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Methods and Data for Accurate Digital Outcrop Model Construction Using from Upper Miocene Carbonate Complex, Las Negras, Spain

Benson, Gregory S.1; Bova, John 1; Putney, Kevin L.2; Wong, Pak 3; Gorman-Johnson, Imelda 2; Glover, Clare 3; Quevedo, Heather 4; Hinds, David 3; Stephens, Nat 4; Muratov, Nurlan 3; Franseen, Evan 5; Goldstein, Robert 5
1 ExxonMobil Upstream Research Company, Houston, TX.
2 ExxonMobil Exploration Company, Houston, TX.
3 ExxonMobil International, Ltd, Leatherhead, United Kingdom.
4 ExxonMobil Production Company, Houston, TX.
5 Department of Geology, University of Kansas, Lawrence, KS.

Outcrop analogs used for 3D geologic model construction and simulation can provide for improved understanding of fluid flow in carbonate systems, leading to better understanding and managing of hydrocarbon reservoirs. Superb exposures of Upper Miocene carbonate complexes in southeastern Spain provide an analog for heterozoan, fringing reef, and oolitic/microbial systems. An ExxonMobil team, in collaboration with the University of Kansas, conducted an integrated field study using high resolution photo mosaics, measured sections, and aerial photographs. One project goal was to construct a 3D outcrop-based geologic model to be used for reservoir characterization and simulation experiments testing the relative importance of facies and stratal geometries on fluid flow. The ExxonMobil team members were participants in one of the company’s continuing education programs designed to build expertise in carbonate reservoir characterization and provide experience in geomodel construction.

The outcrop (La Molata) is laterally continuous and exposed over a distance of 2 km. Key measured sections were recorded in strategically important locations to place important stratal surfaces, facies, geometries, and stacking patterns in the geologic model. Accuracy was assured by tracing facies, key surfaces, and strata in the field as well as on high-resolution photomosaics. GPS units and triangulation were used for accurate geospatial location of collected outcrop data.

Initial setup of the model in Petrel™ involved draping satellite imagery onto a topographic model (the interpretable “virtual outcrop model”). In addition, outcrop descriptions were digitized and imported as “log” curves (pseudo-wells). Structure surfaces were built on the major interpreted timelines. Environment of Deposition maps of the key stratigraphic units were interpreted and used to influence the location of rock types in the geologic model. Model cells were then populated with petrophysical properties based on data from measured sections, facies associations, cross sections, and oilfield analogs.

The resultant La Molata outcrop-based 3D Petrel™ model has been used in subsequent ExxonMobil-sponsored geologic modeling training courses and internal symposia to illustrate the methods of data collection, data processing, and construction procedures that are required to create an accurate 3D digital representation of an outcrop.


AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009