塔中地区奥陶系典型地质体地震识别模式

The Seismic Wave Field Recognition Mode of Typical Geological Bodies in the Ordovician in Tazhong Area

针对塔中地区奥陶系岩溶缝洞型储层类型多、埋藏深且非均质性强的难点,设计了符合实际地层条件的地震地质模型,对储集体内部结构和参数采用微小管网和孔洞组成的等效储集空间进行精细刻画。应用波动方程交错网格高阶有限差分法进行波场正演模拟,选用常规处理和波动方程叠前深度偏移处理方法,得到偏移剖面,验证储层解释结果。从振幅、相位和频率等信息分析模拟记录地震波场特征,研究储层与围岩接触关系以及储层内部结构的变化对地震波场特征的影响,建立了缝洞储层和火成岩的地震识别模式。该地区存在层状火成岩、火成岩颈、顺层侵入火成岩等地震反射特征,碳酸盐岩储层表现为表层弱振幅、空白反射结构和内幕中强振幅反射结构。

There are various types of fracture-cavity deeply buried reservoir with strong heterogeneity in the Ordovician in Tazhong area, The model is designed in accordance with real condition in Tazhong area. The complex fracture-cavity reservoir has been found to be equal to a geological model composed of staggered micro-network and cavity which can depict the inner fracture-cavity reservoir structure and parameters variation accurately, It applied the staggered-grid high-order finite difference method of wave equation forward modeling technology to simulate seismic wave field, and used the conventional processing methods and wave equation prestack depth migration to get the migration profiles. The interpretation＇ could be evaluated and verified by the migration result. The amplitude, phase and frequency information are used to analysis the seismic wave field characteristics. It studies that the reservoir location and structure variety effect on the seismic wave field. Then it combines the well-to-seismic relation and the seismic simulation response characteristics to establish the recognition mode. It identifies that the seismic response of layered igneous rock, volcanic neck and intrusive igneous rock exist in this area. It the inner of the carbonate illustrates the fracture-cavity reservoir seismic structure in the top surface and layer.