Sub-Terra Surveys

A new concept in downhole compressional wave seismic sources offered for sale and rental.

Sub-Terra Surveys has recently been recognised for its innovative design with the award of the much coveted DTI Smart Award to develop the next generation of downhole seismic sources for the new millennium.

Encompassing a variable shot period and multi-frequency operation, the sPark seismic source now provides the operator with a choice of the right equipment for the investigation. Versatility is the key word in the design ‚ one set of equipment covers your shallow seismic applications, from cross-hole to VSP and borehole to shallow water applications.

This source operates from a battery power supply and enables surveys to be undertaken in remote locations afforded by its small size and light weight. The high power output (500 joules on 50 metres of cable) source provides an omni-directional compressional wave seismic signal at a frequency, between 400 Hz to 5kHz, selectable by the operator in the field.

In air-filled boreholes the Packer sParksonde enables the transmission of the compressional (P) wave signal. An expandable packer system couples the spark chamber to that of the formation from the surface control module.

Operating from the standard sPark control unit, the operator may choose the variable shot period for their survey.

SPECIFICATIONS

CONTROL UNIT

Size: 407 (W) x 254 (D) 229 (H) mm
Weight: 7 kg
Power: 24 V DC
Recycling period: 2, 3, 4, 5, 6, 8, 10, 20, 30 seconds
Remote operation: Remote push button or TTL pulse

sPark SONDE

Diameter: 42 80 (selectable ‚ 5 sizes) mm
Length: 420 mm
Power output:
500 Joules on 50 metres cable
Frequency: 400 ‚ 5000 (selectable) Hz
Weight: 2.0 kg

The operational frequency of the equipment can be extended to 100 Hz for use in large diameter boreholes or shallow water environments. This option is available to special order and interfaces with the standard downhole sPark sonde.

PACKER sPark CONTROL UNIT

Size: 250 (W) x 160 (D) x 150 (H)

Weight: 2 kg
Power: 24
Reservoir: 480 (H) x 170 (Diameter) mm
Inflation medium: Salt (NaCl) saturated solution

PACKER sPark SONDE

Diameter: 50
Length: 420mm
Power output: 500 Joules on 50 metres cable
Weight:2.5kg
Borehole diameter: 75 ‚ 150

The system is normally supplied with 50 metres of cable and hoses although its operation may be extended down to 100 metres. This extended operation is to special order.