Loose bed and bedrock layer mixed water-intaking and well-forming process for geothermal well

Abstract

The invention discloses a loose bed and bedrock layer mixed water-intaking and well-forming process for a geothermal well, and the process provided by the invention comprises the following steps: 1) using a slurry positive circulation well drilling process to perform well drilling till the depth of 5-10m below a complete bedrock surface; 2) sinking pipes, namely sinking a well wall pipe at the section below the bedrock surface and the section of a non-loose porous water layer of a loose bed and sinking a water-permeable pipe below the section of a loose porous water layer of the loose bed; 3)filling annular holes, namely pouring cement slurry into the annular holes corresponding to the section below the bedrock surface, putting a filter material into the annular holes corresponding to the loose porous water layer and putting clay balls into the annular holes corresponding to the section of the non-loose porous water layer of the loose bed; and 4) further using a drill bit with the diameter being 5-10mm smaller than the inner diameter of the well wall pipe to continue drilling in the bedrock layer through a clear water drilling process or a negative circulation well drilling process till a bedrock fracture water layer after the cement slurry waits on cementing for 72 hours and completing the well when the water temperature achieves the design temperature. The well drilling process for the geothermal well is suitable for developing geothermal resources in regions with poor geothermal resources and non-developed bedrock structures.

Description

technical field [0001] The invention relates to a well drilling technology, in particular to a technology for forming a well by taking water from a loose layer of a geothermal well and a bedrock layer by mixing. Background technique [0002] In areas rich in geothermal resources, when digging geothermal wells, only loose layer pore water or only bedrock layer fissure water, structural water and cave water are taken as the target production layer of the well. However, for areas with poor geothermal resources and undeveloped bedrock structure, if the conventional well-forming process is followed, it will often appear that: when the pore water in the loose layer is taken as the target production layer of the well, the water volume can meet the design requirements, and the water temperature is low; When the fissure water in the rock formation is the target production layer of the well, the water volume is small, but the water temperature has increased. If the water from two pro...

AI Technical Summary

Problems solved by technology

However, for areas with poor geothermal resources and undeveloped bedrock structure, if the conventional well-forming process is followed, it will often appear that: when the pore water in the loose layer is taken as the target production layer of the well, the water volume can meet the design requirements, and the water temperature is low; When the fissure water in the rock formation is the target production layer of the well, the water volume is small, but the water temperature has risen

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