RU1776761C - Plugging mixture - Google Patents

Abstract

The inventive grouting composition contains components, parts by weight: slag-sand cement JOO, ferric chloride 0.5-1.0, polyacrylamide 0.05-0.10, ethyl silicate 1.0-3.0, water 48.25-51.40. Cement is mixed in an aqueous solution of ferric chloride and ethyl silicate. When a polyacrylamide solution is added, a paste forms. The tampon stone has a high sulfur and hydrogen resistance. 2 tab.

Description

The invention relates to the field of drilling deep and ultra-deep wells, in particular to the production of cement slurries for the elimination of complications (open core, lens, tubular, cavernous. Absorbing and developing channels) in the presence of aggressive hydrogen sulfide in the zones at a temperature of 100-160 ° C. It can be used for drilling in the field of geology, oil and gas industry.

Known polyacrylamide paste for insulating work at normal temperatures, prepared by mixing two cement slurries, in the following ratio of ingredients, parts by weight:

Portland cement

tamponage

Polyacrylamide

(PAA)

Chloride

calcium

Water

100 0.14-0.20

3.5-5.0 55-60

(see Bulatov A.I. and Daniushevsky B.C. Grouting materials. - M.: Nedra, 1987, p. 242).

The basis of this paste is Portland cement for cold wells that do not have corrosion resistance in aggressive environments, so the paste cannot be used at high temperatures in the presence of hydrogen sulfide.

A well-known grouting composition for isolating the zones of absorption of washing liquid in the zones of salt karst in the presence of low mineralized and hydrogen sulfide-containing water, consisting of caustic magnesite, magnesium chloride, polyacrylamide and water in the following ratio of ingredients, wt.%:

Caustic Magnesite Magnesium Chloride Polyacrylamide Water

46.66-49.00 12.45-15.34

0.24-0.33 Else

Ј

CH VI

About VI

ABOUT

(see ed. St. USSR No. 1051232, class E 21 B 33/138. 1983).

However, the well-known grouting composition is intended for low positive temperatures and cannot be used when drilling deep wells under high temperature conditions due to the short setting time.

Also known is a grouting composition for fastening oil and gas wells at a temperature of 100 ° C, containing cement, sodium and water adaptates in the following ratio of ingredients, parts by weight: Slag cement ШПЦС100,0

Adapts: 0.4-2.5

Water47.5-49.6

(see ed. St. No. 1167306, class E 21 B 33/138, 1985).

However, the well-known grouting composition is spreadable (AzNII cone spreadability 220 mm, see table) in the complication zone is easily diluted with formation water and does not provide isolation of porous-karst formations during intense absorption and aggressive water flows.

Closest to the technical nature of the proposed composition is grouting mortar for fixing high-temperature oil and gas wells under conditions of hydrogen sulfide aggression, described in the method of chemical treatment of grouting mortars (see ed. St. USSR No. 927972. class E 21 B 33 / 138, 1982). As a containing composition, it contains metallurgical slag with sand, salts of ferric iron salts dissolved in an aqueous solution, and additives of the PFLH plasticizer (wood-chemical polyphenol) in the following ratio of ingredients, parts by weight:

Slag 60.0

Sand40.0

Iron Nitrate 5.5

PFHL0.5

Water55.0

However, this solution at the early stage of hardening spreads and does not allow high-quality isolation of zones of intense absorption of flushing fluid and water penetration in large-porous, cavernous formations, despite the preliminary cementing to reduce the absorption rate.

The aim of the invention is to increase the efficiency of eliminating the complications of open vein, lens, tubular, cavity, absorbing and developing channels under conditions of hydrogen sulfide aggression at high temperatures

by eliminating the spreadability of the cement composition.

