RU2360940C1 - Expanding plugging material - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: expanding plugging material contains the following components, wt %: Portland cement 91.3-98.3; specified expanding agent 0.5-5.0; setting accelerator 0.1-3.0; fluid loss agent 0.1-0.5; superplasticiser 0.1-0.7; defoaming agent of POLYCEM DF brand 0.1-0.3. Expanding plugging material additionally contains locking liquid - water at water-cement ratio of 0.47-0.78, as setting accelerator - calcium or sodium chloride, as superplasticiser - melamine formaldehyde or CEMPLAST MF or C-3 or Melflux, as fluid loss agent - oxyethyl cellulose.

EFFECT: higher insulation capacity of cement stone produced from plugging material, due to higher extent of its expansion and increased strength of adhesion to column and walls of well at broad range of water-cement ratio.

5 cl, 2 tbl, 1 ex

Description

The invention relates to the field of well construction, in particular to grouting compositions used in cementing casing strings for oil and gas wells.

Known expanding grouting material containing Portland cement, gypsum, the additive is hydrocarbon aluminosilicate material, a plasticizer C-3 and a loss of water loss, in the following ratio of components, wt.%: Portland cement 86-95, gypsum 2-7, hydrocarbon aluminate material 2-7, plasticizer C -3 0.1-0.2, water loss reducer 0.2-0.4 (RF Patent No. 2301823, class C09K 8/467, publ. 2007).

The disadvantage of this known material is that it contains gypsum, which during prolonged use of wells is subject to dissolution in the aquatic environment, which subsequently can lead to a violation of the tightness of the cement ring.

Closest to the proposed invention is a cement slurry consisting of cement and a complex reagent (0.6-1.5 wt.% To cement), containing, wt.%: Fluid loss reducer 30-94; plasticizer 2-25; defoamer 1-14; structure-forming agent 3-25 (RF Patent No. 2259468, CL ЕВВ 33/138, publ. 2005).

The disadvantage of this known cement slurry is the lack of expansion of the formed cement stone and the insufficient adhesion of this stone to the casing and the walls of the well, which can lead to micro-gaps and a violation of the insulating properties of the cement ring.

The technical result achieved by the present invention is to increase the insulating ability of cement stone formed from grouting material, by increasing the degree of expansion and increasing adhesion to the column and the walls of the well with a wide range of water-cement ratios.

The specified technical result is achieved by the claimed expanding grouting material containing Portland cement, a fluid loss reducer, a superplasticizer, an antifoam and a reagent based on an aluminum compound, while according to the invention it additionally contains an accelerator of setting time, as a reagent based on an aluminum compound it contains an expanding additive - aluminum oxide and / or calcium sulfoaluminate, and as an antifoam - defoamer brand POLITSEM DF, in the following ratio of ingredients, wt.% :

Portland cement 91.3-98.3 Specified Expansion Supplement 0.5-5.0 Setting accelerator 0.1-3.0 Water loss reducer 0.1-0.5 Superplasticizer 0.1-0.7 Antifoam brand POLITSEM DF 0.1-0.3

The grouting material additionally contains a mixing fluid - water at a water-cement ratio of 0.47-0.78.

As an accelerator of the setting time, the grouting material contains calcium chloride or sodium chloride.

As a superplasticizer, the grouting material contains melamine formaldehyde, or CEMPLAST MF, or C-3, or Melflux.

As a fluid loss reducer, the grouting material contains hydroxyethyl cellulose.

The achievement of the specified technical result is ensured by a certain selection of ingredients (qualitative and quantitative) in the inventive grouting material, i.e. this result is synergistic.

Thanks to the introduction of a fluid loss reducer - hydroxyethyl cellulose into the grouting material, low filtration is ensured, sedimentation processes are removed, which ensures zero water separation of the grouting solutions obtained. And due to the synergistic effect in interaction with other ingredients, the indicated filtration rate approaches the level of drilling fluid filtration, which will allow in field conditions during cementing to exclude premature thickening of the cement slurry.

As an expanding additive, it is proposed to introduce inorganic compounds — aluminum oxide and / or calcium sulfoaluminate — into the proposed material, which are related in composition to the minerals that make up Portland cement, which are modified calcium and aluminum sulfates.

Introduction to the proposed grouting material of an expanding additive of the specified type and in the proposed ratio allows the expansion of grouting composition at an early stage of hardening and formation of grouting stone, which avoids self-destruction of its structure (cracking, decrease in strength).

It is important that the expansion process is completed at the stage of early hardening of the cement stone, since a long hardening process is accompanied by self-destruction of the cement stone. In addition to the temporary factor in the expansion process, the expansion volume, which is expressed as the linear expansion of the cement stone, is equally important. Since the purpose of the expansion process is to form a more tight contact of the cement stone with the surrounding surfaces, the linear expansion of the cement stone should not exceed 1.0%. A larger expansion volume in the cement stone may result in a loss of strength.

The presence of setting times in the accelerator allows for acceptable setting and hardening of grouting material, and at the same time, it apparently has a synergistic chemical effect on the expanding additive with the formation of complex compounds that ensure uniform expansion of the material at the stage of its strength set, without fracture structure of the resulting stone. This also allows to reduce the setting time to the limits necessary for a particular well and at the same time to obtain a uniform expansion of the cement stone, which does not adversely affect its strength properties.

It was established experimentally that the combination of these ingredients, with their stated ratio, can also significantly enhance the adhesive properties (adhesion to the casing and well walls) of the cement. This can be explained by the fact that the resulting expansion of cement stone allows for more tight contact with the surrounding surfaces.

