Near-bit measurements
Flashlight
Inclination, azimuth and gamma at the bit.
Positioned between the motor and bit, Flashlight measures inclination, azimuth, gamma and azimuthal gamma near the cutting structure. An EM short-hop carries data to a receiver in the MWD string for transmission to surface.
- sensor offset
- 12 in
- temperature rating
- 175°C
- combined motor + string
- 250 rpm
Measurements & capabilities
- Continuous inclination and azimuth at the bit
- Gamma and azimuthal gamma
- Real-time transmission and memory recording
- At-bit vibration, temperature and tool-health flags
- Operation in oil- and water-based mud
Applications
- Geosteering in dipping formations
- Casing-point selection
- Near-bit directional and formation context
MEASUREMENT IN CONTEXT
Reduce the distance between the bit and the measurement.
Flashlight places inclination and gamma measurements near the cutting structure. The supplied illustration shows why sensor position matters when the bit crosses a formation boundary; distances in the example describe the scenario, not a guaranteed response.
Open the full graphic
Published technical parameters
System specifications
Sensor measurements
| Parameter | Published value |
|---|---|
| Inclination accuracy | ±0.25° |
| Inclination range | 0–180° |
| Sensor / gamma offset | 12 in |
| Gravity accuracy | 0.0005 G |
| Gravity range | 0–2 G |
| Gamma resolution | 1 AAPI |
| Gamma range | 0–1023 |
| Temperature | 175°C / 347°F |
Operating considerations
| Parameter | Published value |
|---|---|
| Formation resistivity | 2–200 ohm·m optimal |
| Mud system | Water- or oil-based |
| Differential pressure | Avoid spikes above 300 psi |
| Torque | Avoid spikes above 1,500 ft·lbf |
| Rotary measurement limit | 250 rpm, motor + string combined |
| Axial shock | 20 G maximum |
| Agitator separation | 800 m / 2,625 ft behind |
| Reaming | Keep to an absolute minimum |
| Battery, inclination + gamma | 160 hours per 14 V cell |
| Battery, inclination + azimuthal gamma | 128 hours per 14 V cell |
Battery figures are published per-cell figures, not guaranteed run duration.
Transmitter configuration
| Nominal tool size | 4.75 in | 6.5 in | 8 in |
|---|---|---|---|
| Length | 34 in | 34 in | 34 in |
| Diameter | 5.0 in | 6.5 in | 8.0 in |
| Makeup torque (ft·lbf) | 14,200 | 23,000 | 57,000 |
| Max drilling torque (ft·lbf) | 9,900 | 22,500 | 47,000 |
| Surface RPM | 30 | 50 | 50 |
| Max sliding dogleg (°/100 ft) | 28 | 20 | 12 |
| Max rotating dogleg (°/100 ft) | 12 | 10 | 7 |
Connection nomenclature in the source requires confirmation and is not reproduced here. Use configuration-specific limits.
Technical documentation
Flashlight technical sheet
Reformatted specifications and application notes, with source qualifications retained. Technical-review edition; confirm the current assembly rating with MWD Solutions before use.