--> Abstract: Understanding the Effect of Faulting on Production Forecasting & Reserves, Negage Field, Block 14 Deepwater Angola, by Kathleen Mabe, Luis Fernandes, Masroor Chaudhri, and Zhanat Sarsembayeva; #90072 (2007)

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Understanding the Effect of Faulting on Production Forecasting & Reserves, Negage Field, Block 14 Deepwater Angola

Kathleen Mabe1, Luis Fernandes2, Masroor Chaudhri3, and Zhanat Sarsembayeva1
1Chevron International Exploration & Production, Houston, TX
2Cabinda Gulf Oil Co. Ltd, Houston, TX
3Chevron Energy Technology Company, Houston, TX

The Negage field was the first discovery south of the Congo Canyon in Angola Block 14 by the contractor group consisting of CABGOC (the operator, a Chevron company) Sonangol P&P, ENI, GALP, and Total. Discovered in October 2002, Negage field is located in 4500 feet of water. The Congo River Canyon separates the Negage field from other Block 14 infrastructure, including the BBLT and Tombua-Landana developments. The reservoirs consist of high-quality deepwater turbidite channel sands of Miocene age.
Faults play a significant role in modeling fluid flow within many reservoirs. Over the past ten years, fault model construction has significantly improved in ease of use and capability to incorporate 3D characterization of faults with spatially-varying flow properties in reservoir simulation. Faults act as flow barriers by offsetting permeable strata and creating low permeability gouge. Conversely, faults act as flow conduits if continuous fracture and joint networks develop. Faults in the stratigraphic grid are modeled with split-nodes to capture cross-fault juxtaposition relationships. 3D fault variability is captured using a Vshale property conditioned to seismic and wells using principle component analysis. The fault geometry and Vshale property are used to estimate the impact on fluid communication in the model. Multiple examples of modeling faults in simulation will be discussed.
The important question of “when is a fault important to model in simulation?” will be addressed. Faulting uncertainties are prioritized using design of experiments and mitigation plans are developed to reduce associated risks with a deepwater development. Probabilistic fault seal cases are defined to determine the range in recoverable hydrocarbons.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece