Analysis And Application Of Seismic Wave Attenuation Characteristics Inyakela 3-D Survey

A number of structural oil and gas reservoirs have been found on the Yakela anticline structure which is in the middle of the Yakla fault in the Shaya uplift in the northern Tarim Basin,showing good petroleum geological conditions.However,facing the increasingly protruding complexity and concealment of exploration objects,it is difficult to ensure the authenticity of the existence of oil and gas reservoirs only by analyzing the geological elements of traps.Therefore,the effectiveness of traps should be further ensured by means of seismic hydrocarbon detection.Based on this,this paper has carried out seismic hydrocarbon detection research and trap element analysis in the three-dimensional area of Yakela anticline.Based on the 3D seismic observation data and drilling oil and gas geological data of the known anticline reservoirs in the Yakla bulge in the northern Tarim Basin,based on the theory of sequence stratigraphy and petroleum geology,the gas-bearing layer is predicted by the frequency-dividing attenuation property.As the main technical method,it predicts the possibility of oil and gas accumulation in the Yakla area.When the seismic wave passes through the gas-bearing formation,its longitudinal wave attenuation intensity is significantly larger than that of other fluid-bearing formations.The low-frequency component is relatively enhanced,the high-frequency energy is relatively low,and the dominant frequency moves toward the low-frequency direction.The higher the gas saturation,the stronger the attenuation and the lower the main frequency,so the energy difference in the gas-bearing formation is negative compared with the non-gas bearing layer.The discrete Fourier transform method is used to decompose the time domain Yakla 3D seismic data into discrete data energy bodies with a frequency domain interval of 5Hz.The spectrum energy difference method is used to calculate the layer and region of the attenuation anomaly along the layer.Hydrocarbon detection for the target horizon.Combined seismic wave attenuation theory and geological conditions analysis,this thesis made a trial study in yakela in order to find non-structural reservoir.First of all,studying the condensate reservoirs in the Lower Cretaceous of yakela by using the method of seismic wave attenuation,then finding attenuation in other formations in this area by using this method.We can discoverer attenuation area in Suweiyi Formation.After analyzing the structural and sedimentary facies,maybe it is a fault nose trap reserve.The analysis of proved gas shows that the flat area between condensate gas reservoir and gas-water layer in Yakela and attenuation anomaly basically tallies.It works well in dentitying formation and area through the method of seismic wave attenuation,however thickness of gas bearing formation.trap closure and attenuation intensity without overt linear relationship.The area of petroleum reservoir is about 35km~2,the closure height is 100m,and the gas layer is35m in Suweiyi Formation by using the method attenuation and trap analysis,it has certain scale.good reliability and exploratory drilling potential.The hydrocarbon detection technology provides a reference for the search for hidden traps in the Tabei area,which can achieve focus and precision research in the target area and improve the effectiveness of trap exploration.