琼东南盆地深水区BSR带裂隙系统空间分布特征

为解决甲烷渗漏系统末端裂隙系统空间分布规律问题,基于南海北部深水区高分辨率三维地震数据,采用可视化与相干体技术描述似海底反射层分布区裂隙空间结构与分布特征,阐述了裂隙产生的地质成因类型,讨论了裂隙与其他类型输导体系对甲烷气成藏的关系。似海底反射层界面上部空间裂隙远少于下部空间的地质结构体,使水合物成藏过程中甲烷气供大于散,对研究水合物成藏和检测甲烷气的渗漏有普遍指示作用。根据裂隙的发育规模,研究区大致可以识别出短裂隙、长裂隙、裂隙束、裂隙群(组) 4种类型,它们对流体的渗漏能力依次增强,这些裂隙在地层中往往以多类型共存的方式,或与其他地质构造共同构成渗漏系统。这些结果和认识对完善深水盆地甲烷气渗漏系统水合物成藏模式及成藏机理有广泛意义。

Spatial distribution characteristics of fracture system in BSR zone in deep water area of the Qiongdongnan Basin

In order to solve the problem of spatial distribution of fracture system at the end of methane leakage system, based on the high-resolution three-dimensional seismic data in the north of South China Sea, the spatial structure and distribution characteristics of fractures in bottom simulating reflector (BSR) distribution area are described by using visualization and coherent body technology. The geological genetic types of fractures are described. The relationship between fractures and other types of transport systems on methane gas accumulation is discussed. The fractures in the upper part of BSR interface are far less than those in the lower part of BSR interface, which makes the methane gas supply larger than that in the process of hydrate accumulation. It has a general indicating role in studying hydrate accumulation and detecting methane gas leakage. According to the development scale of fractures, the study area can roughly identify four types of fractures, they are each short fractures, long fractures, fracture bundles, and fracture groups, which enhance the leakage capacity of fluids in turn. These fractures often coexist in multiple types in the stratum, or form a leakage system together with other geological structures. These results and understandings are of great significance to improve the gas hydrate accumulation model and mechanism of methane leakage system in deep-water basin.