从川东北长兴组沉积相展布规律探讨地震异常体与生物礁的相关性

CORRELATION OF SEISMIC ANOMALY TO ORGANIC REEFS BASED ON THE DISTRIBUTION OF SEDIMENTARY FACIES IN THE CHANGXING FORMATION IN NORTHEASTERN SICHUAN

礁型气藏(井)是四川油气勘探的一个新领域。然而,这些礁型气井都是在钻探过程中偶然发现的,这就向地质学家们提出了一个问题:怎样利用地震资料发现地下生物礁,并指导钻探?本文拟从沉积相的角度出发,探讨所发现的地震异常体的性质、类型以及与生物礁的关系,进而指出有利的礁型气藏(井)的勘探类型及地区。

Twelve seismic anomalies have been found in northeastern Sichuan and its adjacent areas according to the direct or indirect criteria used for recognizing seismic anomalies. They can be classified into three types: lenticular seismic anomaly, elongated seismic anomaly and unreflecting seismic anomaly. All these anomalies occur above the T_8 reflector or in the sedimentary facies and organic reefs in the Changxing Formation, the author contends that the seismic anomalies are associated with the organic reefs rather than the other factors such as hummocky sandstone bodies, igneous masses, salt and mud mounds. Thus the potential seismic anomalies are determined on the basis of the characteristics of the seismic anomalies and well data.