孟加拉湾浅层气成藏条件及地震识别技术

为了有效识别和预测孟加拉湾浅层气的分布规律，在弄清浅层气的成因、特点、油气成藏条件（浅层气类型、生储盖等）的基础上，通过对某三维地震资料解释，分析浅层气地震响应特征，明确浅层气的地震识别方法。结果表明，孟加拉湾浅层气为深水沉积中自生自储的构造-岩性复合型气藏，具有亮点、相位反转和低频等3种典型地震反射特征。在三维工区应用地震亮点技术、远近道振幅比较法、相位属性、频率属性、叠前AVO等技术方法进行了浅层气识别，预测成果与钻井结果吻合较好，为快速高效识别浅层气提供了技术依据。

Accumulation conditions and seismic identification techniques of shallow gas in the Bay of Bengal

In order to identify and predict the distribution of shallow gas effectively in the Bay of Bengal, this paper demonstrated the genesis, features, and accumulations conditions of shallow gas, such as the type of shallow gas, source rocks, reservoirs and seals. According to the 3D seismic data interpretation and analysis of seismic characteristics of shallow gas, three typical characteristics of shallow gas were drawn:(1)Bright spot characteristics. It has "double track" seismic reflection and middle-high amplitude characteristics. (2)Phase reversal characteristics. It represents obvious polarity reversal phenomenon in the shallow gas boundary. (3)Low frequency. It has low frequency phenomenon in the shallow gas interval. A set of technical methods was formed to identify shallow gas, including bright spot technology, amplitude comparison method, phase attribute, frequency attribute, pre-stack AVO, etc. It provides a technical support to identify the shallow gas quickly and efficiently, and plays an important role in the shallow gas prediction and offshore geologic hazard prevention, and achieves good results in the Bay of Bengal.