【作者】 何文刚；

【导师】 梅廉夫；

【作者基本信息】 中国地质大学 ， 地质工程， 2011， 硕士

【摘要】 缅甸海域及邻区底辟构造特征多,分布范围广,成因机理复杂,对油气成藏有重要的影响。缅甸海域及邻区属于主动大陆边缘,位于欧亚板块的南部,印度洋板块-澳大利亚板块北部,太平洋板块西部,西紧邻孟加拉和孟加拉湾,南部紧邻苏门达腊,东部紧邻泰国和马来西亚,北部紧邻Mishmi逆冲断裂带,即印度板块与欧亚板块以及太平洋板块交汇区。从构造动力学及运动学特征分析,该构造带处于印度板块向北、北东向斜向俯冲和实皆走滑断裂双重机理控制下所发育形成的主动大陆边缘构造。据区内构造演化特征划分为五个构造带、九大坳陷。缅甸海域及邻区底辟构造就发育于印度板块、欧亚板块及太平洋板块交汇区的特殊构造环境下,因而底辟构造比较复杂,研究难度相当大。本文主要应用地震资料,测井资料和钻井资料研究底辟构造特征；结合区域地质背景资料,沉积资料,断裂体系特征研究底辟构造分布；综合底辟构造几何学、运动学、动力学特征解决底辟构造的成因机理,最后得出与油气成藏的关系。缅甸海域经历了被动大陆边缘,过渡型大陆边缘以及演化到现今的主动型大陆边缘三个阶段,因而形成三期构造演化格局。复杂的构造背景形成了增生楔混合介质底辟构造、火山岛弧带岩浆热液底辟构造,弧后盆地安达曼海坳陷泥底辟构造。增生楔底辟构造主要分布在若开海岸增生楔段的A4区块,Rmree岛、A7区块、A2区块、M2区块、M5区块、M8区块；安达曼海-尼科巴增生楔北段底辟构造分布在M2区块、M5、M8区块。其中A4、Rmree岛、A7区块、M5、M8区块底辟属于冷底辟,冷底辟沿增生楔长约500 km。在不同构造位置,冷底辟东西宽度存在差异；热底辟分布在M2区块。底辟构造的特征主要是泥火山、泥底辟和混合介质底辟。底辟作用形成刺穿、龟背型、树枝式,圆柱构造。其中M2区块底辟作用形成了许多断块构造。增生楔底辟构造形成的机理复杂：混合介质底辟是印度洋板块俯冲过程中产生的岩浆热液及海水、熔融物质,玄武质岩浆以及异常岩浆混合作用形成的底辟,是研究中发现的复杂底辟。增生楔底辟构造类型分别有低能量的低幅隆起、中等能量龟背上隆和高能量的刺穿底辟构造,甚至还发育大量的泥火山。增生楔盆地主要有两套烃源岩发育层位：深部的始新统泥岩和浅部的中新统泥岩。增生楔构造带上已勘探到油气田,但与底辟构造紧密相联的构造带油气发现很少。如增生楔斜坡盆地A7区块-M2区块烃源岩厚度较大、类型好,但其有机质成熟度偏低,普遍处于未成熟-低成熟阶段,不利于成烃转化和油藏的形成。火山岛弧岩浆热液底辟分布在火山岛弧构造带上,分割弧前、弧后坳陷。研究区主要分布在M2区块和M3区块、M5区块和M6区块、M8区块和M9区块等区块之间。火山岛弧带高温热流体能量强,火山岩刺穿上覆岩层,底辟核顶部地层埋深浅,底辟核顶部是上中新统地层以及上新统地层。底辟核被张性断裂分割,断面弯曲,断裂剖面形态“包心菜”结构。底辟核周围形成周缘向斜构造,中新统地层褶皱变形,形成一系列相似褶皱。缅甸海域火山岛弧带西部是弧前坳陷,东部是弧后盆地安达曼海弧后坳陷。岛弧带渐新统-中新统沉积较薄。岛弧带主要发育刺穿型底辟构造。岩浆热液底辟构造成因是岩浆熔融体向上顶托侵位、穿刺围岩的作用或由于重力不稳和侧向挤压导致岩浆垂直上升,岩体没有增生现象,岩浆上升和围岩相对下降造成两者之间的剪切作用,在围岩中形成周缘向斜,底辟岩体常呈倒水滴状,形成一系列的刺穿构造。弧后坳陷底辟主要分布在弧后盆地安达曼海弧后坳陷北部,紧邻马达班湾地区的M1、M3、M4、M6、M7、M9等区块,泥底辟以气烟囱状为主。该构造带发育的底辟走向近南北向,底辟数量多,大小各异。最大的泥底辟南北长达125km,东西宽达5.7km。最小的泥底辟南北长达13km,东西宽达4km。其中,M3、M4区块泥底辟数量较小,但底辟幅度较大。M1区块底辟构造分布最多,底辟构造幅度较小。在纵向上,泥底辟分布层位分别是白垩系、始新统、渐新统、下中新统、中中新统、上中新统、上新统及全新统。弧后坳陷的底辟成因机理因素多,主控因素是地温梯度高,走滑断裂作用,伊洛瓦底江搬运的沉积物沉积作用,以及重力和侧向应力等综合作用的结果。缅甸海域及邻区三类不同底辟对油气成藏影响很大,分别对烃源岩、储集层、盖层等油气成藏作用造成不同程度的影响。增生楔底辟构造对油气的成藏破坏性较大,成藏有利因素较差；火山岛弧岩浆热液底辟位于构造高隆起位置,其烃源岩来自弧后坳陷,独特的构造位置有利于形成油气藏。弧后泥底辟对油气成藏影响具有双重作用,底辟发育区的断裂开启造成大量油气散失,在断裂发育微弱构造带则有利于形成良好的油气藏；底辟构造主要沿实皆走滑断裂发育,沿走滑断裂发育的底辟规模大。弧后坳陷底辟发育的集中区,跟马达班湾和伊洛瓦底江沉积物搬运和实皆断裂的走滑作用以及异常高温热流体作用有关。因此,泥底辟构造及其伴生断裂控制了弧后盆地安达曼海弧后坳陷油气成藏作用。更多还原

【Abstract】 There are lots of diapirs characteristics in Myanmar Sea and adjacent regions.Distribution is range,formation mechanism are complex.It may be a major effect for possession of hydrocarbon accumulation.Myanmar Sea and adjacent area belong to active continental margin.It is located at the south of the Eurasian plate, the north of the Indian plate-Australian plate,the west of the Pacific plate, and the north of west Bengal.It is adjacent to Bangladesh and the west of Sumatra, The eastern of Myanmar Sea and adjacent regions close to southern Thailand and Malaysia, the north of Myanmar Sea and adjacent regions are adjacent to Mishmi thrust fault zone, namely the Indian plate with the Eurasian plate, and the Pacific plate intersection. From structural dynamics and kinematics characteristic analysis, the India plate tectonic belt is located at the north and north-east to oblique subduction and strike-slip faults under double mechanism control of active continental margin development structure formation. According to the characteristics of structural evolution, Myanmar Sea and adjacent regions are divided into five tectonic belts, and nine depressions. Myanmar Sea and adjacent regions