AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Using a Numerical Forward Model to Investigate Stratigraphic Onlap Traps in a Deepwater Field. Marlim Case Study
(1) Shell International Exploration and Production, Houston, TX.
(2) Civil Engineer Department, University of South Carolina, Columbia, SC.
In this work we describe a series of numerical simulations that have been performed in order to investigate the stratigraphic trap that characterizes the Marlim reservoir. Simulations are made using a physics-based model called TCsolver that represents, at this date, the most advanced model for the fluid flow simulation of turbidity currents at field scale. Due to the computational cost of the model, investigation is at bed scale (single event).
Simulation results show deposits created by spilling from the levees and from the flow expansion from the channel to the basin system. Interaction between the two types of deposits creates relatively complex inter-fingering of levee and fan deposits.
The results indicate that channel relief is an important variable controlling grain size variation and distribution in the levees. A low relief channel allows for a relatively coarse grain size to be spilled onto the levee, reducing the sealing capacity of the stratigraphic pinchout in that area and potentially creating an updip waste zone that goes far beyond the anticipated edge of reservoir. A higher relief channel spills finer material onto the levees, resulting in reduced lateral seal risk and updip (and perhaps vertical) communication with other sand systems. This observation is crucial in systems like Marlim, where the decapitation of feeder systems by mud-filled channels or faults is the critical trapping element. The lateral pinchout down-dip of the feeders is primarily determined by the flow expansion in the basin.