RU2745980C1 - Backfill compound - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to backfill mixtures intended for cementing oil, gas, hydrogeological and geothermal wells that cover the intervals of permeable layers at normal, moderate and high temperatures. The backfill composition includes Portland cement PCT-I-50, carbon black, plasticizing additive and water. As a plasticizing additive, PVA-M “Extra” glue or a “Universal” deep penetration primer 2-in-1 is used.

EFFECT: claimed backfill mixture will improve quality of cementing casing strings and durability of wells in normal, moderate and high temperatures.

3 cl, 2 tbl

Description

The invention relates to the oil and gas industry, in particular to grouting mixtures intended for cementing oil, gas, hydrogeological and geothermal wells overlapping intervals of permeable formations at normal, moderate and elevated temperatures.

Known composition for obtaining building materials (patent RU No. 2345968, published 02/10/2009), containing cement, sand, water and carbon nanomaterial - soot obtained by the electric arc method and containing 7.0% of carbon nanotubes, with the following ratio of components, wt. %: cement - 20-30, filler - 50-70, carbon nanomaterial - 1-2, water - the rest.

The disadvantage of the known composition is the complexity of industrial production of soot by the electric arc method in large volumes.

A known composition based on mineral binders (patent RU No. 2233254, published on July 27, 2004), including a mineral binder selected from the group consisting of cement, lime, gypsum, or mixtures thereof and water, additionally contains carbon clusters of the fulleroid type with the number of carbon atoms 36 and more with the following ratio of components in the composition (wt.%): mineral binder - 33-77; fulleroid carbon clusters - 0.0001-2.0; water is the rest. As carbon clusters of the fulleroid type, the composition may contain polydisperse carbon nanotubes, polyhedral multilayer carbon nanostructures with an interlayer distance of 0.34-0.36 nm and a particle size of 60-200 nm, or a mixture of polydisperse carbon nanotubes and fullerene C ₆₀ .

The disadvantages of this composition are the complex component composition and the complexity of industrial production of fulleroid-type carbon clusters in large volumes.

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, гидрированные углеродные фрактальные структуры с размерами 1000

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и активный рыхлый углерод с размерами дефектных микрокристаллитов графита, примерно равными 10

при следующем соотношении компонентов в композиции, мас. %: портландцемент - 25-50, песок - 30-60, Водная суспензия КАУМ - 0,024-0,64, вода - остальное.A known composition based on mineral binders (patent RU No. 2447036, published 04/10/2012), including Portland cement, sand, water and carbon material, and as a carbon material contains an aqueous suspension of a cavitation-activated oleoresin-containing material - KAUM, which includes multilayer carbon nanostructures with an interlayer distance of 0.34-0.36 nm and a particle size of 60-200 nm, polydisperse carbon tubular formations with a size of 100,000

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, hydrogenated carbon fractal structures with sizes 1000

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and active loose carbon with the size of defect microcrystallites of graphite, approximately equal to 10

with the following ratio of components in the composition, wt. %: Portland cement - 25-50, sand - 30-60, Aqueous suspension of KAUM - 0.024-0.64, water - the rest.

The disadvantages of this composition are the complexity of industrial application, due to the lack of technology for producing ulerod-containing material - KAUM in large volumes.

Known grouting material (patent RU No. 2151268, published 06/20/2000), including Portland cement, a carbon-containing additive and calcium or sodium chloride, as a carbon-containing additive contains carbon black in the following ratio of components, wt. %: Portland cement 44-46, carbon black 30-50, calcium or sodium chloride - the rest. The technical result is an increase in the sedimentation stability of the solution and the production of an electrically conductive cement stone.

The disadvantage of the known grouting material is its low compressive and flexural strength.

Known grouting material (inventor's certificate SU No. 1645461, published 04/30/1991), taken as a prototype used for fixing oil and gas wells containing wt. %: alinite cement 95.0-99.8, carbon-containing material - 0.2-5.0. In the grouting material, carbon black, waste carbon black, soot, graphite can be used as a carbon-containing material. The grouting material makes it possible to obtain a gas-tight cement stone with increased adhesion to the column.

The disadvantages of the prototype are low flowability and the effect of freezing of the grouting material in containers.

The technical result is the creation of a grouting mixture with certain structural and rheological properties of the solution, the strength characteristics of the stone, allowing for effective isolation of permeable layers.

The technical result is achieved in that the composition additionally contains a plasticizing additive and water, Portland cement PCT-I-50 is used as cement, with the following ratio of components, wt. %:

Portland cement PCT-I-50 66.0-63.0 water 33.0-31.0 carbon black 0.1-5.0 plasticizing additive rest

PVA-M "Extra" glue is used as a plasticizing additive. As a plasticizing additive, a 2-in-1 "Universal" deep penetration primer is used.

