Oil wells and natural gas are generally drilled into the earth and the underground oil or gas deposits are forced to the surface along the well bore by the underground pressure, or, pumped up using one or more pumps (often in a series). The well-bore is drilled from an oil-rig on the surface of earth using a rotating drilling bit. When the rotating drilling bit is driven into the earth, it cuts through layers of soil and rocks using a continuous flow of compressed drilling fluid (also known as “drilling mud”) supplied through a conduit, which can be coiled tubing or a drill string (composed of a contiguous series of pipes).
During drilling, hollow metallic tubes (also known as “casings”) are inserted within the drilled bore to prevent the walls of bore from collapsing. In a deep enough bore, multiple hollow casings are installed vertically one above the other by screwing ends of adjacent sections with each other, thus forming a “bore casing.” For reliable installation of bore casings (and for proper functioning of equipment set-up within it), the well-bore should be kept clean by efficiently removing mud, rock debris and dirt generated during drilling, and it should also be periodically cleaned to maintain reliable functioning of the in-well equipment.
Various tools and methods have been proposed for cleaning of an oil well-bore. For example, U.S. Pat. Nos. 7,686,102 and 8,151,908 (both incorporated by reference) disclose well-bore cleaning devices which use jets of pressurized fluid ejecting from one end of a tool to dislodge mud, dirt or rock debris in an oil well-bore. While drilling the oil well-bore, these tools are not very efficient in removing mud/dirt stuck on inner walls of the bore casing at positions already passed by the end of the tool from which jets of pressurized fluid are ejected. So in order to clean such portions, the tools may be required to pass multiple times up and down the oil well-bore. Hence, there's need for an improved cleaning device which more efficiently and effectively cleans the base and internal walls of a well-bore without multiple passes up and down being required.