Hydrocarbon-bearing reservoirs in heterozoan carbonate deposits currently lack the necessary predictive facies models and reservoir analogs for successful hydrocarbon exploitation. The Neogene heterozoan carbonate complexes of the Cabo de Gato region of SE Spain provide ideal outcrop analogs for modeling sedimentologic and reservoir properties of such deposits. A suite of sedimentologic models, a reservoir analog model, and a reservoir property database will be developed to provide data on the sedimentologic characteristics, statistical and geometric features of facies, reservoir character, and the controls of these attributes for heterozoan shoaling and abrading-upward cycles.

To demonstrate which sedimentological controls create the most economic portions of heterozoan reservoirs, the following hypothesis will be tested: 1a) Reservoir quality is greatest in coarse-grained facies at the base of each fining-upward Miocene cycle and downdip on Pliocene clinoforms because of coarse grain size; 1b) Reservoir quality is greatest in fine-grained facies from the Miocene cycle tops and updip on Pliocene clinoforms because of well sorting. 2) Alternatively, reservoir quality may not correlate with facies because of diagenetic alteration, yielding different relationships for non-dolomitic Pliocene and dolomitic Miocene strata.

Methods include measuring and describing proximal and distal vertical sections of the Miocene strata, and proximal to distal lateral transects in the Pliocene clinoforms. Lab work will include porosity and permeability analyses, 3-D reservoir modeling analyses, and quantification of sedimentologic variables.

These results will greatly enhance the understanding of heterozoan carbonates and aid in the prediction of reservoir character in current exploration and production of hydrocarbons from heterozoan reservoirs.