Seismic Wave Modeling Under The Complex Marine Conditions

In recent years with the social development, the need of the energy resource isgetting more and more, especially the oil cannot meet the demand. Simply explorationfrom the land area has been unable to meet the need of oil and gas, which makesoil-gas exploration target shifts gradually from land to ocean. However with theconstant improvement of the marine oil-gas exploration degree, the difficulty ofexploration is also increasing. Marine oil-gas exploration and development are facedwith the transformation from simple structural to complex one, from the shallow seaarea to the deep areas. Deep oil and gas exploration has become a hot problem in themarine oil-gas exploration in recent years, with the difficulty of deep sea lowresolution, lower imaging reliability and lower reservoir evaluation in the process ofresearch.The seismic wave modeling is more complex than the common one. Because ofthe wind, the sea surface is always rugged. In addition, the physical properties of thesea should be considered in the deep area. In conventional Marine seismic exploration,the sea is regarded as homogeneous medium, where the speed of sound usually takes1500m/s. But as to the seismic exploration in the deep sea, the sea of acousticvelocity is affected by factors such as temperature, pressure and salinity, which is theformation of deep channel. In addition, there are a lot of suspended particles in water,such as aerosol, water vapor condensed matter and bubbles, etc. It makes the speed ofsound different with randomness and uncertainty. These small velocity anomalies cancause scattering and absorption of seismic waves. In view of the deep seismicexploration, it’s necessary to take these factors into account to the marine seismicwave modeling.In this paper accounting to the rugger sea surface and the velocity changing invertical stratification and the small scale abnormal, the marine seismic wave modelingused a rugged sea surface model based random media. The involved contents in this paper include four aspects, as follows:①Introduce the ocean physics propertiesincluding the rugged sea surface, the velocity changing in vertical stratification and insmall scales.②Summarize the development of random media and introduce themathematic principle. According to the factors talking above, model the rugged seasurface model based random media.③Summarize the modeling method to deal withthe rugged surface. And in this paper the non-equidistant difference scheme is used.④In the rugged sea surface random media, use the non-equidistant difference schemeto model the seismic wave propagation. After modeling the seismic wave propagationin the rugged sea surface random media and conventional model respectively, thencompare the kinematics and dynamics character differences of the modeling results.It’s obvious that the rugged sea-surface and the sea velocity changing have an effecton the seismic wave propagation. The result of this paper can provide a reference inthe marine seismic data processing.