Delivered yel is achieved in that the composition containing slag sand cement, polymer, ferric salt and water additionally contains ethyl silicate and all ingredients are taken in the following ratio, parts by weight: Cement

SHPTsS-120 100.0

Ferric Chloride 0.5-1.0

PAA 0.05-0.10

Ethyl silicate 1.0-3.0

Water48.25-51.40

Comparative analysis with the prototype allows us to conclude that the inventive grouting composition differs from the known one by the introduction of new components, namely, the organosilicon compound - ethyl silicate. Thus, the claimed technical solution meets the criterion of novelty. An analysis of the well-known grouting compositions (2,3.4) used in drilling to eliminate complications in aggressive media has shown that some substances introduced into the proposed solution are known. For example, slag cement, ferric chloride, polyacrylamide. However, the use of these substances in known grouting compositions does not provide them with the properties that are manifested in the claimed solution. It is also known to use ethyl silicate to increase the corrosion resistance of cement stone.

If on the basis of cementitious Portland cement a paste is obtained when polyvalent metal and polyacrylamide are introduced into the composition, with a certain ratio of ingredients (analogue 1), then the conditions on the slag-based composition have changed, and polyacrylamide alone is not enough to obtain a paste (experiment 3, Table 1 ) Ethyl silicate within these limits does not exclude spreadability (experiment 4, table. 1), and

in combination with polyacrylamide at a certain ratio of ingredients helps to achieve this goal. That is, in addition to the known quality in this composition, Ethylsilicate acts in a new quality.

Thus, this composition of the components gives the claimed tamponage composition a new property, which allows us to conclude that the claimed

solving the criterion of significant differences.

According to the authors, polymers and iron chloride perform several functions here together:

thicken the solution, eliminate the flowability, increase the plastic strength of the solution;

contribute to the setting and hardening of the mixture in an aggressive environment.

In addition, small PAA additives prevent early setting of cement slurry at high temperatures.

The thickening mechanism of the solution can obviously be explained by the fact that when PAA is added to the cement solution containing iron chloride, the formation of stable new bonds between PAA molecules and the ferric salt begins, as a result of which an additional amount of solid substance forms in the interparticle pore space. increases the viscosity of the pore fluid. In all likelihood, ethyl silicate enhances this process.

After the cement slurry hardens, a cement stone forms, the pore volume of which is filled with a solution of ferric salts and the products of its reaction with polymers and some grouting materials. When an aggressive environment containing hydrogen sulfide is exposed to such a cement stone, conditions are created for the chemical bonding of the hydrogen sulfide penetrating the cement stone to iron chloride. The reaction products fill the pore space of the cement stone at the boundary of its contact with the aggressive medium (reduce porosity), further gas filtration through it is difficult.

In the final result, this leads to an increase in the strength of cement stone and its resistance in aggressive environments.

The mechanism of the action of reagents on the hydration hardening of cementitious materials is difficult to explain. It is likely that retardation in this case can be explained by the adsorption of positively charged amide groups of the polymer on the surface of negatively charged slag particles.

Paste is formed only at a given ratio of ingredients.

An example of the preparation of the proposed composition in laboratory conditions.

To obtain the proposed grouting composition, the following substances were used:

Slag sand cement ШПЦС-120 - ОСТ 39-017-80

Iron chloride (3 chloride 6 water) GOST 4147-74

Polyecrylamide - TU 6-16-15-3-73

Ethyl silicate - TU 6-02-06-67-86

Tap water

Initially, a 1.5% aqueous polyacrylamide solution was prepared in a separate container. For this purpose, 0.05-0.1 g of dry polyacrylamide was dissolved in 3.25-6.40 ml of water at a temperature of 40-60 ° C (the powder was poured into water gradually, with stirring).

In another vessel, a solution of the iron salt was prepared, for which 0.5-1.0 g of salt was dissolved in 45.0 ml of water. A calculated amount of silicate was added to the same container. On the resulting solution, slag cement Ciz was calculated (100 g of cement per 46-48 ml of mixing liquid) and the previously prepared 1.5% solution of polyacrylamide was added to it, and then the whole mixture was stirred using a laboratory stirrer for 1 min. at a speed of 90-100 rpm, as a result of which an inventive grouting composition was obtained.

In the course of laboratory tests, the structural and mechanical properties of the obtained composition were determined, namely, the flowability, density, setting time and strength of the forming stone.

Spreadability was determined according to GOST 1581-85; density, setting time of the mortar and strength of cement stone - in accordance with GOST 310.3.76.