The use of superplasticizer in the proposed grouting material allows you to modify the structure of grouting mortar, compacting it, which in turn contributes to an increase in the strength of grouting (cement) stone.

Introduction to the proposed grouting material of an antifoam brand POLITSEM DF provides a reduction in pricing, which favorably affects the work of cementing equipment.

To obtain the inventive cementing material in laboratory conditions, the following substances were used:

- grouting portland cement of the PTsT brand IG-CC-1;

- hydroxyethyl cellulose brand HYDROCEM N, C according to TU 2231-009-40912231-2003;

- superplasticizer based on melamine-containing resins CEMPLAST MF according to TU 2223-011-40912231-2003;

- superplasticizer based on naphthalene-containing resins C-3 according to TU 6-360204229-625-90;

- a superplasticizer based on MelfluxF polyether carboxylates - a water-reducing additive according to the degree of plasticization according to GOST 24211-91 - belongs to the group of superplasticizing agents;

- setting accelerator: calcium chloride, sodium chloride;

- antifoam brand POLITSEM DF - modified organosilicon reagent according to TU 2228-010-40912231-2003;

- expanding additive - amorphous aluminum oxide of grades RU-1, "EXCEM SA" according to TU 2123-020-53501222-2001;

- expanding additive calcium sulfoaluminate brands RU N, RU according to TU 2157-034-40912231-2005;

- technical water.

The possibility of carrying out the claimed invention is confirmed by the following example.

Example. To obtain the proposed grouting material in laboratory conditions, 95 g of Portland cement were taken; 5 g of expanding additive of amorphous alumina grade RU-1; 1.9 g of calcium chloride; 0.19 g of hydroxyethyl cellulose; 0.19 g of a superplasticizer based on melamine-containing resins CEMPLAST MF and 0.19 g of antifoam POLICE DF. As a result, a grouting material was obtained with the following content of ingredients, wt.%: Portland cement 92.7; amorphous alumina expanding additive 4.87; calcium chloride 1.86; HYDROCEM C 0.19 hydroxyethyl cellulose; superplasticizer based on melamine-containing resins CEMPLAST MF 0.19; antifoam brand POLITSEM DF 0.19.

Grouting materials with different contents of ingredients were prepared in a similar way.

Next, from the obtained grouting material, a grouting solution was prepared by mixing it in industrial water at a water-cement ratio of 0.47. Calcium chloride in a calculated amount of 1.9 g was previously dissolved in a mixing liquid.

In the course of laboratory tests, the following properties of grouting mortar prepared from the inventive grouting material were determined by well-known methods:

- density;

- plastic viscosity;

- filtrate recovery;

- water separation

and also determined the following properties of cement stone:

- linear expansion of the stone;

- ultimate strength in bending, in compression;

- force to push out the sample (characterizes the adhesive properties of cement stone).

Data on the ingredient composition of the investigated grouting materials are shown in table 1. And data on the properties of grouting mortars, shut on the proposed and known grouting materials are shown in table 2.

The data shown in tables 1 and 2 show that the proposed grouting material allows to obtain grouting solutions, characterized by the following advantages over the known:

- the presence of expansion of cement stone;

- strong adhesion of the cement stone to the containing surfaces, which is characterized by the force of ejection of the samples;

- high strength characteristics of cement stone.

Due to these properties, grouting mortars obtained from the inventive grouting material will allow in field conditions to obtain an expanding groutstone with high strength properties, which allows to increase the density of contact of cement with the surrounding surfaces, thereby increasing the insulating properties of cement stone.

Notes:

1. As a superplasticizer used in experiments 1 and 3 - C-3; in experiment 2 - Melflux; in the rest - ZEMPLAST.

2. As an accelerator of the setting time in experiments 1-4, calcium chloride was used; in the rest - sodium chloride.

3. As an expanding additive in experiments 1 and 3 used calcium sulfoaluminate RU-N; in experiments 2 and 4 used aluminum oxide EXCEM CA; in experiments 5 and 6 used a mixture of aluminum oxide and calcium sulfoaluminate (a mixture of reagents EXCEM CA and RU-N) in a ratio of 1: 1.

4. In experiment 7, polyvinyl alcohol was used as a fluid loss reducer; as a plasticizer, a superplasticizer based on naphthalene-containing resins C-3; as a structurant - aluminum hydroxychloride; tributyl phosphate as a defoamer; as a binder - cement, facilitated by microspheres.

5. In experiment 8, sulphacel was used as a fluid loss reducer, and an expanding cement as a binder.

Claims (5)

1. An expanding grouting material containing Portland cement, a fluid loss reducer, a superplasticizer, an antifoam and a reagent based on an aluminum compound, characterized in that it additionally contains an accelerator of setting time, as a reagent based on an aluminum compound it contains an expanding additive - aluminum oxide and / or calcium sulfoaluminate, and as an antifoam - antifoam brand POLITSEM DF in the following ratio of ingredients, wt.%:
Portland cement 91.3-98.3 Specified Expansion Supplement 0.5-5.0 Setting accelerator 0.1-3.0 Water loss reducer 0.1-0.5 Superplasticizer 0.1-0.7 Antifoam brand POLITSEM DF 0.1-0.3 2. The grouting material according to claim 1, characterized in that it further comprises a mixing liquid - water - at a water-cement ratio of 0.47-0.78. 3. The grouting material according to claim 1, characterized in that it contains calcium chloride or sodium chloride as an accelerator of the setting time. 4. The grouting material according to claim 1, characterized in that as a superplasticizer it contains melamine formaldehyde, or CEMPLAST MF, or C-3, or Melflux. 5. The grouting material according to claim 1, characterized in that it contains hydroxyethyl cellulose as a fluid loss reducer.