Geometry analysis and oil reservoirs prediction in the Lower Cretaceous clinoforms of the northern Priobskoye field

Abstract

. Developing of the exploration criteria for oil reservoirs and non-structural traps in the clinoform successions are the key target as for detailed field appraisal in the West-Siberia basin well as for exploration in the clinoform complexes in the new sedimentary basins without drilling. Based on complex analysis of the seismic, well logs, well tests and core data in the northern Priobskoye field, the correlation between clinoform geometry, edge trajectory and distribution pattern of the reservoirs in the productive formation AS is established. The highest flow rates and reservoir properties are typical for bar deposits, proximal fan and slope channels. Deposits of bars are formed at the high stand system tract and at the beginning of the falling system tract on the edges of tangential clinoforms with gently ascending, flat and descending edge trajectory. Deposits of basin floor fans and slope channels are confined to the drop in the relative sea level and its low stand; it is advisable to search for them at the bottomset of tangential clinoforms with a descending edge trajectory and in gently cross-bedded clinoforms.

Sequence stratigraphy and palaeogeography of the Upper Jurassic and Lower Cretaceous in the Eastern Barents Sea

“…The J3 clastic wedge in the South Barents Sea Basin represents the same tectonic event and most likely connected to the Arctic Ocean opening, however, it is younger and might indicate a time lag in the response to the events. Figures 4, 5, 7, 12, 17 and 18. In the Lower Cretaceous succession of the West Siberia Basin, three main clinoform geometries are identified: (i) sigmoidal and tangential clinoforms with ascending to flat shelf edge trajectory that are relatively high relief (up to 180-300 m, without decompaction), (ii) tangential clinoforms with descending shelf edge trajectory and (iii) lowangle clastic wedges that have relatively high relief (up to 150-240 m without decompaction) (Babina et al, 2022), which corresponds to a relatively deep basin 200-400 m depth (Ershov, 2016;Kontorovich et al, 2014).…”

“…The distribution of the clastic reservoirs in the West Siberia Basin was controlled by depositional environments, which also impact which clinoform type developed in each area. In the bottomset of the tangential clinoforms with descending shelf edge trajectory, reservoirs are associated with basin floor fans (Babina et al, 2022;Borodkin & Kurchikov, 2015). On the edge of the tangential clinoforms with flat to descending trajectory, and also in the topset of sigmoidal clinoforms, reservoirs are interpreted to be associated with bars and deltaic distributary channels (Babina et al, 2022;Borodkin & Kurchikov, 2015;Ershov et al, 2001;Gurari, 2003).…”