RU2399643C1 - Cement grouting light-weight mixture - Google Patents

Abstract

FIELD: oil and gas industry. ^ SUBSTANCE: cement grouting light-weight mixture includes the following, wt %: grouting portland cement 65.9-69.5; water-soluble polymer 0.1-0.5; complex mineral addition - KMD-SO with the following chemical compound, wt %: SiO2 55.0-70.0; Al2O3 16.0-25.0; Fe2O3 1.0-4.0; CaO 10.0-20.0; MgO 0.1-3.5; Na2O 0.1-1.4; K2O 0.2-3.5; TiO2 0.6-1.5 with particle size of not more than 500 mcm, the rest. ^ EFFECT: decreasing density, water segregation and filtration speed, increasing strength and adhesive characteristics. ^ 4 cl, 2 tbl

Description

The invention relates to grouting mixtures used for the preparation of grouting mortars for cementing oil and gas wells, and can be used in the oil and gas industry, construction and other fields of activity.

Well-known grouting material, including Portland cement, an expanding additive, gypsum, a hardening accelerator, a plasticizer, as an expanding additive contains at least one additive from the group: alumina, sulfoaluminate cement, aluminate-containing slag waste from the production of ferrotitanium, ferroboron, secondary smelting , as a plasticizer - a mixture of triethanolamine and a silica-containing additive with multifunctional effect - KMX in a ratio of 1: 1 to 1:10 and a lightening additive, in which zuyut aluminosilicate microspheres, or microsilica or expanded vermiculite or expanded perlite in the following ratio of grouting material,% by weight: 2-15 expanding additive;. gypsum 7-9; hardening accelerator 2-8; the specified plasticizer 0.3-0.8; lightweight supplement 3-10; Portland cement - the rest. As a hardening accelerator, grouting material may contain a chloride salt of alkaline or alkaline earth elements (patent RU No. 2235857, IPC 7 ЕВВ 33/138, 09/10/2004).

Known cementing material is intended for cementing normal temperature oil and gas wells. The disadvantage of this binder is the insufficiently low density of the cement slurry, as well as the low strength and adhesive characteristics of cement stone, which negatively affects the quality of the wells.

Known lightweight grouting mixture, which includes the following components, wt.%: Portland cement grouting 72.7-81.0, aluminosilicate microspheres 11.7-14.6, fused silica fume silica MK-85 as a filtering rate reducer 4.9-9 , 7, granular calcium chloride 2.4-3.1 (patent RU No. 225205, IPC 7 ЕВВ 33/138, 06/27/2005).

The specified mixture is characterized by increased strength characteristics of cement stone and low filtration rates, while the minimum possible density of cement slurry is 1350 kg / m ³ , which is not low enough to secure a larger number of production casing wells under construction in the conditions of oil production. In addition, the specified grouting composition forms a non-shrink stone with insufficient adhesive characteristics due to the absence of the expansion effect.

The closest analogue to the invention in its technical essence, which is selected as a prototype, is grouting mortar, which contains the ingredients in the following ratio, wt.%: Portland cement grouting 36.47-57.34; aluminosilicate hollow microspheres 6.47-17.65; carboaluminate additive 1.18-2.67; gypsum 1.18-2.67; water or a 4% solution of calcium chloride - the rest (patent RU No. 2151271, IPC 7 ЕВВ 33/138, September 3, 1999).

The specified mixture is characterized by a fairly low density of the cement slurry (up to 1240 kg / m ³ ), but it has insufficient adhesion in the initial period of hardening, increased water separation and an increased rate of filtration of the cement slurry. In addition, there is increased foaming, which makes it difficult to mix in commercial conditions.

The objective of the invention is the development of cement slurry with a low density, having lower values of water separation and filtration rate, as well as increased strength and adhesive characteristics of cement stone.

