A detailed study of modern washover fan (fan) morphologies will clarify common fan geometries, lead to a better model for a “typical” fan, identify the preservation potential and probable geometries of fan facies in subsurface datasets and outcrops, and ultimately improve hydrocarbon recovery in barrier island reservoir systems. This study uses satellite imagery to conduct a spatial analysis of 118 modern fans to quantify geomorphologic attributes of fans. A new classification scheme for fans is proposed that refines the current fan model, dividing fans into channelized and non-channelized fans. Channelized fans are subdivided according to the location of primary deposition: barrier depo-center or lagoonal depo-center. Non-channelized fans are subdivided based on morphology: dissipative, lobate, or apron-sourced. Quantitative cross-plots of morphologic relationships are analyzed to define trends in fan morphologies. The most common type of fan encountered in our study is a non-channelized, line-sourced, lobate washover fan with an area of less than 1 km2 that is fully contained on a barrier and exhibits no subaqueous deposition in back-barrier waters. The Lower Cretaceous McMurray Formation is the primary reservoir of the Athabasca Oil Sands in Alberta, Canada. The upper McMurray is commonly interpreted as deposits of embayed coastal systems. Our location is in an under-studied area located 80 km northwest of Fort McMurray. Lateral and vertical facies changes, sedimentary structures, key surfaces, trace fossils, and bitumen saturation were documented in eight cores located along a 20 km transect situated paleo-landward of a Devonian paleo-high acting as a bedrock-barrier. Our data indicate that a flood tidal delta complex prograded landward into a back-barrier embayment through the stable, bedrock-controlled inlet. This system overlies middle McMurray fluvial sands and Devonian basement and was transgressed by marine waters prior to deposition of the overlying Wabiskaw Formation. Flood tidal delta sandbodies are bitumen saturated and therefore make good reservoirs; however, heavily bioturbated tidal flats can act as a barrier to flow where they encase flood tidal deltas, as encased sands were devoid of bitumen. This complex coastal paleogeography produced back-barrier deposits that contain a slightly more diverse, marine trace fossil assemblage than might otherwise be expected. / text

The principle source of heterogeneity affecting flow behavior in conventional clastic reservoirs is discontinuous, low-permeability mudstone beds and laminae (shales). Simple ‘streamline’ models have been developed which relate permeability anisotropy (kv/kh ) at the reservoir scale to shale geometry, fraction, and vertical frequency. A limitation of these models, especially for tidally-influenced reservoirs, is the lack of quantitative geologic inputs. While qualitative models exist that predict shale character in tidally-influenced environments (with the largest shales being deposited near the turbidity maximum in estuaries, and in the prodelta-delta front), little quantitative shale character data is available. The purpose of this dissertation is to collect quantitative data to test hypothetical relationships between depositional environment and shale character and to use this data to make geologically-based estimates of for different reservoir elements. For this study, high-resolution, lidar point-clouds were used to measure shale length, thickness, and frequency. This dissertation reports a novel method for using distance-corrected lidar intensity returns to distinguish sandstone and mudstone lithology. Lidar spectral and spatial data, photo panels, and outcrop measurements were used to map and quantify shale character. Detailed shale characteristics were measured from four different tidally-influenced reservoir analogs: estuarine point bar (McMurray Formation, Alberta, Canada), tidal sand ridge (Tocito Sandstone, New Mexico), and unconfined and confined tidal bars (Sego Sandstone, Utah). Estuarine point bars have long (l=67.8 m) shales that are thick and frequent relative to the other units. Tidal sand ridges have short (l=8.6 m dip orientation) shales that are thin and frequent. Confined tidal bars contain shales that are thin, infrequent, and anisotropic, averaging 16.3 m in length (dip orientation). Unconfined tidal bars contain nearly equidimensional (l=18.6 m dip orientation) shales with moderate thicknesses and vertical frequency. The observed shale geometries agree well with conceptual models for tidal environments. The unique shale character of each unit results in a different distribution of estimated . The average estimated kv/kh values for each reservoir element are: 8.2*10^4 for estuarine point bars, 0.038 for confined tidal bars, 0.004 for unconfined tidal bars, and 0.011 for tidal sand ridges. / text