Propagation resistivity
Omega
Four investigation depths. Two measurement frequencies.
Omega measures phase-shift and attenuation resistivity at 400 kHz and 2 MHz. A retrievable probe lands in a slotted collar, using symmetrically positioned transmitters to compensate for borehole effects.
- frequencies
- 400 kHz / 2 MHz
- investigation depths
- 4
- temperature rating
- 150°C
Measurements & capabilities
- Phase-shift and attenuation resistivity
- Four investigation depths
- Retrievable probe and modular sensor placement
- 40,000-record memory
- Oil- and water-based mud compatibility
- Q-bus / CAN-bus compatibility subject to configuration
Applications
- Oil/water contact evaluation
- Bed-boundary mapping
- Logging while tripping
- Measurement after drilling
Published technical parameters
System specifications
Operating parameters
| Parameter | Published value |
|---|---|
| Collar outside diameters | 3.75, 4.75, 6.75 and 8 in |
| Tool length | 138.31 in |
| Collar length | 130.5 in |
| Maximum dogleg | 15° / 100 ft |
| Operating temperature | 150°C / 302°F |
| Operating pressure | 20,000 psi |
| Maximum sand content | 0.50% |
| Recorder capacity | 40,000 records |
| Input voltage | 18.5–30 VDC |
Power-source notation in the original brochure requires confirmation.
Depth of investigation
| Measurement | At 1 ohm·m | At 10 ohm·m |
|---|---|---|
| 2 MHz phase | 18 in | 28 in |
| 400 kHz phase | 24 in | 37 in |
| 2 MHz attenuation | 30 in | 48 in |
| 400 kHz attenuation | 41 in | 76 in |
Radius where the integrated geometrical factor reaches 0.5 in the specified formation. Inches retained because some source metric conversions conflict.
Vertical resolution
| Measurement | At 1 ohm·m | At 10 ohm·m |
|---|---|---|
| 2 MHz phase | 12 in | 21 in |
| 400 kHz phase | 16 in | 28 in |
| 2 MHz attenuation | 22 in | 40 in |
| 400 kHz attenuation | 33 in | 58 in |
Width at 50% of the vertical response function.
Ideal operating range
| Measurement | Resistivity |
|---|---|
| 2 MHz phase | 0.4–2,000 ohm·m |
| 400 kHz phase | 0.1–1,000 ohm·m |
| 2 MHz attenuation | 0.4–200 ohm·m |
| 400 kHz attenuation | 0.1–50 ohm·m |
Technical documentation
Omega technical sheet
Reformatted specifications and application notes, with source qualifications retained. Technical-review edition; confirm the current assembly rating with MWD Solutions before use.