature of +20°C and +85°C. Delamination or erosion resulting crystalline precipitate was observed that says o high strength and adhesion durability of the resulting mixture.

Laboratory tests demonstrate the advantages of the proposed method over the known methods:

- above is by plugging ability of the insulation material;

- high mobility in the fluid flow with subsequent bridging effect;

- the instantaneous speed of a homogeneous, crystalline structure backfill mixture with a high level of adhesion;

- the stability of the cement mixture to the effects of reservoir temperatures up to +85°C;

- increases the degree of elimination of areas of intensive absorption layer in the well.

The method of liquidation of the absorption zones in the borehole, wherein the sequential injection into the absorption zone of the reservoir organosilicon reagent AKOR-bn 102 and liquid glass for greater penetration into permeable reservoir rock and deceleration time of gelation in the hole consistently pumped liquid glass density 1360-1450 kg/m3, liquid glass density 1100-1200 kg/m3and the organosilicon reagent AKOR-bn 102 density 980-1100 kg/m3then consolidate in formation water for better implementation of the method the composition is used in the following ratio of components,%:

liquid glass density 1360-1450 kg/m310-20
liquid glass density 1100-1200 kg/m310-20
the organosilicon reagent
AKOR-bn 102 density 980-1100 kg/m360-80

and between the liquid glass and silicone reagent AKOR-bn 102 fetch buffer of fresh water.



 

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