Term
| Field Acceptance criteria for G |
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Definition
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Term
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Definition
| +-6 counts or 300 nT (nano teslas) |
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Term
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Definition
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Term
| working definitive surveys |
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Definition
| most accurate description of the well path to present TD |
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Term
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Definition
| most accurate description of the entire wellpath |
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Term
| Anticollision: classifying wells. What is the difference between single wells and nearby wells |
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Definition
Single well: at surface has separation of 41,000 ft + its own measured depth from all other wells
Nearby well: all wells that do not meet the criteria for a single well |
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Term
| Ellipsoids of uncertainty use what percent confidence? |
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Definition
| These are calculated using error models, to a confidence of 95% in 3D |
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Term
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Definition
| Oriented separation factor, this is the method SLB uses unless there is a more conservative method used by the client. It does a scan, any well with an OSF less than 5 must be considered for a more detailed anticollision analysis. |
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Term
| Minor risk anticollision well |
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Definition
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Term
| Major risk anticollision well |
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Definition
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Term
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Definition
| Minimum allowable separation |
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Term
| 2 rules used to define MAS |
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Definition
Surface rule: single MAS is calculated at the well reference point, usually at surface, maximum 10 meters separation between wells.
OSF rule: the OSF between the planned trajector and all offset wells must be greater than 1.5 (not a minor nor a major OSF risk well) |
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Term
| Resistivity phase shift measurement limits |
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Definition
0.2 ohmm to 60 ohmm (for 2 MHz)
0.1 ohmm to 10 ohmm (for 400 kHz) |
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Term
| Resistivity attenuation measurement limits |
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Definition
0.2 ohmm to 25 ohmm (for 2 MHz)
0.1 ohmm to 3 ohmm (for 400 kHz) |
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Term
| Four Rules for Depth of Investigation |
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Definition
DOI increase with increasing resistivity
Attenuation measurements read deeper than phase shift
DOI increases with increasing transmitter spacing
400 kHz (lower freq) reads deeper than 2 MHz |
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Term
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Definition
| Thinnest bed that the tool can detect (koala bears are thin) |
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Term
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Definition
| thickness that the bed must be for the tool to read atleast 90% of its true resistivity value |
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Term
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Definition
| width at 50% of the vertical response function |
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Term
| Four Rules for Vertical Resolution |
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Definition
VR decreases with increasing resistivity
Phase shift measurements have better VR than attenuation
2 MHz (high freq) has better VR than 400 kHz (low freq)
VR remains constant for transmitter spacing |
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