A center pipe lowering process in a vertical well

Abstract

The invention provides a downward-putting technology for central pipes in a vertical well. The downward-putting technology comprises the following steps that 1, when the specific gravity of the central pipes is smaller than 1, a metal pipe is selected as the first central pipe; 2, screw threads are machined at the two ends of the central pipes, and couplings are mounted at one ends of the screw threads; 3, a circular hole is drilled in the circumferential wall of the first central pipe; 4, an elevator is clamped at the bottom of the corresponding coupling, the coupling end of the correspondingcentral pipe is lifted through drilling machine hanging tongs till the central pipe is completely located in the vertical direction, and at the moment, the central pipe is downwards put into the wellslowly the well through the drilling machine hanging tongs; 5, the coupling end of the other central pipe is lifted till the central pipe is vertical, the other end of the central pipe is separated from the ground, and the lifted central pipe is connected with the coupling end of the central pipe in the well; and 6, the step 5 is repeated till the downward-putting depth of the corresponding central pipe meets the design requirement. According to the downward-putting technology, downward putting of the central pipes in the vertical well can be quickly and safely achieved.

Description

technical field [0001] The invention belongs to the technical field of running a center pipe in a middle-deep hydrothermal geothermal well, and in particular relates to a process for running a center pipe in a vertical well. Background technique [0002] At present, the depth of medium-deep geothermal wells using single-well heat exchange technology is generally 1500m to 2500m. The realization of single-well heat exchange technology generally uses the heat preservation technology of the central tube and the efficient heat exchange technology of the water flow inside and outside the central tube to achieve heat extraction. Not for the purpose of fetching water. [0003] The central pipe is different from various iron casings and drill pipes used in geothermal well construction and well completion. Its specific gravity is relatively light, slightly smaller than that of water, and its strength is much lower than that of various iron casings. There are three practical problems:...

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Problems solved by technology

[0003] The central pipe is different from various iron casings and drill pipes used in geothermal well construction and well completion. Its specific gravity is relatively light, slightly smaller than that of water, and its strength is much lower than that of various iron casings. Three practical problems: one is that the center tube is easy to break, the other is that a counterweight needs to be added, and the third is that there is currently no special tool for the connection of the collar thread

Therefore, how to smoothly lower the center pipe with a length of more than 1500m into the geothermal well under the condition of ensuring safety, there is still no mature center pipe lowering process, especially the threaded central pipe lowering process.

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