Methodology of Detecting Bright-Spot Gas-Bearing Reservoirs Using Amplitudes in Different Frequency Components Extracted From Seismic Data

A large amount of gas-bearing reservoirs, with a thickness of 2–8m, are developed in the shallow layer of BX oilfield. These gas-bearing reservoirs exhibit relatively strong seismic reflections called ‘bright-spot’. The water-bearing reservoirs with the tuning thickness have the same large reflection amplitudes, and interfere with the detection of thin gas layers. In order to solve the problem, this paper analyzes the characteristics of amplitudes of the water layers and gas layers in different frequency components extracted from seismic data, and use the amplitudes to detect gas layers with different thicknesses. The method is successfully applied on the prediction of the distribution of gas-bearing reservoirs in BX oilfield.