The Study Of The Relationship Between Seismic Attenuation And Pore Fluids

With the rapid development of oil and gas exploration,the research object is changing from structural reservoirs to lithological reservoirs.Up to now,the exploration towards lithological reservoirs has become the main exploration object in the continental basin of the west and east China.However,there are a lot of disadvantages in the exploration of lithological reservoirs since the cause of it is more complicated than the structural reservoirs,the style is of a wide range,most have a hidden form and occur with a larger change in the lateral and vertical directions.In addition,the exploration difficulty of lithological reservoirs is much larger because of the influence of reservoir quality and heterogeneity.So it is very necessary to study a method of recognizing the property of reservoir fluids.The rocks in the earth are all non-perfect elastic,the seismic waves are subject to attenuation in these medium.The attenuations fall into two types,intrinsic attenuation and non-intrinsic attenuation.The non-intrinsic attenuation is mainly caused by wave front diffusion,reflection or transmission attenuation,converted waves and multiples waves.The intrinsic attenuation has no connection with the propagation path but is related to the structure of rocks,the fluid properties of the fluids,porosity,permeability and saturation.Since the attenuation properties contain many features connected with the pore and fluid,it is a much more sensitive parameter for reservoir fluid recognition.The paper begins with the study of rocks attenuation models,studied the influence of pore fluid to the seismic wave by frequency analysis,attenuation parameters calculation and frequency-dependent AVO properties analysis.