准噶尔盆地腹部断裂和不整合面流体活动特征对比

断裂和不整合面是油气流体运移的良好通道,但对其流体活动特征的差异研究却不甚深入。以准噶尔盆地腹部地区为例,主要从流体活动的矿物岩石学记录入手,对断裂和不整合面的流体活动特征进行了对比研究。结果表明,断裂带流体活动复杂,在活动期均是油气流体运移的良好通道,并呈现出“幕式”特征,流体来源以深源含油气流体与大气降水影响为主。相比而言,不整合面之上流体来源较为单一,主要是含油气流体,而不整合面之下与断裂带地区类似,受到深源含油气流体与大气降水的复合影响。总体而言,断裂带流体活动强度要比不整合面上下的储层更强,断裂与不整合面纵横交叉之处是油气流体活动的有利通道,距不整合面越远,其流体活动强度越弱。这些认识可为区域油气勘探提供科学依据,也可供国内外同类研究类比参考。 

Comparison of Fluid Activities between Fault and Unconformity Zones in the Central Junggar Basin

Fault and unconformity are important conduits for hydrocarbon migration and accumulation.However,the difference of fluid activities between these two conduits is not well constrained.In this paper,we address this issue based on a case study in the central Junggar Basin,mainly by the analysis of mineralogical and petrological records of fluid activities.Resultsshow that the fluid activity in the fault zones is complex.The fault acts as good conduits for hydrocarbon migration in an episodic style during activating period,with the fluid source mainly coming from deep petroleum fluid and meteoric water.This is similar to the case in the reservoir underlying the unconformity.In contrast,the fluids activating in the reservoir overlying the unconformity are different and relatively simple,i.e.,petroleum fluid.Generally,the intensity of fluid activity in fault zones is stronger than that in unconformity zones.The cross of fault and unconformity is the most favorable for the activity of petroleum fluid.Along the distance to unconformity,the fluid activity decreases.These results provide scientific foundation for regional petroleum exploration,and can also be referred by similar studies in other cases.