垂直缆地震资料鬼波压制及多次波成像技术研究

The vertical cable seismic (VCS, vertical cable seismic) exploration technique has many advantages such as convenient data acquisition, high data’s signal to noise (S/N) ratio, high data’s vertical resolution, high data’s fidelity, large dip angle geological structure's accurate imaging, convenient real-time monitoring and so on. So in recent years, using the VCS technique to explore the marine mineral resource is gradually adopted by many countries around the world. The ghost wave's trap frequency and the air gun source’s bubble effects are always the emphasis and difficulty in the marine seismic data processing. Here in order to eliminate the two kinds of negative effects mentioned above, some research on how to extract and apply the far-field wavelet in vertical cable seismic data is going to be conducted, then the vertical resolution can be improved. At present, only the primary reflections of VCS data are used to build the velocity-depth model and image the geological layers beneath the ocean bottom, but because of the VCS’ special shot-receiver geometry, its illumination area is too narrow to cover the shallow layers in the lateral directions below the ocean bottom, which reduces the high S/N ratio, high vertical resolution and high fidelity advantages of the VCS technique severely. To solve these problems, research on the unified velocity inversing technology combining the primary reflections with the multiples of VCS data is going to be done, so a wider and more accurate velocity-depth model can be achieved. In order to make up the shortcomings of the VCS’ primary reflections' short range imaging and poor imaging quality, research on how to image the VCS' multiples using the reverse time pre-stack depth migration technique is going to be carried out. The proposed research is of great importance in improving the gas hydrates exploration accuracy and its later production monitoring in South China Sea.

近年来世界各国逐渐采用垂直缆地震(VCS)技术探测海底矿产资源。VCS勘探具有施工方便，资料信噪比、分辨率、保真度高（三高），适于对大倾角地质构造成像，易于对开发过程进行监测等特点。气泡及鬼波压制一直是海洋地震资料处理的难点，项目拟利用VCS能够直接接收到地震远场子波的优势，开展远场子波提取及应用技术研究，用以衰减炮点端鬼波陷波及气枪震源气泡效应，提高纵向分辨率。目前成像VCS资料主要是应用一次反射波，但由于VCS勘探时特殊的炮检点分布，使得一次反射波的照明范围很窄，严重影响了该技术的“三高”勘探效果。项目拟对VCS资料中的一次反射波及一阶多次波开展联合速度反演方法研究，获取较宽范围、更高精度的速度-深度模型；拟开展激发时间成像条件逆时法叠前深度偏移技术研究，对一阶多次波进行成像，以扩大成像范围，提高成像质量。拟研发技术对提高海域水合物勘探精度及后期开发监测等方面具有重要的理论及实际意义。

近年来世界各国逐渐采用垂直缆地震(VCS)技术探测海底矿产资源。VCS勘探具有施工方便，资料信噪比、分辨率、保真度高（三高），适于对大倾角地质构造成像，易于对开发过程进行监测等特点。气泡及鬼波压制一直是海洋地震资料处理的难点，项目拟利用VCS能够直接接收到地震远场子波的优势，开展远场子波提取及应用技术研究，用以衰减炮点端鬼波陷波及气枪震源气泡效应，提高纵向分辨率。目前成像VCS资料主要是应用一次反射波，但由于VCS勘探时特殊的炮检点分布，使得一次反射波的照明范围很窄，严重影响了该技术的“三高”勘探效果。项目对VCS资料中的一次反射波及一阶多次波开展联合速度反演方法研究，获取较宽范围、更高精度的速度-深度模型；开展了激发时间成像条件逆时法叠前深度偏移技术研究，对一阶多次波进行了成像，扩大了成像范围，提高了成像质量。另外项目还研究了干涉法提取格林函数技术，编写了干涉法形成虚拟炮集程序，对实际垂直缆资料进行了分析和处理，形成了虚拟炮集地震记录，对生成的虚拟炮集地震记录进行了常规处理，形成了叠加和偏移数据体。项目研发的技术对提高海域水合物勘探精度及后期开发监测等方面具有重要的理论及实际意义。