【作者】 李洪博；

【导师】 梅廉夫；

【作者基本信息】 中国地质大学 ， 能源地质工程， 2010， 硕士

【摘要】 惠州凹陷作为珠江口盆地的油气主产区,是已证实的富烃洼陷。东沙隆起是临近惠州凹陷重要的油气聚集区,在东沙隆起上及隆凹过渡边缘勘探也发现了很多油气藏和含油构造,且证实了惠州凹陷的优势烃源供应,因此东沙隆起是在惠州凹陷成油体系范围内的,并具有很好的油气远景的有利区带。受勘探历史和研究程度的限制,东沙隆起结构、构造及演化等方面研究比较薄弱,且缺乏统一的隆凹联合研究思路。本文在现代石油地质理论及盆山耦合理论研究指导下,以隆凹一体化为切入点,以凹陷研究带动隆起研究为思路,以多种数据、技术、模拟等综合分析为手段,从隆凹格局及构造特征、联合演化特征及油气成藏关系等几个方面出发,在一定程度上丰富勘探新领域,完善东沙隆起惠州凹陷及东沙隆起耦合关系。1、惠州凹陷及东沙隆起在同一构造应力场作用下耦合存在,在结构、构造上存在一定的响应关系和差异性。惠州凹陷断陷期隆洼结构构造复杂,而东沙隆起此时由于持续隆升未沉积文昌及恩平地层,只是局部发育一些小型恩平期断陷,结构构造相对简单。凹陷内部发育多个洼陷结构,以断隆联控型为结构样式,并发育多级隆起构造。断裂体系也具有不同的级别和控制作用,分别为一级控凹型、二级控洼型和三级调节型。断层走向大致分为NE或NEE向、NW或NWW向和近东西向三类,这与东沙隆起断层走向是一致的,体现了应力场的统一控制作用。惠州凹陷和东沙隆起受先存构造控制明显,东沙隆起上表现为“三阶两脊一过渡”的构造形态和地层逐层超覆结构特征,惠州凹陷则表现为基底潜山控制沉积充填和复合半地堑结构特征。在拉张应力场作用下,惠州凹陷构造样式表现为张性断块为主,伴随扭动因子的存在,其断块类型也存在张扭性断块,因此可以识别出背斜潜山披覆构造、同向掀斜断块、反向掀斜断块、半地垒披覆构造、地垒构造、断层相关褶皱构造、牵引滑动构造等几种典型构造组合特征。2、从珠江口盆地所处的大地构造位置来讲,受到来自印度板块、欧亚板块的挤压碰撞,以及太平洋板块的俯冲挤压的影响,控制并决定了其形成条件及复杂的演化进程。在多期复杂的构造应力背景下,隆凹耦合更具有多期性和相互匹配性。惠州凹陷是典型的断陷盆地,具有完整的断陷演化序列,与不同演化阶段的东沙隆起构造特征相匹配,结合构造发育史及古构造演化图,将惠州凹陷及东沙隆起联合演化分为四个时期：①晚白垩世至古新世,强烈断块活动,隆凹格局初步形成；②晚始新世至早渐新世,强烈构造运动,隆起快速剥蚀与凹陷抬升相耦合；③晚渐新世至早中新世,拗陷作用为主,隆起持续沉降与凹陷沉降相匹配；④中中新世至上新世,断块活化作用,隆起先升后降与凹陷先隆后沉相匹配。惠州凹陷在晚始新世至早渐新世构造演化复杂,而东沙隆起表现为快速的隆升。通过剥蚀厚度恢复及盆地原型分析,断陷期惠州凹陷两幕演化具有一定的继承性,但恩平幕断陷作用减弱,洼陷逐渐连通；断陷作用范围扩大,在北部断阶带和南部东沙隆起均分布有恩平期断陷。3、讨论构造演化与成藏关系,选取了HZ27-3及LH11-1两个典型的油气藏进行解剖。对Hz27-3含油构造解剖分析,具有烃源充足、断层或地层复杂运移路径、多种圈闭样式叠合及近源成藏的特点,LH11-1油藏的分析,具有大型生物礁滩圈闭,珠海组高孔高渗的砂岩输导体,同时验证了惠州凹陷及东沙隆起沿构造脊长距离油气运移的存在。总结起来构造演化对不同时期储层建造和改造有重要作用,晚渐新世至早中新世是构造脊形成的重要时期,为LH11-1油气成藏做了突出贡献,形成了以“边界断裂—珠海组砂岩输导体—不整合面—构造脊—礁滩油气藏”的优势运移通道。揭示了不同构造演化阶段在东沙隆起上建造不同类型的圈闭,纵向上表现为“基岩潜山—披覆背斜—生物礁滩—地层或岩性”的圈闭配置关系,横向上的地层超覆关系和岩性展布特征,也是控制超覆圈闭、砂岩透镜体和上倾尖灭圈闭的重要因素。更多还原

