A kind of retarded cement slurry used in drilling well construction by freezing method

Abstract

The invention discloses a slow-setting cement slurry used for well-sinking construction by freezing method, which belongs to the technical field of slurry. The key point is that, in parts by weight, the cement slurry comprises the following components: 190-210 parts of cement , 780-820 parts of fly ash, 970-1030 parts of water, 180-200 parts of glycerin, 1.3-4 parts of sulfonated lignite resin. Under the premise of ensuring that the final setting strength reaches 10 MPa, the cement slurry can retard setting for 45 hours at a high temperature of 40° C., and meanwhile, the cement slurry has high fluidity 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] Sinking by freezing method is to use artificial refrigeration method before the wellbore is excavated to freeze the bottom layer of the water-containing loose and unstable shock layer and bedrock aquifer around the wellbore to form a closed frozen wall with a certain thickness and strength. 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 ...

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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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