塔里木盆地古城地区奥陶系鹰山组层序地层划分及其地质意义

发布时间：2018-05-27 13:05

本文选题：层序地层学 + 奥陶系　；参考：《东北石油大学学报》2017年01期

【摘要】：为研究塔里木盆地古城地区储层、确定奥陶世沉积环境并建立层序地层格架,分析古城地区中下奥陶统岩石学、地震与测井特征,并对5口井岩心及井壁取心进行碳、氧同位素实验。结果表明:古城地区鹰山组划分为两个三级层序,SQ1沉积时期发育弱镶边结构的半局限—开阔台地沉积,顶部层序界面SB2为平行不整合面,下部经历早成岩期岩溶作用,是研究区储层规模化发育的主控因素;SQ2沉积时期受到快速海侵,由半局限台地转变为开阔台地沉积,层序界面SB3的暴露规模与强度小于SB2的,对区域性储层发育控制能力较弱;层序SQ1及SQ2的分界在岩石地层单位上大致与鹰山组三段白云岩及鹰山组二段灰岩的分界对应,界面附近表现显著的碳同位素负漂移。在三级层序划分基础上,在SQ1内部识别8~9个四级层序,在SQ2内部识别4~6个四级层序,其中海侵体系域主要表现为对称性良好的加积型叠置样式,高位体系域表现为向上变浅的加积—进积型叠置样式;四级层序界面对储层的控制作用有限,主要发育准同生期岩溶作用,与古地貌较高部位叠合在小范围内并形成孤立透镜状储层。古城地区奥陶系受加里东运动影响较小,不发育隆起显著的风化壳型岩溶。有利沉积相带与三、四级层序界面叠合区是区域性优质储层的主要勘探目标。
[Abstract]:In order to study the reservoir in Gucheng area of Tarim Basin, determine the sedimentary environment of Ordovician and establish sequence stratigraphic framework, analyze the petrology, seismic and logging characteristics of middle and lower Ordovician in Gucheng area, and take carbon from core and wall of 5 wells. Oxygen isotope experiment. The results show that the Yingshan formation in Gucheng area can be divided into two semi-localized-open platform deposits with weak edge structure developed in the third order sequence SQ1 sedimentary period, the SB2 at the top sequence interface is a parallel unconformity surface, and the lower part is karstification during the early diagenetic period. It is the main controlling factor of reservoir development in the study area that SQ2 is under rapid transgression during the sedimentary period, from semi-limited platform to open platform, the exposure scale and intensity of SB3 in sequence interface is smaller than that of SB2, and the ability to control the development of regional reservoir is weak. The boundary of sequence SQ1 and SQ2 corresponds roughly to the boundary of dolomite and limestone of the third member of Yingshan formation and the second member of Yingshan formation on the lithostratigraphic unit. The boundary of sequence SQ1 and SQ2 shows significant negative drift of carbon isotope near the interface. On the basis of third-order sequence division, 8-9 fourth-order sequences are identified within SQ1 and 4-6 four-order sequences are identified within SQ2. Transgressive system tracts are characterized by well-symmetric and accretive overlay patterns. The upper system tract is characterized by an upward shallower accretion-precession type superposition, and the fourth sequence interface has limited control over the reservoir, and the quasi-syntectic karstification is mainly developed. Superimposed with the higher paleogeomorphology in a small area and formed an isolated lenticular reservoir. The Ordovician in Gucheng area was less influenced by Caledonian movement and did not develop weathered crust karst. The favorable sedimentary facies zone and the third and fourth order sequence interface overlap area are the main exploration targets of regional high quality reservoirs.
【作者单位】：中国石油勘探开发研究院;
【基金】：国家科技重大专项(2011ZX05004-001)
【分类号】：P618.13;P534.42

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