【摘要】 裂陷盆地断层分段生长具有普遍性,为了定量表征断层分段生长过程及组合模式的正确性,以塔南凹陷为研究靶区,以三维地震为基础,应用"三图一线"方法有效表征断层分段性;利用断裂平面分段生长连接定量判别标准,可以定量判别断层组合的正确性;同时,提出了应用"最大断距相减法"定量恢复断层形成演化过程,探讨断层分段生长对洼槽油气成藏的控制作用.结合洼槽结构和油藏精细解剖,研究结果表明:1)塔南凹陷边界断裂TN1和TN2具有典型分段生长特征,其分别由多个小断层连接而成;2)应用"断距回剥"技术定量恢复了TN1和TN2断层南一段上部和南二段沉积时期断层分布规律;3)基于断层分段生长定量判别标准,TN1和TN2断层组合与实际断层平面组合特征相符,证实了塔南东次凹TN1和TN2断层组合的可靠性;4)断陷湖盆具有典型主干边界断层"强烈活动段控洼槽并控优质烃源岩"和"变换构造带控砂体展布"的特征;5)盆地边界断裂分段生长、洼槽迁移与变换带控砂耦合关系导致形成4种类型油气藏:断层遮挡油气藏、近岸水下扇形成岩性油气藏、横向背斜形成的构造油气藏和岩性上倾尖灭油气藏.更多还原

【Abstract】 The fault segmentation growth is universal in rift basin.Taking Tanna sag as a study example,fault combination mode and process of fault segmentation growth were quantitatively characterized based on three-dimensional seismic technology.The method of three-figure(displacement-distance curve,throw contour in the fault plane and depth contour in the fault plane)and one-profile(seismic cross-section along the fault strike)was used.Fault combination mode was verified quantitatively based on fault segmentation growth quantitative discrimination criterion in fracture plane.This paper proposed the method of maximum fault throwsubtraction to restore fault evolution quantitatively and to discuss the control action of fault segmentation growth on hydrocarbon accumulation in the trough.According to the analysis of trough structure and fine reservoir characteristics,this paper indicates that:1)The boundary fractures of Tanan sag(fracture TN1 and TN2)are characterized by typical segmentation growth and linked by many small faults.2)By means of the fault throw backstripping analysis,the fault distribution rule of sedimentary period,in the upper part of Nan1 member and Nan2 member in fracture TN1 and TN2,is restored quantitatively.3)Based on fault segmentation growth quantitative discrimination criterion,the obtained fault combination modes of fracture TN1 and TN2are in agreement with the actual fault combination characteristics,which validates the reliability of fault combination of fracture TN1 and TN2in east sug-sag of Tanan sag.4)The fault-depressed lacustrine basin is with the characteristics of typical main boundary faults,i.e.,both sug-sag and high-quality source rock are controlled by intense activity regions,and sandbody distribution is controlled by the tectonic transfer zone.5)The coupling relationship,among the segmentation growth of basin boundary faults,the sug-sag migration and the sandbody distribution controlled by tectonic transfer zone,results in four kinds of hydrocarbon reservoirs:fault-screened hydrocarbon reservoir,lithologic reservoir formed nearshore subaqueous fans,structural reservoir formed in cross anticline and lithologic updip pinch-out hydrocarbon reservoir.更多还原