节点文献
参数展开共反射点叠加方法研究
Research of Parameter Evolving Common Reflection Point Stack
【作者】 周青春;
【导师】 刘怀山;
【作者基本信息】 中国海洋大学 , 海洋地球物理学, 2009, 博士
【摘要】 零偏移距剖面在地震资料处理及质量控制、解释和反演各个阶段都占有重要地位,是非常重要的中间成果。获得零偏移距剖面的方法有很多,本文根据前人的研究,简述了几种主要的获取零偏移距剖面的方法(共中心点动校正叠加、倾角时差校正叠加、叠前偏移和共反射面叠加等),指出它们各自的作用和优缺点。在此基础上引出椭圆展开CRP叠加方法。椭圆展开CRP叠加方法具有一定的特殊性和新颖性。它摈弃了传统的CMP抽道集和动校正叠加的思想,从射线理论出发,采用信号的椭圆展开和包络线干涉叠加成像技术,在叠加过程中同时求取准确的CRP叠加速度。当地下为均匀介质覆盖时,无论地下反射界面的形状如何,椭圆展开CRP方法求取的速度就是介质的真实速度,所获得的叠加剖面是真实的零偏移距剖面。该方法对CRP成像方法和速度估算方法的研究有重要的参考价值。椭圆展开CRP叠加方法基于水平地表和均匀地下介质的假设,限制了该方法对复杂地区地震资料的成像能力。本文根据复杂地区的地震勘探难题,通过引入一系列的参数对椭圆展开CRP叠加方法进行改进,获得了包含三种叠加方法(椭圆展开CRP叠加、双参数展开CRP叠加和基于起伏地表的椭圆展开CRP叠加)的参数展开CRP叠加方法。取得了三项理论研究成果和三项应用技术创新成果。①推导论述了椭圆展开CRP叠加方法。详细研究了椭圆展开CRP叠加方法的理论基础——影像展开、切变换和三元论,推导了椭圆展开CRP叠加算子,讨论了椭圆展开CRP道集抽取和叠加实现方式。指出了椭圆展开CRP方法可以实现非规则观测系统成像的理论根据,形象的展示了其覆盖次数高于常规CMP方法的原因。讨论了速度分析的基本原理和实现方法。结合理论模型和实际地震资料处理试算证实,均匀介质条件下椭圆展开CRP方法所求得的速度是真正的共反射点叠加速度,所获得的叠加剖面是真正的零偏移距剖面,利用该方法得到的成像效果优于传统CMP方法。②推导实现了双参数展开CRP叠加方法。基于有效性概念,推导得到了适应于非均匀介质的双参数展开CRP叠加算法,并提出了相应的转换波计算方法原理。为了提高椭圆展开CRP方法对非均匀介质条件的成像和速度求取能力,引入反映速度横向变化的双参数(上行波与下行波速度的平均速度和速度比)对算法进行改进。论述了双参数展开CRP道集抽取和叠加实现方法,讨论了速度分析方法、实现和优化方法。理论模型和实际地震资料试算证实,改进后的算法尽管仍然使用了近似,并且也有一定的适用限制,但是它对实际地质地球物理场的近似程度更好,取得的处理效果也更好,向理想状态迈进了一大步。③首次研发了基于起伏地表的椭圆展开CRP叠加方法。研究分析了复杂地表问题对地震资料成像的极坏影响和已有解决方法的优缺点。研究并提出了基于起伏地表的椭圆展开CRP叠加方法。论述了基于起伏地表的椭圆展开CRP时间校正原理,讨论了时间校正后叠加成像实现方法,研究了相应的速度分析方法。理论数值模型和实际地震资料试算证实,利用该方法可以实现起伏地表条件下直接的椭圆展开和时间校正叠加成像,无需事先进行任何静校正处理,只需事先将炮点、检波点的准确坐标和高程、炮点井深等信息记录在固定的道头字内即可。目前,该方法已基本实现,但还需进一步的研究和改进。④进行了参数展开CRP叠加方法的应用研究,形成三套创新性应用技术。非规则观测系统地震资料成像技术。通过对椭圆展开CRP叠加方法的研究,找到了该方法可以实现非规则观测系统地震资料成像的理论依据,并通过非规则观测系统的单点数值模型(水平地表和起伏地表)和复杂地下构造模型(水平地表和起伏地表)论证了该技术的理论可实现性。复杂地表表层结构调查技术。充分发挥参数展开CRP方法速度求取准确的先天优势,研发了MEECRP技术来估计表层速度分布和对表层做校正。帮助解决复杂地区的静校正问题。多属性参数剖面综合进行含油气检测技术。参数展开CRP方法求取的速度与反射界面的形状无关,具有实际地质意义。由此得到的平均速度、层速度、速度梯度等属性参数含有丰富的地质信息,可以利用它们方便直观地分析识别速度异常体、进行地应力的研究等,进而综合进行含油气检测。实际生产中,该技术已取得不少地成功实例,具有很好地推广和使用价值。
【Abstract】 It is well known that zero-offset section is very important in seismic data processing and interpretation, which is also the objective of conventional CMP (Common Midpoint) stack. There are many methods to obtain zero-offset section. The paper briefly outlines several main stack methods (NMO (Normal Moveout) stack, DMO (Dip Moveout) stack, prestack migration, CRS (Common Reflection Surface) stack, et al.), and introduces their respective advantages and disadvantages. Then, the ellipse evolving common reflection point (CRP) stack is brought in with innovation and distinction, which abandons conventional CMP gathering and NMO stack. Based on ray theory, the ellipse evolving CRP stack adopts the technology of ellipse evolving and envelops intervening and stacking to image. When the media were homogeneous, velocity calculated by ellipse evolving CRP is the real velocity of media, as well as the stack section is the real zero-offset section. Ellipse evolving CRP stack has important reference value to study CRP imaging and velocity estimating.Ellipse evolving CRP stack has several theoretical limitations—horizontal surface and homogeneous subsurface media, which limit its imaging ability in complex areas.Rooted in solving seismic exploration difficulties, the paper introduces several parameters to improve the ellipse evolving CRP stack and obtains parameter evolving CRP stack, which includes three stack methods—ellipse evolving CRP stack, dual parameters evolving CRP stack and ellipse evolving CRP stack based on rugged surface. The author