Tight gas reservoir characterization from seismic attributes

Abstract

With the development of seismic technology, more and more seismic attributes come into being. More information than just time reflection is used to prospect hydrocarbon reservoirs. The study and interpretation of seismic attributes provided researchers with some details about geometry and physical parameters related to sedimentary facies, sands and fluids. In the prediction of tight gas reservoirs, seismic attributes analysis should be executed in a hierachical structure for staging objects (facies, sands, porosity and gas saturation) with different scales. A case study dealing with reservoir characterization is presented in this paper. 3D Seismic attributes have been used to map the reservoir facies and sand distribution in the area where identification of tight gas sands is a major challenge to development drilling. The whole process is divided into 3 steps - using waveform and coherence to delineate the sedimentary environment controlling the sands distribution, applying seismic amplitude analysis for sands predicting, combining acoustic impedance and corresponding logs to characterize porous and gassy sands. The above results ware validated by drilling a number of wells afterwards.