The GeochainTM VSP array has been designed for use in open and cased holes using standard 7 conductor wireline. The array is based on the field-proven ASR-1 downhole geophone and can be used in wells up to 25,000 psi (1,750 bar) and hole sizes from 3 1⁄2”-22” (89 to 559mm). The modular nature of the ASR-1 tool allows quick optimisation for various surveys ranging from high temperature deep well check shot to complex high sensitivity micro-seismic monitoring.
All the satellites’ locking arms open and close simultaneously and the entire string can lock into a 9 5⁄8” (244mm) well in only 30 seconds. All satellites have a failsafe arm mechanism for retrieval of the string in the event of power failure. All Inter-Tool Cables (ITC) use standard 7 conductor wireline. The cable heads have graduated weak links and composite pressure bulkhead connectors are used throughout. A rigid ITC (RITC) option is also available to preserve sensor orientation.
An optional TCU-2 tension head and motion detector provide real time surface read out to prevent tool hang up. A threshold alarm can be set to warn the wireline operator if tension or motion levels change. Full in-field processing is provided by our highly praised ACQ Software Suite featuring the latest VSProwess processing package.
Gamma Ray tool or CCL can be used for depth correlation and an auxiliary line is free for use with a downhole source or gyro tool. The system is tractor deployable for deviated wells.