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海底地层速度结构是识别海洋天然气水合物储层的直接依据,本文应用地震反射走时层析成像建立了海底地层速度模型.采用不规则网格对模型进行离散化,使速度单元与反射界面单元完全耦合;利用基于不规则单元波前扩展和走时插值的射线追踪方法,精确确定反射射线路径和反射波走时;在反演中同时使用先验约束、平滑约束、归一化和正则化技术,提高了层析反演的稳定性和结果的可靠性.对南海北部神狐海域SH2井附近的二维地震测线资料,利用多域人机交互法拾取了反射走时,用反射走时层析成像方法获得了SH2井附近含水合物目标区的速度结构.该反演结果与测井声波速度和钻探结果一致,其中的高速带对应水合物储层,表明反射走时层析成像能够有效地得到海洋天然气水合物储层的速度结构,为海洋天然气水合物储层识别提供依据.
Seabed strata velocity structure is a direct basis for identifying marine gas hydrate reservoirs. In this paper, the seabed stratigraphic velocity model is established by seismic reflection time-history tomography. The model is discretized by an irregular grid so that the velocity unit and the reflecting interface unit are completely Coupling; using ray tracing method based on irregular unit wavefront expansion and traveltime interpolation to accurately determine the reflected ray path and reflected wave travel time; in the inversion simultaneously using priori constraints, smoothing constraints, normalization and regularization techniques to improve The stability of the tomographic inversion and the reliability of the results are obtained.Seismic data of two-dimensional seismic near SH2 in Shenhu sea area of the northern South China Sea are picked up by multi-domain human-computer interaction method and analyzed by reflection time-lapse tomography Obtained the velocity structure of hydrate target zone near SH2 well.The inversion result is consistent with the logging acoustic velocity and drilling results, of which the high velocity zone corresponds to the hydrate reservoir, indicating that reflected traveltime tomography can effectively obtain marine natural gas The velocity structure of hydrate reservoirs provides the basis for the identification of marine gas hydrate reservoirs.