海上地震勘探模拟实验研究及二次定位理论探讨

【作者】 杨正华；

【导师】 朱光明；

【作者基本信息】 长安大学 ， 地质工程， 2004， 博士

【摘要】 21世纪将是新一轮认识、调查和开发海洋的时代。由于海上石油天然气等矿产资源的巨大潜力,国际上对海上地震勘探开发和研究至今方兴未艾。但我国不仅在勘探技术上落后于发达国家,在实验模拟和理论研究等方面也有很大差距。目前,我国也很重视这方面的研究和开发,863计划也将《海上多波地震勘探技术研究》列为国家重大科技攻关项目,本文是该项目的后续研究工作。 本文以海上地震勘探模拟为主题,展开了一些物理模型实验模拟、数学模拟和理论方法技术等方面的研究。主要内容有以下四个方面。 1)海上地震物理模型实验研究:采用先进的模型实验手段,进行了陆地—海上拖缆—海底电缆联合实验模拟,共作实验项目达100项,在大量实验分析研究基础上,从物理模型的角度,对海上鸣震、转换波、多次波、广角反射、极性和水的吸收等进行了研究,并取得了一些新成果。同时取得了盐丘物理模型数据包4套。另外还发现了一个很难解释的震相,并对该震相做了详细描述和探讨。 2)海底数学模型模拟研究:以理论研究为基础,基于海底数学模型,从海底波特性和海底界面能量分配特征两方面进行研究。(1)建立了三层海底模型,重新推导了三层海底模型的位函数特解方程组和系数项方程,并对两层模型海底波特性进行了分析讨论。(2)推导了流-固界面反射透射系数方程式,并进行了相关模拟计算。着重对7种岩性海底地震波能量分配特征进行了数值模拟分析研究,取得了不同岩性海底对地震勘探影响的新认识。 3)物理模型正演模拟系统:尽管正演模拟的大型软件很多,但都不能方便地进行全波多震相模拟分析。针对这种现状和本次实验分析的需要,特研制了物理模型正演模拟软件系统。该软件的特色是可以灵活方便地进行全波多震相模拟,有助于正确识别震相,减少工作量,尤其适合海上地震勘探的正演模拟,具有较高的推广使用价值。 4)海上二次定位新技术研究:该问题在国内外是一个前沿性研究课题。本文在国内外首次提出并创建了近正四面体法二次定位原理。与常规方法相比,原理简单,能在众多的炮点数据中,优选炮点,最大限度地降低误差,有效地提高计算精度,减少计算时间。它在计算方法的关键技术上有所突破。更多还原

【Abstract】 21 century is a new era that another round of research and exploitation of ocean resource will start. Because of the huge amount of petroleum and gas below ocean floors, more and more attention is paid to the research and exploitation of marine seismic survey all over the word. But both the prospecting and modeling technology and the theoretical research are not as advanced as that in developed countries. Now the government has think much of the research and exploitation of ocean, and has arranged this subject as the national science and technology subject in 863 planning. This paper is the continue research of this subject.Aiming at the modeling of marine seismic survey, this paper studies the physical and mathematical modeling and the corresponding theory, the main content includes:1) Study on physical modeling of marine seismic survey: Using advanced physical instruments, the author models the combined acquisition process of land-streamer-OBC(ocean bottom cable) survey, tests more than 100 items, study the property of reverberation, converted wave, multiple wave, wide-angle reflection, polarity and the water attenuation by analyzing the mass of physical modeling data, and obtains some new results, moreover, the author also discoveries a mystical orientation and tries to discuss it. Such a full physical modeling research of marine seismic survey has not been reported in this country.2) Study on mathematical modeling of marine seismic survey: Based on the mathematical theory of ocean bottom, the author studies the property of seismic wave on ocean bottom and the distribution of the wave on the ocean bottom boundary. (1) Founding a ocean bottom model and deducing the grouped equation of its potential function and the equation of the coefficient and discussing the property of the seismic wave on ocean bottom under the circumstances of 2 layers. (2) Deducing the reflection coefficient equation on the boundary of liquid and solid and modeling the result. The different point of this research lies in that the author studies and models the distribution of the wave power on 7 different kind of ocean bottom and gets the new knowledge of the effect of different ocean bottom on marine seismic survey.3) Physical modeling soft system. Although there are a lot of large modeling soft, most of them are not satisfied with the need of the phase analyzing of multiple wave. Aimed at the need of the test, the author develops the physical modeling soft system which can be used flexibly to analyze the multiple phase of full wave and help to recognize the orientation and reduce the work and especially adapt to marine seismic survey modeling. So this soft is an innovation to some extent and is worth spreading for use4) Study on ocean secondary orientating. This problem is a preceding subject all over the world. This paper presents the principle of secondary orientating by approximate tetrahedron for the first time. Compared with the general methods, the principle of this method is simple and this method can select the shot among shot date, reduce the error maximally and cut the computing time. This method has some innovation about the key technology.更多还原