Delayed coagulation cement paste for freezing shaft sinking construction

Abstract

The invention discloses delayed coagulation cement paste for freezing shaft sinking construction and belongs to the technical field of slurry. The cement slurry comprises the following components in parts by weight: 190-210 parts of cement, 780-820 parts of fly ash, 970-1030 parts of water, 180-200 parts of glycerol and 1.3-4 parts of sulfonated lignite resin. On the premise that the final settingstrength of the cement paste reaches 10 MPa, the cement paste can be set slowly for 45 hours at the high temperature of 40 DEG C, and meanwhile, the cement paste has high flowability and low water loss.

Description

technical field [0001] The invention belongs to the technical field of slurry, and relates to a cement slurry, in particular to an ultra-retarded cement slurry used for well-sinking construction by freezing method. Background technique [0002] Freezing drilling method is to use artificial refrigeration method to freeze the water-containing loose and unstable shock layer around the wellbore and bedrock aquifer to form a closed frozen wall with a certain thickness and strength before the wellbore is dug. Shaft excavation work is carried out under the protection of the frozen wall. The freezing depth of the air inlet shaft in the west area of ​​Gaojiabao reaches 990 meters, which is the highest freezing depth in the country. The full-depth freezing method is adopted for the drilling project, in which the freezing hole needs to pass through the auxiliary chamber of the shaft such as Matoumen. The annular space inside the hole and outside the frozen pipe is easy to form a verti...

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Problems solved by technology

[0003] In order to ensure the safety of the project, it is necessary to perform solid pipe sealing water treatment on the freezing hole passing through the auxiliary chamber of the wellbore, that is, before the completion of the construction of the freezing hole and before the installation of the freezing pipe, the drilling cement within a certain height above the bottom of the hole shall be first The slurry is replaced with a cement slurry that has a certain retarding time and can successfully sink the tube within the specified time. Through the solidification of the cement slurry, the cementation between the frozen tube and the formation is realized, and the water-conducting channel is cut off. The liquid column pressure is high, the medium-grained and coarse-grained sandstone formations are prone to water loss, and the ground temperature is as high as 38°C. These environmental factors put forward high requirements on the retarding performance, water loss prevention, fluidity and rheological properties of the cement slurry. Traditional cement slurry cannot meet the construction requirements

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