CAJ | 학술논문

孟加拉湾深海扇构成了深海层序 LST 的主体,沉积了巨厚的第三系复合体砂体,可识别出5套层序界面.该深海扇中新统Bhuban 组、渐新统 Jenam 组、始新统 Kopili 组3套烃源岩生烃期分别为早上新世(5 Ma)、渐新世末(29.3 Ma)、古近纪末(23.3 Ma).储层以深水浊积砂岩为主,具有多期垂向叠置的沉积模式.渐新统—中新统储盖组合为最有利的储盖组合.垂向断层、不整合面、连续分布的砂体构成了良好的输导体系,其成藏模式为“下生上储型”地层或复合气藏类型.孟加拉湾深水区主要以天然气为主,其有利勘探层系为恒河水系中上部扇带和印度东部海域中上部扇带等环孟加拉湾深水盆地第三系加积局限型水道复合体,以及中下部扇带“无底水道”附近潮道天然冲积堤砂体.
맹가랍만심해선구성료심해층서 LST 적주체,침적료거후적제삼계복합체사체,가식별출5투층서계면.해심해선중신통Bhuban 조、점신통 Jenam 조、시신통 Kopili 조3투경원암생경기분별위조상신세(5 Ma)、점신세말(29.3 Ma)、고근기말(23.3 Ma).저층이심수탁적사암위주,구유다기수향첩치적침적모식.점신통—중신통저개조합위최유리적저개조합.수향단층、불정합면、련속분포적사체구성료량호적수도체계,기성장모식위“하생상저형”지층혹복합기장류형.맹가랍만심수구주요이천연기위주,기유리감탐층계위항하수계중상부선대화인도동부해역중상부선대등배맹가랍만심수분지제삼계가적국한형수도복합체,이급중하부선대“무저수도”부근조도천연충적제사체.
The deep-sea fan of the Bay of Bengal served as the main body for the LST of deep sequence. Tertiary complex sand bodies with giant thickness deposited. 5 sequence boundaries were identified. 3 sets of source rocks in the Bhuban Formation of Miocene, the Jenam Formation of Oligocene and the Kopili Formation of Eo-cene gave birth to hydrocarbon during the early Pleiocene (5 Ma), the end of Oligocene (29. 3 Ma) and the end of Paleogene (23. 3 Ma), respectively. Deepwater turbidity sandstones worked as the main reservoir, and were featured by a depositional model of multi-period vertical overlap. Oligocene-Miocene reservoir and seal assem-blage was the most favorable. Vertically, faults, unconformities and continuously-distributed sand bodies provid-ed good pathways for petroleum migration. The possible accumulation models belong to stratigraphic reservoirs of“above-generation and below-storage” or complex ones. Natural gas is the dominant product in the deep water zone of the Bay of Bengal. Therefore, the Tertiary aggradational confined channel complexes in the deep-water basin of the Bay Rim of Bengal, such as the upper-middle deep water fans of the Ganges river system and the In-dian eastern sea, as well as the natural alluvial sand embankments near to “bottomless channel” in the middle-lower deep water fans are considered as the most potential zones.