Method for reaming by explosion of detonating cord under well

Abstract

The invention relates to a method for reaming by detonation of a detonating cord under a well. The method comprises the following steps: sequentially mounting a pilot reamer, an explosion reamer and avariable-diameter hole trimming device at the lowest end of a drill stem from bottom to top; enabling the drill stem to rotate and descend simultaneously, and when the drill stem descends until the explosion reamer is completely flush with the height of a predetermined reaming section, enabling the drill stem to stop descending and rotating; opening a mud pump and pressurizing same to the set detonation pressure to detonate the detonating cord of the explosion reamer, wherein shock waves generated by the explosion act on rocks of a well wall to cause stratum rocks on the entire periphery of this section to be crushed and fractured, thereby achieving reaming; opening the mud pump to the construction displacement and taking rock debris generated by the explosion reaming out of the well; enabling the drill stem to continuously descend, so that the variable-diameter hole trimming device reaches the reaming section to trim the well wall of the reaming section; and pulling the drill stem out of the well, putting a hole diameter logging unit into the well to detect the hole diameter and determining whether predetermined reaming requirements are met. By adopting the method, the reaming speed is high, risks under the well are low, the phenomena of repeatedly pulling a drill out of the well and putting the drill into the well is avoided and the well drilling efficiency is improved greatly.

Description

technical field [0001] The invention relates to a downhole detonating cord explosion hole reaming method, which belongs to the technical field of petroleum drilling equipment. Background technique [0002] In oil drilling operations, the creep and extrusion of salt-gypsum layers can cause borehole diameter shrinkage, pipe sticking, difficulty in running casing, poor cementing quality, and casing collapse, leading to serious drilling accidents. When drilling into salt-gypsum formations, the conventional method is to start the pump early, remove the pump late, ream frequently, strictly control the drilling speed, increase the drilling fluid density, and prevent the salt-gypsum layer from creeping through the pressure difference. Can not fundamentally solve the above hidden dangers. A more secure approach is to use downhole reaming technology to expand the wellbore in the salt-gypsum layer section to offset the displacement caused by the creep of the salt-gypsum layer, thereby...

AI Technical Summary

Problems solved by technology

The chip return channel is small, and it is easy to hold the pump when lifting up and down

Images