RU1789014C - Expanding bridging compound - Google Patents

Abstract

SUMMARY OF THE INVENTION: An expandable grouting composition contains, wt.%: Cement 75-90; dust from bag filters for gas cleaning furnaces for the production of low-carbon ferrochrome 10-25. Uniform expansion during structural formation and preservation of feather pressure at a temperature of 20-160 ° C is achieved through the use of any type of blowing agent and dust from bag filters of gas purifiers from the production of low carbon ferrochrome. The pore pressure is between 0.95 and 1.01, which is practically the same as the original. The strength of the cement stone is 9.1-18.6 MPa in the temperature range 22-140 ° S. 1 tab. ate with

Description

The invention relates to the fastening of wells, in particular to cementing materials for cementing casing strings of oil and gas wells.

Expandable grouting material is known including Portland cement, chromate slurry and a component containing CaO in active form.

A grouting composition is also known, including cement, a waste product from the production of chromium salts and a waste product from the production of sodium sulfide. The disadvantage of these formulations is the lower sedimentation stability of the rasters obtained from them, lowering the threshold pressure during hardening. In addition, a sufficiently complete reduction of hexavalent chromium to trivalent does not eliminate the toxicity of the material.

The closest in composition and technical essence is the grouting composition, having a temperature expansion of 20-160 ° C based on synthetic slag and dust from the purification of silica chromium production. The disadvantage of this solution is the small expansion (1.44-2.05%), which does not fully compensate for the decrease in the volume of cement slurry during em structure formation as a result of concentration and other phenomena. In addition, pore pressure is significantly reduced during the process of structure formation, which leads to annular oil and gas production.

The purpose of the invention is the prevention of casing oil and gas occurrences due to the preservation of the first-initial feather pressure N

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laziness in the process of structure formation of cement slurry and ensuring its uniform expansion in the temperature range from 20 to 160 ° C.

This goal is achieved in that the expanding grouting composition, including a cementitious and siliceous additive, contains dust from bag filters for gas cleaning furnaces for the production of low-carbon ferrochrome as an expanding additive in the following ratio of components, wt.%: Burning 75-90 Dust from bag filters gas purification of furnaces for the production of low-carbon ferrochrome 10-25 The presence of distinctive features in comparison with the prototype confirms the novelty of the claimed technical solution.

By introducing into the grouting composition of dust from bag filters of gas cleaning of furnaces the production of new low-carbon ferrochrome, materials not previously used in grouting materials, ensures the achievement of the object of the invention, annular oil and gas manifestations are prevented. The total effect - uniform expansion during the structure formation of cement stone and preservation of feather pressure at temperatures of 20-160 ° C is achieved by the combined use of any cement and dust from bag filters, gas purification eliminates the production of low-carbon ferrochrome.

Dust from bag filters for gas cleaning furnaces for the production of low-carbon ferrochrome is a highly dispersed powder of the following chemical composition

Cr20z33.5-42.7 Si 02 11.5-15.3 CaO. 0.7-0.9 MdO 20.8-24.0 6.1-6.4 FeO 8.6-10.3 C 5.3-7.3 ppm 5.8-8.3 As in cement, various types of cement can be used, for example: Portland cement, slag cements, etc.

An expanding grouting composition is prepared by mixing and activating the additive and binder in the claimed proportions in a disintegrator. The resulting mixture was sealed with water and tested.

Example. 750 g of cement and 250 g of additive were added to the mixing cup.

the second cup was made with 950 g of cement and 50 g of the additive, in the third 900 g of cement and 10 g of the additive, in the fourth 800 g of cement and 200 g of the additive were mixed for 3 minutes. The mixture was passed through a laboratory disintegrator, where mixing and mechanical activation of the grouting composition was carried out simultaneously. Then, to 100 g of the treated formulations were added, respectively: in 1 cup 650 g of water, in a second cup of 500 g of tap water, in 3 cup of 550 g of water, in a fourth 600 g of water, all mixtures were mixed and tested according to GOST 1581-85.

The table shows the compositions and technological parameters of the expanding grouting composition.

As can be seen from the table, the pore pressure of the prototype in the process of structure formation is reduced to 0.6 initial. In the proposed composition, the pore pressure is close to the original (from 0.95 to 1.01).

The compressive strength in the prototype from 1.7 to 2.9 MPa at various temperatures in the range of 22-140 ° C. In the proposed composition from 9.1 to 18.6 MPa.

The expansion of the proposed composition provides a traction force depending on the ratio of components equal to from 1.8 to 2.4 MPa, in the prototype from 1.27 to 1.93.

The claimed composition, due to the specificity of the material gostaz of dust of electrostatic precipitators, which also contains expanding components like CaO and MdO in significant quantities and the specificity of the material composition of the grouting composition itself, has a significant expansion of 2.45-5.15% versus 1.44-2.05 according to the prototype, the ability to maintain pore pressure in the process of structure formation almost at the initial level, to a P / pH value of 0.99-1.01 versus 0.6-0.7 for the prototype. One of the overall effects is an increase in the adhesion force of cement stone to the column to 240 versus 1.25-2.35 for the prototype and to increase the sealing of the annular spaces of the wells, which prevents oil and gas manifestations.

From the table it follows that the proposed composition has a number of advantages with the prototype, namely, the best ability to maintain pore pressure in the process of structure formation. higher mechanical parameters.

The proposed grouting composition provides reliable tight contact of the cement stone with the column and rocks and allows to improve the quality of formation separation.

Used as one of the components of industrial waste, it saves scarce cement.

Claims (1)

SUMMARY OF THE INVENTION An expandable grouting composition comprising a cementitious and expandable additive, characterized in that, in order to prevent annular oil and gas manifestations by maintaining the initial pore pressure during the structure formation of the grouting creature and ensuring its uniform expansion in the temperature range from 20 to 160 ° C, it contains dust from bag filters for gas purification of furnaces for the production of low-carbon ferrochrome as an expanding additive in the following ratio of components, wt.%: Burning 75-90 Dust from bag filters for gas cleaning furnaces for the production of low-carbon ferrochrome 10-25 97 Limit values 3 30 5 thirty (O60 6040 0.65 0.65 0.65 0.9 O.S5 2.45-5.15 0.32-1.01 2.10-8.8 0.16 0.25 0.2 4.7 4.9 5.5 5.6 3.0 3.5 3.9 4.2 4, 0.5 0.55 0.7 0.85 4.4 4,55 4.7 49 0.8 0.8 0.8 1, 06 1, 06 1.06 0.35 0.95 0.95 0.95 1.01 1, 01 1.01 1.01 0.8 4-20 5-10 1-40 2-CO eleven 0.9 1.6 9-20 -10-ZS 3-30 3-50 1.8 1.7 2.6 7-50 9-40 2-55 3-10 2.7 2.9 3.0 2.8 10-20 12-30 4-15 5-10 2.9 3.2 3.3 2.1 4.1 b, 8 5.5 2.6 4.7 5.5 5.3 1.4 1.86 2.05 2.35 1,63 1.95 2.0 2.1 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 1.25 1, 49 1.73 1.95 1.87 2.05 2.11 2,35 4-15 5-20 3-20 3-50