fmi fullbore formation microimager log.. topics applications tool history current tool theory...
TRANSCRIPT
FMI
Fullbore Formation
MicroImager Log.
Topics
• Applications
• Tool History
• Current Tool Theory
• Factors Affecting Log Results
• Log Quality
• Tool Setup & Operations
• Tool Maintenance
Applications
• Azimuthal Micro-Resistivities for dip, bed and fracture analysis
• Dip calculation data is a major input in reservoir modeling and interpretation
• Inclinometry for directional surveys.
• Borehole geometry from calipers.
• Hole volume
Tool History
• SHDT (Stratagraphic High-Resolution Dipmeter Tool)
• FMS/MEST (Fullbore Micro-Scanner)
• FMI/FBST (Fullbore Scanning Tool)
• OBDT (Oil Based Dipmeter Tool)
Slim - FMS (MEST-B)
• MEST-B (Above) is the slimhole version of the FMS. Two rows of 8 buttons on 4 pads.
• MEST-B 3 3/8” closing diameter.
• MEST-C 5” closing diameter.
• CTS telemetry.
• Bottom only
FMI
• 4 pads, 4 flippers
• DTS telemetry
• 5” closing diameter
PADS & FLIPPERS?
• Pads are connected to the calipers.
• Flippers are hinged to the pads, and are not hydraulically controlled
• Pad pressure can be hydraulically increased. Pad
Flipper
Resolution
• Samples: 62.5 Hz
• 5mm resolution (Button
Size)
• Logging Speed must be less than 1800 fph
5mm
FMI PADs Have Guts Too!
• Button signals are multiplexed at the pads to reduce noise.
• Don’t hit them with hammers!
EMetteur d’EXcitation
• Uphole power supply
• Phantommed on lines 1 and 4 to tool.
• Magnitude and Gain controlled either automatically (changes with formation) or manually.
Passive Focusing
• As opposed to Active Focusing (Dual-Laterolog).
• Simple but has limited functionality.
• Current is emitted from buttons and pads, creating an equipotential surface parallel to the borehole wall. The current returns to the cartridge.
Passive Focusing
Dips
• Dips show up as sinusoidal features on an FMI Image
• Colors represent different micro-resistivities
Dips
Dips
Dip Calculation
h
Diam
= ATan ( h / Diam ) = Dip Angle
h
Circumference
(Known Diameter)
Geographic Features
Tool Rotation
• Since the tool will rotate during the log, we must know “HOW” it is rotating.
• If we don’t know the rotational position of the dipmeter tool, then we will not know which direction the dip is.
With Orientation
N S N
No Orientation
Inclinometry
• “Where” the data came from is as important as the data itself.• Images can be oriented with respect to North or to
the top of the borehole.
• Compare it to taking a core or sample but not knowing what depth it came from.
• For this reason, and inclinometry tool is required: GPIT
Inclinometry, GPIT
• The GPIT is located inside the FMI sonde (FBSS).
• It can be removed and placed into its own housing.
GPICAH-184
FBSS
FBCC
GPIT Block Diagram
• GPIC-AC : DTB
• GPIC-C : FTB
Magnetic Field Strength
• A Triaxial magnetometer (three single axis magnetometers) are used to determine the rotational position of the tool, relative to the Earth’s magnetic field. (Magnetic North)
• FNOR = (FX2 + FY
2 + FZ2)
• FNOR = Depends on where you are.
Flux Gate Magnetometer
E
RLSignal FEXT
I2
• Pad 1 Azimuth
• Degrees from Magnetic north on a horizontal plane.
• I.e.: P1AZ = 180 means Pad 1 is south.
Inclinometry, P1AZ
Longitude / Latitude
• LATD: Latitude (in degrees)
• LOND: Longitude (in degrees)
• Relative Bearing
• Degrees from “UP” on a vertical plane
• i.e. RB = 180 means Pad 1 is down.
Inclinometry, RB
Inclinometry, Deviated Well
• Relative Bearing& P1AZ Trackeach other
• In deviated wells, both can be used to orient images
Inclinometry
• HAZI• Direction the hole is travelling (N,S,E,W)
• DEVI• Deviation of the hole (From Vertical)
• i.e.: Vertical well = 0 deg deviatedHorizontal well = 90 deg deviated
Worst Case
• In the event of the failure of one (and only one) of the GPIT accelerometer in the Ax or Ay or magnetometer channels, the job can still be rescued in a computing center. If the accelerometer along the z-axis fails, speed correction can no longer be performed.
From LQCRM FMI 5.2
Repeatabliltiy
• AZIM ± 2°
• DEVI ± 0.2°
• CALI ± 0.25 in.
From LQCRM FMI 4.5
FMI_WRAP_BY_P1AZ FMI_LQC
FMI_WRAP_BY_P1AZ FMI_TEVAL
FMI_WRAP_BY_P1AZ FMI_TEVAL