Taking the risk out of a seismic survey

HiSeis' Derisking Model

Seismic services potentially offer substantial value to the minerals industry in a range of environments but there are some applications and environments not suited to seismic imaging. HiSeis has developed a derisking process which applies increasing levels of expenditure with increasing levels of confidence that the method will address the exploration problem. The process is summarised below:



Rock Property Measurements  

The first step is to measure the properties which control the seismic response of the rocks within a range of core samples that represent the target geology. The properties affecting the seismic response of the geology are density and velocity. The product of these two properties is the acoustic impedance.



If favourable results are achieved in the rock property analysis, these measurements are used to create synthetic seismic models. The modelling of the predicted geological scenario is used to determine the behaviour of the reflections at the lithological interfaces and identify where propagating seismic energy can be detected.


Down-hole Surveying 

If the above two milestones are achieved and the synthetic models indicate the detection of seismic energy, borehole seismic methods: Full Wave Sonic (FWS) and Vertical Seismic Profiling (VSP) measurements will be recorded in approximately 3 holes. The FWS tool measures in-situ seismic velocities every 10cm. The VSP data will determine whether the mineralisation is reflecting the seismic energy and whether the reflections reach the surface. In addition, these datasets are used to control and inform the processing and interpretation of the complete seismic dataset.



Site Visit / Noise Assessment

This part of the process can be carried out at the same stage as the down-hole surveying. This involves assessing the noise level with a geophone and noise monitor.  At this stage, scoping of the area takes place to determine terrain suitability and potential survey line locations.   


Seismic Survey  

With positive results from the above processes, the risk of not mapping the mineralisation with a properly designed seismic survey is significantly reduced. From here, it will be determined whether 2D or 3D seismic will best suit the exploration problem and the design phase of the survey begins.