The inventive grouting composition for increasing the strength of cement stone for well casing includes the following reagents and commercial products containing them:

Portland cement PCT-I-50, produced in accordance with GOST 158196 66.0-63.0; water 33.0-31.0; carbon black produced in accordance with GOST 7885-86 0.1-5.0; plasticizing additive: PVA-M "Extra" glue, manufactured according to TU 2385-008-51309101-01 or 2-in-1 deep penetration primer "Universal" for external and internal works, manufactured according to TU 2313-037-76174671-2005 rest.

Portland cement grade PCT-I-50 has a number of advantages, namely widespread availability, high rate of strength gain, early formation of closed porosity, high strength of cement stone, resistance to moderate and high temperatures. Portland cement mortars are characterized by fast setting and fast hardening, especially at moderate to elevated temperatures. Cement mixtures based on Portland cement are significantly superior in this respect to alinite cement. The use of the proposed grouting mixture makes it possible to more effectively bind water and compact the structure of the stone, and thereby ensure its increased fluid resistance and durability.

Carbon black is one of the varieties of carbon material, which is a highly dispersed black powder obtained by thermal decomposition or incomplete combustion of carbon-containing substances, mainly hydrocarbons, in the temperature range from 1200 to 1700 ° C. Carbon black is used as a reinforcing component in the production of rubbers and plastics.

The optimum content of carbon black is from 1.2 to 2.5 wt. %. With an increase in the content of carbon black over 4 wt. % decreases the strength and penetrating characteristics of the cement stone. The addition of carbon black is less than 0.5 wt. % leads to a weak increased water separation of the cement slurry, reduced adhesion of cement particles, and reduced strength of the cement stone, which negatively affects the physical and mechanical characteristics of the cement stone.

The plasticizing additive is designed to increase the mobility of the cement mixture and regulate its setting and thickening times. Plasticizers are also used for gluing cement particles and compacting concrete and mortar mixtures.

PVA-M "Extra" glue TU 2385-008-51309101-01 is intended for use in technological processes of casing wells for various purposes in order to regulate rheological properties. The reagent has a high adhesive capacity and is used as a sealing and plasticizing additive. PVA-M "Extra" glue does not have the effect of slowing down the setting time of the cement slurry, remains operational at temperatures up to 210 ° C and does not thicken the mortar. The additive is characterized by high adhesive properties and promotes tight adhesion of the stone to the rock and casing. The optimum content of polyvinyl acetate is 2.5 wt. %. With an increase in the content of polyvinyl acetate more than 5 wt. %, there is a decrease in the strength properties, as well as the adhesion of cement particles.

Deep penetration primer 2-in-1 "Universal" for external and internal work TU 2313-037-76174671-2005 deeply penetrates and strengthens concrete structures, improves adhesion of the coating to the surface, evens out the absorbency of cement. The reagent includes natural or synthetic, liquid or solid film-forming substances - drying oils, alkyd resins, urea-formaldehyde resins, epoxy resins, etc. They are used in repair work for facades, walls, ceilings, ceilings, as well as for finishing furniture and other items. The primer of deep penetration 2-in-1 "Universal" for external and internal works is fire- and explosion-proof, does not have an unpleasant odor. The use of a primer helps to achieve a high-strength bond of the painted surface with paint or varnish. The reagent protects the painted surface from corrosion and flaking. In addition, primers can perform other functions: protect metal from corrosion, block pores and other defects of the painted surface, as well as provide adhesive adhesion in anti-corrosion protection systems for metal, wood and concrete, as well as protect surfaces from mold and mildew. In addition, this supplement is readily available and cost effective.

The optimum content of the primer is 2.5 wt. %. With an increase in the content of polyvinyl acetate more than 5 wt. %, a decrease in the structural and rheological properties of the cement slurry is observed.

The grouting mixture is prepared as follows. First, to regulate the spreading index, it is necessary to mix the liquid components: water, a plasticizing additive in the form of polyvinyl acetate with a mass fraction of 0-3% or a primer with a mass fraction of 0-3% for 15-30 seconds. Second, add carbon black with a mass fraction of 0.5-4%, continuing stirring for 15-30 seconds. Then add cement PCT-I-50 with a water-cement ratio of 0.5. Stir the resulting composition for 3-5 minutes.

Example 1. To prepare a solution of the proposed mixture (table 1, composition 3), you need 64.93 wt. % PCT-I-50; 32.47 wt. % water; 2.60 wt. % carbon black. First of all, it is necessary to mix water with carbon black for 15-30 seconds. Next, a cement slurry is prepared from it by adding cement at a water-cement ratio of 0.5. After stirring for 3-5 minutes, the density (g / cm3), spreadability (mm), water separation (ml), the time of thickening to a consistency of 30 Vs, (min) of the resulting solution are determined. The rest of the mixture solution is poured into molds to determine the ultimate strength of the stone (MPa) under uniaxial compression, stored at a temperature of 22 ° C for 1, 3, 10 days.

