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Cementing Equipment includes various items used while drilling oil/gas/water wells. Casing will be installed at various depths while drilling. It is held in place by cement, which also provides zone isolation. Down-hole equipment such as Centralizers and Turbolizers is used to ensure obtaining satisfactory zone isolation. Float Shoes and Collars (float valves) prevent backflow after the cement has been pumped into place. == Centralizers, Turbolizers and Scratchers== Devices fitted with hinged collars and bow springs help keep the casing or liner in the center of the wellbore to help ensure efficient placement of a cement sheath around the casing string. If casing strings are cemented off-center, there is a high risk that a channel of drilling fluid or contaminated cement will be left where the casing contacts the formation, creating an imperfect seal.〔http://www.glossary.oilfield.slb.com/Display.cfm?Term=centralizer〕 Turbolizers have added fins to "stir" up the drilling fluid and cement to keep the flow turbulent in order to make sure the cement flows all the way around the casing in order to prevent channeling. Scratchers use metal wires to scrape mud cake off permeable zones to help obtain a solid cement column. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cementing equipment」の詳細全文を読む スポンサード リンク
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