Barton, Mark¹, Ciaran O'Byrne², Carlos Pirmez², Brad Prather², Pieter Slik², Ru Smith³, Gary S. Steffens², Frans Van der Vlugt²
(1) Shell International Exploration and Production, Houston, TX
(2) Shell International Exploration and Production,
(3) Shell International Exploration and Production, Netherlands

ABSTRACT: Understanding Hydrocarbon Recovery in Deepwater Reservoirs: Modeling Outcrop Data in the Third Dimension

Deepwater outcrops provide valuable information on the presence and probability of occurrence of baffles and barriers to hydrocarbon flow within analogous reservoirs. Understanding the impact that these features have on fluid flow requires that two-dimensional outcrop data sets be extended into three-dimensional reservoir models. This is particularly important for complex deepwater channel reservoirs, whose large capital development expenditures drives the need for wells capable of delivering high ultimates at high rates. Several methodologies are used to construct realistic 3D models of turbidite channel architectures from 2D outcrop data with a few simple geologic rules.
Channel to inter-channel architecture is modeled in 3D by combining outcrop data on channel-form width and thickness, the proportion of channel to interchannel facies, channel-form density, and channel stacking patterns through time (compensating, laterally migrating, vertical stacking) with information on channel planform geometry (sinuosity, wavelength, amplitude). Intra-channel architecture is modeled in 3D by combining outcrop data on bed thickness, frequency and distribution of channel base drapes, frequency and distribution of intra-channel shales, and the cross-sectional infill geometry (layered, convergent, accretionary) with information on sand and shale bed lengths parallel to the channel axis. Petrophysical properties are assigned by facies from similar subsurface data sets.
Models honoring all these outcrop measurement statistics provide the ability to test scenarios that address specific variables that cannot be measured directly. Results of dynamic simulations in several deepwater outcrops illustrate the impact that various geologic features have on fluid flow and recovery efficiency.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.