Extracting Stratigraphic Information from 3D: Exploiting the Seismic Data

Louis M. Liro and Kimberly Cline:Veritas DGC, Inc., Houston, Texas

Abstract

Sequence stratigraphy has evolved as a descriptive science largely based on investigations of well logs, 2D seismic (2D data and 2D sections extracted from 3D data volumes), and outcrop studies. Although these data sets may be utilized to define the sequence stratigraphic framework, they are not capable of fully describing the 3D sequence stratigraphic architecture. Detailed description of the 3D architecture is particularly important in field development and production models. We employ 3D visualization methods to supplement and enhance conventional techniques to identify significant surfaces and systems tract elements.

We present in this paper description and visualization methods for examining and describing sequences in the deepwater Gulf of Mexico. For exploration applications, we describe the sequence architecture through a deep mini-basin. Through-going events and surfaces are identified and auto-tracked through the basin. These surfaces are utilized as flattening surfaces, and visualization techniques (opacity, slabs, stacked vertical sections, coherency, etc.) applied to both these flattened intervals and the normal structural view to extract the stratigraphic geometry within each unit. Once the internal architecture is examined, surface and systems tracts interpretations are made.

For development applications, we identify the sequence stratigraphic architecture of a 3D seismic volume using a discovery well. The apparent sequence stratigraphic architecture in the well is compared to the seismic volume using visualization techniques in a fashion similar to the exploration application above. Extent of the reservoir unit, both hydrocarbon-charged and wet, is placed in a sequence stratigraphic context to assist with the reservoir development model.