【摘要】 塔里木盆地古城低凸起在下奥陶统鹰山组下段白云岩储层中发现重要的油气资源,而断裂作为油气运移的通道,起着重要的作用。通过对古城低凸起三维地震资料的精细解析,结合主要界面的最大负曲率属性分析,对主要断裂带的剖面特征、平面特征、活动期次、成因机制及对油气成藏的影响进行了详细研究。结果表明,古城低凸起在剖面上主要发育负花状构造和平行高陡断裂2种构造样式;平面上主要发育NW向、NE向和NNE向共3个方向的断裂。结合对不整合面、生长指数和上覆地层的变形特征等综合分析,厘定出断裂的活动主要有3期,包括加里东早期(中寒武世)、加里东中期(晚奥陶世早期)和加里东晚期—海西早期(志留纪—泥盆纪)。加里东中期发育的张扭断裂,主要受控于先存基底薄弱带和阿尔金山北缘发育的沟—弧—盆构造体系的影响;加里东晚期—海西早期发育的张扭断裂是在加里东中期的拉张断裂的基础上继承发育的,受控于右旋走滑的古城北断裂和左旋走滑的车尔臣断裂。断裂的发育对古城低凸起的油气成藏有着重要的作用,主要表现在2个方面:断裂作为重要的油气通道,控制油气垂向运移;断裂也是热液流体的通道,利于白云岩化,改善储层物性。更多还原

【Abstract】 Important oil and gas resources have been found in the dolomite reservoir of the lower segment of the Lower Ordovician Yingshan Formation in the Gucheng Lower Uplift.Faults are pathways of oil and gas and play an important role.Based on the detailed interpretation of 3 Dseismic data and maximum negative curvature attribute along main interface from Gucheng Lower Uplift,Tarim Basin,main fault zones were identified,and its profile characteristics,planar characteristics,active stages,genetic mechanism and influences on hydrocarbon accumulation were also studied.Research shows that two kinds of structural styles were formed,including negative flower structure and parallel high steep fault.On the plane,there were main development of NW,NE and NNE trending.Analysis combined with unconformity,growth index,overlying strata deformation characteristics,the faults were active mainly during the Early Caledonian(the Middle Cambrian),the Middle Caledonian(early in the Late Ordovician)and the Late Caledonian-Early Hercynian(Silurian-Devonian).The Middle Caledonian tension-shear faults developed based on previous basement weak zone,and were influenced by trench-arc-basin tectonic system in the northern margin of Altun.The Late Caledonian-Early Hercynian tension-shear faults developed based on the middle Caledonian tension-shear faults,and were controlled by the dextral strike-slip Guchengbei fault and the sinistral strikeslip Cherchen fault.Fault development plays an important role in the oil and gas accumulation.Mainly in two aspects:fault acts as an important channel to control oil and gas vertical migration;fault is the hydrothermal fluid channel,which will help dolomitization,improve reservoir property.更多还原