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松潘—阿坝盆地构造演化与石油地质基本条件
The Tectonic Evolution and the Basic Petroleum Condition in Songpan-Aba Basin
【作者】 刘春平;
【作者基本信息】 中国地质大学(北京) , 矿物学、岩石学、矿床学, 2006, 博士
【摘要】 对松潘—阿坝盆地沉积充填、构造变形、火成岩及变质岩研究的基础上,完成了本论文,取得了如下主要认识与新进展:1、松潘—阿坝盆地存在4个重要区域不整合,相应地构造演化分为:基底形成、早古生代被动大陆边缘、晚古生代复合被动大陆边缘、三叠纪被动大陆边缘至前陆盆地和三叠纪后的陆内盆地构造演化5个主要演化阶段。2、提出在晋宁运动期间,松潘—阿坝古地块由北向南与扬子古板块碰撞、形成的岛弧型火山岩变质后成为本区刚性基底,若尔盖附近基底的刚性强于周缘地区。基底自形成以来,一直与扬子板块保持一体。龙门山造山带中的彭灌杂岩体是晚印支运动中被推出地表的基底,并提出了相应的运动模式。3、造山隆起带构造样式较复杂,发育大量的逆冲断裂与断块体;坳陷带构造样式相对简单,构造样式表现出较大的层次性,总体为盖层滑脱式逆冲褶皱型,滑脱面为三迭系与晚古生界之间的界面和震旦系与前震旦系界面。4、早古生代,本区为被动大陆边缘,沉积了高质量的烃源岩;晚古生代盆地主体为稳定克拉通盆地,广泛发育碳酸盐岩台地,形成了性能良好的储集岩,进入三叠纪,本区为克拉通盆地至前陆盆地演化阶段,由碳酸盐岩台地转换为海槽,形成逾万米浊积岩,是本区有效区域盖层;三叠纪末的晚印支运动形成现今地质格架并使本区抬升成陆;从侏罗纪开始本区进入受印支期断裂控制的陆内盆地演化阶段,推测喜马拉雅运动对本区构造格架的影响较小。5、提出二叠纪末期阿尼玛卿断裂带以南发生重力滑覆,在盆地主体部位形成收缩构造。计算了三叠系剥蚀厚度和残存厚度,并提出本区烃源岩的高成熟度受控于三叠系原始埋深、火成岩活动与地层层间滑动摩擦热能,三叠系变质作用类型以区域变质作用为主,变质作用程度极低。6、本区烃源岩已进入过成熟阶段,有过多次排烃过程,现今的油气状态以干气为主。两套生储盖组合中,三叠系封盖能力优于志留系,三叠系覆盖区的油气远景较好。二叠纪末期的重力滑覆运动形成圈闭,能够较早捕获油气,有利于本区油气成藏;三叠纪末期的晚印支运动对早期油藏有改造作用,但同时也为油气的再次聚集提供了圈闭条件。提出摩天岭下组合是可供勘探的现实区带。
【Abstract】 On the basis of the study of depositional basinfilling, tectonic deformation,igneous rock and metamorphic rock in the Songpan-Aba basin, the paper drawsprimary conclusions and new fruits as follows:1、There are four primary regional unconformity for the Songpan-Aba basin,andthe corresponding structural evolution can be subdivided into 5 primary phases: Thebasement formation, the Eopaleozoic passive continental margin, the Neopaleozoiccraton basin and coexistent passive continental margin, the Trias craton basin toforeland basin and later Trias intermontain basin structural evolution.2、During the Jinning movement, the island-type volcanic rock which generatedby the diastrophic block of Songpan-Aba basin bumping with Yangzi old plate fromnorth to south, formed the rigid basement undergoing metamorphism. The rigidity inthe Ruoergai basement was stronger than that of the peripheral region. After theformation of basement, it always kept in onepiece with Yangzi plate. During the lateperiod of the Indosinian movement, the Pengguan complex rock in the LongmenshanOrogenic Belt was the former basement that thrusted out of the earth’s surface. Thus,the forming process of the basement in the study area is studied in detail and is used tosummarize tectonic-evolutionary model.3、Tectonic style of the orogenic-belt uplift is very complicated,and is markedby the growing of a large number of thrusting rupture and faulted block. But thetectonic style of the geotectogene is relatively simple,which is exhibitted by themajor hierarchy,and generally belongs to the thrust fold pattern induced by cap-rockdecollement;The slip surface includes the interface between argillaceous or silty mudrock of the Triassic and the carbonate rocks of the late Paleozoic, and the sedimentaryrocks of the Sinian and metamorphic rocks of the Presinian.4、During Eopaleozoic, the study area was in a period of the passive continentalmargin where deposited high quality source rock;Neopaleozoic was marked by asteady craton basin with the development of carbonate platform, during which thehigh-quality reservoir rocks were formed. Coming into Trias, the study area became acraton basin to foreland basin evolution period, during which the carbonate platformconversion to ocean trough, while deposited more than myriameters turbidites that formthe effective regional cover. In the end of the Trias, the late of the Indosinian movementformed the present geologic framework and the study area was uplifted and cropped out.At the beginning of Jurassic period, the study area was entered a evolutionary period ofthe inter-mountain basin that is controlled by Indosinian faults. And the Himalayanmovement in the later has a light influence on the tectonic framework of the study area.5、In the south part of Animaqin fault zone, gravity collapse was occurred during theend of the Permain;And contraction tectonics was formed in the main body of basin.Calculating the Trias thickness of both the denude and the remain, and considering thefeature of resource rocks high maturity in the study area that were controlled by the Triasoriginal buried depth, igneous rock action and interlayer frictional heat energy and so on,all of these studies were finished in the first time. The Trias metamorphism was priority toregional metamorphism, and its extent was mighty low.6、The resource rock of the study area had been came into the post mature periodundergoing the multiple migration. Thus, only dry gas is created in today. In the two trapunits, the cover ability of Trias is better than Silurian, and its coverage area has the betterhydrocarbon potential. In the end of the Permain, the gravity-collapse movement formedtrap, which could capture oil and gas that were formed in the early period;the lateIndosinian movement during end of Trias had the rebuilding function to the early oilreservoir, in the same time providing the trap condition for the regroup of the oil and gas.Therefore, the lower association of oil gas in the Motianling unit is thought as the realismlines.
【Key words】 structural evolution; forming oil reservoir; Songpan-Aba basin;
- 【网络出版投稿人】 中国地质大学(北京) 【网络出版年期】2006年 08期
- 【分类号】P542;P618.13
- 【被引频次】7
- 【下载频次】601