Electronic single-shot instrument provides improved accuracy

Drilling technology that has been available to the mining industry for the past 10 years will shortly be tested for offshore applications.

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Standard Reflex EZ-Shot, with running gear and top/bottom subs.
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Drilling technology that has been available to the mining industry for the past 10 years will shortly be tested for offshore applications. Reflex Instrument, based in Vallentuna, Sweden, is planning tests in the Gulf of Mexico of its Reflex Ez-Shot - an electronic probe for drillhole surveying. The tests will be completed later this year in cooperation with drilling contractors and will show how well the probe performs in offshore oil and gas drilling applications.

The Reflex Ez-Shot is an easy-to-use electronic solid state single-shot instrument, claimed by the company to be one of the most accurate systems available, compared with other single-shot probes. The operator chooses the time delay and accordingly takes readings in the hole. Once in the collar position, the probe automatically resolves readings into a borehole path defined by 3D coordinates. The more closely spaced the readings, the more accurate the results.

The probing tool, available in sizes from 25.4 mm up, fits most standard pressure barrels and running gear. It can therefore be used either with existing equipment or with new equipment supplied for Reflex by a Canadian company.

The pressure barrels are made with heavy-duty brass walls and have a triple O-ring seal to prevent drilling fluid from getting into the probe. All have a safety collar in the top sub-instrument hanger to prevent the tool from being accidentally dropped while assembling the pressure barrel. The whole package can also be protected with heat shields.

No film processing

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The Ez-Shot keypad.
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In addition to the 3D components, the Reflex Ez-Shot records magnetic field, temperature at tool core and roll toolface relative dip and magnetic north. Stabilization of internal operations is achieved by keeping a constant log of its instrument casing temperature.

Data taken by the Reflex Ez-Shot is readable from a membrane keypad with a four-figure LCD display as soon as the instrument is recovered from the well. This eliminates the need for film processing, cabling in the well or calculation of the results.

The Reflex Ez-Shot can be run in any direction. Provided there is no magnetic disturbance, the data can be used to calculate the borehole path. If the survey is being run either on the drill pipe, or through the pipe on a wireline, the instrument should be isolated by at least three meters of non-magnetic pipe.

Simple operation

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Reflex Instrument's single-shot instrument improves accuracy of downhole surveys.
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In the well, the Reflex Ez-Shot system records data automatically in accordance with the built-in time delay function. According to Reflex Instrument, the system should lead to considerable cost reductions by enabling accurate surveying of drilling locations and preventing the need for costly deviations.

The compact instrument, measuring only 846mm (2 3/4-ft-long, with a 25.4 mm (1.00-in.) outer diameter provides a direct LCD four-figure digital readout of six parameters (see table below).

All values selected and readable from the membrane keypad can be displayed in less than one second. The instrument has a shock resistance - 6,000 g, 0.5 ms, half-sine period; pressure rating: 55 Mpa (8,000 psi).

For more information, contact Yngve Lennerstrand, Reflex Instrument. Tel: +46 8511 80610, Fax: +46 8511 80620, E-mail: yngve.lennerstrand@reflex.se.

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