深大断裂特征及其对天然气成藏的影响——以松辽盆地德惠断陷万金塔地区为例  

Characteristics of deep large fault and its effects on gas accumulation: A case study on Wanjinta area in Dehui fault depression of the Songliao Basin

作　　者：刘玉虎[1] 李瑞磊[1] 赵洪伟[2] 王伟[1] 王晓峰[3] 曹春辉[4] 

机构地区：[1]中国石化东北油气分公司勘探开发研究院 [2]中国地质调查局沈阳地质调查中心 [3]中国石化东北油气分公司松原采气厂 [4]中国科学院油气资源研究重点实验室

出　　处：《天然气勘探与开发》2017年第1期23-31,共9页Natural Gas Exploration and Development

摘　　要：深大断裂控制着含油气盆地的构造格局、圈闭发育演化过程及油气成藏疏导体系,对深层天然气的成藏控制尤为重要。通过对松辽盆地德惠断陷万金塔地区区域地质、钻井及三维地震解释资料的系统研究,对深大断裂平面及剖面特征进行深入分析;采用位移—长度分析法对深大断裂带进行分段解剖;利用3Dmove平衡剖面构造恢复技术对典型剖面进行构造复原,重塑了圈闭构造演化历史;基于断裂控藏作用,提出了"三参数评价法"定量评价深大断裂的活动程度。结果表明:1万金塔地区NE向展布的边界断裂及深大断裂控制着成盆构造格局,并形成地堑式系列断裂,控制了气源岩的空间分布;2位移剖面显示深大断裂呈分段发育的演化特点,在不同地段对应不同发育特征的构造样式;3在挤压背斜带中部应力集中表现为正花走滑,断裂活动程度相对高,控制了平面上CO_2气藏的富集,而在深大断裂活动程度相对低、靠近下白垩统沙河子组气源岩的地区,原生有机烃类气藏可能保存较为完整;4深大断裂、不整合面及浅层断裂系统一起组成有机烃类气输导体系。A deep large fault controls the tectonic patterns of petroliferous basins, the development and evolution of traps and the conduct- ing systems of oil and gas accumulation, and it is particularly important for deep gas accumulation. In this paper, the characteristics of deep large faults in planes and profiles were analyzed deeply by performing systematic research on regional geology, drilling and 3D seismic data of Wanjinta area in Dehui fault depression of the Songliao Basin. Then, deep large fault belts were analyzed sectionally by means of displace- ment-length analysis method. The typical sections were structurally restored by using the 3Dmove balanced sectional structure reconstruction technology to rebuild the structural evolution history of traps. Based on the controlling effect of fractures on hydrocarbon accumulation, it was proposed to evaluate quantitatively the activity intensity of deep large faults by means of ＂three-parameter evaluation method＂. It is indicated that in Wanjinta area, NE trending boundary faults and deep large faults control the patterns of basin forming structures, and a graben fault sys- tem is formed, controlling the spatial distribution of gas source rocks. The segmental development characteristics of deep large faults are pre- sented in the displacement profile, and structural styles in different sections correspond to different developmental characteristics. The stress in the middle of compressional fault belt is mainly represented as the positive flower strike slip with higher faulting activity degree, controlling the areal enrichment of CO2 reservoirs. In the areas near the Lower Cretaceous Shahezi Formation gas source rocks whose activity degree of deep large faults is relatively low, the primary organic hydrocarbon gas reservoirs may be preserved more completely. The conducting systems of or- ganic hydrocarbon gas consist of deep large faults, unconformities and shallow faulting systems.

关 键 词：松辽盆地 万金塔地区 深大断裂 活动强度 气源岩 输导体系 

分 类 号：P618.13[天文地球—矿床学]