TY - JOUR
T1 - On the origin of crevasse-splay amalgamation in the Huesca fluvial fan (Ebro Basin, Spain)
T2 - Implications for connectivity in low net-to-gross fluvial deposits
AU - van Toorenenburg, Koen
AU - Donselaar, Rick
AU - Noordijk, Niels
AU - Weltje, Gert Jan
PY - 2016
Y1 - 2016
N2 - Floodplain deposits are abundant in low-gradient dryland river systems, but their contribution to connected reservoir volumes has not yet been fully acknowledged due to their poor detectability with typical wireline log suites and relatively-lower reservoir quality. This study presents an analysis of stacked crevasse splays in the distal part of the Miocene Huesca fluvial fan (Ebro Basin, Spain). Vertical stacking of crevasse splays implies local aggradation of the active channel belt. Lateral amalgamation of crevasse splays created an elevated rim around their feeder channel, raising its bankfull height. Subsequent crevasse splays were deposited on top of their predecessors, creating sand-on-sand contact through incision and further raising the active channel belt. This process of channel-belt super-elevation repeated until an upstream avulsion occurred. Amalgamated crevasse splays constitute connected reservoir volumes up to ~ 107 m3. Despite their lower reservoir quality, they effectively connect channel deposits in low net-to-gross fluvial stratigraphy, and hence, their contribution to producible volumes should be considered. Unswept intervals of amalgamated crevasse splays may constitute a secondary source of natural gas. Their interval thickness can serve as a proxy for feeder-channel dimensions, which can in turn be used to estimate the degree of stratigraphic connectivity.
AB - Floodplain deposits are abundant in low-gradient dryland river systems, but their contribution to connected reservoir volumes has not yet been fully acknowledged due to their poor detectability with typical wireline log suites and relatively-lower reservoir quality. This study presents an analysis of stacked crevasse splays in the distal part of the Miocene Huesca fluvial fan (Ebro Basin, Spain). Vertical stacking of crevasse splays implies local aggradation of the active channel belt. Lateral amalgamation of crevasse splays created an elevated rim around their feeder channel, raising its bankfull height. Subsequent crevasse splays were deposited on top of their predecessors, creating sand-on-sand contact through incision and further raising the active channel belt. This process of channel-belt super-elevation repeated until an upstream avulsion occurred. Amalgamated crevasse splays constitute connected reservoir volumes up to ~ 107 m3. Despite their lower reservoir quality, they effectively connect channel deposits in low net-to-gross fluvial stratigraphy, and hence, their contribution to producible volumes should be considered. Unswept intervals of amalgamated crevasse splays may constitute a secondary source of natural gas. Their interval thickness can serve as a proxy for feeder-channel dimensions, which can in turn be used to estimate the degree of stratigraphic connectivity.
KW - Low-gradient dryland river systems
KW - Low net-to-gross fluvial stratigraphy
KW - Huesca fluvial fan
KW - Crevasse splays
KW - Stacking mechanism
KW - Connectivity
U2 - 10.1016/j.sedgeo.2016.08.008
DO - 10.1016/j.sedgeo.2016.08.008
M3 - Article
SN - 0037-0738
VL - 343
SP - 156
EP - 164
JO - Sedimentary Geology
JF - Sedimentary Geology
ER -