塔里木油田奥陶系碳酸盐岩缝洞储层的定量地震描述

Quantitative Seismic Characterization of Ordovician Fracture-Cavity Carbonate Reservoirs in Tarim Oilfield

综合地震数据、地下的测井和钻井资料,对塔里木盆地中—下奥陶系的碳酸盐岩缝洞系统进行三维的空间雕刻和描述。利用地震数据,提取地震几何属性,成像和描述了与岩溶储层相关的地质特征,这些特征包括了岩溶河道、溶洞、平面的圆形或椭圆形断裂特征和裂缝通道等。地震相分析可以用于确定主要岩溶特征,如溶洞和裂缝通道的空间分布及其地震几何属性的门限值;构建构造网格模型并使其与地震数据有同样的分辨率,可以有助于准确地模拟岩溶储层的地质特征;对主要岩溶地质特征(溶洞和裂缝通道)的空间连通性进行分析,可以建立缝洞连通体的空间结构模型;通过测井相分析以及通过井的地质资料、成像测井和钻井资料对其标定,可以建立井的储层类型地质模型;通过地震的约束及测井信息,利用建模技术可以描述储层内部的非均质性,如储层类型和孔隙度分布的地质模型;与缝洞连通体的空间结构相结合,可以得到缝洞连通体的储层地质模型。该研究介绍了定量地震描述方法在奥陶系碳酸盐岩缝洞储层中的应用,研究表明,对岩溶储层缝洞系统的定量地震描述,有助于进一步了解缝洞储层的地质成因及其对储层的地质控制作用。

3D spatial carving and description are conducted on Lower-Middle Ordovician fracture-cavity carbonate system in Tarim Basin, based on integrating seismic data, underground logging and drilling data. Seismic geometric attributes are extracted by utilizing seismic data to describe such geological properties as karst watercourse, karst cave, plane round or elliptic fracture features and fracture channel related to karst reservoirs. Seismic facies analysis could be used to confirm the spatial distribution of major karst features like karst cave and fracture channel and the threshold value of seismic geometric attributes. The geocellular model is constructed to keep the same resolution with seismic data, which could be helpful to simulate geological properties of karst reservoir accurately. The spatial connectivity of major karst features is analyzed to build the spatial structural model of fracture-cavity connectors. Log facies analysis and calibration with core data and borehole imaging logs lead to the definition of reservoir rock types at wells. Modeling techniques help to characterize reservoir heterogeneity such as reservoir types and porosities derived quantitatively from log information and conditioned with seismic impedance. Fracture-cavity connectors could be incorporated with spatial structure to obtain the reservoir geological model of them. This paper introduces the application of quantitative seismic characterization approaches to the fracture-cavity carbonate reservoirs of the Ordovician. It is shown that quantitative seismic characterization of karst reservoirs provides new understandings of reservoir origins and underlying geological determination.