AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
3-D Characterization of Wave-Influenced Deltaic Reservoir Analogs: An Example from Ferron Notom Delta, Utah, USA
(1) University of Houston, Sugar Land, TX.
In order to perform better reservoir production prediction and management, accurately characterizing reservoir heterogeneities is critical. For deltaic reservoir heterogeneity characterization, the first key step is identifying the right type of delta based on the tripartite classification. The second key step is to appropriately characterize the heterogeneities of the identified deltaic reservoir type. Unfortunately, most reservoir modelers from industry often force-fit their particular deltaic reservoir into one of the end-member categories for simplification, even though those deltas are likely to be mixed-energy and plot somewhere within the tripartite classification. From the observation of modern deltas, many wave-influenced deltas show asymmetric features in both geometry and internal structure. Existing numerical deltaic reservoir model (tear-dropped geo-object) are symmetric. Using the symmetric delta model may not correctly capture the heterogeneities of asymmetric deltaic reservoirs. Three-dimensional characterization of wave-influenced deltas in outcrop can provide quantitative information for subsurface reservoir modeling.
Outcrops of the Ferron Notom Delta in southern Utah show the features of fluvial-, wave- and flood-mixed environment. Three-dimensional outcrop investigations provide an excellent reservoir analog for subsurface reservoirs in a similar depositional environment. The modeling area is a 14km ×14km square. The modeling interval is parasequence 6, which is interpreted as a wave-influenced (asymmetric) delta by previous workers. The ancient delta shows asymmetric features: the main feeding distributary channel separates the delta lobe into two asymmetric parts, the updrift shoreface and the downdrift fluvial-dominated portion.
This study collected 3D outcrop data to build numerical models for capturing the heterogeneity of the asymmetric deltaic reservoir analog. The static and dynamic properties of these models were investigated and compared with the traditional symmetric model based on same dataset. Finally, the major control parameters of heterogeneity of asymmetric deltaic reservoirs are analyzed. This study also includes reservoir rock physics study on deltaic seismic interpretation based on seismic forward modeling method.