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This page contains general information about how to install an SOV. The overall architecture of the SOV system depends upon the objectives of the seismic monitoring program and the sensing array used as the seismic receiver. Pairing SOVs with fiber-optic distributed acoustic sensors (DAS), referred to as SOV-DAS, provides a highly repeatable, on demand permanent monitoring system for acquiring time-lapse vertical seismic profiles (VSPs). SOVs can also be paired with conventional surface sensors or buried DAS cables for reflection imaging. The number of SOVs required, their energy level, frequency content and optimal placement should be determined through a careful review of existing seismic data and predictive modeling of SOV seismic response. Near-surface conditions, as with any active source seismic method, can greatly impact the quality of the data collected and determine the source energy and stacking required to obtain acceptable data.
Class VI Solutions' SOV system is provided with the following components:
SOV foundation steel reinforcement
SOV motor(s) and motor fasteners
Direct burial 3-C geophone
SOV control panel
Solar powered seismic recorder panel
A local processing server installed in the field can perform SOV-DAS data alignment, filtering, noise suppression, source-receiver deconvolution and stacking. Normally the workflow for data migration and time-lapse processing would be performed off-site.
The following list of equipment and materials should be locally provided:
Excavation equipment to dig the SOV foundation pit
An augur to create a 5 m deep boring for geophone installation
Fabrication of a rebar cage around the supplied steel foundation reinforcement
Form work to shape the top of the concrete foundation pad
Concrete sufficient to fill excavated pit
Lifting equipment appropriate for transporting the SOV motors and installing them on the steel foundation reinforcement
Mounting poles or backboards for supporting the SOV control panel and seismic recorder panel
A torque wrench of sufficient capacity to tighten the SOV motor fasteners
WARNING: An SOV installation contains both electrical and mechanical hazards that can cause injury and death. Only qualified personnel should install and operate an SOV installation after they have an understanding of the hazards present. A lock-out tag-out system should be used to prevent the exposure of workers to electrical and mechanical hazards while an SOV is undergoing installation, adjustment or maintenance.
Images below show the installation sequence for an SOV
SOV Foundation Design
SOV Foundation Design
The SOV foundation is designed to transfer the compressive and shear loads generated by the vibratory motors through the reinforced concrete block and out into the surrounding formation. The weight and dimensions of the concrete block is determined by the maximum motor force and the strength of the near-surface soils. Stiffer soils allow for a more compact foundation block, whereas weaker soils and sands require careful attention to foundation design to prevent the block from moving excessively.
The supplied steel reinforcement has rebar welded onto the vertical wide flanged beams. The rebar should be tied into the surrounding rebar cage, which is typically a rectangular mat with a 12" spacing.
SOV Foundation steel reinforcements designed to hold a 15 T-force and 10 T-force dual motor SOV
3-C Geophone for direct burial - markings on the geophone show the orientation for the horizontal sensors
Foundation Excavation with the geophone location marked with an X prior to auguring the boring
Foundation Excavation after the geophone is installed in flexible conduit and buried at the base of the excavation
Installation of a rebar cage
Installation of the steel reinforcement and additional rebar ties along with form work to raise the concrete pad above grade
Placement of concrete in the excavated pit
The top surface should be damp cured
SOV control panel mounted on a 3" pole
Seismic digitizer (left), SOV control panel (center), and cellular modem tower (right)
Installing an SOV motor using a hydraulic torque wrench to fasten the bolts
These SOV motors are set on plates that allow for adjustment of the motor orientation
Once the motor is set on the foundation, the weights can be adjusted and torqued
The SOV control panel VFDs are connected to the SOV motor using VFD rated cable. The network is connected to the Ethernet switch in the seismic receiver panel and the control panel
After the SOV motors are installed, power and communication cables terminated, and seismic digitizer connected, the system is now ready for commissioning. The motors when first installed have a break in period, and need to be operated for several hours at low power before increasing to full power. This picture is from the CO2CRC Otway Project, in Victoria, Australia
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