深水盆地中大型侵入砂岩的地震识别及其成因机制探讨  

Seismic Identification and Formation Mechanism of Large-scale Sandstone Intrusions in Deep-water Basin

作　　者：吴时国[1] 孙运宝[1,2] 孙启良[1,2] 董冬冬[1,2] 袁圣强[1,2] 马玉波[1,2] 

机构地区：[1]中国科学院海洋研究所,中国科学院海洋地质与环境重点实验室,山东青岛266071 [2]中国科学院研究生院,北京100049

出　　处：《地球科学进展》2008年第6期562-569,共8页Advances in Earth Science

基　　金：中国科学院知识新工程重要方向项目“南海北部深水海域油气勘探的关键问题研究”(编号:KZCX2-YW-203);863项目“浅水流形成机理及其地球物理识别技术研究”(编号:2006AA09Z349)资助

摘　　要：侵入砂岩是深水盆地中常见的地质现象,由于本身具有高孔隙度、高渗透率的特点,对深水油气储集、运移和成藏均有重要的影响。综合国内外研究成果,探讨了深水盆地中大型侵入砂岩的地震特征和成因机制。研究表明侵入砂岩具有明显的强振幅地震反射,这些振幅异常一般呈V字形反射形态,沿着走向反映出一系列的特点,如阶梯性、分支性等,并伴有极性反转和高速度异常,在侵入砂岩下部的喉道出现上拉现象;关于侵入砂岩的成因,认为是未固结成岩阶段深水盆地中的异常超压砂体的向上侵位形成,大型的侵入砂岩及其伴生的断裂系统为流体运移提供渗流通道,深部水道或深水扇系统为侵入砂岩提供充足的物源。Large-scale sandstone intrusions are important components of many deep-water clastic systems. They were formed by the unconsolidated sandstones of early burial stages remobilizing and injecting into the overlying strata and were commonly found in fine-grained argillaceous sediments developed in polygonal fault network. They can affect the distribution of sandstone reservoir, the vertical migration and oil/gas accumulation for their high porosity and high permeability. By integrating the research results at home and abroad, the seismic character and formation mechanism of large-scale sandstone intrusions are discussed. Results shows that they often form complex and spectacular features on 3D seismic data, such as a distinctive suite of discordant, high-amplitude reflections, the opposite polarity of upper and lower reflections, conical amplitude, horizon pull-down and so on. The sandstone intrusions are resulted from extremely high pressure in deep water environment. The presence of a widespread region of conical sandstone instrusions in the deep-water basin has important implications for vertical fluid migration in the region.

关 键 词：侵入砂岩 多边形断裂 深水盆地 水道沉积 地震属性 

分 类 号：P315.1[天文地球—地震学] P544.4[天文地球—固体地球物理学]