THE APPLICATION OF SEISMIC ATTRIBUTES TO THE PREDICTION OF GAS HYDRATES

The seismic attributes, either describable or quantifiable, are regarded as the useful information derived from the original seismic data. The goal of seismic attribute analysis is to extract various characteristics from the seismic data for further study. The interstitial pores filled with gas hydrates may cause the change in physical attributes, making them completely different from those without gas hydrate fillings. Those changes would influence the condition of the seismic wave kinematics and dynamics, and further give rise to the variation in seismic attributes. In this article, we make use of the seismic data from the Northern Slope of South China Sea to extract the various seismic attributes for gas hydrate study, which include instantaneous amplitude, instantaneous phase, instantaneous frequency, relative polarity, energy half period, AVO1, AVO9 and wave impedance. Through establishing the relationship between the seismic responses and gas hydrate bearing sediments, we set up a model for recognizing the seismic attributes of gas hydrate-bearing sediments. In addition, by applying the means of statistics and cluster analysis with the results of seismic deduction, we try to carry out gas hydrate reservoirs forecasting, to reveal the planar distribution pattern of gas hydrate, and at last to provide reliable guidelines for appropriate borehole positioning.