Research Of Parameter Evolving Common Reflection Point Stack

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.