SU692982A1 - Plugging composition - Google Patents

Description

(54) SPRAYING MIXTURE

The term relates to the drilling of oil, gas and support wells, namely, the compositions for the iol of the absorption zones: to prevent leakage of flushing fluid.

Cement-based grouting mixtures are known; With additions of hydrolyzed pryacrylonitrile a (hypan) in small quantities.

However, such a mixture in the initial period does not have high structural strength, while moving along the wellbore to the absorbing zone, the mixture is mixed with the annular fluid (drilling mud, formation water), which drastically reduces the insulation qualities of the mixture.

Also known is the composition of the cementing cvrecHj containing portland cement, an aqueous solution of calcium chloride and a polymer additive, for which a copolymer of methacrylic acid and methacrylate amide l is used.

However, this cement mixture cannot be used in wells complicated by intensive water flows, as with the 1-2 cm / s Flows, the cementing properties of the mixture are sharply reduced.

The aim of the invention is to create a grouting mixture which, in the cured state, has a high structural strength under the conditions of intestinal water flow.

This is achieved by the fact that, as a binder, the mixture contains gypsum-alumina cement and, as a polymer additive, hydrolyzed polyacrylonitrile (hypan) in the following ratio of components, wt.%:

Gypsum-alumina cement41-51

Tshan38-23

An aqueous solution of calcium chloride (density 1.06-1.10 g / cm) 21-26.

The mixture is prepared directly in the drill pipe during the process of pumping components into the absorption zone. At the same time pumped hypan - 38% of total

the amount of the mixture, water solution calo chloride (sp. weight 1.06-1.08 g / cm) 27% of the total amount of the mixture, cement51% of the total amount of the mixture.

The amount of the mixture of dd isolate tires and the absorption take in th & from the characteristics of the zone from 2 m to 21 m. CMecib immediately after mixing the stack, it has high plastic strength

(15-20 g / cm), increasing in 60 minutes to 70 g / cm. When moving it through the drill pipe and the wellbore to the absorption zone, this mixture is not eroded by the drilling fluid and various annular bore holes in the well (pressure or mineralized water).

Claims (1)

The change in the cementing properties of the proposed and known mixtures (metasocement) is given in the table. - / ;. . 7.. /. J: E & Thus, we propose that the right mixture is a practically unbreakable mixture, capable of operating under conditions of intense water flow, and its consumption is approximately a factor of less than that of plug-in mixtures of other compositions. The invention The plugging mixture for isolating the absorbing formations containing a staying, aqueous solution of calcium chloride and a polymeric additive, characterized in that, in order to obtain a plugging mixture that has a high structural CL-a. .8 is tricity under conditions of intensive water flows, as a mortar it contains gypsum-alumina cement, and as a polymeric additive is hydrolyzed polyacrylonitrile / hypan / at the following ratio of components, wt.%: Gypsum-alumina cement 71-51 Gypsy 38-23 Aqueous solution of calcium chloride; density 1.06-1.10 g / cm) 21-26. Sources of information taken into account in the examination 1. Proceedings of VNIIBT, vol. 27, Chemical Treatment of Drilling and Cement Plants, 1971, p. 188.