SU1502810A1 - Lightweight plugging composition - Google Patents

Abstract

The invention relates to the drilling of oil and gas wells. The goal is to reduce the density of cement slurry while maintaining the structural and mechanical properties of the solution and stone. Cement slurry contains components in the trail. ratio, wt.%: cement 2-6, sawdust 1-10, sodium silicate 5-10, complex foaming agent 1-7.5, clay mud the rest. Complex foaming agent contains components, wt.%: Oil 1-10, sulfonic acid 1-10, carbomethylcellulose 1-10, water the rest. Cement slurry is obtained by successively adding cement, sawdust, water glass and a complex foaming agent to the mud solution while stirring. The use of a lightweight cement slurry can improve the quality of the insulation and prevent hydraulic fracturing. 1 tab.

Description

The invention relates to the drilling of oil and gas wells, in particular to cement mixtures for isolating the absorption zones of drilling fluid in wells in intervals with low formation pressures.

The aim of the invention is to reduce the density of the solution while maintaining the structural and mechanical properties of the solution and stone.

Lightweight cement grout on clay base contains cement, sawdust, sodium silicate, as well as a complex foaming agent in the following ratio of components,

Cement

Sawdust Sodium silicate Complex foaming agent Clay solution

2-6

1-10

5-10

1-7,5 Else

moreover, a complex foaming agent includes the ingredients in the following ratio, wt.%:

Oil Sulphate. Carboxymethyl Cellulose Water

1-10 1-10

1-10 Else

3150

The preparation of the cement slurry is carried out in the following sequence.

First, a complex foam is prepared,

With the stirring, the calculated amount of process water is charged with CMC-500 and allowed to swell for 10-12 hours.

For better dissolution, preheated water (40-45 ° C) is used. After 10-12 hours, the required amount of surfactant, sulfonol is loaded into this solution, and then the required amount of oil is added and the resulting solution is again mixed to obtain a homogeneous composition.

Then, a mud solution with a density of 1.06 g / cm is fed into the vessel equipped with a mixer, into which the following components are successively introduced: cement-filler (sawdust) and structurant — sodium silicate, after the introduction of each of which stirring is performed. Then the complex foaming agent is introduced and again mixed.

Examples of cement slurries prepared according to the described technology and their properties are presented in the table;

The use of cement slurry allows to reduce the repression on the reservoir, which contributes to effective isolate and prevent fracturing of the reservoir.

Claims (1)

Invention Formula A lightweight cement slurry containing cement, sawdust, soda silicate and clay mud, characterized in that, in order to reduce the density while maintaining structural and mechanical properties, it additionally contains a complex foaming agent in the following ratio of components, wt.%: Cement2-6 Sawdust 1-10 Sodium silicate 5-10 Complex frother 1-7,5 Clay mudEsalite and the complex foaming agent contains oil, sulfonol, carboxymethylcellulose and water in the following ratio, wt.%: Oil1-10 Sulfonol1-10 Carboxymethylcellulose1-10 WaterEverything