Geophysical Signature And Geologic Evolution Of Carbonate Platform In The Shelf Margin Of The Northern South China Sea

Three quarters of world's major oil and gas reservoirs was found in carbonate reservoirs .the reef carbonate platform is much developed in continental margin zone of the northern South China Sea, Since the Miocene the reef carbonate is development, and developed very quickly in this area. Dongsha massif in the East Pearl River Mouth Basin is the most typical area, and the carbonate in this area is a very important class of hydrocarbon reservoirs. As the complexity of carbonate properties and special development, the study of physical properties of carbonate rocks and the heterogeneity resulting in the process of development, which is with important theoretical and practical significance.In this thesis, Made a study of the seismic sequence of the northern margin of the South China Sea combined with regional geological data, seismic calibration with wells were fine, do much work of the evolution of sequence stratigraphy of the Pearl River Mouth Basin in the South China Sea. And my emphasis is upon the study of the physical characteristics of Dongsha massif carbonate platform, meanwhile discussed the heterogeneity of Dongsha massif carbonate rocks, by the analysis of the seismic attribute and seismic inversion with logging, doing some precise characterization of the heterogeneity of the reef carbonate. Get the following conclusion:1 ) In terms of the seismic reflection characteristics, carbonate platform performance is for the high amplitude reflection on top and bottom, the strong event at the top and bottom for is regular reflection. reflection of the area in Dongsha massif showed the internal of the strength and weak reflection, the event is horizontally relatively discontinuous, there is serious dislocation horizontal and the vertical2)Geophysical characteristics of the study area, carbonate platform was strongly acousic impedance is greater than 9000(m / s)*(g / cc) ,in the part of lower speed changes, relative to the overlying shale and the lower sandstone ,The results show that there had probably existed a low-velocity anomalous region, the gamma curve expressed as low value, reflection coefficient and amplitude envelope attribute can be better used to characterize carbonate boundary.3) the seismic amplitude class properties can better used to characterize the heterogeneity characteristic of carbonate platform in Dongsha massif through a large number operations and experiments of seismic characteristic. By precise accuracy geological interpretation of the seismic, there are RMS amplitude, the average reflected energy and the properties such as coherence tomography slice can be used to characterize distributional characteristics of the carbonate heterogeneity , the seismic attribute analysis and inversion profile on the basis of further characterization of properties are researched.