地震波形相控反演在天草凹陷白垩系薄储层预测中的应用

Application of Seismic Waveform Facies-Controlled Inversion in the Cretaceous Thin Reservoir Prediction in Tiancao Sag

针对银额盆地天草凹陷东部缓坡带白垩系巴音戈壁组油藏含油储层薄、横向变化快,常规反演无法有效识别等问题,采用天草地区"两宽一高"三维地震资料,井震结合,运用地震波形的聚类识别方法,对储层横向展布趋势进行合理表征;同时,应用频率域曲线重构技术,获得纵向高分辨率储层敏感曲线。在此基础上,利用地震波形相控反演方法精细刻画了巴二段薄储层展布特征,预测出自南向北发育的3个湖底扇富砂区,有利砂体与构造叠合面积为37.6km2。该方法准确预测了薄至5m的含油砂体,为低勘探程度区薄储层的研究提供理论基础。

The Cretaceous Bayingebi reservoirs in the eastern gentle slope zone of Tiancao Sag in Yin'e Basin are characterized by small thickness,significant lateral variation and inefficient identification by conventional inversion.The "Dual-Width and One-Height" 3D seismic data of Tiancao was used to identify the reservoir in this area.The well-seismic combination and clustering identification with seismic waveform were adopted to characterize the lateral reservoir distribution.At the same time,the curve reconstruction in frequency domain was selected to obtain the longitudinal high-resolution reservoir sensitivity curve.On this basis,the seismic waveform facies-controlled inversion was used to finely characterize the distribution of Bayingebi-2 reservoir.3 sub-lacustrine fan sandbody-rich zones had been predicted from south to north and the corresponding superposition area between favorable sandbodies and structure is 37.6 km 2.This method accurately predicts the oil-bearing sandbodies as thin as 5 m,which could provide a theoretical basis for thin reservoir characterization in low exploration level area.