缅甸若开海域块体搬运沉积地震响应及典型地质特征

doi:10.11743/ogg20110514

摘要/Abstract

摘要：

块体搬运沉积是深水沉积体系的重要组成部分,在世界范围内的深水盆地均有发现,其对深水油气勘探及生产均有重要影响。利用深水三维地震资料,对缅甸若开海域上上新统底部块体搬运沉积进行了追踪分析。基于地震剖面及时间切片,认为上上新统底部块体搬运体系发育3种地震相类型:弱振幅半透明杂乱地震相、叠瓦状变振幅地震相及中-强振幅丘状地震相。杂乱半透明地震相为块体搬运体系中段层状流态典型地震响应特征;叠瓦状变振幅地震相为同沉积变形的证据,为块体搬运趾部沉积;中-强振幅为搬运沉积内部漂浮块体响应特征。基于均方根属性、相干切片及构造图等,分别从顶、底界面以及内部对块体搬运体系沉积的典型地质特征进行了分析,底界面主要表现为侵蚀现象,顶界面反映了块体搬运沉积具有层状流态和塑性流态的性质,内部特征主要表现为变形及挤压现象。

关键词: 地震相, 地质特征, 块体搬运沉积, 深水沉积体系, 若开次盆, 缅甸

Abstract:

Mass-transport deposits(MTD)are an important component of deepwater deposition system.They occur in many deepwater basins around the word and play an important role in petroleum exploration and production.Using deepwater 3D seismic data,we predicted mass-transport deposits in the lower of the Upper Pliocene in Rakhine Sub-Basin,offshore Myanmar.Based on the seismic sections and time slices,we recognized 3 seismic facies in the MTD:low amplitude,semitransparent and chaotic seismic reflections,imbricate variable amplitude reflections and moderate-high amplitude reflections.The first seismic facies is the typical seismic response of laminar flow in the middle MTD,the second seismic facies is the evidence of the syndepositional deformation at the toe of MTD,and the third seismic facies is the seismic response of the floating blocks in the MTD.Based on RMS,coherence slices and structure maps,we analyzed the typical geologic features on the top boundary,bottom boundary and in the interior of MTD.The bottom boundary is mainly characterized by erosion,and the top boundary reveals the laminar flow and plastic flow regimes of MTD,while the interior mainly features in deformation and compression.

Key words: seismic facies, geological characteristics, mass-transport deposit, deepwater deposition system, Rakhine Sub-basin, Myanmar

中图分类号:

TE121.3

马宏霞,吕福亮,范国章,等. 缅甸若开海域块体搬运沉积地震响应及典型地质特征[J]. 石油与天然气地质, 2011, 32(5): 751-759. doi: 10.11743/ogg20110514 Ma Hongxia,Lü Fuliang,Fan Guozhang,et al. Seismic responses and geological characteristics of mass-transport deposits in the Rakhine Basin,Offshore Myanmar[J]. Oil & Gas Geology, 2011, 32(5): 751-759. doi: 10.11743/ogg20110514

参考文献

[1] Paul Weimer, Roger M. Slatt. Introduction to the petroleum geology of deepwater settings [M]. Tulsa: AAPG, 2007: 1-2. [2] 陈欢庆, 朱筱敏, 董艳蕾,等. 深水断陷盆地层序地层分析与岩性-地层油气藏预测--以中国南海C盆地深水区古近系T组为例[J]. 石油与天然气地质, 2009, 30(5): 626-634. Chen Huanqing, Zhu Xiaomin, Dong Yanlei et al. Sequence stratigraphy analysis and lithologic-stratigr aphic reservoir predication in deepwater faulted basins-an example from the Paleogene T Formation of the deepwater C Basin in South China Sea[J]. Oil & Gas Geology, 2009,30(5): 626-634. [3] Lorena Moscardelli, Lesli Wood, Paul Mann. Mass-transport complexes and associated processes in the offshore area of Trinidada and Venezuela [J]. AAPG, 2006, 90(7): 1059-1088. [4] Maslin M, Mikkelsen N, Vilela C, et al. Sea-level and gas hydrate-controlled catastrophic sediment failures of the Amazon Fan[J]. Geology, 1998, 26(12): 1107-1110. [5] Lorena Gina Moscardelli. Mass transport processes and deposits in offshore trinidad and Venezuela, and their role in continental margin development . Autin: The University of Texas, 2007. [6] Newton C, Wach G, Dalhousie U, et al. Mosher. Importance of mass transport complexes in the Quaternary development of the Nile fan, Egypt//Annual Offshore Technology Conference. Houston, OTC Paper 16742, 2004: 10. [7] Maslin M, Owen M, Day S, et al. Linking continental-slope failures and climate change: testing the clathrate gun hypothesis [J]. Geology, 2004, 32(2): 53-56. [8] Hoffman J S, Kaluza M J, Griffiths R, et al. Addressing the challenges in the placement of seafloor infrastructure on the East Breaks slide-a case study: the Falcon field (EB 579/623): Northwestern Gulf of Mexico//Annual Offshore Technology Conference. Houston, OTC Paper 16748, 2004: 17. [9] Lorena Moscardelli, Lesli Wood. New classification system for mass transport complexes in offshore Trinidad [J]. Basin Research, 2008, 20: 73-98. [10] Shipp R C, Nott J A, Newlin J A. Physical characteristics and impact of mass transport complexes on deepwater jetted conductors and suction anchor piles//Annual Offshore Technology Conference. Houston, OTC Paper 16751, 2004: 11. [11] Pirmez C, Marr J, Shipp C, et al. Observations and numerical modeling of debris flows in the Na Kika Basin, Gulf of Mexico//Annual Offshore Technology Conference. Houston, OTC Paper 16749, 2004: 13. [12] Suzanne Bull, Joe Cartwright, Mads Huuse. A review of kinematic indicators from mass-transport complexes using 3D seismic data [J]. Marine and Petroleum Gology, 2009, 26(7): 1132-1151. [13] Moscardelli, Wood L J, Mann P. Debris flow distribution and controls on slope to basin deposition, offshore Trinidad . Dalla: AAPG Annual Meeting Program, 2004: 13, A100. [14] Schwenk T, Spieβ V, Breitzke M, et al. The architecture and evolution of the Middle Bengal fan in vicinity of the active channel-levee system imaged by high-resolution seismic data [J]. Marine and Petroleum Geology, 2005, 22(5): 637-656. [15] James R, Cochran. Himalayan uplift, sea level and the record of Bengal fan sedimentation at the ODP Leg 116 sites [J]. Proceeding of the ocean drilling program, Scientific Results, 1990, 116: 397. [16] Ashraf Uddin, Neil Lunberg. Miocene sedimentation and subsidence during continent-continent collision, Bengal basin, Bangladesh [J]. Sedimentary Geology, 2004, 164(1): 131-135.