Application of seismic attributes and spectral decomposition for reservoir characterization of a complex fluvial system: Case study of the Carbonera Formation, Llanos foreland basin, Colombia

Abstract

Hydrocarbon exploration in the Llanos foreland basin of eastern Colombia has traditionally focused on structural traps. However, in the past decade, the country’s oil demand has generated an increased interest in exploration for stratigraphic traps. We integrated [Formula: see text] of 3D seismic data volumes with eight wells in the Central Llanos area to assess the reservoir potential of the fluvial channel deposits of the Late Eocene–Oligocene Carbonera Formation in the Casanare Province. Distinguishing nonproductive, mud-filled channels from productive sand-filled channels is of economic importance for hydrocarbon exploration because both channel types can exhibit a similar seismic character. Our interpretation of the fluvial sandstone and the reservoir identification was based on 3D seismic attributes, including coherence, curvature, and spectral decomposition, and the analysis of fluvial geomorphology. Analysis of stratal slices through coherence, isofrequency amplitude cubes, and curvature cubes revealed (1) a northeast-trending meandering fluvial system with changes in the rivers’ paleoflow direction from southwest to northeast during the period of the Late Eocene to the Early Miocene, (2) development of prospective sandy point bars, scrolls, and sand bar deposits, and (3) channel ridges and bases accentuated by differential compaction dependent on the channel’s filling material. Based on our attribute analysis, we were able to characterize nonprospective mud-filled channels versus prospective sand-filled channels.

Application of Spectral Decomposition and Seismic Attributes For Channel Geometry and Infill Lithology Determination: A Case Study from The Southern North Sea Basin

“…Sandstones and claystones are the main infill rock types of paleo channels [39]. Each of these lithotypes has different responses to compaction, hence the lateral changes that accompany compaction of a rock volume as it lithifies in a channel depends on the type of lithology [40,41]. Because shales compact faster than sand [40], a channel filled with sand and suspended in a shaly matrix may look like a mound or 'structural' high while a channel that is filled with shale in a sandier interfluve may appear as structural low [41][42][43].…”

“…Since coherence and curvature attributes are sensitive to tectonic deformation including incisement and differential compaction of stratigraphic horizons [35], we have used the coherence and curvature attributes in a complementary manner through co-rendering to discriminate shale versus sand lithologies based on differential compaction of the channels relative to their edges. In this approach, coherence attribute was used to enhance the channel edges, the most post-positive curvature attribute was used to delineate likely levees and flanks of the channels (red) while the most -negative curvature attribute delineates the edges of the channel (blue) [40][41][42][43].…”

3D seismic attributes and well-log facies analysis for prospect identification and evaluation: Interpreted palaeoshoreline implications, Weirman Field, Kansas, USA

“…7) of the seismic data. Similar cases where channels/palaeovalleys are associated with time anomalies and visible as both time and amplitude anomalies have been published (e,g., Torrado et al, 2014;Lu-Ping et al, 2010). Armstrong et al, (2001), in a modelling study provided an account on velocity "seismic time pull-ups" and "seismic time pushdowns" that are associated with higher and lower velocity, respectively, of sedimentation in channels.…”

Geomorfología sísmica y elementos en ambientes fluvio lacustres en un sector de los Llanos Orientales (Colombia)

“…En ellos se define la estratigrafía y tectónica de la cuenca, a partir de datos sísmicos y de pozos. En otros abordajes, se tienen aproximaciones aloestratigráficas [10], o trabajos con descripciones e interpretaciones, por ejemplo, litoestratigrafía y estratigrafía de secuencias [11] a abordajes secuenciales [12][13][14][15]. …”