--> Abstract: Evaluating Water-Flooding Incremental Oil Recovery Using Experimental Design, Middle Miocene to Paleocene Reservoirs, Deep-Wat; #90063 (2007)

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Evaluating Water-Flooding Incremental Oil Recovery Using Experimental Design, Middle Miocene to Paleocene Reservoirs, Deep-Water Gulf of Mexico

 

Dessenberger, Richard1, Kenneth McMillen2, Joseph Lach1 (1) Knowledge Reservoir, Houston, TX (2) Consultant and Knowledge Reservoir, Sonoma, CA

 

Many deep-water Gulf of Mexico discoveries and field development plans of the past five years involve middle Miocene to Paleocene reservoirs with lower porosity and permeability resulting from compaction and cementation. Middle Miocene fields and discoveries include Atlantis, Neptune, K-2 and Shenzi. Eocene-Paleocene fields and discoveries include Great White, St Malo, Jack and Cascade. In this setting, rock compaction may be less important as a production drive mechanism, and aquifer support (possibly augmented by water flooding) assumes more significance. Porosity and permeability decrease is related to greater burial depth and compaction as well as temperature-related cementation. Structural styles of these fields include compressional anticlines, turtle structures and sub-salt three-way dip closures. Some of these structures are highly compartmentalized by faulting.

 

We used an experimental design approach to analyze dynamic simulation of two static models loosely based on the stratigraphy and reservoir properties from a thick-bedded middle Miocene reservoir (e.g. Tahiti Field) and a thinner-bedded Paleocene (e.g. Great White Field). Modeled variables included geological parameters (structural dip, faulting, facies and aquifer size), reservoir parameters (absolute permeability and heterogeneity), fluid properties and production variables.

 

The results of the dynamic simulation were evaluated using Experimental Design. The interpretation process involved five steps: identifying uncertainty parameters and ranges, running simulations for a wide variety of parameters, generating relationships of recovery factor as a function of uncertainty, identifying parameter importance and determining incremental oil recovery due to water injection. For these experiments, the incremental recovery for aquifer-supported fields is small with a P50 value of 7%. Key water-flooding variables are depofacies, aquifer size, permeability, fault transmissibility and oil saturation. The least important are bed dip, injection voidage-replacement, and PVT properties.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California