diapirs developed in the special tectonic environment where India plate, Eurasian plate and the Pacific plate intersect, so diapirs are more complex,and the research is extremely difficult.This paper mainly applied seismic data,logging data and drilling material to research the diapirs features and the diapirs distribution in combination with regional geological background material,sedimentary material and faults system features of this area Comprehensive geometry, kinematics and dynamics characteristic of diapirs to solve diapirs formation mechanism, Finally concluded that the relationship of diapirs and hydrocarbon accumulation.Myanmar Sea experienced passive continental margin, transitional continental margin and evolution to today’s active continental margin three stages, It is formed phase iii tectonic evolution patterns.Complex tectonic background formed Mixed media diapirs in accretionary wedge, volcanic island of diapirs magmatic hydrothermal and Mud diapir of back-arc depression of back-arc basin the Andaman sea. The accretionary wedge diapirs is mainly distributed section A4 block,Rmree island, and the A7 block,M2 block,M5 block and M8 block in the Arakan’s coast area. The Andaman sea-nicoba accretionary wedge section diapirs distribute in M2 bloc, M5, M8 block.In these areas,Rmree island, A4 block, and A7 block, M5 block, M8 block are belong to cold diapirs, cold diapirs of the accretionary wedge are 500km long. In different tectonic settings, cold diapirs width of stope have some differences between that.The main feature of diapirs is mud volcano or mud diapirs and mixed medium diapirs.Role in the formation of diapirs have many Pierce types and create branch type, tortoise type, and cylindrical structures.especially M2 block formed many fault block structures.Accretionary wedge diapir’s mechanism is complex. Mixed media diapirs is India Plate produced during subduction of magmatic hydrothermal and seawater, molten material, the connection basaltic magma and magma mingling of abnormal role in the formation of diapirs, is found in the research of complex diapir. Accretionary wedge diapirs type is respectively the low energy and low-rising uplift, medium energy turtle on high-energy pierced and augmentation of diapirs, even development a lot of mud volcano. Accretionary wedge basin basically has two sets of source rock developmental horizon. Deeper Eocene formation is mudstone and shallow Miocene is mudstone. It is found oil and gas in the Accretionary wedge, but already exploration to closely related with the structure of diapirs oil and gas found few of the tectonic belt. If Accretionary wedge slope basin block-M2,A7 block hydrocarbon source rocks thickness, good types, but larger organic matter maturity is low, the universal in immature-low in mature stage, to the detriment of hydrocarbon reservoir into the transformation and the formation.Volcanic island of magmatic hydrothermal diapirs are distrubuted in volcanic island-arc bring,segmentating back-arc depression before Arc former and back-arc depression. In research area, they are mainly distributed between the M2 and M3 blocks, M5 and M6 blocks, M8 and M9 blocks and so on. Volcanic island has high temperature hot fluid of strong energy. Volcanics penetrate overlying