The essence of the invention lies in the fact that the claimed grouting mixture containing Portland cement grouting with targeted additives, which, unlike the known, as an additive contains a complex mineral additive (CMD-CO) of the following chemical composition, wt.%: SiO ₂ 55.0 -70.0; Al ₂ O ₃ 16.0-25.0; Fe ₂ O ₃ 1.0-4.0; CaO 10.0-20.0; MgO 0.1-3.5; Na ₂ O 0.1-1.4; K ₂ O 0.2-3.5; TiO ₂ 0.6-1.5 and a water-soluble polymer in the following ratio of components, wt.%:

Portland cement grouting 65.9-69.5 water soluble polymer 0.1-0.5 the specified complex mineral additive KMD-CO with a particle size of not more than 500 microns rest

The proposed complex mineral additive KMD-СО is produced on an industrial scale according to TU 5712 - 011 - 80338612-2008 and consists of particles of different fractional composition: particles of a fine fraction (up to 10 μm) of the additive KMD-СО due to the high specific surface (not less than 12 m ² / g) provide stabilization of the cement slurry, coarse particles (from 100 to 500 μm) due to the low bulk (not more than 450 kg / m ³ ) and apparent density (not more than 0.85 g / cm ³ ) provide the properties of a lightweight additive in the composition of CMD-CO, and the particles of the middle fraction (from 10 to 100 microns) due to p eobladaniya consisting of calcium carbonate and magnesium carbonate fillers provide active properties, and firing the hardening process of expansion of cement slurry and stone.

The complex mineral additive KMD - СО, introduced in the indicated amounts in the composition of the cement mixture, allows to provide:

- decrease in the density of cement slurry to minimum values;

- the expansion of cement stone, which improves its adhesive characteristics;

- increase the strength of cement stone by enhancing the hydraulic properties of Portland cement;

- reducing the permeability of the stone, which also increases the strength of the cement stone.

As Portland cement, Portland cement is used that meets the requirements of GOST 1581-96, for example, the PTsT 1-50 grade or the PTsT I-G-SS-1 grade.

As the water-soluble polymer, for example, sulfacell-2 or carboxyethyl cellulose (CMC) or hydroxyethyl cellulose (OEC) or another known similar water-soluble polymer can be used.

The introduction of a water-soluble polymer in the claimed amounts allows in combination with the specified complex mineral additive to reduce the water separation of the cement slurry and the filtration rate.

Comparison of the proposed composition with the prototype allows us to conclude that the claimed composition is characterized by new additives that ensure the achievement of new properties. The above allows us to conclude that the claimed solution meets the criterion of "novelty."

Various aluminosilicate additives are widely known in science and technology as additives facilitating the cement mixture. However, the known compositions of cement mixtures with various additives do not allow to increase the strength and provide good adhesive properties while reducing the density of the cement mixture. The proposed composition of the grouting mixture due to the ingredients included in it in the indicated amounts allows to obtain a new technical result - reducing the density of grouting mortar to the minimum acceptable values while increasing the strength of the cement stone, improving its adhesion characteristics, as well as reducing the water separation and the rate of filtration of grouting grout.

Complex additive SiO ₂ 55.0-70.0; Al ₂ O ₃ 16.0-25.0; Fe ₂ O ₃ 1.0-4.0; CaO 10.0-20.0; MgO 0.1-3.5; Na ₂ O 0.1-1.4; K ₂ O 0.2-3.5; TiO ₂ 0.6-1.5 (wt.%), Introduced into the inventive composition in combination with the addition of a water-soluble polymer, leads to an improvement in the basic properties of the cement mortar, allowing us to solve the problem. The chemical composition of the complex mineral additive differs from conventional aluminosilicate microspheres in the ratio of silicon oxide and aluminum oxide, a high content of calcium oxide and iron oxide, and, in addition, the presence of titanium oxide. The high specific surface area of the particles of the fine fraction of the additive allows stabilization of the grouting mortar (lower water separation and filtration rate), the increased content of calcium oxide provides increased adhesion of the cement stone. The chemical composition of the introduced complex mineral additives and its sizes (not more than 500 microns) provide a low bulk and apparent density, which allows to reduce the density of the resulting cement mortar and increase the strength of the final product.

