Recent developments in study of the typical superimposed basins and petroleum accumulation in China:Exemplified by the Tarim Basin

Most of petroliferous sedimentary basins in China have experienced multiple phases of tectonic evolution and deposition, and are characterized by tectonic and depositional superimposition. The term "superimposed basin" is suggested to describe those basins which consist of two or more simple prototype basins superimposing vertically and/or coalescing laterally. The characteristics of petroliferous superimposed basins are "multiple stages of basin forming and reworking, multiple layers of source rocks, multiple periods of hydrocarbon generation and expulsion, multiple periods of petroleum migration-accumulation-escape". Therefore,applying the wave process analysis method to studying the process of basin formation, hydrocarbon generation, and reservoir formation, and then establishing theory of "petroleum accumulation system" is helpful to enhancing petroleum exploration efficiency in superimposed basins.This paper will, based on case study in the Tarim basin, report the major developments in studying basin formation, hydrocarbon generation and petroleum accumulation. In study of basin formation, (1) geophysical comprehensive profiles reveal that the Tarim plate has been subducted beneath the Tianshan orogenic belt with an interfinger structure and that the deep structure in the eastern section of the Tianshan orogenic belt is different from that in the western section. (2) The vertical variation in debris and geochemical composition reveals the nature and Mesozoic-Cenozoic evolution history of the Kuqa Depression. (3) Field investigation and paleostress reconstruction show that the Kuqa Depression has undergone gravity-driven extension in sedimentary cover when the Tianshan uplifted vertically. In hydrocarbon generation study, new developments include (1) setting environmental index to judge high grade source rocks in marine carbonates, and (2) establishing the lower limit of the organic carbon content for effective carbonate source rocks. In petroleum accumulation study, (1) methods of determining paleopressure and paleotemperature of forming fluid inclusions have been established. (2) The petroleum source analysis has indicated that the crude oil in the Lunnan and Tahe oilfields are derived from the source rocks of the Middle and Upper Ordovician. (3) Three generations of oil inclusions from the Lunnan oilfield have been recognized and dated.     

Hydrocarbon accumulation in network and its application in the continental rift basin

The concept of hydrocarbon accumulation in network was presented on basis of the overall analysis of the formation and evolution characteristics of the continental faulted basin and of the systemic re-search on the major controlling factors on the hydrocarbon accumulation. The hydrocarbon accumu-lation in network can be defined as hydrocarbon accumulation in a three-dimensional network system which is constituted by the hydrocarbon migration passages under multiple dynamics,following the hydrocarbon generation from source rocks. The research shows that the hydrocarbon accumulation in network is composed of four elements,i.e.,hydrocarbon source (source rock kitchen),hydrocarbon accumulation terminal (trap),network pathway connecting source and terminal (transporting system),and network potential driving hydrocarbon migration in the network pathway (migration dynamics). Compared with other networks,hydrocarbon accumulation in network has three basic characteristics: the irreversible geological process of material and information flow in the network; the loss of material and information in the flow process in the network; the multiple dynamics in the flow process. Interac-tion of all the elements in the geological process can be called hydrocarbon accumulation in network. There are three basic models for hydrocarbon accumulation in network,that is,hydrocarbon accumu-lation in the network source area,hydrocarbon accumulation in the network pathway,and hydrocarbon accumulation in the network terminal. The key in the application of the hydrocarbon accumulation models in network in practice is to confirm the major accumulation stage and the function range of the four elements controlling the hydrocarbon firstly,to predict the profitable accumulation region by su-perposition of the favorable areas confirmed by four elements consequently,and to evaluate the oil-bearing property of the trap as well as confirm drilling targets. This paper takes the Dongying De-pression in the Bohai Bay Basin as an application example.     

塔里木盆地下古生界烃源岩二次生烃范围研究

塔里木盆地是一个多旋回叠合盆地,下古生界烃源岩具有典型的二次生烃特征.当前关于二次生烃的研究集中在通过热模拟方法认识生烃机理和模式等方面,关于典型盆地二次生烃发生范围、分布规律、影响因素研究相对较少.本文在认识塔里木盆地构造背景和热演化规律的基础上,选取不同构造单元具有代表性的50余口井,利用Basin Mod 1D盆地模拟软件对多口井进行烃源岩成熟史模拟,结合现有的镜质体反射率数据,研究奥陶系和寒武系烃源岩是否存在二次生烃以及二次生烃发生时期和规律.综合分析单井模拟结果发现,奥陶系烃源岩二次生烃发生范围分布在沙雅隆起、卡塔克隆起中部和古城墟隆起西端,寒武系烃源岩二次生烃发生范围分布在沙雅隆起、巴楚隆起和卡塔克隆起中部.不同构造单元二次生烃开始的时间不同.二次生烃生烃史受盆地构造-热演化史控制,且对油气藏形成和分布有一定影响.     

