RU1808995C - Expandable bridging material - Google Patents

Abstract

SUMMARY OF THE INVENTION: grouting material contains;, in wt.%: Portland cement 73.5-84; gypsum 8-10; sulfoaluminate hydraulic cement 7-15, highly dispersed pyrogenic hydrophobized silica 1-1.5. The components of the grouting material are mixed and closed in tap water. Characterization of grouting material: the shelf life of grouting material has practically no effect on the expansion properties of cement stone due to the preservation of its physical and mechanical properties. 2 tab.

Description

FIELD OF THE INVENTION This invention relates to compositions used in drilling, in particular, to cementing materials for the fastening of oil, gas, and other wells.

The purpose of the invention is to increase the preservation of the physicomechanical properties of cement stone while increasing the shelf life of grouting material.

New in the proposed expandable grouting material is that as an additive it contains highly dispersed fumed hydrophobized silica and a new quantitative ratio of components.

Highly dispersed pyrogenic hydrophobized silica is produced in accordance with TU 39-08-125-77 and represents

free-flowing powder preserving flowability at a temperature of from -40 to + 50 ° С. Its hydrophobicity is 90%, the pH of the aqueous suspension is 3.6, the true density is 2.2 g / cm, bulk density is 25-50 g / l, the particle size is 0.004-0.04 microns, and the specific surface is 175 ± 25 m2 / h.

It is used in technology as an emulsifier, stabilizer, invert emulsion and antifoam drilling mud.

The authors experimentally established that expanding grouting material containing highly dispersed pyrogenic hydrophobized silica after storage for 4 months or more slightly reduces the physical and mechanical; properties satisfying the requirements of GOST 1581-85, while the formed CE00

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the cement stone remains impervious to gas.

According to the authors, particles of highly dispersed pyrogenic hydrophobized silica due to the specific surface area exceeding more than 200 times that of Portland cement envelop the particles of cement with a hydrophobic film and do not allow moisture from the air to penetrate into the cement mass. This allows the grouting material to retain its physical and mechanical properties, while cement stone based on both freshly prepared material, as well as material after storage for 3-4 months, remains gas impervious.

Expandable grouting material is obtained by simply mixing finely ground components or by co-milling them under laboratory conditions, or at existing cement plants using standard equipment.

The finished grouting material is closed with water. Casing cementing technology is no different from conventional.

To carry out the study, a grouting material was prepared under laboratory conditions by co-milling the following components:

- grouting Portland cement of Novotroitsky and Kuvasayskog cement plants of mark P ЦТ Д20-100;

-sulfoaluminate hydraulic binder, which is a mixture consisting of limestone, an aluminosilicate component (alumina-containing raw material) and two-water gypsum subjected to calcination at 1200-1300 ° C;

- two-water gypsum according to GOST 4013-74;

- highly dispersed pyrogenic hydrophobized silica.

For the study, grouting materials with different component contents were taken and grouting mortars with a water-cement ratio of 0.5 were prepared and their boundary and average values were determined.

The research results are presented in table. 1 and 2.

Example. To prepare the grouting mortar (experiment 12), 500 g of water and 1000 g of grouting material containing components were taken, wt.% (G):

Portland cement 78.5 (785 g)

Gypsum 9.0 (90 g)

Sulfoaluminate

hydraulic cement 11.0 (110 g)

Fine

hydrophobized pyrogenic

silica 1.5 (15 g)

The grout is prepared by simply mixing grout in the tap water.

The sequence of preparation of the remaining proposed compositions specified

0 in the table are similar to those described above and differ only in the content of the components. The physical and mechanical properties of the claimed material (cement slurry; mortar and stone) were determined according to GOST

5 1581-85 and GOST26798.0-85-GOST26798.2- 85.

The gas permeability and expansion of cement stone were determined by known methods.

0 From table 1 it can be seen that the content of highly dispersed pyrogenic hydrophobized silica is optimal in the range of 1.0-1.5 wt.%. The content of finely divided pyrogenic hydrophobic silica of more than 1.5 wt.% (Experiment 14} with average values of the content of other components even in freshly prepared material sharply reduces the strength of cement stone, and less than 1.0

May 0% (experiment 13) does not ensure the preservation of physico-mechanical properties.

The content of sulfoaluminate hydraulic binder of more than 15.0 wt.% Is impractical, as it causes a strong

5, the expansion (experiment 18) of the stone and its strength are degraded, and when the content is less than 7.0 wt.%, The stone formed does not have expansion.

The optimum gypsum content in the cementing material is in the range of 8.0-10.0 wt.%, Since with a lower content it reduces the setting time of cementing mortar (experiment 15), and with a higher content (experiment 16) the induction hardening period increases 5 s , the formed stone is permeable and has little strength. Table 2 shows the expansion of freshly prepared grouting materials of known and declared after a period of up to 6 months, as well as of declared material after 3 and 4 months of storage.

From the tables it can be seen that the storage time has practically no effect on the expansion property of the stones in both formulations.

Thus, the proposed expandable grouting material has improved physicomechanical properties while increasing shelf life.

The proposed grouting material can be used for cementing casing strings under normal temperature conditions and is recommended for oil and gas producing regions where it is periodically necessary to store it directly at the objects of use.

Claims (1)

Formula for gaining Expandable grouting material, including Portland cement, gypsum and a sulfoaluminate hydraulic cement, characterized in that, in order to increase the preservation of physical and mechanical 5 properties of cement stone with an increase in the shelf life of grouting material, it additionally contains highly dispersed pyrogenic hydrophobized silica in the following ratio of components, May. %: Portland Cement73.5-84 Gypsum 8-10 Sulfoaluminate hydraulic in 7-15 Fine hydrophobized pyrogenic silica-1,5 T a 6 l and 1 Physico-mechanical properties of fusion yutsegosp tenfonzhnogo material Note. 1. Tests were carried out at a temperature of 22i3eC and a pressure of O, T MPa Z. In experiments 1,3, f, 7, 0515,16,17, the cement used was used in the Kuaasai plant, in the rest the cement of the Novotroitsk plant. 3- Sulfoaluminate hydraulic carrier (SAGV) prepared at the Nonotroitsk cement plant -Tablstsa2 Expansion of cement stone over time at different storage periods 1 expanding cement material Note: Component composition and physico-mechanical properties of the compounds . . ..in experiments 1,2,3,4,8,12 are given in table 1