FullWave Sonic Log

Approximate OverallLength • Standard configuration • Extra-Long configuration	637 in. 728 in.	16.18 m 18.49 m
Temperature Rating	400°F	204°C
Pressure Rating	20,000 psi	137 900 kPa
Recommended Hole Sizes •Minimum Borehole Diameter •Maximum Borehole Diameter	4.5 in. 20 in.	445 mm

Transmitter

• Type

• Resonant Frequency

Piezoelectric, metal-covered 15 kHz

Receivers

• Type

• Frequency Response

Piezoelectric, metal-covered Flat from 700 Hz to 30 kHz

Transmitter-To-Receiver Offsets Standard Configuration Extra-Long Configuration Short Configuration

10, 11, 12,13ft 17.5,18.5, 19.5 and 20.5ft 3 and 5 ft

3.05,3.35,3.66,3.96m 5.33, 5.64, 5.94 and 6.25 m 0.91 and 1.52m

The sonic logging system developed by Halliburton provides more acoustic information than ever before.

From 1997, Vietsopetro L&TD successfully evaluated potential zones in fractured basement using FWST data.

Using a piezoelectric transmitter and four long‑spaced receivers, the FWS system records the entire acoustic wavetrain. Digital processing techniques extract compressional, shear, and Stoneley t; shear wave and compressional wave amplitudes; and Stoneley wave attenuation. These basic measurements provide valuable information on rock types, gas zones, porosity naturally fractured intervals, formation elastic properties, stress field around the borehole, permeability, and acoustic impedance.

FWS APPLICATIONS

Improved porosity estimates using both t_c, and t_s
Lithology identification by means of velocity ratio, t_s /t_c
Location of gas zones, even in poor hole conditions and cased holes
Indication of permeability variations with depth from Stoneley wave attenuation
Detection of naturally fractured zones
Determination of rock elastic constants
Estimation of formation strength and least horizontal stress
Prediction of vertical extent of hydraulic fractures

FWST – An effective tool to evaluate the potential zones in fractured basement.

FWST has been used by Vietsopetro L&TD to investigate the characteristics of fractures in basement of Cuu Long basin. The t_c, t_s and t_st and energy attenuation measurements have been used for:

- Detection of naturally fractured zones.

- Indication of permeability variations with depth from Stoneley wave attenuation.

- Lithology identification by means of velocity ratio, t_s /t_c

In fact, surveys in basement of Cuu Long basin indicated that FWST is an effective tool for evaluation of fracture zones in basement.

This FWS primary log example displays the raw waveform data from Receiver 1 in the right track. Processed results, including compressional and shear slowness curves (tc and ts), are shown in the center track, along with a shear slowness quality indicator Caliper and Gamma Ray information, along with a gain curve, are displayed in the left track

Instantaneous Waveform Characteristics IWC analysis allow users better evaluation of fracture zones as spectrum of amplitude, phase and frequency of waveform

This plot shows potential zones in White Tiger fractured basement by mean of the energy loss of Stoneley wave (Track 5). In fact, these zones are highly productive.

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