| Cable |
Logging cable used for carrying insulated electrical conductors for SRO logging. |
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| Cable Head |
A device mounted at the end of a cable, to provide a means of mechanical and electrical connection between the cable and the logging tool. |
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| Cable Tension |
Toolstring and cable weight measured at surface on the logging unit with a tension device, or locally at the tool head using a HTU. |
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| Caged Fullbore Flowmeter (CFB) |
A type of Sondex flowmeter, mounted at the bottom of a toolstring, providing accurate flow data over a wide cross section of the casing. |
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| CAL3 |
Sondex MIT control software. |
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| Calibration |
The generation of coefficients to convert from raw tool readings to engineering units. |
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| Caliper log |
The representation of the diameter of a borehole along its depth. Usually achieved by measuring several locations simultaneously with a Multifinger Caliper Tool (MIT). |
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| CalTran |
Sondex software to model tubular deformity using MIT data. |
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| Capacitance Array Tool (CAT) |
Tool with 12 micro capacitance probes to measure the holdup or fraction of the well occupied by oil, gas or water. |
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| Capacitance Water Holdup Tool (CWH) |
Tool which responds to the dielectric properties of the well fluids. Principally to measure the fraction of the well fluids occupied by water. |
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| Cased Hole |
The part of the well which has casing to maintain the integrity of the well. |
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| Casing |
Metal pipe cemented into the wellbore to provide, for example, structural stability and a secure environment for downhole measurement equipment. |
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| Casing Collar Locator (CCL) |
Device which detects changes in metal volume by the disturbance of a magnetic field. Typically used for depth correlation. |
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| Casing Inspection |
Examining the casing or tubing to ascertain the condition. |
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| Casing String |
The steel tubing that lines a well after it has been drilled. It is formed from sections of steel tube screwed together. |
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| CATView |
Software for showing 3D images from horizontal wells. |
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| Cement Bond Tool (CBT) |
Typically an acoustic device to determine the quality of the bond of the cement sheath around the casing. |
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| Central estimate |
A range of exploration drilling scenarios from which the following activity levels, based on recent historical experience, are adopted as the central estimates. |
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| Centraliser |
A device which positions the logging tool in the center or near center of the wellbore. aligned with the wellbore axis. |
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| Christmas tree |
The assembly of fittings and valves on the top of the casing which control the production rate of oil. |
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| Collar |
A threaded coupling device to join two pieces of pipe of the same diameter. Identified by a CCL as part of depth correlation during completions. |
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| Commercial field |
An oil and/or gas field judged to be capable of producing enough net income to make it worth developing. |
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| Completion |
The installation of permanent wellhead equipment for the production of oil and gas. |
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| Condensate |
Hydrocarbons which are in the gaseous state under reservoir conditions and which become liquid when temperature or pressure is reduced. A mixture of pentanes and higher hydrocarbons. |
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| Coning |
An effect whereby the gas-liquid ratio is distorted by withdrawal of oil at an excessive rate, resulting in unwanted water production. |
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| Connate water |
Salt water occurring with oil and gas in the reservoir. |
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| Continuous Flowmeter Spinner (CFS) |
A fixed diameter flowmeter, running on ball bearings, at the bottom of the toolstring for logging in tubing. |
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| Continuous Flowmeter, Jewelled Bearings (CFJ) |
A fixed diameter flowmeter, running on jewelled bearings, at the bottom of the toolstring for logging gas wells. |
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| Coring |
Taking rock samples from a well by means of a special tool -- a "core barrel". |
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| Corrosion |
A complex chemical or electrochemical process by which metal is destroyed through reaction with its environment, eg rust. |
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| Countrate |
The output frequency of a tool measured in counts per second. |
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| Coupling |
A threaded collar for joining two pieces of pipe, casing or tubing. |
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| Crane barge |
A large barge, capable of lifting heavy equipment onto offshore platforms. Also known as a "derrick barge". |
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| Creaming Theory |
A statistical technique which recognises that in any exploration province after an initial period in which the largest fields are found, success rates and average field sizes decline as more exploration wells are drilled and knowledge of the area matures. |
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| Crossover |
i. Device which converts from one telemetry format to another; ii. Completion item to convert from one tubing size to another. |
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| Cubic foot |
A standard unit used to measure quantity of gas (at atmospheric pressure); 1 cubic foot = 0.0283 cubic metres. |
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| Curie |
A standard measure of the rate of nuclear transformations, or disintegrations equal to that of one gram of radium. This rate is 3.70 × 1010 disintegrations per second. |
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| Curve |
In well logging, a trace representing a continuous record of some property or occurrence in the wellbore environment versus depth. One or more curves may constitute a well log. |
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| Cuttings |
Rock chippings cut from the formation by the drill bit, and brought to the surface with the mud. Used by geologists to obtain formation data. |
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