Application of Seismic Attributes for Identification of Channel Sand Gas Reservoir beneath Volcanic Rocks: A Case Study from Oued Mya Basin, Algeria

Here we show a case study of applying seismic attributes combining seismic inversion to image channel sand body beneath igneous rock. The study area lies in the northeastern of Oued Mya Basin, Algeria, which is located at the northern Africa. It’s very difficult to locate channel sand body gas reservoir beneath volcanic rocks because of (1) the uncertainties and poor quality of seismic data due to the attenuation of volcanic rocks over the target layer; (2) target gas reservoir buried in depth in a range from 3000m to 4000m; (3) target layer is thin with thickness of less than 10m revealed by drills.

In this study, we present a suite of seismic techniques for imaging channel sand, which is considered as favorable gas reservoir. Firstly, we employed seismic interpretation including well-seismic tie, horizons interpretation, faults identification. The formation of gas reservoir is governed by low-amplitude structures. To reveal the distribution of channel sand body, we classified the litho-facies using well log data. We utilized seismic amplitude attributes and Neutral Networks Technology (NNT) to predict seismic facies in horizon. Additionally, seismic attributes, seismic attenuation, and constrained sparse spike impendence seismic inversion were conducted for better understanding the sedimentary and tectonic characteristics in study area and hence fine imaging the channel river sand body and prediction the favorable reservoir. The results demonstrate that a variety of seismic technique combining together can be valid for locating thin sand gas reservoir and thereby decreasing exploration risk. This study provides an alternative technique strategy for the identification of channel sand beneath volcanic rocks.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California