In order to study the comparative stability of cement stone in an atmosphere of hydrogen sulfide, the technique described in the literature was used (see Gracheva O.P., Barbakadze

E.O. The chemistry of the interaction of products of hydration of asbestos cement with hydrogen sulfide. Tr. Research Institute of Asbestos Cement. - M.: Gosstroy- publ., 1963, no. 17, p. 36-55).

Data on ingredient composition and

The properties of the proposed and known compositions are shown in table 1.

The experimental data of the table indicate that the addition of iron chloride in an amount of 0.5-1.0 wt.h. while maintaining the limiting values of the remaining components, it imparts the property of non-flowability (density) to the claimed composition (experiments 6-15). A decrease in the content of iron chloride makes the composition spreadable and reduces

stone stability in a hydrogen sulfide environment (experiments 5, 6). An increase in the content of iron chloride sharply reduces the setting time of the composition (experiments 17 and 18). Reduced polymer content with minimal iron chloride

makes the composition spreadable (experiment 5). An increase in the polymer content also reduces the structural and mechanical properties of the composition (experiments 16 and 18).

The boundaries of the temperature regime are determined by the temperature of hardening of the binder itself (ШПЦС-120 is intended for downhole temperatures of 80-160 ° C).

The density of the claimed composition during the test was 1660-1720 kg / m3.

The limiting and optimal quantitative values of the ingredients of the proposed composition were determined on the basis of laboratory tests and are given in table. 2.

Under production conditions, the proposed composition is obtained as follows:

In the measuring compartment of one cementing unit, a 1.5% solution of polyacrylamide is prepared according to the calculation. In the measuring compartment of the other unit, a solution of iron chloride is prepared on the remaining water, after dissolving the salt, the calculated amount of ethyl silicate is added thereto. Slag cement is mixed with this solution at a water-cement ratio of 0.46-0.48. The resulting suspension is pumped into pipes. A 1.5% solution of polyacrylamide is supplied in parallel with other aggregates. By mixing the solutions, the inventive composition is obtained which is pressed into the absorption zone.

On the basis of laboratory studies, the technical and economic advantages of the claimed composition as compared to the known one are revealed. what

the inventive grouting composition became non-dispersible;

the density of the proposed composition is 12-32 times higher than that of the known;

The claimed grouting composition is technologically advanced;

PAA consumption per share of cement decreased by 2.8-5.6 times, and iron salts by 4-16 times.

The above advantages allow reducing the time for elimination of complications due to the elimination of the filling up of fillers and refilling, which leads to a 1.5-fold reduction in fuel consumption, energy, and labor costs.

The use of the proposed cement composition is intended for drilling from super deep wells of the Caspian region. Due to the high structural and mechanical properties of the compositions, as well as the preservation of the corrosion resistance of the stones for a long period of time, the inventive composition will increase the efficiency of isolation of complication zones in this complex region.

Claims (3)

SUMMARY OF THE INVENTION A grouting composition comprising slag sand cement, polymer, ferric salt and water, characterized in that, in order to increase the efficiency of isolation of the complication zones under conditions of hydrogen sulfide aggression by eliminating spreadability, it additionally contains ethyl silicate as a polymer - polyacrylamide, and as the salt of ferric iron - ferric chloride in the following ratio of components, parts by weight: Slag sand cement 100 Chloric iron0.5-1.0 Polyacrylamide 0.05-0.10 Ethyl silicate 1-3 Water 48.25-51.40 The composition and properties of the proposed and known compounds The composition and properties of the proposed and known compounds 19 Portland Calcium Chloride Note. I. Setting time: in the numerator - the beginning, in the denominator - the end 2. Stone strength: in the numerator - in bending, in the denominator - in compression (temperature of experiment 1-18 21 22-C ° experiments 19, 20 - 20 ° С) 3. The resistance coefficient is the ratio of the strength of the hardening samples in an aggressive environment to the strength of the control sample after 3 ns. Analogue I Limit and optimal quantitative values of the ingredients of the proposed cement composition table 2