RU2484115C1 - Method for obtaining expansion agent to plugging material - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: in the method for obtaining an expansion agent, which involves roasting of raw mixture containing chalk and additive that contains sodium adipate, further grinding of roasted product, as the additive there used is alkali adipic plasticising agent - AAPA-1 or alkaline drain of produced caprolactam - LDPC; raw mixture is prepared, which has humidity of 5-7%, by through mixing; then, stable forms with dense structure are obtained by pressing the prepared mixture, roasted at the temperature of 850-950°C; at that, temperature rise rate during the roasting process is 5.0-20.0 deg/min; roasted product is cooled down uniformly.

EFFECT: increasing expansion degree.

1 ex, 1 tbl

Description

The invention relates to the oil and gas industry, and specifically to the field of production of additives for producing special cements, namely grouting 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.

At the same time, expanding additives for grouting materials, in addition to the effect of expansion, should have optimal expansion kinetics. Rapid expansion will lead to the fact that the additive will expand even before the injection or during the injection of cement into the well, and after the cement has solidified, there will be no expansion. Later expansion of the additive leads to the destruction of the cement stone.

Known methods for producing expanding additives by mixing rationally selected ingredients, for example, gypsum, with high alumina slag or alumina cement [Danyushevsky B.C. and others. Reference manual for cementing materials. - M .: Nedra, 1987, p. 154]. The disadvantage of this method is the lack of effectiveness of the resulting expanding additives.

There is a method of producing an expanding additive by burning magnesite, in which the expansion of cement stone is provided by hydration of magnesium oxide (MgO) formed during the firing process [Daniushevsky B.C. and others. Reference manual for cementing materials. - M .: Nedra, 1987, p. 161]. The disadvantage of this method is the insignificant amount of expansion of cements at normal and low temperatures.

Expanding additives obtained by calcining limestone at temperatures of 900-1200 ° C [Danyushevsky B.C. and others. Reference manual for cementing materials. - M .: Nedra, 1987, p. 157]. Firing limestone at temperatures of 900-950 ° C leads to the formation of quick-quenching lime, the use of which in cement cements is ineffective due to the high rate of hydration. 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 costs for its production.

Closest to the claimed object in terms of technical nature and the achieved effect is a method of producing an expanding additive by co-firing chalk with the addition of sodium adipate in a ratio of 95: 5, followed by grinding the firing product [RF Patent No. 2153061, BI 20, 2000. Expanding grouting material].

The disadvantage of this method of obtaining an expanding additive to the grouting material is the low expansion value. The aim of the invention is to remedy these disadvantages. The problem is solved in that in the method of producing an expanding additive, including firing a raw mixture, including chalk and an additive containing sodium adipate, subsequent grinding of the firing product, an adipic alkaline plasticizer (PASCH-1) or an alkaline stock of caprolactam production (ShchSPK) is used as an additive ), prepare the raw material mixture with a moisture content of 5-7% by thorough mixing, then obtain stable forms with a dense structure by pressing the prepared mixture, burn it at a temperature of 850-950 ° C, and in the process of roasting n is the temperature set 5,0-20,0 dg / min, calcination product is cooled uniformly.

The essence of the invention is as follows, an adipic alkaline plasticizer (PASCH-1) and an alkaline effluent from caprolactam production (SHPSPK) contain sodium adipate, which reduces the formation of lime by 100-200 ° C during chalk firing. At the same time, with a decrease in the firing temperature, the shape and size of the crystals change, which, being more crystallized, slowly hydrate with water, leading to a later expansion of the cement stone.

Mixing chalk with PASCH-1 or ShchSPK and obtaining a raw mix with a moisture content of less than 5-7% ensures the production of a raw mix in the form of granules or samples having a stable form that does not deteriorate under external influences during the firing process, which ensures firing of the entire volume of the raw mix.

At the same time, the mixing of chalk with PASCH-1 or ShchSPK and obtaining a raw mixture with a moisture content of less than 5% leads to the spreading of the mixture into powder, a significant part of which is removed during the firing process together with flue gases. At the same time, a significant part of the sodium adipate contained in PASCH-1 and ALPA is removed, which reduces the effectiveness of the firing results. In particular, the firing product is quick-extinguishing, which makes it unsuitable as an expanding additive in grouting materials.

Obtaining a raw mix with a moisture content of more than 10% leads to the fact that sodium adipate together with steam is intensively evaporated from the raw mix in the kiln, which leads to a loss of the expanding properties of the product. In addition, increased humidity leads to increased energy consumption during firing.

The firing of the raw mixture, which is in the form of stable forms with a dense structure, leads to the most complete process in the entire volume of the fired mixture. Firing the raw mix in powder form leads to the evaporation of sodium adipate and reduces the expansion.

