fmi fullbore formation microimager log.. topics applications tool history current tool theory...

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