RU2525885C2 - Plugging material with controlled kinetics of expansion - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the oil and gas industry and in particular to the field of obtaining special cements, namely to plugging materials for consolidation of oil and gas wells. A plugging material with controlled kinetics of expansion includes plugging Portland cement, an expanding component, additionally contains hydrophobisator sodium oleate or potassium oleate, with the said hydrophobisator being preliminarily mixed with the expanding component with the following component ratio, wt %: plugging Portland cement - 85-95, expanding component - 4.975-14.5, sodium oleate or potassium oleate - 0.025-0.5.

EFFECT: creation of the plugging material with controlled kinetics of expansion.

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Description

The invention relates to the oil and gas industry, and specifically to the field of producing special cements, namely cementing materials for attaching oil and gas wells.

To improve the quality of fastening of oil and gas wells, expanding cement cements are used, in which the expansion effect is provided by a special expanding additive.

Known expanding grouting material containing a binder - grouting Portland cement and a rationally selected mixture of ingredients, such as gypsum, with high alumina slag or alumina cement [Danyushevsky B.C., Aliev P.M., Tolstykh I.F. Reference guide for cementing materials. - 2nd ed., Revised. and add. - M .: Nedra, 1987. p. 154-161]. The disadvantage of this method is the lack of effectiveness of the resulting expanding additives.

Known expanding grouting material containing grouting Portland cement and expanding additive caustic magnesite [Royak S.M., Royak G.S. Special cements. Textbook manual for universities. - 2nd ed., Revised. and add. - M.: Stroyizdat, 1983. C.189]. In this grouting material, the expansion of cement stone is ensured by hydration of magnesium oxide (MgO) formed during the firing process. The disadvantage of this method is the insignificant amount of expansion of cements at normal and low temperatures.

Grouting materials are the most widely used in wells for fixing, in which expanding additives obtained by calcining limestone at temperatures of 1100-1200 ° C are used as an expanding additive to cement Portland cement [Danyushevsky B.C., Aliev P. M., Tolstykh I.F. Reference guide for cementing materials. - 2nd ed., Revised. and add. - M .: Nedra, 1987, pp. 154-161]. Firing limestone at temperatures above 1100 ° C allows you to get an expanding additive with a slowed down rate of hydration, while significantly increasing energy consumption for its production. The disadvantage of this grouting material is its low expansion at temperatures less than 50 ° C.

Also known is expanding grouting material obtained by mixing grouting Portland cement and an expanding additive represented by calcined lime at temperatures of 900-950 ° C [Daniushevsky B.C., Aliev P. M., Tolstykh I.F. Reference guide for cementing materials. - 2nd ed., Revised. and add. - M .: Nedra, 1987. p. 154-161].

The disadvantage of this binder is the fast hydration rate of the expanding component.

Closest to the claimed object in technical essence and the achieved effect is a grouting composition for isolating absorption zones, including Portland cement, an expanding additive, a hydrophobizing additive, which is used as an organosilicon liquid based on sodium methylsiliconate [Patent RU No. 2444553, publ. 03/10/2012]. As an expanding additive, a copolymer of acrylic carboxylic acids, their esters and salts is used.

The disadvantage of this binder is the fast hydration rate of the expanding component. In addition, the prototype used an organic expanding additive, which has a low heat resistance, and with increasing pressure, the expansion effect is sharply reduced.

The aim of the invention is to remedy these disadvantages.

This goal is achieved in that the grouting material with controlled expansion kinetics, including grouting Portland cement, an expanding component, sodium oleate or potassium oleate as a hydrophobizing additive, said water repellent being pre-mixed with the expanding component in the following ratio of components, wt.%:

Grouting Portland cement 85-95 Expansion component 4,975-14,5 Sodium Oleate or Potassium Oleate 0.025-0.5

The invention consists in the following.

