SU632826A1 - Plugging mortar - Google Patents

Description

one

The invention relates to lightweight cement slurry compositions for plugging operations at high temperature wells.

Cementing solutions containing slags of the metallurgical, chemical and fuel industries are known, which show their adhesion properties only at high temperatures, and their relative lightness and increased water demand contribute to obtaining a low-density cement slurry G | .

The use of such solutions is complicated due to the difficulty of adjusting the setting time at temperatures above 200 ° C,

Also known are grouting solutions containing, as a base, a grounded, facilitating additive and

Bennonite clays, diatomite, flask, tripoli, volcanic pumice and tuff are used as lightening additives.

. Along with the possibility of adjusting the setting time, these grouting solutions have a low thermal stability at high temperatures.

The aim of the invention is to increase the thermal stability of a lightweight cement slurry at high temperatures.

This goal is achieved by the fact that, as a mortar, cement slurry contains light slags and, as a facilitating additive, marl rocks containing more than 25% carbonates in the following ratio of components, in weight parts:

Light slags SO

Margelye breeds 5-40 Water58-65

As light donkeys, for example, slags from phosphate production, decomposed highly basic low iron slags (slag dust) from ferrochrome, ferrovanadium, ferromolybdenum and ferrotitanium, as well as energy slags and ashes can be used; light hydration-active products of chemical processing of mineral raw materials, which can be considered as slags of chemical reactions.

For marl rocks, for example, opoka-like and trefoil clays, which consist of a mixture of calcite, magnesium carbonate and clay minerals from dio-trioctahedral groups, mainly hydromica and montmorillonite, can be used.

In addition, carbonized clay, aluminosilicate, and loess can be used as marly rocks.

Slag and marly rocks are mixed dry when milled or the already crushed components are wet when mixed with water in a cement mixing unit.

The amount of added marly rocks is determined by the clay content in them, the hydration activity of the slag component and the bottomhole temperature.

In the case of using highly basic granulated slags with the addition of alkaline and sulphate hardening activators, the proposed lightweight cement slurry can be used at relatively low temperatures, but not lower.

In the case of the use of highly mineralized and saline ground and stratal waters in the preparation of the cement slurry, as well as with an increase in the amount of introduced marl rocks with a high content of clay, the water requirement of the solution to obtain the required consistency may increase by up to 70–100 vas.

The water requirement of the solution also increases with the use of fine dispersed slags (slag dust) and ashes with a high content of alumina. With an increase in bottomhole temperatures, the content of marly rocks in the cement slurry increases, while that of slags decreases.

With an increase in the clay content in the marl rocks, the consumption of the latter, under constant bottomhole conditions, decreases and the slag component increases.

Of the proposed methods for mixing the components of the solid phase, preferred grinding is joint grinding, since this ensures the greatest homogeneity of the cement slurry.

When grinding the mixture to a specific surface area of 1500, stabilizers such as sodium aluminate, polyacrylamide, etc., or highly colloidal mineral dispersant additives, such as bentonite clays, should be added to increase stability.

The proposed cement slurry composition can also be used in the manufacture of lightweight hydrothermal hardening products.

Claims (2)

 1. Danushevsky B.C. and others. Reference guide for grouting materials, M., Nedra, 1973, pp.92-93 2. Grankovsky I.G. et al. Thermosolestability of disperse systems, Kiev, Naukova Dumka, 1971, p. 186-. 189 (prototype).