Seismic Waveform Structure Feature Attribute Analysis Research

The fluvial face is an important depositional system in nonmarine environment, its sand body is good hydrocarbon pore volume. In hydrocarbon basin of Mesozoic Era and Cenozoic era of China, oil reserves of fluvial face sand body account for 46 percent of discovered reserves. The deposit characteristic of fluvial face forms complicatedly in cross direction, its lithologic character changes much. In vertical direction it presents sand and mud alternate layer. As fluvial face sand body thickness of one contributing factor unit is smaller than 10 meters, its ratio of breadth and thickness is smaller than 100, it is to say, the individual layer thickness of sand is small and horizontal change is complex, it is difficult to recognize sand directly because of the limit of seismic resolution. At the same time, the geophysics response between different rock types does not have obvious divergence, which increases the difficulty of fluvial face sand reservoir prediction further.Waveform is regarded as the original and ultimate manifestation of seismic exploration, it has much information, which is also the most complex attribute parameter. Conventional seismic attributes are calculated in one characteristic of waveform, which is hard to express the characteristic of reservoir discontinuity and relative change of waveform. Generally waveform consists of amplitude, phase and frequency. The predecessors have made more researchs on waveform figure, used geometric attributes to describe waveform and achieved some results. At the same time, full-waveform research has been developed, which is applied into research on seismic facies and sedimentary facies. This thesis researchs reservoir and hole fluid information of waveform by summary and modification of waveform seismic attributes, proposing a new concept of waveform structural characteristic attributes innovatively. At the same time, some sand models such as variation of sand thickness, superimposition boundary of sand and condition of mud intermediate layer will be designed to extract and analyse the waveform structural characteristic attributes, and analyse the recognition condition of waveform structural characteristic attributes to variation of sand thickness, superimposition boundary of sand and condition of mud intermediate layer and analyse the stability of waveform structural characteristic attributes. Finally the waveform structural characteristic attributes will be applied into actual work area. Proving the sensitivity of waveform structural characteristic attributes to sand thickness through attributes extraction and analysis and attributes optimization. At last, the waveform structural characteristic attributes will be used into predicting reservoir parameter. The coincidence rate of sand body thickness prediction involved with waveform structural characteristic attributes is higher than the coincidence rate of sand body thickness prediction uncovered with waveform structural characteristic attributes, the accuracy of prediction of sand body thickness is more than 75 percent.