Tectonic stress field and its effect on hydrocarbon migration and accumulation in Mesozoic and Cenozoic in Kuqa depression, Tarim basin

Through rock acoustic emission experiments and structural deformation analysis, the tectonic stages in Meso-Cenozoic in the Kuqa depression of the Tarim basin are firstly divided. Then, combining with rock magnetic fabric analysis and memory information, the distribution characteristics of tectonic stress field of every tectonic stage are quantificationally resumed. At the same time, according to the distribution relation of tectonic stress field of hydrocarbon formation stage by the finite element numerical simulation method and the known hydrocarbon reservoirs, the effects of tectonic stress field on hydrocarbon migration and accumulation are further analyzed. The Kuqa depression has mainly experienced six tectonic movements since Mesozoic. Except that the tectonic stress field of the Early Yanshan stage (208-135 Ma) showed northeast-southwest extensional stress field where the orientation of the maximum principal compressive stress (σ1) was northwest-southeast, the others were compressive stress field where the orientations of the maximum principal compressive stress (σ1) were near north-south. Along with the closure of the paleo-Tethys ocean, the Kuqa depression in the Indosinian stage (250-208 Ma) was in strong compressive circumstance with apparently big maximum principal stress (σ1) magnitude. Due to the equilibrium adjustment of interior Eurasia, the Kuqa depression in the Early Yanshan stage (208-135 Ma) was in weak extensional circumstance with apparently small maximum principal stress (σ1) magnitude. From the Late Yanshan stage (135-65 Ma) on, with a series of collision events occurring at the south edge of Eurasia, the Kuqa depression was in compressive circumstance again in which the maximum principal stress (σ1) magnitude was from small to big in turn. The Late Himalayan stage (2.6-0.7 Ma) was the main tectonic deformation stage with the biggest principal compressive stress (σ1) magnitude. Tectonic stress field plays a dominant role in hydrocarbon formation, it not only forms migration channels and trap structures for hydrocarbon accumulation, but also is the main drive power for hydrocarbon migration vertically along faults.     

2003年2月24日新疆巴楚-伽师6.8级地震发震构造

2003年2月24日发生在新疆塔里木盆地的巴楚-伽师6.8级地震可能是1997—1998年伽师强震群的继续,但其震源机制解、破裂过程与1997—1998年的强震群有一定的差别。从地震重新定位的结果看,巴楚-伽师6.8级地震与塔西南坳陷东侧麦盖提斜坡带上发育的一组NWW向隐伏逆断层有关,地震宏观考察①所发现的与构造变形有关的地裂缝也与这一隐伏断层带的位置相吻合,等震线形态与隐伏断层带的走向一致,极震区的形态与断层的破裂方向基本一致。这些均表明这次地震是盆地内一条近EW向北倾逆断层自NW向SE由深至浅破裂的结果     

渤海新构造运动及其对晚期油气成藏的影响

自中新世晚期（大约5.2 Ma B.P.）以来,渤海海域盆地进入裂后构造活动最活跃的新构造运动时期,致使渤海海域沉降沉积中心迁移、玄武岩喷发、地震频繁活动、深大断裂继承性活动和大量晚期断裂的生成．该期构造运动海域强度明显高于相邻陆域,呈现出幕式活动的特征．在新构造运动的影响和控制作用下,渤海海域含油气盆地形成了一批大型浅层背斜圈闭,油气输导体系得到优化,烃源岩晚期快速生烃,油气幕式充注成藏．本文以PL19-3油气藏为例,初步总结了渤海新构造运动控制油气晚期快速动态成藏的模式．     

沉积盆地形成的张性模式

在过去的十余年中,对沉积盆地的成因已取得了很大进展,并提出了许多定性和定量的模型。本文旨在对张性盆地进行讨论,并简要分析影响盆地发展的主要因素和导致岩石圈内部张应力的力源。本文对三种主要模型进行了详细讨论,即纯剪切模型,简单剪切模型和纯剪切－简单剪切联合模型。所有模型虽都建立在对不同盆地的研究基础之上,但它们都揭示出盆地的发展主要受岩石圈内部热动力学过程和沉积物负载作用的控制。其它因素,如拆离面的     

Rifting and basin inversion in the eastern margin of the Japan Sea

Abstract Extensional basin formation and subsequent basin inversion in the southern area of the eastern margin of the Japan Sea were studied on the basis of the interpretation of seismic profiles (total length approximately 15 000 km) and the fossil analyses of 77 sea-bottom samples. Rift (Early to Early Middle Miocene), post-rift (Middle to Late Miocene), pre-inversion (Late Miocene to Pliocene) and inversion stages (Pliocene to Quaternary) were differentiated by the extension and contraction of the crust. Many small-scale rifts were formed in the Sado Ridge and the Mogami Trough during the rift stage, simultaneous with back-are spreading of the Japan Sea. Most of the rifts were east- or southeast-facing, rotational half-grabens bounded by west-dipping normal faults at their eastern boundaries. The syn-rift sequence can be divided into lower and upper units by an erosional surface. The sequences are presumed to be composed mainly of fining-upward sediments. The trend of most rifts is north-northeast with the remainder being of east-northeast-bias. The north-northeast trending rifts are distributed widely in the Sado Ridge and Mogami Trough and do not show an en échelon arrangement, suggesting that they were formed mainly by pure extension nearly perpendicular to the arc. The east-northeast trending rifts are presumed to have been developed by a north-northwest extension in the late rift stage, which may have accompanied a right-lateral movement in the eastern margin of the Japan Sea. During the post-rift stage, the rifts and adjacent horsts subsided and became covered by the post-rift sequence, characterized by parallel and continuous reflections. This suggested no significant tectonic movements in this period. In the pre-inversion stage many of the rifts subsided again, presumably because of down-warping due to weak compressional stress. The normal faults reactivated as reverse faults during the inversion stage due to an increase in compressional stress. Many of the rifts have been uplifted and transformed into east-vergent asymmetric anticlines. The basin inversion is greatest in the Sado Ridges and in the Dewa Bank Chain, while it is least developed in the Mogami Trough and in the western slope of the Sado Ridge, in which some normal faults have not been reactivated. The increase and decrease of the inversion corresponds to the peak and trough of undulation at an interval of about 50 km trending parallel to the arc.     

