摘要
已有的钻井资料表明,麻黄山地区延安组具有良好的油气勘探潜力。通过对地震资料、岩心资料、测井曲线、薄片鉴定等分析,认为鄂尔多斯盆地西缘延安组经历了下切河谷充填、三角洲平原、前三角洲、三角洲前缘、三角洲平原和曲流河沉积的演化过程,为一个完整的湖侵—湖退旋回。低位体系域主要为下切河谷充填砂岩,其分布受早侏罗世古地貌的控制,优先堆积在古地貌较低的区域;水进体系域为三角洲平原沉积,最大湖泛面处于前三角洲的黑色泥岩中;高位体系域由三角洲平原和曲流河沉积组成。最大湖泛面的存在将延安组油藏分为源外组合和远源组合。源外组合,特别是低位体系域的下切河谷充填砂岩具有砂体厚、储集物性好、离烃源岩近、圈闭类型丰富等成藏条件,利于油气的聚集;而远源组合只是源外组合破坏后,油气运移至高位体系中形成次生油藏。
Yan＇an Formation has great potential for oil and gas exploration in Mahuangshan area of western Ordos Basin.Based on the analysis of seismic data,well cores,well logging and cast slice,it is believed that Yan＇an Formation experiences evolvement of incised valley filling,delta plain,prodelta,and delta plain-meandering river,so it is a whole transgression and regression cycle.Low system tract is composed of filling sandstones of incised valley,of which the distribution is controlled by Early Jurassic palaeogeomorphology,and the sandstone deposited in lower places.Transgressive system tract consists of delta plain,and maximum flooding surface lies in black mudstones of prodelta.High system tract is composed of delta plain and meandering river.Outside-source play and distal-source play are distinguished by maximum flooding surface.Filling sandstones of incised valley of low system tract have thick sandstones,high reservoirs,near resources and plentiful traps,so outside-source can trap petroleum easily.However,distal-source plays are secondary reservoirs which formin high systemtract and are destroyed fromoutside-source play.
出处
《岩性油气藏》
CSCD
2010年第3期43-47,共5页
Lithologic Reservoirs
基金
国家自然科学青年基金项目(编号:40602012)"鄂尔多斯盆地晚三世延长期几个关键性事件沉积及其与油气聚集关系研究"资助
关键词
层序
下切河谷
体系域
沉积相
延安组
麻黄山地区
鄂尔多斯盆地
sequence
incised valley
system tracts
sedimentary facies
Yan＇an Formation
Mahuangshan area
Ordos Basin
