Monopole Cross-Dipole Tool

Providing advanced acoustic measurements forconfident decision making about reservoirs 


  • Geophysics
  • Velocity calibration, time/depth conversion
  • Amplitude variation with offset (AVO) calibration
  • Petrophysical
  • Porosity estimation and lithology
  • Gas identification
  • Geomechanical
  • Anisotropy presence, amount and orientation
  • In-situ stress orientation
  • Pore pressure
  • Wellbore stability modeling
  • Hydraulic fracture design
  • Natural fracture identification and orientation
  • Sand production in unconsolidated formations
  • Stoneley wave-permeability estimates
  • Optimized well placement for maximum reservoir drainage

Features and Benefits

  • Proprietary transmitter and receiver design delivers high-quality data over a broad range of environmental conditions.
  • The unique design of the receiver array (below the transmitters) puts the first read closer to bottom, reducing the need for extensive over hole.
  • The tool can be combined with almost all standard openhole tools to reduce the number of trips into the well, which saves significant operation cost.

Tool Description

The Weatherford standard cross-dipole sonic (MDX) tool combines monopole and cross-dipole sonic technology to provide acoustic data for a wide variety of geophysical, petrophysical, and geomechanical applications. The data obtained by the MDX tool assists in improving reservoir characterization and ultimately maximizes well and reservoir productivity.

The MDX tool incorporates three high-powered transmitters—one monopole and two wideband, low-frequency, dipole transmitters perpendicular to each other. The receiver section has an array of eight receiver stations, each consisting of four gain-matched, piezoelectric transducers that are aligned with the dipole transmitters. Ninety-six, high-fidelity wideband waveforms are recorded and provide excellent quality control.

The tool can measure the slowness of the compressional, shear, and Stonely waves. Running the MDX tool in combination with the with the high resolution navigation package (HNC) or the high-resolution microimager (HMI) tool produces anisotropic orientation data.




Compressional (P-wave), shear (S-wave), and Stoneley slowness, fast shear azimuth

Logging speed *

1,800 ft/hr (9 m/min)

Measurement range compressional slowness

30 to 250 µs/ft (98 to 820 µs/m)

Measurement range shear slowness

70 to 1,000 µs/ft (230 to 3280 µs/m)

Measurement range Stoneley slowness

70 to 1,000 µs/ft (230 to 3280 µs/m)

Vertical resolution

3.5 ft (1.1 m) enhanced: 12 in. (304 mm)


± 2%

Depth of investigation

1.5 ft (46 cm) shear slowness in soft formations

Borehole fluids

WBM, OBM, salt



Maximum outer diameter

3.375 in. (86 mm)


29.5 ft (9.0 m)

Weight (in air)

525 lb (238 kg)

Maximum temperature

350°F (177°C)

Maximum pressure

20 kpsi (138 MPa)

Minimum borehole diameter

4.5 in. (114 mm)

Maximum borehole diameter

21 in. (533 mm)

Monopole Cross-Dipole Tool

The MDX tool incorporates three high-powered transmitters—one monopole and two wideband, low-frequency, dipole transmitters perpendicular to each other

Reach out to optimize reservoir performance

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