东营凹陷古近系超压顶界面分布特征及其影响因素

Distribution of top of Paleogene overpressure system and its influencing factors in Dongying depression, Jiyang Basin，East China

关键词:  超压顶界面  分布特征  影响因素  古近系  东营凹陷

Key words:  top of overpressure  distribution characteristics  influencing factors  Paleogene  Dongying depression

摘要:

对比分析利用实测压力和超压层段的测井响应特征两种方法研究超压顶界面的优缺点，认为后者具有更加坚 实的理论基础,并采用该方法对东营凹陷古近系超压顶界面的分布特征及其影响W素进行研究。结果表明:古近系 超压顶界面主要分布于沙三中亚段的厚层泥岩中,反映在地震层序上为T4与^反射界面之间，表现出一定的“层控 性”特征,其埋藏深度主要为2. 4-2. 8 km,在平面上表现为M陷中心深而边缘浅的特征;超压顶界面之下的岩性为 一套以深灰色泥岩、灰质泥岩及砂质泥岩为主的泥质岩组合，泥质岩的岩性构成及沉积速率在一定程度上控制了超 压顶界面的层位分布，而抬升剝蚀、断裂活动及盐底辟作用是造成部分地区超压顶界面变浅的主要因素。

Abstract:

Pressure measurement and logging response analysis are two common methods used to study the top of overpressure (TOO) in petroleum industry. Due to the more reliable theory basis, the latter was used to analyze the distribution and influencing factors of the Paleogene TOO in Dongying depression, Jiyang Basin. The results show that ihe Paleogene TOO is mainly restricted within the thick mudstones in the middle part of the third member of Shahejie formation and corresponds to the interval between T4 and T6 reflecting interfaces in seismic sequences, which suggests the feature of strata-controlled. The burial depth of this TOO ranges from 2, 4 km to 2. 8 km and shallows from the central to the margin. Sedimentary rocks below the TOO are composed of dark grey mudstone, calcareous mudstone and sandy mudstone. The horizontal distribution of TOO is partly controlled by lithology and deposition rate of underlying argillaceous rock，while tectonic uplift and denudation, faulting movement as well as salt diapirsm are the primary causes of the shallowing of the TOO in certain areas.