【作者】 闵慧；

【导师】 任建业；

【作者基本信息】 中国地质大学 ， 海洋地质， 2011， 硕士

【摘要】 论文主要从富烃凹陷的概念及其构造控制要素总结分析入手,通过对惠州凹陷进行详细的地震剖面解释,确定盆地的结构特征构造特征；划分盆地的构造阶段,确定其沉降演化过程；分析惠州凹陷的石油地质特征；对盆地的静态构造要素和动态构造要素进行定量化分析；在此基础上确定惠州凹陷这类富烃凹陷的构造定量化指标。论文取得的主要认识如下：1.综合盆地结构、构造及沉降演化史分析的结果,可将盆地的新生代演化划分为三个演化阶段：即断陷期(文昌组—恩平组)、断坳转换期(珠海组)、拗陷期(珠江组—今),其中断陷期以T8为界面又可划分为两幕。断陷Ⅰ幕控制了文昌组的沉积,为惠州凹陷强烈断陷期,该时期盆地发育孤立的、由断层控制的单个地堑或半地堑,常有一套频率较低,能量较强,同相轴较连续的反射层,是文昌组中深湖相泥岩的标志性反映,也是凹陷内的主要生烃岩系；断陷Ⅱ幕控制了恩平组的沉积,结束了早期的分隔性的孤立断陷的发育,所形成的断陷盆地广覆于下部的地堑或半地堑式的断陷之上,—般为河沼—滨湖相,也是比较重要的生烃和储层岩系。2.惠州凹陷发育丰富的有利油气聚集的构造样式,组成了惠州凹陷主要的油气圈闭。惠州凹陷新生代演化的不同时期形成了类型丰富的构造样式,主要有同向掀斜断块、反向断块、堑垒构造、潜山披覆构造、滚动背斜构造及挤压背斜构造、单断山、基底挠曲背斜、沉积滚带背斜等等。这些不同类型的构造—地层的组合样式,可以形成基岩隆起上的披覆背斜圈闭以及断裂两侧的背斜和半背斜圈闭等主要的油气圈闭类型,为油气的聚集提供了可利用的空间。3.通过物理模拟实验结果对比分析、动力学背景等方面综合研究认为惠州断陷是典型的斜向拉伸裂谷盆地。古新世南海北部形成的一系列北东向断裂控制了珠江口盆地的基本格局,后期古南海俯冲导致南海北部地区发生南北向断陷作用并导致南海扩张,一直持续至南海扩张停止。这两个因素共同控制了惠州凹陷的发育,使惠州凹陷成为典型的斜向拉伸裂谷盆地。将惠州凹陷与K.R.McClay等人的沙箱模拟实验对比可见,导致惠州凹陷斜向拉伸作用力与盆地边界走向之间的角度约为60°。4.总结了惠州凹陷作为富烃凹陷发育的静态构造要素及动态构造要素定量指标。重点对惠州凹陷中惠州26洼、西江24洼、陆丰13洼和外围番禺四洼四个洼陷内能表征富烃洼陷的一些静态构造要素和动态构造要素进行了定量计算和分析,并以此为基础提炼了富烃凹陷的主要定量构造要素指标,即烃源岩的埋深和厚度,烃源岩段的沉降速率及断层活动速率等。具体是：这四个富烃洼陷烃源岩层段最大顶界埋深都超过了4000米,其中文昌组烃源岩最大底界埋深都超过了6000米,恩平组烃源岩最大埋底界深都超过了5600m；各个洼陷内文昌组和恩平组烃源岩厚度都超过了1500米,陆丰13洼文昌组烃源岩甚至达到3000米；各主力烃源岩段发育时期的断层活动速率也都比较高,都超过了140 m/Ma,尤其是文昌组断层活动速率都超过了150m/Ma,特别是陆丰13洼和惠州26洼,文昌组断层活动速率都超过了250 m/Ma,恩平组烃源岩的断层活动速率略小,在150 m/Ma左右；各洼陷主力烃源岩段发育时期,盆地的沉降速率也都较高,尤其是文昌组,沉降速率均超过了270m/Ma,陆丰13洼和惠州26洼最高,在400m/Ma左右。恩平组烃源岩发育时期盆地的沉降速率稍低但也在160m/Ma左右。5.惠州凹陷后期断裂活动形成的断层及继承性活动的控凹边界断层是后期油气运移的优势通道。对惠州凹陷及外围共4个富烃洼陷的结构构造研究发现,这些富烃凹陷后期都遭受了构造活动的叠加和改造。在后期构造活动中早期断层可以继承性活动或者产生的一系列新断层通过沟通深部的烃源岩层与浅部的储集层,构成油气输导的优势通道。更多还原

