惠民南部地区油水物化性质与油气运移方向和模式

Changes of Oil-water Physical and Chemical Properties Affect Oil-gas Migration Direction and Mode in Southern Region of Huimin Sag

油水物化性质变化可以从古水文演化角度反应油气运移方向。本文以惠民凹陷南部地区沙河街组三段为例,利用原油密度、黏度、地层水矿化度、水型及离子组合参数变化特征,研究油气运移规律。平面上,研究区原油密度、黏度整体具有西北高、东南低的分布规律,局部具有一低四高的分布特征,反映出原油密度、黏度随运移距离的增加而增大;地层水矿化度具有以夏口断裂为中心,向南北两侧逐渐变小的分布特征,矿化度高值区的分布与夏口断层油气运移聚集有关;地层水水型和离子组合参数变化特征表明沿夏口断裂带具有两个油气聚集区,分别为双丰、江家店—瓦屋鼻状构造。通过对油气运聚关系的分析,以油气源、输导因素为基础,沿油气主要运移方向,建立了研究区近源侧向砂体输导、近源混向反Z型输导、远源混向阶梯状输导、远源混向多级反Z型输导4种油气运移模式。

Changes of oil-gas physical and chemical properties affect the oil and gas migration direction based on the evolution of ancient hydrology.By taking Shahejie three sections in southern region of Huimin Depression as examples,crude oil density,viscosity,formation water salinity,water-based,and ionic composition parameters are used to study oil and gas migration and accumulation.On the whole plane,the study area of crude oil density,viscosity has the distribution characteristics of northwest high,southeast low;locally,there are one low part and four high parts.It reflects that crude oil density and viscosity increase with the migration distance;formation water salinity has the distribution characteristics that centers at Xiakou Fault zones and decreases along the north and south sides.High value zones of formation water salinity has relation with the oil and gas migration and accumulation of Xiakou Fault zone;formation water type and characteristics of plasma parameters reflect that have two oil and gas accumulation zones along with Xiakou Fault zone.They were Shuangfeng and a nose structure extended from Jiangjiadian to Wawu.Through analysis on the relationship between hydrocarbon migration and accumulation,based on the factors involving oil and gas sources,migration direction,and migration process,the oil and gas accumulation mode of the study area is divided into four types,namely,side sand body of near the source transport oil-gas mode,near-source mixing to the anti-＂Z＂ shaped transport oil-gas mode,far-source mixing to the multi-level anti-＂Z＂ shaped transport oil-gas mode,and far-source mixing to the ladder-like transport oil-gas mode.