Low Frequency Measurements

Service/Product Title

 

Low-Frequency Laboratory Measurements on Rock Samples

 

Core Lab operates a full service geomechanics laboratory that provides customers with multi-frequency acoustic velocities and elastic properties for revolutionary seismic and log calibration.

Low-Frequency Measurements
Why low-frequency data are useful

  • Most rock elastic properties are frequency dependent
  • Seismic attributes such as formation reflectivity vary with frequency
  • Low frequency data provide a baseline of known rock properties that tie seismic and sonic measurements to ground truth
  • Calibrating logs with low-frequency lab data elucidates dispersive and viscoelastic effects

Solutions provided by core testing

  • Differentiate dry gas from fizz water gas
  • Determine gas/oil/water influences
  • Vp/Vs ratio determination for seismic analysis
  • Vp and Vs versus frequency and saturation
  • Acoustic velocities in crude oils and brines
  • Cross-well seismic calibration
  • Fracture mapping using microseismic calibration

Low-Frequency Measurements

Low-frequency determination of the behavior of reservoir rocks under changing fluid states and reservoir pressures establishes correlations between static and dynamic data.

 

Low-Frequency Measurements

Frequency effects: Both P-wave (compressional) and S-wave (shear) velocities increase as frequency increases from low frequency to seismic to logging and ultrasonic frequencies. Calibration with only ultrasonic data results in overestimation of velocities at lower frequencies. Elastic moduli change dramatically with frequency whereas Poisson’s ratio varies less.

Low-Frequency Measurements

Low-Frequency Measurements

Low-Frequency Measurements

Correlations between static and dynamic elastic constants are difficult to establish because they depend on many reservoir-specific variables. Without core data acquired at low frequencies in the lab, reservoir models are highly variable and subjective.

Low-Frequency Measurements