【Abstract】 Huizhou depression has been confirmed as a typical hydrocarbon-rich depression in offshore of China. Based on the concept of hydrocarbon-rich depression and its tectonic control elements, this thesis in-depth study the textures and structures of Huizhou depression and its sedimentate process,especially quantitative determinate and analyse the static and dynamic structural elements of Huizhou depression which provide practical basis for determination quantitative indicators structural elements of hydrocarbon-rich depression in offshore of China. The main results in the thesis are as follows:1. Integrated the textures, structure and evolution of sedimentation result of Huizhou depression,its Cenozoic evolution can be divided into three evolutionary stages:rift period (Wenchang to Enping), conversion from rift to depression period (Zhuhai), depression period (Pearl to today). Rift period can be divided into two episodic rifting by interface T8.The fist episodic rifting controlled of the Wenchang formation’s deposition, which is strongly rift period of Huizhou depression, isolated half graben or graben controlled by fault developed in this period and there were a lower frequency with stronger swing and continuous phase axis reflective layer which is the landmark reflection of Wenchang formation’s deep lacustrine mudstone,Tt is also the main hydrocarbon source rocks in Huizhou depression. The second episodic rifting controlled of the Enping formation’s deposition, which finished the development of early separated and isolated fault deposition, the early graben or half graben fault deposition was widely covered,it is usually river marsh-lake phase, which is also an important hydrocarbon source rock and reservoir rock.2. Huizhou depression developed abundant structural style which benefict for oil and gas accumulating,and those structural style compose oil and gas trapstypes of the depression. Huizhou depression formed different types of structural style during the Cenozoic evolution, including:the same direction tilted fault block, reverse direction tilted fault block, horst, buried hills, rolling anticline, extrusion anticline, mono-faulted hill,floor inflex anticline,sediment rolling anticline and so on. These different types of tectono-stratigraphy style can form anticline covered on bedrock uplift and anticline or half-anticline of both sides of the fault traps and other types of oil and gas trapstypes, which provide available oil and gas accumulation space. 3. By comparative analysing the result of physical simulation and dynamics factors, it is believed that Huizhou depression is a typical oblique stretching rift basin. A series east-northern fault controled basic pattern of the Pearl River Mouth Basin in the Paleocene. Later Ancient Nanhai’s subduction led to north of the South China Sea’s expanding with south-north rift and it continued until South China Sea stop expanding. Both these two factors controled the development of Huizhou depression and made it as a typical oblique stretching rift basin. Comparing between Huizhou depression and K.R.McClay’s sandbox simulation, the results of 60°diagonal tension is similar to the Huizhou depression, which confirmed that Huizhou depression is a oblique stretching depression.4. Epurate quantitative static and dynamic structural element indicators of Huizhou depression. Emphasis on the sags of Huizhou 26sag, Xijing24 sag, Lufengl3 sag,Panyu 4 sag, this thesis quantitative determinate and analyse the static and dynamic structural elements of these sags, and based on this epurate quantitative structural element indicators of hydrocarbon-rich depression, including the thickness and the depth of source rocks, sedimentation rate and fault activity rate. the maximum up depth of hydrocarbon source rocks of these four hydrocarbon-rich sags is more than 4000 meters; the maximum down depth of hydrocarbon source rocks of Wenchang Formation is more than 6,000 meters; the maximum down depth of hydrocarbon source rocks of Enping Formation is more than 5,600 meters. The maximum thickness of Wenchang and Enping formation is more than 1,500 meters in every sag, and in Lufeng 13 sag, the maximum thickness of Wenchang formation is more than 3,500 meters. the fault activity rate in the period when the main source rock developed is also high, which is more than 140 m/Ma, the fault activity rate of Wenchang Formation is more than 150 m/Ma, especially in Huizhou 26 sag and Lufeng13 sag, the fault activity rate of Wenchang Formation is more than 250 m/Ma, but the fault activity rate of Enping Formation is lower. the sedimentation rate in the period when the main source rock developed is also high especially Wenchang Formation which is more than 270m/Ma, the fault activity rate of Huizhou 26sag and Lufengl3sag is more than 400m/Ma higher than Xijing24 sag and Panyu 4sag, but the sedimentation rate of Enping Formation is slightly lower about 150m/Ma.5. early faults’ inherite activity and a series of new faults generated in latter tectonic activity, are the predominant pathway of oil and gas transportation. By study the textures and structure of four hydrocarbon-rich sags, it is found that all of these sags suffered superposition and transformation by tectonic activity.The early faults could inherite activity and a series of new faults generated in latter tectonic activity, which constituted the predominant pathway of oil and gas transportation through deep source rocks and shallow reservoirs.更多还原