The firing of the raw mix is carried out at temperatures of 850-950 ° C, at which the most complete firing of the raw mix is achieved to obtain well crystallized firing products in the form of CaO.

Firing at temperatures below 850 ° C leads to the fact that the mixture is completely fired, but the firing products do not have time to crystallize, and therefore they have a high quenching rate, i.e. the firing product cannot be used in the form of an expanding additive, since it can interact with water (hydrate) even during the preparation of grouting mortar.

Firing at temperatures above 950 ° C leads to the fact that the fired mixture is burned and is able to interact with water only at elevated temperatures, to increase energy consumption and load on the lining of the kiln. In addition, as a result of burning out and slowing down the hydration rate, expansion can occur already after the formation of a solid stone, which will lead to the appearance of internal stresses in the cement stone and the formation of cracks in it.

Maintaining the rate of temperature set-up is 5.0-20.0 deg / min during the firing process, which ensures uniform heating of the raw material mixture during the temperature setting and its uniform cooling throughout the volume of the firing product, which makes it possible to uniformly crystallize the fired firing and prevent its recrystallization.

A faster rate of temperature rise leads to uneven firing of the raw material mixture, and its inner part may remain unburnt compared to the outer layers. The rate of temperature gain slower than 5.0 deg / min leads to a lengthening of the firing process and increases the cost of production.

Thus, in the present invention, the production of an expanding additive to the grouting material is possible only under the combination of all the conditions contained in the characterizing part of the claims, namely the use of PASCH-1 or ShchSPK; moisture content of the raw mix 5-7%; firing material in the form of stable forms with a dense structure; firing temperature 850-950 ° C; the rate of temperature set during firing 5.0-20.0 deg / min.

Thus, in the present invention uses new ingredients - PASCH-1 or ShchSPK, new technology elements: moisture of the raw material mixture, the dense structure of the mixture being fired, the firing temperature; the rate of set and temperature reduction during firing, which gives reason to assert that the proposed solution meets the criterion of "novelty."

In the scientific, technical and patent literature, it is known to use the calcining product of the limestone component and sodium adipate as a raw material mixture to produce a destructive material. At the same time, the use of adipate-containing products PASCH-1 or ShchSPK in the composition of the raw material mixture upon receipt of an expanding additive to the grouting material is not known.

In the scientific, technical and patent literature [Butt Yu.M. Technology of cement and other binders. - M .: Stroyizdat, 1976, pp. 84-85] it is known to produce lime by calcination at temperatures of 850-950 ° C. At the same time, it is not known to obtain an expanding additive based on calcium oxide by calcination at given temperatures.

In the scientific, technical and patent literature, it is not known to regulate the humidity of the raw material mixture during firing and to regulate the rate of set and lowering the firing temperature in the process of obtaining expanding additives to grouting materials.

Thus, the foregoing confirms the compliance of the claimed invention with the criterion of "inventive step".

An example implementation of the invention.

To obtain an expanding additive, a mixture is prepared containing 1000 g of chalk and PASCH-1 or ShchSPK in an amount providing a moisture content of 6%. The mixture is thoroughly mixed and pressed, then fired at a constantly rising temperature at a rate of 10 deg / min. Up to a temperature of 900 ° C, the temperature rise time was 1 hour. Then, the raw mix after cooling at a temperature of 900 ° C was cooled and milled.

With the obtained expanding additive, a grouting material was prepared containing 900 Portland cement PCT-1-50 and 100 g of the obtained expanding additive. The mixture was closed with 500 g of water (W / C = 0.5). The resulting solution according to GOST measured the spreadability and density. In addition, molds were poured to obtain specimens - beams for determining the strength of cement stone in bending after 2 days of hardening under normal conditions. The properties of the mortar and the resulting cement stone are shown in the table, which shows that the main properties of the mortar and stone are within the requirements of GOST 1581-96. The same table shows the characteristics of the traditionally used cement Portland cement.

An example implementation of the proposed method indicate compliance with its criterion of "practical applicability".

Claims (1)

A method of producing an expanding additive, including firing a raw mixture, including chalk and an additive containing sodium adipate, subsequent grinding of the firing product, characterized in that an adipic alkaline plasticizer - PASCH-1 or alkaline stock production of caprolactam - ShchSPK, is used as an additive, a raw material mixture is prepared having a moisture content of 5-7% by thorough mixing, then stable forms are obtained with a dense structure by pressing the prepared mixture, they are fired at a temperature of 850-950 ° C, and during the firing process, the pace of the tempera the temperature is 5.0-20.0 deg / min, the firing product is evenly cooled.