A blowout prevention cementing method and device for high-temperature geothermal wells

Abstract

The invention relates to a blowout prevention cement slurry well cementation method and device for a high-temperature geothermal well. The method comprises the steps that clear water is pumped into the high-temperature geothermal well so that the formation temperature can be reduced to the preset temperature; a casing pipe is placed in the high-temperature geothermal well to the preset position; a lower rubber plug, isolating fluid and cement slurry of a certain density are sequentially pumped into the casing pipe to the position of a casing pipe opening; after a first preset time, an upper rubber lug and drilling fluid are sequentially pumped into the geothermal well till pressure bumping of the upper rubber plug is achieved; and after pressure bumping of the upper rubber plug is achieved, whether the cement slurry meets the preset conditions or not is judged within a second preset time, and if yes, well cementation work of the high-temperature geothermal well is completed. The device is achieved based on the above method. The density of the cement slurry is adjusted, and therefore the speed of pressure of the cement slurry entering the casing pipe and the well wall can be controlled, then the leakage amount of the cement slurry during well cementation can be controlled, and the aim of improving the well cementation quality is achieved.

Description

technical field [0001] The invention relates to a drilling method, in particular to a blowout prevention cementing method and device for high-temperature geothermal wells. Background technique [0002] The main feature of high-temperature geothermal wells is that the temperature in the well is high, usually up to 150 ° C ~ 300 ° C, this temperature can directly affect the silicate, causing it to produce undesirable hydration reactions, and the generation of digestion reactions will reduce the strength of cement, thus Cause well kick or lost circulation in high temperature geothermal wells. In addition, the above temperature will also shorten the solidification time of the cement slurry. Therefore, before injecting the cement slurry, it is necessary to inject a large amount of cold water into the well for circulation to reduce the temperature in the well, and add a retarder to prolong the solidification time of the cement slurry. However, due to the uncertainty of the densit...

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Problems solved by technology

[0003] Aiming at the deficiencies in the prior art, the present invention provides a blowout prevention cementing method and device for high-temperature geothermal wells, which are used to solve the differences in the formation where the geothermal well is located and the temperature in the well and the density of cement slurry in the prior art. Poor cementing effect of geothermal wells caused by determinism

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