地震分频AVO技术在孟加拉湾海域深水沉积储层烃类检测中的应用

The application of seismic frequency decomposition AVO method in offshore deep-water sedimentary reservoirs hydrocarbon detection in the Bay of Bengal

直接利用叠前地震资料进行烃类检测在海洋深水油气勘探中具有重要作用。传统的AVO方法在烃类检测中应用广泛,但在薄层、高孔隙度含水砂岩、低含气饱和度等情况下存在多解性和不确定性。实际上,地震波在油气储层中传播会产生较强的频散和能量衰减,这种变化在叠前地震资料振幅和频率上均存在响应。因此把分频技术与AVO技术结合起来是解决烃类检测多解性的有效方法之一。针对传统AVO方法和分频技术进行烃类检测存在不足,通过模型正演、AVO技术和分频技术以及它们的有效结合应用,集成了地震分频AVO烃类检测方法,在孟加拉湾海域深水沉积储层烃类检测中取得了良好的应用效果,验证了该方法在海洋深水沉积储层烃类检测的可行性及有效性,进一步提高了储层烃类检测的可靠性,有效地降低了烃类检测的多解性。

Hydrocarbon detection using pre-stack seismic data directly plays an important role in deep-water sediments petroleum exploration. Traditional AVO method has been widely used in hydrocarbon detection,but has multiple solutions and uncertainties,especially in the situations of thin bed,high porosity wet sand and low gas saturation sand. In fact,when seismic waves spread in oil and gas reservoirs,they will produce strong dispersion and energy attenuation,which are responsive on the amplitude and frequency of pre-stack seismic data.Therefore,the combination of frequency decomposition and AVO is one of the effective ways to solve multiple solutions. In this paper,seismic frequency decomposition AVO method is integrated through the combined analysis of model forward,AVO analysis and frequency decomposition in terms of the problems of traditional AVO method and simple frequency decomposition in hydrocarbon detection. This method has achieved good application effect in the deep-water reservoirs in offshore of Bay of Bengal. The feasibility and effectiveness of hydrocarbon detection in offshore deep-water sedimentary reservoirs are verified by actual data. The reliability is further improved,and the multiple solutions of hydrocarbon detection are reduced effectively.