【Abstract】 The Huizhou depression is a confirmed depression with rich hydrocarbons, which is a major producing area of the Pearl River mouth basin. The Dongsha Massif is a important hydrocarbon accumulation adjacent with the Huizhou depression. Because mass hydrocarbon reservoirs and pay structures has been found in the Dongsha Massif and the transitionally peripheral uplift and depression area, the prevailing hydrocarbons source has displayed in the Huizhou depression, the Dongsha Massif is profitable hydrocarbon potential ranges in the range of petroleum system, the Huizhou depression. The study on the Dongsha Massif architecture, structure and evolvement is weak dimension, especially the joint study methods of uplift and depression is lack and little. The fundamental purpose is reinforced study on the relation with the Huizhou depression and the Dongsha Massif by analyzing the upwarping-downwarping pattern of the basin, the structural feature, the joint evolution and the hydrocarbon reservoir forming, taking the modern oil geological theory and basin-mountain coupling as a guide, taking integration of uplift and depression as a breakthrough point, taking the comprehensive analysis of the multiple dates, the methods and the modeling as new measures. It’s enriching exploration targets.(1)Huizhou Depression and Dongsha Massif coupling exists at the same tectonic stress field and they have certain response relationship and differences to each other. Huizhou depression formed the complex structure with the Massif alternating with the low-lying; however, Dongsha Massif losted the Wenchang and Enping strata because of continuing uplift at that time, only some small faults developed partially during the Enping period, and the structure of the Dongsha Massif is relatively simple. Several low-lyings exsist as the structural style of combined controlling by the faults and upthrusts in the internal of the depression as well as multi-level uplift structure. Fault system also has different levels and the role of controls, respectively, concave control, low-lying control and regulation. Faults are divided into three types:the NE or NEE, NW or NWW and near EW directions which are consistent with the Dongsha Massif and this is the just reflection of the controlling of the unified stress field. Huizhou Depression and Dongsha Massif are controlled by the pre-exsisting structure significantly:in the Dongsha Massif it register as structures morpha of "three terrace- two ridges -one transition" and the structure character of ground layer overlap; Huizhou depression is shown as substrate controlling the deposition filling and composite half-graben structure characteristics. In the extensional stress field, the structural styles of Huizhou depression shows as mainly for the tension block, with the presence of the twist factor, shear type of block companied, wherefore Buried Hills anticline, the tilting off block, reverse tilted fault block, half base drape structures, horst structure, fault-related fold, traction slip fault characteristics such as composition of several typical structures can be identified.(2)Being established in the tectonic location of the Pearl River Mouth Basin, the study area consequents upon the following factors, the pressing and collision between the India plate and Eurasian plate, the subduction belt of Pacific plate. And those factors control its forming and complex evolution. Coupling upwarding and depression presents multiphase and couple mechanism under the multiphase tectonic setting. Huizhou depression is a classic faulted basin, and with integral evolution of faulted depression. Huizhou depression and the Dongsha massif are coupling on the tectonic feature during the evolution. The paper establishes in the structural history, palaeostructure maps, and classifies the evolution of study area into four phases. The followings:①Late Crataceous-Palaeocene, strong block movement, formed the initial frame of upwarding and depressionging;②late Eocene-early Oligocene, strong tectonic movement, coupling the fast denude on uplifting and the uplift of depression;③late Oligocene-early Miocene, depression in the predominant, the uplift coupling with depression on duration subsidence;④Middle Miocene-Pliocene, block activization, coupling the elevation and subsidence of uplift with the subsidence and elevation of depression. Huizhou depression during late Eocene-early Oligocene has the complex evolution; however, Dongsha massif displays the fast uplifting.(3)For discussing the relationship between tectonic evolution and accumulation, this paper selects two typical oil and gas reservoir of HZ27-3 and LH11-1 to autopsy. The anatomical analysis of Hz27-3 oil-bearing structures suggest that Hz27-3 has the features of enough source rocks, complex migration path of faults or stratum, composite multi-trap style and reservoir near the source. The analysis of LH11-1 suggest that LH11-1 characters with a large reef trap, high porosity sandstone transmission conductor of Zhuhai formation, and verify the existence of long-distance oil migration in the Huizhou Depression and east Sharon along the structural ridge. We have the conclusions that tectonic evolution plays an important role in the construction and transformation of reservoir of different periods and late Oligocene to early Miocene is an important period for the formation of structural ridge, making outstanding contributions for the LH11-1 oil and gas accumulation, engendering the dominant migration pathway of "boundary fracture-sandstone transmission conductor of Zhuhai formation-unconformity-structural ridge-reef reservoir ". This paper revealed that the different stages of tectonic evolution in East Sharon built different types of traps, and suggest the character of "rock hill-drape anticline-reef-stratum or rock" traps configuration relations in cross, and the overlap of stratum relations and lithology distribution in horizontal, which control the overlap trap, sand lens and the tilting wipe out an important factor in traps.更多还原