The foregoing allows us to conclude that the claimed combination of essential features, being new in terms of the qualitative and quantitative content of ingredients, allows us to obtain a new technical result, i.e. The claimed technical solution meets the criterion of "inventive step".

The proposed composition can be manufactured by methods known in the industry from known materials, which allows us to conclude that the criterion of "industrial applicability" is met.

The preparation of the proposed cement mixtures are as follows.

The required amount of a complex mineral additive is mixed with cement, then a water-soluble polymer is added in predetermined proportions.

A cement slurry is prepared from the obtained dry cement grouting mixture by adding water. In the process of mixing the mixture add antifoam - tributyl phosphate (TBP).

Comparative data of the properties of the known and proposed compositions are shown in table 2. Examples No. 1-No. 3 according to the invention, example No. 4 according to the prototype.

In the experimental data presented, we used Portland cement grouting PCT I-50 GOST 1581-96 OAO Sukholozhskcement, a complex mineral additive KMD-СО according to TU 5712-011 - 80338612-2008, of the following chemical composition, wt.%: SiO ₂ 55.0- 70.0; Al ₂ O ₃ 16.0-25.0; Fe ₂ O ₃ 1.0-4.0; CaO 10.0-20.0; MgO 0.1-3.5; Na ₂ O 0.1-1.4; K ₂ O 0.2-3.5; TiO ₂ 0.6-1.5, with a particle size of not more than 500 microns, a water-soluble polymer sulfacell-2 TU 6-55-221-1473-97, antifoam - tributyl phosphate (TBP) TU 2435-305-05763458-2001.

Based on the resulting grouting mixture, grouting mortar was prepared and tested with 11 production oil wells fixed at the Vat-Yeganskoye field in Western Siberia.

An example of a grouting mixture and the use of grouting mortar.

For cementing the production casing of a well at the Vat-Yeganskoye field (cementing interval 0-2400 m), a dry cement grouting mixture of the composition was previously prepared on the basis of the workshop for fastening wells in the mixing chamber:

- Portland cement grouting - 31 188 kg (67.8 wt.%);

- KMD-СО complex mineral additive - 14720 kg (32.0 wt.%);

- water-soluble polymer (sulfacell-2) - 92 kg. (0.2 wt.%)

The components are mixed for 30–40 min, and the prepared homogeneous mixture is drained with compressed air and fed to cement trucks or hoppers of mixing machines. At a water-cement ratio of 0.85, the mixture was mixed, TBP - 46 kg (0.1 wt.%) Was added to the solution when the mixture was mixed. The density of the cement slurry was 1250 kg / m ³ .

After waiting for the cement to harden, standard geophysical studies were carried out to determine the quality of fastening in the contact zones of the cement stone - rock and cement stone - the walls of the column, the height of the grout and its uniformity in density.

The density and spreadability of the lightweight cement slurry were determined at a temperature of 20 ± 2 ° C and atmospheric pressure according to the procedure described in GOST 26798.1-96 "Cement grouting. Test methods". The density of the cement slurry was determined by a pycnometer, and the spreadability was determined by the cone of the AzNII. The filtration rate of the cement slurry was expressed as a conditional value — the filtration rate in 30 minutes and was determined on a VM-6 device after exposure to an autoclave at a temperature of 40 ° C and a pressure of 30 MPa for 10 minutes.

The water separation of the cement slurry is determined after it is kept in an autoclave at a temperature of 40 ° C and a pressure of 30 MPa for 10 minutes. The solution is poured into a cylinder with a volume of 250 cm ³ , after settling for 2 hours, the volume of separated water is measured and the result is calculated in percent.

To determine the strength of cement stone, cement stone is made in molds of size 20 × 20 × 100 mm. Before this, the solution is kept in an autoclave at a temperature of 40 ° C and a pressure of 30 MPa for 10 minutes. After filling the molds with cement mortar, they are placed in a thermostat. The strength of the stone is determined after its exposure in accordance with GOST 26798.1-96 at a temperature of 40 ° C after 24 hours. The bending strength of the stone is on the MII-100 testing machine, the compressive strength of the stone is on the P-10 hydraulic press.

