潍北凹陷孔店组异常低压分布特征及成因机制-x修改稿_20141201101345207..docVIP

潍北凹陷孔店组异常低压机制摘 要：异常低压，主要分布在北部洼带孔二段中流体包裹体方法模拟方法恢复古压力油气充注时古压力系数1.12到1.66之间，表现为超压状态。凹陷压力场演化经历了“压力积累-压力释放-压力分异”三个阶段，古压力演化分为三种模式北部地区“超压-低压-弱超压”压力演化模式部地区“超压-低压-低压”压力演化模式南部地区 “常压-低压-常压”压力演化模式认为条件1 现今地层压力分布特征关键词：；盆地模拟； 中图分类号：TE 文献标识码：ADistribution characteristics and mechanism of Kongdian formation abnormally low pressure zones in Weibei Sag Abstract：Kongdian formation abnormally low pressure zones in Weibei Sag, abnormally low pressure mainly distributed in member 2 of kongdian formation of northern sag. Restored the ancient pressure by fluid inclusions and basin simulation methods, Found ancient hydrocarbon filling pressure coefficients distributed between 1.12 to 1.66, Showed widespread overpressure. Pressure field Evolution experienced three stages : pressure buildup, pressure release and pressure differentiation. Ancient pressure evolution can be divided into three modes, Overpressure - Low pressure- weak overpressure evolution models developed in northwest region, Overpressure - Low pressure- low pressure evolution models developed in northeast region, normal pressure - low pressure - normal pressure evolution model developed in southern region. Analysts believe that the Combined action of tectonic uplift and temperature reduction is the basic condition about low-pressure can be developed in Weibei Sag. Underground fluid supply-discharge imbalance and concentration effect promote the development of abnormal low pressure. Key words: abnormally low pressure; ancient pressure; mechanism; fluid inclusion; basin simulation; Weibei Sag 0 引言 正常地层压力等于地表到某一地层深度的静水压力，凡是偏离静水压力的地层压力均为异常地层压力。常用压力系数来表示异常压力的相对高低，实际研究中考虑到实际测试和计算带来的误差，用一定的压力系数范围表示压力状态更合理并更好操作。 [1,2]，面积约880km2，划分为瓦城断阶带、灶户断鼻带、北部洼陷带和南部斜坡带 4 个次级构造单元（图1）。盆地主要形成于古近纪，孔店组是勘探开发的主要目的层系。由于经历过构造回返和长期暴露剥蚀，造成孔店组地层压力特征复杂，给盆地成藏研究带来很大困难，为此对压力演化及分布特征进行了深入研究，对压力演化过程进行了探讨。 图1 潍北凹陷构造位置及构造格局 Fig.1 Regional tectonic location and structural development features of Weibei Sag 1 现今地层压力分布特征 潍北凹陷存在明显的低压层段，当地层埋深小于2300m时地层压力与静水压力趋势基