CAST-V Circumferential Acoustic Scanning Tool-Visualable

CAST-V – A COST-EFFECTIVE TOOL TO EVALUATE THE POTENTIAL ZONES IN FRACTURED BASEMENT.

The newest generation Circumferential Acoustic Scanning tool, the CAST-V made by Halliburton, provides a wealth of information in both open and cased holes. In open holes, the CAST-V provides complete borehole imaging for accurate formation evaluation. In cased holes, ultrasonic pipe inspection and cement evaluation can now be obtained simultaneously.

Operating over a wide range of downhole environments, the CAST-V data can be presented in a variety of two- and three- dimension formats. Powerful, yet user-friendly imaging analysis software is available to process the images, histograms and curve-type data.

Specifications

Temperature

Rating

Pressure Rating

OutsideDiameter

Length

Weight

350^oF 20,000psi 3.625 in. 215 in. 316 lb

175^oC 137900 kPa 92 mm 5.46m 143 kg

Openhole Operation

Recommended

Range of

Openhole Sizes

5 1/2 to 13 3/8 in

139 to 340 mm

Azimuthal Resolution	1.8^o
Vertical Sample Rate	0.3 in.
Logging Speed	20 ft/min.
Vertical Resolution	0.3 in.
Accuracy	±5%
Primary curves	Max. reflected amplitude and time of fight for each shot (200 shots/scan), borehole fluid slowness
Secondary curves	Amplitude and borehole radius images (200 dots/scan), hole ovality, tool eccentricity, hole deviation, and tool RB

with interchangeable transducer heads

Primary applications include:

• Open Hole Borehole Imaging.

• Fracture Detection.

• Casing Inspection (Both Thickness And Diameter).

• Ultrasonic Cement Evaluation/ Imaging.

CAST-V HAS BEEN USED POPULARLY BY L&TD, VSP FOR STUDYING THE CHARACTERISTICS OF FRACTURES IN BASEMENT, CUU LONG BASIN.

The energy levels of reflected ultrasonic wave have been used:

- To locate the fracture zones.

- To differentiate between open fractures and filled fractures.

- To determine the geometric characteristics of fractures: dip, azimuth dip, and aperture.

In fact, surveys in basement of Cue long basin indicated that CAST-V is the most effective tool for studying basement fractures.

	This open-hole CAST-V imaging was logged from fractured basement reservoir of White Tiger oil field. The upper plot shows clearly the open fractures both on amplitude (left) and transit time (right). These fracture zones are highly productive zones.
	This plot clearly shows the closed fractures both on the amplitude (left) and transit time (right). These fracture zones are non-productive zones
	A productive zone was identified by CAST-V and traditional log (LLD, LLS, DT, NPHI, RHOB etc) measurements. This was confirmed with production logging data