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.
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,
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