Abstract: Seismic Facies Maps: A Quick Exploration Tool

ADDY, SUNIT K. , CGG Petrosystems, Houston, Texas

The concept of tying seismic facies with well information and predicting lithology away from the well using seismic facies map has been used successfully in several instances. But in most cases seismic facies maps are results of a process of visually recognizing the reflection patterns in the seismic data and classifying them into descriptive classes such as, continuous, sigmoidal, discontinuous, hammocky, transparent etc. This is a process, which is painstakingly slow and interpretative. The maps are manually drawn and are subject to change from interpreter to interpreter. Since the shape of the seismic traces contain all relevant information, such as, reflection patterns, phase, frequency, amplitude etc., a classification of the trace shapes using the computational power of a modern computer should result into a similar map showing areas of similar trace shapes which can in turn be interpreted as a seismic facies map.

In this session, I would like to present a case history in which seismic facies maps were generated by Stratimagic, CGG Petrosystems' latest 3D stratigraphic interpretation system utilizing a neural network classification technology. The process is extremely fast and many facies classifications can be performed in a relatively short time for several horizon intervals in the seismic volume. This patented technology is licensed from Elf Aquitaine. In a 3D survey in central south Texas using seismic facies maps, we were able to identify porosity in Edwards limestone, define the Sligo reef trend, map complex channel systems in the upper Wilcox and Frio sections and determine the extent of lower Wilcox onlapping sands in the Lavaca channel.

The process is fast and the ability to create numerous facies maps quickly and repetitively in the beginning of an exploration phase enables the interpreter to effectively scan through the data and to concentrate in areas of significance.

AAPG Search and Discovery Article #90936©1998 AAPG Southwest Section Meeting, Wichita Falls, Texas