The prepared grouting slurry has a density of 1.87 g / cm3, spreadability of 220 mm, water separation of 1.2 ml, the time of thickening to a consistency of 30 Vs 305 min, the ultimate strength of the cement stone under uniaxial compression is 14.9; 25.07; 31.23 MPa after 1, 3, 10 days of hardening.

Compositions and structural and rheological results of the inventive grouting mixture are shown in Table 1. The obtained results of strength tests are shown in Table 2.

Table 1 - composition and structural and rheological results of the inventive grouting mixture.

No. Composition, wt. % Density, g / cm3 Spread, mm Water separation, ml Thickening time to a consistency of 30 Sun, min PCT-I-50 Carbon black PVA-M "Extra" glue Deep penetration primer 2-in-1 "Universal" Water one one 2 3 four four five 6 7 eight one 65.79 1.32 - - 32.89 1.86 230 2.35 330 2 64.1 1.28 2.57 - 32.05 1.87 200 1.80 270 3 64.93 2.6 - - 32.47 1.87 220 1.20 305 four 63.29 2.53 2.53 - 31.65 1.82 200 0.85 240 five 63.29 2.53 - 2.53 31.65 1.78 240 1.05 290 6 64.1 3.85 - - 32.05 1.89 190 0.95 300

Example 2. Carbon black in the amount of 1.28 wt. % mixed with glue PVA-M "Extra" 2.57 wt. % and water 32.05 wt. %. Portland cement grade PCT-I-50 is added to the solution in an amount of 64.10 wt. %. The resulting composition is thoroughly mixed until a homogeneous mass is obtained. The solution is prepared in the same way as in example 1.

The composition of the composition and the strength characteristics are shown in tables 1 and 2.

Example 3. The grouting composition is obtained, as in example 1, with the following mass ratio (wt.%):

Portland cement PCT-I-50 64.93 Water 32.47 Carbon black 2.60

The solution is prepared as in example 1. The composition of the composition and the strength characteristics are shown in tables 1 and 2.

Example 4. The grouting composition is obtained as in example 1, with the following mass ratio (wt%):

Portland cement PCT-I-50 63.29 Water 31.65 Carbon black 2.53 PVA-M "Extra" glue 2.53

The solution is prepared as in example 1. The composition of the composition and the strength characteristics are shown in tables 1 and 2.

Example 5. The grouting composition is obtained as in example 1, with the following mass ratio (wt%):

Portland cement PCT-I-50 63.29 Water 31.65 Carbon black 2.53 Deep penetration primer 2-in-1 "Universal" 2.53

The solution is prepared as in example 1. The composition of the composition and the strength characteristics are shown in tables 1 and 2.

Example 6. The grouting composition is obtained as in example 1, with the following mass ratio (wt.%):

Portland cement PCT-I-50 64.10 Water 32.05 Carbon black 3.85

The solution is prepared as in example 1. The composition of the composition and the strength characteristics are shown in tables 1 and 2.

The use of the proposed grouting solution will expand the scope of the grouting mixture and provide long-term reliable fastening of the casing strings at normal, moderate and elevated temperatures and increase the strength of the adhesive bond of the grouting mixture with the rock and casing.

Table 2 - results of strength tests.

No. Uniaxial compressive strength of cement stone, MPa 20 ° C 75 ° C 1 day 3 days 10 days 1 day 3 days 10 days one 2 3 four five 6 7 one 11.14 22.43 25.45 10.48 20.17 24.20 2 9.31 18.11 22.97 8.59 17.30 21.03 3 14.90 25.07 31.23 12.98 23.91 28.72 four 9.08 15.56 22.17 7.43 13.56 18.92 five 10.95 19.75 24,80 9.61 15.95 22.57 6 7.49 15.04 19.65 7.02 14.52 18.62

Thus, the claimed grouting mixture will improve the quality of casing cementing and the durability of wells in conditions of normal, moderate and elevated temperatures.

Claims (4)

1. The grouting composition, including cement, carbon black, characterized in that it additionally contains a plasticizing additive and water, Portland cement PCT-I-50 is used as cement, with the following ratio of components, wt%: Portland cement PCT-I-50 66.0-63.0 Water 33.0-31.0 Carbon black 0.1-5.0 Plasticizing additive rest 2. The grouting composition according to claim 1, characterized in that PVA-M "Extra" glue is used as a plasticizing additive. 3. The grouting composition according to claim 1, characterized in that a 2-in-1 "Universal" deep penetration primer is used as a plasticizing additive.