strata. The top formation overlying on diapirs nuclear lies shallow in the earth, which are upper Miocene and Miocene strata. Diapirs is divided by tensional fracture with bending profile and "cabbages" structure in profile. The area around diapirs nuclear form incline with Miocene formations foilding and forming a series of somillar folid. Myanmar sea with volcanic island arcs depression before the west is eastern of back-arc basin, the Andaman sea back-arc depression.the tectonic belt’s new series-Miocene wudaoliang sedimentary of gradually is thinner and mainly develop pierced type diapirs. Magmatic hydrothermal origin is the founction of diapirs magma body up top Joe emplacement and puncture of surrounding rock or magma vertical rise caused by unstable gravity effects or and lateral extrusion. Rock has no hyperplasia phenomenon.Shearing action between magma rises and relative decline in surrounding form incline in surrounding rock. Diapirs rock often submit pour water droplets shape and form a series of piercing structure.Back-arc depression diapirs is mainly distributed in the back-arc basin, the Andaman sea back-arc depression north, close to the M1, M3, M4, M6, M7, M9 etc block of motor class bay area, characterized with gas chimney mud diapirs. The diapirs developed in the tectonic belt strikes almost NS, has large qualities and various sizes. The biggest mud diapirs measures 125km from north to south and 5.7 km from east to west, the smallest 13km and 4km. Among them, M3, M4 block has smaller amount but higher mud diapirs, but Ml block is on the contrary.Mud diapirs are vertically distributed in Cretaceous,Eocene,Oligocene,Lower Miocene,Middle Miocene,Upper Miocene,Pliocene, Quaternary, formation.The formation mechanism of Back-arc depression diapirs is diverse. The major controlling factors is high temperature gradient, strike-slip faults effect, the Irrawaddy handling of sediment deposition and the result of comprehensive effect of gravity and lateral stress. The three different diapirs of Myanmar Sea and adjacent regions have great impact on the oil-gas accumulation, with respectively fifferent degee of influence on hydrocarbon, source rocks, reservoir,layer etc. Hyperplasia wedge of diapirs has bigger destructiveness on hydrocarbon accumulation, and poor accumulation factors, which promote the formation of oil-gas accumulation with its source rocks from back-arc depression. Back-arc mud diapirs has dual effect on oil-gas accumulation. Open fractures developed from diapir caused massive hydrocarbon dissipation, but in structural belt where fracture development is weak good reservoirs are formed. The structure of diapirs mainly follows the real are strike-slip faults along the strike-slip faults development, development of the size of monarch. Diapir distribute mainly along the Sagaing strike-slip faults, and the scale of the diapir developed along the Sagaing strike-slip fault is large. Back-arc depression diapir development focus areas, with the mataban Bay and Irrawaddy sediment transport and strike-slip movement of Sagaing faults and abnormal high temperature thermal fluid effects. Therefore, diapir and its associated faults control oil and gas accumulation depression effection of the back-arc basin, the Andaman Sea更多还原