【作者】 汪旭东；

【导师】 查明；

【作者基本信息】 中国石油大学 ， 矿产普查与勘探， 2011， 硕士

【摘要】 本文是在充分调研国内外关于超压研究的新理论、新方法的基础上,利用东营凹陷丰富的资料,并充分吸收了前人研究成果,针对东营凹陷压力系统特征、压力演化史、超压发育演化的主控因素等3方面问题,开展了压力系统划分、超压顶界面确定、超压定量计算、古压力恢复等研究,进一步明确了东营凹陷中深层的压力系统特征和超压的发育演化史,建立了超压发育与演化的多因素耦合关系。东营凹陷超压主要分布于沙三中、下及沙四上亚段的中深部地层中；超压顶界面主要分布于沙三中亚段(T4与T6反射界面之间),具有一定的“层控性”,而不具有前人提出的“等深性”特征；超压封闭层为一组深灰色泥岩、钙质泥岩及砂质泥岩的组合,泥质岩的成岩作用处于伊/蒙混层矿物的迅速转化期,且对应于第一、二期碳酸盐的大量产出段。超压顶界面的分布受构造和沉积的双重控制作用,其中岩性组成和沉积速率控制了超压顶界面分布的层位,而构造活动对超压顶界面的控制具有阶段性——断陷期的构造活动促使超压体系的形成,而拗陷期的构造活动则控制了超压顶界面的现今埋藏深度。通过丰富的实例证明超压系统内部由超压封闭层、超压带和超压降压带3部分组成,由此推测东营凹陷沙四下及其以下地层的压力状况以弱超压—常压为主；以此为基础,并结合盆地的构造及超压顶界面的分布特征建立了东营凹陷单井及剖面的压力系统分布模式。采用盆地数值模拟和流体包裹体热动力学模拟两种方法恢复了中深层的压力演化史,综合分析认为：东营凹陷超压最早发育于沙三上亚段沉积期,至东营组沉积末期剩余压力持续增大；东营运动中,各构造区均遭受抬升剥蚀,导致剩余压力降低,随着整个凹陷又开始沉降并接受沉积,剩余压力又逐渐升高。东营凹陷超压的形成主要受封闭层的形成、欠压实增压、生烃增压及剥蚀泄压等4方面因素的控制；分别讨论了这些因素的发生和发展过程,并建立了这些因素与超压发育演化的耦合关系。更多还原

【Abstract】 So as to research the characteristicsof pressure system of medium-deep strata and its evolution and the main controlling factors which cause the overpressure in Dongying Depression, the thesis has developed 4 respects of research, including pressure system division, the top overpressured surface confirming, overpressure quantitative calculation, and paleo-pressure reconstruction, based on previous study and underground data. After the research, the thesis further clarified the characteristics of pressure system of medium-deep strata and its evolution in Dongying Depression, and establishshed the coupling-matching associations between the process of overpressure evolution and the controlling factors which cause the overpressure.The overpressure located mainly in the middle and lower 3rd member and the middle upper 4th member of Shahejie Formation. And the top overpressured surface located mainly in the middle 3rd member of Shahejie Formation (between the seismic reflector T4 and T6). The seal formed by a group of dark gray mudstone, calcareous mudstone and sandy mudstone. Mudstone diagenesis reaches the rapid transformation of the illite-montmorillonite interlayer minerals, and corresponds to the mass outcrop sections of the first and second carbonate minerals.These characteristicss are primarily controlled by both sedimentation and tectonism. On one hand, the lithologic character and sedimentation speed of sediments controlled the distributed horizon of the top overpressured surface. On the other hand, the controlaction of tectonism on the distribution of the top overpressured surface could be divided into two different stages. In the stage of faulting, tectonic movements controlled the formation of overpressured bodies, and in the stage of depression, tectonic movements controlled the current burial depth of the top overpressured surface by controlling differential settlement of formation in two fault walls.The thesis proved that the inside of overpressure system is composed of 3 sections, which are the overpressured seal, overpressured belt and overpressured blowdown belt on the basis of prolific illustrations. According to this, the author inferred that the pressure situation in the lower 4th member of Shahejie Formation and its following formations was mainly weak overpressure to atmospheric pressure. On this basis, and combined with the structural characteristics and the top overpressured surface distribution of the basin, the author established the pressure system distribution pattern of single well and profile in Dongying Depression.Through numerical simulation and thermodynamic modeling of fluid inclusions, the pressure evolution history of medium-deep strata was studied. It is concluded that the overpressure was first developed in the upper 3rd member of Shahejie Formation depositional stage, and the excessive pressure was growing until the late Dongying formation sedimentary period. The excessive pressure was lowering in the period of Dongying Movement due to the uplift and erosion of formations, and it gradually increased again with the deposition in the basin.It is concluded that the formation of seal, the undercompaction, hydrocarbon generation and stratum denudation are the 4 main controlling factors to fluid pressure buildup. Then, the thesis researched the occurrence and development of these factors, and finally established the appropriate coupling-matching associations between these factors and the process of overpressure evolution.更多还原