黔北正安区块牛栏组基于叠后地震属性的多尺度裂缝预测

Multi-scale Fracture Prediction of Shiniulan Formation in Zheng'an Block of Northern Guizhou Province Based on Post-stack Seismic Attributes

黔北正安地区安场向斜石牛栏组为一套深水陆棚沉积的泥灰岩地层,前期钻探显示,石牛栏组气藏分布与裂缝发育程度密切相关,为典型的裂缝型气藏。为进一步对安场向斜石牛栏组储层的裂缝平面展布规律进行研究,该文通过岩心、成像测井等资料分析目的层的裂缝发育特征,优选裂缝预测敏感地震属性,基于地震像素处理的裂缝增强属性对石牛栏组裂缝分布进行了预测。研究结果表明:利用常规的地震曲率属性预测裂缝识别能力有限,而基于地震像素处理的地震数据能够有效改善小断层及构造形变特征成像,在此基础上开展的裂缝增强属性可大大提高裂缝的识别能力,经实钻井验证,基于叠后地震属性裂缝分布预测方法的结果与钻井泥浆漏失点综合吻合率达83.3%以上,预测结果较为可靠,该研究为石牛栏组区带优选及钻井风险预警提供了技术支撑。

The Shiniulan Formation of Anchang syncline in Zheng′an Area of northern Guizhou Province is a set of marl strata deposited in deep-water shelf.Previous drilling results show that the distribution of the typical fractured gas reservoirs in the Shiniulan Formation is closely related to the degree of fracture development.In order to further study the fracture plane distribution law of the Shiniulan reservoir in Anchang syncline,the authors analyzed the fracture development characteristics of the target layers through core and imaging logging data,optimized the seismic attributes sensitive to fracture prediction,and predicted the fracture distribution of the Shiniulan Formation by using the fracture enhancement attribute based on seismic pixel processing.The research results show that the ability to identify fractures using conventional seismic curvature attributes is limited,and the seismic data based on seismic pixel processing can effectively improve the imaging of small faults and structural deformation features.On this basis,the recognition ability of fracture enhancement attributes is greatly improved.The actual drilling results verify that the comprehensive coincidence rate between the fracture prediction results based on post-stack seismic attributes and the leakage points of drilling mud is more than 83.3%,thus the prediction result is reliable.This study provides technical supports for optimizing zones and early warning of drilling risk in the Shiniulan Formation.