Adhesion (adhesion strength of cement stone to the bounding surface) was determined after holding the cement mortar in an autoclave at a temperature of 40 ° C and a pressure of 30 MPa for 10 minutes, then the cement mortar was poured into metal cylindrical molds with an inner diameter of 50 ± 0.1 mm and 50 ± 0.1 mm high, cover with a lid and placed in a thermostat. The adhesion of the stone (the adhesion strength of the cement stone to the bounding surfaces) is determined after exposure to it, at a temperature of 40 ° C after 24 hours on the SP-10 press by the method of shifting the cement stone in the bounding surface.

In similar conditions, cement grouting mixtures and grouting mortars were prepared and tested according to other examples of the invention (examples No. 1-No. 3), as well as the composition of the prototype (example No. 4). In total, tests were carried out on the inventive composition in 11 wells. The research results for all 11 wells are positive.

The compositions of examples No. 1-3 are shown in table 1. Comparative experimental data are shown in table 2.

As can be seen from the presented comparative experimental data (table 2), the inventive cement mixture allows to reduce the density of the cement slurry to the level of 1200-1250 kg / m ³ , while the cement stone has a higher adhesion to the limiting compared to the prototype (example No. 4) surfaces, water separation and filtration rate of the inventive cement slurry (examples No. 1-No. 3) is lower than that of the prototype.

The use of the proposed cement grouting mixture will increase the contact strength of cement with the column and rock and will ensure the rise of grouting mortar to the design height.

Table 1 The compositions of cement grouting lightweight mixtures according to the invention Ingredients, wt.% Case Studies one 2 3 Portland cement as well exactly: - brands PTsT I-50 - 67.8 69.5 - PTsT brands I-G-CC-1 65.9 - - Water soluble polymer, namely: - sulfacell-2 - 0.2 - - carbooxyethyl cellulose (CMC) 0.1 - - - hydroxyethyl cellulose - - 0.5 (OEC) Complex mineral KMD-СО additive, mass%: A) SiO ₂ - 55.0; Al ₂ O ₃ - 34.0 20.0; Fe ₂ O ₃ - 4.0; CaO - 20.0; MgO - 0.1; Na ₂ O - 0.1; K ₂ O - 0.2; TiO ₂ 0.6. B) SiO ₂ - 70.0; Al ₂ O ₃ 16.0; Fe ₂ O ₃ - 1.0; CaO - - 32,0 - 10.0; MgO - 0.3; Na ₂ O 0.3; K ₂ O - 0.9; TiO ₂ - 1.5. C) SiO ₂ - 55.0; Al ₂ O ₃ - 25.0; Fe ₂ O ₃ - 1.0; CaO - - - 30,0 10.0; MgO - 3.5; Na ₂ O - 1.4; K ₂ O - 3.5; TiO ₂ 0.6. TOTAL: one hundred one hundred one hundred

Claims (4)

1. Cement grouting lightweight mixture containing Portland cement grouting with additives, characterized in that as additives it contains a complex mineral additive - KMD-CO of the following chemical composition, wt.%: SiO ₂ 55,0-70,0; Al ₂ O ₃ 16.0-25.0; Fe ₂ O ₃ 1.0-4.0; CaO 10.0-20.0; MgO 0.1-3.5; Na ₂ O 0.1-1.4; K ₂ O 0.2-3.5; TiO ₂ 0.6-1.5 and a water-soluble polymer in the following ratio of components, wt.%:
Portland cement grouting 65.9-69.5 water soluble polymer 0.1-0.5 the specified complex mineral additive KMD-CO rest
with a particle size of not more than 500 microns. 2. Cement grouting lightweight mixture according to claim 1, characterized in that as a water-soluble polymer contains sulfacell-2. 3. Cement grouting lightweight mixture according to claim 1, characterized in that as a water-soluble polymer contains carboxyethyl cellulose. 4. Cement grouting lightweight mixture according to claim 1, characterized in that as a water-soluble polymer contains hydroxyethyl cellulose.