CMP域内海洋CSEM法探测海底天然气水合物分辨能力研究

Research on Resolution of Marine CSEM Method in CMP Domain

海洋CSEM法因其对海底高阻体反应灵敏,可用于探测和识别海底天然气水合物储层,然而,由于海底天然气水合物成因和成藏规律复杂,一些区域横向块状分布或是垂向多层分布的成藏模式加大了探测难度和成本,对于探测分辨能力也提出了更高的要求。为了在实际CSEM探测中进行高阻异常的现场快速评估,借鉴地震勘探共中心点道集的转换方式,将二维模型的海洋CSEM响应在CMP域单元内转换为一维模型的响应,进而实现二维模型CSEM资料在CMP域内的近似一维反演,针对不同电阻率模型讨论勘探参数对异常体分辨能力的影响。结果表明,海洋CSEM资料的CMP域反演对横向和纵向上相邻的水合物储集体具有一定的分辨能力,这为海洋CSEM法探测复杂成藏模式的水合物提供理论依据。

The marine CSEM method is sensitive to seafloor high-resistance bodies and can be used to detect and identify seabed gas hydrate reservoirs.Due to the complexity of the distribution,laterally distributed or vertically distributed in some areas,it is difficult and costly to exploration of submarine natural gas hydrates,and higher resolution capabilities are important.By referring to the conversion method of common middle point gathers in seismic exploration,the CSEM response of 2 D model is converted to one-dimensional model response in CMP domain.One-dimensional inversion of the CSEM data of the 2 D model in the CMP domain is achieved.The influence of exploration parameters on the resolving power of anomalous bodies is discussed for different resistivity models.Study the resolving power of CMP inversion by calculating different resistivity models.The results show that CMP domain inversion has certain resolving power for the adjacent hydrate reservoirs in the horizontal and vertical directions.This provides a theoretical basis for the marine CSEM method to explore the complex hydrate reservoir.