Resolution enhancement with relative amplitude preservation for unconventional targets

Abstract

Our primary objective was to evaluate a method that enhances the resolution of 3D seismic data that does not disturb the relative amplitude preservation. The formations that are the subject of the analysis are Lower Silurian: the Jantar Formation and the Ordovician Sasino Formation (the onshore part of the Baltic Basin, northern Poland). Both formations are seismically thin layers and have been recent targets for unconventional exploration. Resolution enhancement designed to help the structural interpretation may enable precise structural interpretation of thinly layered intervals. The method that we applied is poststack spectral blueing. To verify the effectiveness of the spectral blueing procedure, we designed an algorithm that compares the amplitude values along evenly distributed seismic traces. The algorithm addresses the preservation of the relative amplitude ratio. We did not want to disturb the amplitude values by the enhancement algorithm and introduce information that would be false for seismic inversion analysis. Hence, it was crucial for us to obtain the enhanced seismic volume suitable for structural interpretation that holds relative amplitude relation criterion. The algorithm helped obtain the optimal enhanced seismic volume that is preferable for the structural interpretation of seismic data and possibly could be used successfully for a seismic inversion process. With the optimal enhanced seismic volume, we were able to conduct a more accurate structural interpretation — an entirely new seismic horizon that indicates that the top of one of the formations under analysis was clearly visible and thus possible for interpretation. We applied the acoustic inversion to the original and the enhanced seismic data — the latter enabled the determination of two additional anomalous zones that had not been previously possible to distinguish within the seismic volume.

Seismic Signature of Transition Zone (Wolf Ramp) in Shale Deposits with Application of Frequency Analysis

“…More recent well data from other wells estimated the reservoir parameters with the total organic content (TOC) of the Llandovery profile to be at the averaged level between 1 and 6% TOC [14]. Within the study area, the volumetric kerogen content (VKER) of the Pasłęk Formation manifests stable level of about 4-5% [10]. The hydrogen index (HI) varies greatly across the East European Craton, and it is very difficult to indicate the exact type of kerogen by analytical methods due to the high maturity of the sediments [14].…”

“…Such processing would not modulate both amplitude relation and frequency relation [17,18]. More invasive processing sequences may introduce some frequency range [10] that will affect the response for a transition zone. For these reasons for spectral decomposition, we used a seismic volume without amplitude modulations and gain.…”

“…These two complexes are divided by the Variscidian gap that ranges from the Devonian to Carboniferous. The lithostratigraphic profile of the Paleozoic sequence is presented in Figure 6, and a more detailed description of the region can be found in recently published papers [10,11]. Within this sequence, there were two possible shale gas reservoirs-the Sasino claystone formation of Upper Ordovician and the Pasłęk Formation of Lower Silurian (Aeronian-Telychian).…”

Relative amplitude preservation in high-resolution shallow reflection seismic: a case study from Fore-Sudetic Monocline, Poland

“…In the case of imaging shallow exploration targets and lithofacial analysis, it is crucial not to disturb the relative amplitude ratios which are almost impossible to interpret when a seismic wavelet is distorted. Petrophysical parameter determination relies on amplitude value and its changes (Dec and Cichostępski 2017a, b;Kwietniak et al 2018), so it is highly necessary to keep seismic with relative amplitude preservation (RAP) versions for such purposes.…”

Rock physics modelling for determination of effective elastic properties of the lower Paleozoic shale formation, North Poland

“…Brittleness index based on elastic properties of Ordovician and Silurian shales from the Baltic Basin was calculated by Bała Jarzyna et al (2017a), Liana and Papiernik (2017) and Cyz et al (2018). Method of resolution enhancement of seismic data to aid structural interpretation of sweet spots within seismically thin formations in the Baltic Basin was proposed by Kwietniak et al (2018).…”