东辛地区断层调节带的地震识别及特征

东辛地区位于东营凹陷中央隆起带东段,发育平行、叠覆、趋近、内敛、发散五种类型的小型断层调节带。为了识别张扭机制下的小型断层调节带并解剖其几何学特征,研究其油气地质意义,在分析各类断层调节带的构造样式、展布特征等基础上,建立了相应的地震识别标志。研究认为:平行型发育于辛镇构造,调节断层与主断层平行,呈断阶式或复式地堑状展布;叠覆型集中发育在东营构造,调节断层平面上呈雁列式与主断层斜交,剖面上为马尾状或花状;趋近型位于辛镇与东营两大构造的结合部,整体呈扇形展布,在剖面上呈复合花状;发散型位于辛镇构造的西部,调节断层呈凤尾状展布,在剖面上下部呈梳状组合,上部呈包心菜状;内敛型发育在东营构造的西北部,调节断层呈帚状收敛于主断层,在剖面上呈梳状。平行型和内敛型断层调节带最易在地震沿层相干属性及剖面上识别,其次为叠覆型和趋近型,发散型识别难度较大。断层调节带的活动期与油源断层活动性的耦合决定了叠覆型和平行型断层调节带是油气最有利的富集带。该研究成果对张扭断裂系统中断层调节带的识别及有利目标区的选择具有指导意义。

Seismic identification of fault accommodation zones in Dongxin area

Located in the eastern part of the central uplift belt,Dongxin area in Dongying Sag,10 accommodation zones of subtle faults are identified and classified into 5 types.Structural characteristics of different types of fault accommodation zones and the relationship with the hydrocarbon distribution are detailedly analyzed,and seismic identification marks of different types are constructed.Collateral fault accommodation zones mainly developed in Xinzhen structure are paralleled major faults with step-fault patterns or multiple graben patterns on sections.Overlapping accommodation zones mainly developed in Dongying structure are obliqued with major faults in en echelon arrangement in the plane and their structural style is presented in horsetail patterns and flower structure on sections.Approaching accommodation zones formed by one major fault of Dongying structural belt adjoining other 3 major faults of Xinzhen structural belt are fan-like in plane.On sections,their structural style is presented the patterns of compound flower structure.The accommodation zones controlled by single major fault are divided into the types of inward convergence to hinge zone and divergency in pitching end.The inward convergent accommodation zones developed in northwest part of Dong-ying structure are distributed in the manner of brush convergent to major faults with the patterns of pectination on sections.Whereas,fault accommodation zones of divergency in pitching end developed in the west of Xinzhen structure are distributed in the manner of phoenix tail in plane.On sections,the lower structural style is presented in the patterns of pectination and the upper structural style is presented in pattern of cabbage liking.Collateral accommodation zones and inward convergent accommodation zones can be easily identified with coherence attribute and seismic sections.Then overlapping accommodation zones and approaching accommodation zones can also be identified.The most difficult to be identified is the fault accommodation zones of divergency.The collateral accommodation zones and overlapping zones are the most prolific hydrocarbon areas in Dongxin Fault Zone because their development and activity had a very close relationship with oil source fault activity.The conclusions are instructive and meaningful to fault accommodation zone identification and favorable target optimization in the transtensional fault system.