Auditable volumetrics for fast and effective evaluation of hydrocarbon resources Within the newest release 2018.2, GeoTeric is enhancing the exploration workflow by introducing a ‘Volumetrics’ tool which allows calculation of oil and gas resource estimates at any point during horizon interpretation ...
This will be a two-part blog post focusing on ‘Validate’, GeoTeric’s Seismic Forward Modelling module that recently became available with the release of 2018.1. The tool is intended for interpreters to be able to easily test hypotheses by creating models that can be matched back to frequency decomposition results as well as reflectivity data.
This week’s post works through a simple example of testing a hypothesis using Validate. In the next post, we will go over some more advanced topics.
We begin by focusing on the Eskdale reservoir in offshore Australia’s Exmouth Basin. This field is comprised of deepwater channel sands compartmentalized by faults. We’ll be looking at the first exploration well, Eskdale-1 (Fig. 1), which found only residual oil in a 75-meter-thick sand package.
Figure 1: Gamma Ray and acoustic logs over the Eskdale reservoir in the Eskdale-1 well. Note the change in acoustic impedance at the “Intra_reservoir” marker.
Figure 2 shows a map view of the frequency decomposition RGB colour blend draped 10ms below the top of the Eskdale member. The Eskdale-2 well was drilled in a separate fault block and found economic oil, so the task of defining the reservoir extents both in terms of reservoir quality sand and fluid content becomes critical if the field is to continue to be appraised and developed. As evidenced by the map below, GeoTeric’s Frequency Decomposition attributes reveal many aspects of the depositional system. But the question has always been, “what do the colours mean?”. Validate can help answer that question.
RGB Blends of Frequency Decomposition results are very powerful in revealing fine details of the subsurface, but the amount of information that can be extracted from such blends depends on which band-limited response magnitude volumes are used as an input. Selection of the right frequencies depends on the interval, amount of detail and objective of the analysis.
GeoTeric’s Adaptive Horizons tool allows the user to intuitively and interactively edit a tracked surface or interpretation. This is done by identifying the mis-pick in the interpretation, selecting the “3D edit” icon, and re-interpreting the line (we recommend using Piecewise Tracking). This will then update the tracked surface in the surrounding area. The tick-box enables “3D Edit Override”, so any interpreted lines will be removed or overwritten. This is useful when the interpreted lines have been incorrectly positioned by the user.