The rotary percussion drilling is commonly used for shallow wells such as inclinometers, piezometers, wells or geothermal wells with a maximum depth of 250 m. This method applies impact and rotational forces for continuous progression into geological formation. The mobile air compressor on the surface produces a volume of compressed air which is supplied through the annular space of the drill rod to a pneumatic down the hole hammer. Afterwards the piston mechanism of the pneumatic down the hole hammer begins to create impact forces which enable the drill bit to penetrate into geological formation. Rotational forces are produced by the upper rotary head, mounted on the drill carriage, and induce the progression of several tools in the borehole (drill rod, pneumatic down the hole hammer, drill bit). The rotary percussion drilling produces the combination of impact and rotational forces¬ that enable continuous and rapid penetration into geological formation.
The theoretical part of the master’s thesis includes detailed description of the rotary percussion drilling and simultaneous casing of the borehole. The eccentric drill bit, mounted on a pneumatic down the hole hammer, penetrates into geological formation by percussive rotational forces and drills the overprofile of the drill hole. A casing is simultaneously put into the drill hole through the rotation of the lowery rotary head which is mounted on the drill carriage. The casing protects the drill hole from collapsing and functions as a route for the removal of cuttings.
The practical part of the master’s thesis describes the segments of the Mmu-2/19 production well made by rotary percussion drilling and simultaneous casing of the borehole. In the initial part the drilling of the introductory and filter column of the well are presented. The introductory casing was drilled to a depth of 49.5 m with an eccentric drill bit (Ø315 mm) and simultaneously cased with the casing (Ø298.5 mm). The filter section was drilled to a depth of 150.18 m with an eccentric drill bit (Ø237 mm) and simultaneously tubed with the casing (Ø219.1 mm). Furthermore, the calculations of losses of compressed air in individual segments of the drilling set are shown. Logging measurements, activation of the well with air-lift and pumping test are presented at the end. The logging measurement of the Mmu-2/19 production well is attached to the master’s thesis.
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