Description
 The
Array Seismic Imager (ASI) consists of an array of five seismic
shuttles linked by a bridle to a signal-conditioning cartridge.
Each shuttle sensor package contains three mutually orthogonal geophones
fixed relative to the sensor package geometry. One geophone lies
along the axis of the package (z-axis); the other two geophones
(x- and y-axes) form a 45° angle relative to the clamping direction.
This design allows the ASI tool to operate in wells with a 90°
deviation while not exceeding the 45° limitation of the X and
Y geophones. For the study of anisotropy and analysis of split shear,
these features make the ASI tool reliable in both vertical and deviated
wells, with consistent X and Y component response.
The ASI tool is unique in that it ensures consistent, lengthy
coupling periods during downhole seismic acquisition, both in
vertical and deviated wells. This feature makes the ASI tool ideal
for 2D and 3D time-lapse borehole seismic surveys, reservoir monitoring
applications and amplitude variation with offset (AVO) calibration
walkaways.
Applications
The ASI can acquire three-dimension walkaway vertical seismic
profile (VSP) surveys in both vertical and deviated wells. One
of the primary benefits to IODP is its low deployment time, since
multiple geophones are deployed simultaneously.
Tool Specifications
| Temperature rating: |
350° F (175° C) |
| Pressure rating: |
20 kpsi (13.8 kPa) |
| Diameter: |
3.375 in (8.57 cm) |
| Minimum tool length: |
280 ft (85 m) |
| Sampling interval: |
1, 2 and 4 msec |
| Maximum Logging Speed: |
Stationary |
Deployment Notes
The standard ASI tool can be used in cased holes without special
equipment. Adding a bowspring assembly allows surveying of open
holes from 8 1/2 to 13 in (21.5 to 33 cm).
Stuck/lost tool information
* ®trademark of Schlumberger
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