窄方位角地震数据预测裂缝储层方法

现场试验和理论研究表明,裂缝的各向异性会对地震波传播特征产生影响,因此可以利用现有的窄方位角地震数据进行分方位角处理、解释来预测裂缝性储层。文中结合窄方位角地震数据的分方位角处理、解释与地震属性分析等技术对M区的裂缝发育区域进行预测,关键技术如下:①通过采取限炮检距的措施,使分方位角处理数据在不同方位角的分布较均匀; ②在进行数据规则化时, 采用五维插值技术或OVT域处理技术,而不采用面元均化技术或其他缺失方位角和炮检距信息的数据规则化处理技术, 有利于进行方位各向异性分析和裂缝预测; ③采用全方位角数据解释的叠前时间偏移速度场作为最终的分方位角叠前时间偏移速度场而有别于常规方法; ④通过叠前振幅随方位角变化定量识别和表征裂缝的走向、密度及分布范围, 通过属性分析定性识别和表征裂缝的走向、密度及分布范围。结果表明:叠后地震属性反映的裂缝发育方向与区域地质和钻井资料揭示的裂缝发育方向一致, 以北东东向、北西西向为主要优势方向; 叠前地震属性可定量检测裂缝发育程度; 预测结果与非零井源距VSP测井解释结果相吻合。

Fractured reservoir prediction on narrow azimuth seismic data

Field tests and theoretical researches show that fracture anisotropy has influence on seismic wave propagation characteristics. So narrow azimuth seismic data can be processed with azimuth approaches, and interpreted to predict fractured reservoir. In this paper, this proposed approach is applied to narrow azimuth seismic data in M area to predict fracture development zones. The following techniques are involved: ①Sub-azimuth seismic data are evenly distributed in different azimuth by azimuth dividing; ②During data regularization, 5 D interpolation or OVT domain processing approaches are adopted to for better azimuth anisotropy analysis and fracture prediction; ③The pre-stack time migration velocity field for full azimuth data interpretation is adopted as the final pre-stack time migration velocity field for selected azimuth data; ④Fracture orientation, density and distribution are quantitatively identified and characterized with AVA, and they are qualitatively identified and characterized with attribute analysis. Results show that the fracture direction identified with attribute analysis on poststack data matches very well with regional geology and drilling data, and the fracture development identified with attribute analysis on prestack data are consistent with non zero offset VSP interpretation results.