Compact Oil-Base Microimager Tool

Delivers high-definition, fullbore images in nonconductive muds


  • Visualizing complex structures
  • Identifying faults and fractures and their orientation
  • Determining structural dip
  • Defining crossbeds, thin beds, and net-to-gross ratio in sand-shale sequences
  • Identifying sand-shale facies and sand counts
  • Evaluating secondary porosity
  • Depth-matching, orientation and substitution of cores, structural and breakout analysis, and true vertical depth (TVD) analysis  

Features and Benefits

  • Eight pads with 72 measurement electrodes and excellent dynamic range measurement electronics deliver superb pad contact for reliable microresistivity data and six independent caliper readings.
  • Each pad is gimbaled, and pad pressure is selectable.
  • The tool delivers high-definition images in oil-based muds, regardless of borehole conditions that would exclude conventional tools.
  • The microimager records all high-resolution data into flash memory in the time domain, which is independent from the wireline data.
  • The resulting high-definition, fullbore images improve geological interpretation for confident decision making in complex reservoirs.
  • An integrated navigation package is positioned close to the pads.
  • The tool is compatible with Reveal 360° image processing, a digital imaging technology that uses microresistivity measurements to deliver a complete 360° view.
  • The microimager is fully combinable with other Compact logging tools.

Tool Description

The Compact oil-base mud microimager (COI) provides formation images in oilbase muds  for dip and fracture detection, sedimentary structure characterization, thin-bed evaluation, facies analysis, and orientated resistivity and dipmeter computation. The excellent borehole coverage and high-resolution imaging provided by the COI enable detailed reservoir description and enhance decision making.

The tool operates in any oil-, diesel-, or synthetic-based mud. The COI consists of a memory section (MIM) and a measurement section (MOE). High-resolution, time-based data is recorded into the MIM while 3.9-in. (10-cm) depth-based data is transmitted to the surface. 




Microresistivity imaging, borehole geometry, and multi-arm caliper

Logging speed

2,000 ft/hr (10 m/min)

Vertical microresistivity resolution

0.4 in. (10 mm)

Axial microresistivity resolution

0.2 in. (5 mm)


Caliper: ± 0.2 in. (5 mm)
Deviation: ± 0.1°
Azimuth: ± 5°

Depth of investigation

0.5 in. (12.7 mm) nominal for microresistivity

Measurement range

Tilt: 0° to 180°
Azimuth: 0° to 360°
Microresistivity: no practical limit

Borehole fluids

Oil-, diesel-, and synthetic-based muds



Maximum outer diameter

4.10 in. (104 mm)


18.63 ft (5.68 m)

Weight (air)

141 lb (64 kg)

Maximum temperature

320°F (160°C)

Maximum pressure

15,000 psi (103 MPa)

Maximum borehole diameter

13 in. (330 mm)

Minimum borehole diameter

4.6 in. (117 mm)

Compact Oil-Base Microimager

The Compact oil-base microimager (COI) provides high-quality, fullbore images for a variety of applications.

Reach out to optimize reservoir performance

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