帕米尔东北缘及塔里木盆地西北部弧形构造的扩展特征

归纳了帕米尔东北缘弧形构造的基本特征 ,分析了塔里木盆地西北部EW向逆断裂背斜带与NNW向隐伏走滑断裂之间的关系。通过塔里木盆地与西南天山和帕米尔东北缘变形特征的对比 ,认为塔里木盆地西北部的变形样式与帕米尔东北缘的弧形构造类似 ,弧形构造具有由帕米尔东北缘向塔里木盆地扩展的特征 ,这种构造是帕米尔向北挤入运动所特有的变形样式     

近年新疆地震围绕塔里木盆地的顺时针迁移与塔里木盆地的顺时针旋转

塔里木盆地是我国最大的内陆盆地,作为稳定地块,被周围许多深大断裂所围限.王琪等(2000)基于天山及塔里木地区多年的GPS观测结果,认为塔里木盆地整体上作为刚性块体,相对于稳定的西伯利亚地块作顺时针旋转,其内部变形较小或基本不变形.赵俊猛等(2008)应用人工地震和天然地震等综合地球物理探测方法,获得青藏高原壳幔组成、...     

塔里木盆地东缘的若干大地构造问题

塔里木盆地向东在什么地方结束,大盆地是如何与天山地槽分界的,文中对这些问题给出了回答。指出塔里木盆地在E91°附近结束,不再向东延伸。另外新发现了两条重要的岩石圈断裂,它们是塔里木中央纬向（北40）深断裂和罗布庄—尾亚深断裂。根据新获得的区域航磁和地质资料,对这个神秘的地区,提出了一个新的大地构造分区方案。     

浅析太原台记录太原盆地地震波形的特征

选用太原台DD—1仪记录到的太原盆地多种波形并将其整理归纳，总结出了横穿和纵穿盆地到达记录台站的两种波形特点，并分析了它们呈现该特征主要是源于波在传播过程中地壳厚度分布不均、震源机制以及各种波本身的物理性质不同而造成的。     

焉耆盆地活动构造的遥感图像特征

焉耆盆地是一个位于天山东南部的山间盆地 ,在遥感图像上 ,可以看到盆地西面的活动构造在地表留下的痕迹 :清楚的线形构造 ,被错开的水系、冲沟等。经分析认为 ,这些活动构造主要由北边的活动褶皱和南边的右行走滑活动断裂组成。野外的实际调查与图像分析的结果十分吻合 ,表明遥感图像在研究活动构造方面是一个十分有力和快速的工具。活动断层的最大水平位移为 2 10m ,最大垂直位移为 2 0m ,主要以走滑作用为主。天山地区活动构造的发育表明印度板块向欧亚板块的碰撞仍在持续     

河北矾山盆地第四纪活动构造分析

从沉积地层、地貌和构造等方面概述了矾山盆地的基本地质特征。提出矾山盆地是延——怀盆地中的一个相对独立的构造盆地。根据新发现的活动断裂剖面,论述了矾山盆地的构造活动性,指出矾山盆地形成于中更新世初,各主要断裂在晚更新世有强烈活动。     

塔里木盆地东缘的若干大地构造问题

塔里木盆地向东在什么地方结束,大盆地是如何与天山地槽分界的,文中对这些问题给出了回答。指出塔里木盆地在E91°附近结束,不再向东延伸。另外新发现了两条重要的岩石圈断裂,它们是塔里木中央纬向（北40）深断裂和罗布庄-尾亚深断裂。根据新获得的区域航磁和地质资料,对这个神秘的地区,提出了一个新的大地构造分区方案。     

塔里木盆地地球动力学演化与含油气系统旋回

论述了塔里木盆地的地球动力学演化过程,指出震旦-三叠纪和侏罗-第四纪是两个构造巨旋回．在这类旋回中,盆地经历了由伸展到聚敛的完整发育过程塔里木盆地的演化总体上表现为强伸展-聚敛-微伸展-强聚敛的特点盆地动力学旋回决定了油气的生运聚散过程．提出含油气系统旋口的概念．在分析寒武-奥陶系含油气系统旋回、石炭系-下二叠统含油气系统旋回和侏罗系含油气系统旋回的基础上,指出对含油气系统旋回的形成期与调整再分配期的研究更具实际意义．