The expanding component is mixed with a water-repellent additive, which is adsorbed on the surface of the expanding component, blocks its surface, limiting contact with the mixing fluid. In this case, Portland cement actively interacts with water, first forming a coagulation and then crystallization structure. After the strength of the structure of the cement stone has gained sufficient strength, hydration of the expanding component located between the crystals of the hardening products begins. At the same time, the expanding component increases its volume, as a result of which tensile stresses develop inside the cement stone, leading to the expansion of the cement stone.

In the scientific, technical and patent literature, information on the use of sodium oleate or potassium oleate to control the hydration rate of expanding additives has not been previously reported.

Thus, the foregoing indicates the conformity of the claimed invention to the criterion of "inventive step". An example implementation of the invention.

Grouting material is prepared as follows:

The expanding additive is mixed with a water repellent, and then mixed with Portland cement in a predetermined ratio.

The resulting mixture is shut off with water and, when hardened, the expansion coefficient is determined on an APG device, the description of which is given in [Daniushevsky B.C., Tolstykh I.F., Milshtein V.M. Reference guide for cementing materials. - M .: Nedra, 1973, p. 283].

As an example, consider the preparation of grouting material with the ratio: grouting Portland cement - 90; CaO-based expanding component — 9.75; water repellent - 0.25 (composition No. 3 of table 1).

To prepare the grouting material, 450 g of grouting Portland cement PCT 1-50 GOST 1581-96 and 48.75 g of lime and 1.25 g of sodium oleate were taken.

The expanding additive is mixed with sodium oleate, after which the resulting mixture is dry mixed with Portland cement to obtain an expanding grouting material. A grouting mortar with a water-cement ratio of 0.5 is prepared from expanding grouting material. Tests of the resulting grouting material are carried out according to GOST 1581-96, and also determine the coefficient of linear expansion. The tests are carried out under normal conditions. The test results of this sample, as well as other compositions are shown in table 1.

Thus, the example implementation of the invention shows its compliance with the criterion of "practical applicability".

Table 1 Grouting properties No. Composition, wt.% Solution properties Extension% Start of expansion, hour-min End of extension HRC Expanding supplement IT OK W / C 2R mm ρ, kg / m ³ CaO MgO SARD one 90 10 - - 0.5 235 1820 1.28 0-20 1 hour 2 85 14.5 0.5 - 0.5 225 1800 2.78 4-50 44 hour 3 90 9.75 0.25 - 0.5 235 1820 1.85 2-45 30 hour four 95 4,975 0,025 - 0.5 240 1830 1,50 0-35 6 hour 5 85 14.5 - 0.5 0.5 225 1800 2.86 5-25 48 hour 6 90 9.75 - 0.25 0.5 235 1820 1.90 3-00 30 hour 7 95 4,975 - 0,025 0.5 240 1830 1.55 1-10 8 hour 8 90 10 - - 0.5 235 1840 1.22 0-50 3 hour 9 90 9.75 0.25 - 0.5 235 1840 1.25 3-15 40 hour 10 90 9.75 - 0.25 0.5 235 1840 1.25 3-45 44 hour eleven 90 10 - - 0.5 235 1850 1.38 1-30 4 hour 12 90 9.75 0.25 - 0.5 235 1850 1.45 1-45 26 hour 13 90 9.75 - 0.25 0.5 235 1850 1,50 2-00 32 hour Notes: PC - Portland cement; SARD - sulfoaluminate expanding additive OH - sodium oleate; OK - potassium oleate; W / C - water-cement ratio; 2R - spreadability.

Claims (1)

Grouting material with adjustable expansion kinetics, including grouting Portland cement, an expanding component, characterized in that it further comprises a sodium oleate or potassium oleate water repellent, said water repellent being pre-mixed with the expanding component in the following ratio, wt.%:
Grouting Portland cement - 85-95 Expansion component - 4,975-14,5 Sodium oleate or potassium oleate - 0.025-0.5.