Oilfield Terminology & Definitions.
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Drilling & Completions

Drilling and completions are core phases of oilfield development that transform a geological target into a functional well. The process includes well planning, bit selection, drilling, casing, cementing, and final preparation for hydrocarbon flow.

  • Blowout Preventer
    16

    A Blowout Preventer (BOP) is a large, specialized valve or assembly of valves installed at the top of a wellbore during drilling and completions operations.…

  • Cementing
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    Cementing is the process of pumping a slurry of Portland cement and water (and often chemical additives) into the annular space between the steel casing…

  • Completion Fluid
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    Completion fluid is a specialized liquid used during the final phase of well construction—the completion phase—after drilling is finished and before production begins. Its primary…

  • Directional Drilling
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    Directional drilling is a specialized technique in the oil and gas industry where the wellbore is intentionally deviated from vertical to reach a specific subsurface…

  • Drill Bit
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    A drill bit is the cutting tool attached to the bottom of a drill string used to penetrate subsurface rock formations and create a borehole…

  • Drill String
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    A drill string is the entire column of tubular components that extends from the surface drilling equipment (such as the swivel or top drive) down…

  • Drilling Mud
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    Drilling mud, also known as drilling fluid, is a specialized fluid mixture used in rotary drilling operations to drill boreholes into the earth. It is…

  • Electric Submersible Pump
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    An Electric Submersible Pump (ESP) is a multistage centrifugal pumping system deployed downhole in an oil or water well to lift large volumes of fluid…

  • Fracturing
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    Fracturing, also known as hydraulic fracturing or “fracing,” is a well stimulation technique used in the oil and gas industry to enhance the flow of…

  • Horizontal Drilling
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    Horizontal drilling is a directional drilling technique where the wellbore is intentionally deviated from the vertical plane to follow a reservoir layer horizontally or at…

  • Liner
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    A liner is a string of casing that is run into a wellbore and hung from the bottom of a previous casing string, rather than…

  • Lost Circulation
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    Lost circulation is the uncontrolled, partial, or complete loss of drilling fluid (mud) into subterranean formations during drilling, completion, or workover operations. It is one…