RE: Why Would (Part 3 - isdeer)24 Sep 2022 10:37
Don’t worry I’ve found it now. Explanation below and I guess we have to hope that i3’s interpretation is the correct one:
geophysical investigation of well ties, tuning effects and amplitude analysis was undertaken to establish whether an amplitude response seen at Top Rødby is indicative of an oil-filled Captain Sandstone. Based on modelling, TRACS conclude that amplitudes cannot be reliably used as an unequivocal indicator of either fluid fill or net sand thickness. The seismic response is interpreted to be compromised by a ‘tuning’ effect, which is caused by interference of reflectors and is consistent with stratigraphic thinning at the northern edge of the basin. In the western part of the structure, where stratigraphic closure is required, TRACS consider the possibility of an alternative channel fairway edge with a more easterly position compared to i3. This is based on a change in observed seismic character in the western part of Serenity.
As a result, TRACS’ Mid and Low Case STOIIP assumes more limited lateral extent and continuity to the west (channel polygon) and uses net sand thickness assumptions that are guided more by the Serenity well result and seismic character than the Magnolia well data nearly 9km away from the Serenity well. Nevertheless, TRACS consider that other interpretations are credible and adopt the full i3 amplitude polygon and more optimistic net thickness assumptions for high case STOIIP inputs.
TRACS agree that an OWC as deep as 5270 ft tvdss is feasible but that a shallower OWC at 5130 ft tvdss is also possible given the pressure data available and associated uncertainty. TRACS consider a low to high case OWC range from 5130-5270 ft with a mid-point at 5200ft.
The TRACS STOIIP estimates are lower than the i3 Energy volumes and this can be attributed to:
1. smaller net sand thickness used by TRACS – driven by seismic character and observations in the Serenity and Tain wells
2. use of more limited sand polygon in the TRACS Low and Mid case – driven by seismic character
3. use of shallower contact in TRACS’ Low and Mid case; all 3 cases generated by i3 Energy use an OWC of -5270 ft tvdss