obtains three theoretical research results and three application technology results as follows:①the deduction and discussion of ellipse evolving CRP stack. The paper studies the theoretical foundation of ellipse evolving CRP stack—image evolving, contact transformation and trialistic theory, and deduces the stack operator of ellipse evolving CRP. The paper also discusses gathering and stack implementing, and points out the theoretical basis of irregular geometry seismic data imaging, it also explains why its folds are higher than conventional CMP’s, as well as the basic principle and realizing method of velocity analysis. The combination of theoretical model computing and seismic data processing confirms that velocity calculated by ellipse evolving CRP stack is the real velocity of CRP stack, as well as the stack section is the real zero-offset section. Therefore, the effect of imaging is markedly superior to that of conventional CMP method.②the deduction and realization of dual parameters evolving CRP stack. Based on the concept of effective parameter, the paper deduces the dual parameters evolving CRP stack in the heterogeneous media and presents the computing principle of converted-wave. The paper also discusses the gathering and stack implementing of dual parameters evolving CRP stack, as well as the velocity analysis and its optimization method. The combination of theoretical model computing and seismic data processing confirms that the effect of its imaging is superior to that of conventional ellipse evolving CRP stack.③research and development of ellipse evolving CRP stack based on rugged surface for the first time in the world. The paper studies and analyzes the effects of rugged surface, then it develops ellipse evolving CRP stack based on rugged surface. The paper also discusses the time differences moveout and stacking principle on rugged surface, and studies the velocity analysis of rugged surface. The combination of theoretical model computing and seismic data processing confirms that correct zero-offset section could be obtained directly by ellipse evolving CRP stack on rugged surface without any previously statics processing.④three application technologies deriving from parameter evolving CRP stack as follows:Imaging technology of irregular geometry seismic data. Theoretically, parameter evolving CRP stack could process irregular geometry seismic data, and of which the theoretical feasibility is proved by theoretical model (simple and complex, horizontal and rugged surface) computing. Investigation technology on complex surface structure. Take full advantage of velocity estimating of parameter evolving CRP stack to form micro ellipse evolving CRP (MEECRP) technology, and it can be used to solve the statics problem in complex area.Oil and gas detective technology with multi-attribute parameters sections. Velocity calculated by parameter evolving CRP stack has practical geological meaning, and gets rid of the shackle of reflection interface, thus, average velocity, interval velocity and velocity grads from parameter evolving CRP stack also have abundant geological meaning, which could be used in analyzing and recognizing oil and gas pools. Many tests confirm that this method is a good assistant method of reservoir prediction and oil and gas detection.
【Key words】 Ellipse evolving; CRP; Velocity analysis; Zero-offset section; Parameter evolving; Dual parameters; Rugged surface;