安塞油田前侏罗纪古地貌特征及其与油气富集关系

目的深入探究鄂尔多斯盆地安塞油田前侏罗纪古地貌特征,为侏罗系油田开发奠定基础。方法通过野外露头及岩心的详细观察和描述,结合大量测井曲线和测试分析资料,采用印模法对古地貌进行刻画。结果古河谷和河谷平原为研究区前侏罗纪主要的地貌单元,其中河谷平原可进一步分为谷坡及河漫台地;在古河谷和古坡之间形成了许多坡咀。结论古地貌控制着侏罗纪早期沉积相及砂体的发育和分布;古河谷的北缘及次级古河谷的谷坡是侏罗系油藏分布的主要位置;今后在勘探中应该重视次级古河谷谷坡的研究,开展老井复查,以期发现新的油气增长点。

Pre-Jurassic palaeogeomorphology and the relations with oil and gas accumulation in Ansai Oilfield

Aim The characteristics of pre-Jurassic palaeogeomorphology in Ansai Oilfield have been rebuilt.Methods On the basis of the observing of field and core,as well as the analyzing of well logs and test data,the method of mold is applied.Results Pre-Jurassic palaeogeomorphology in studied area has been depicted as: palaeo-valley and its plain are the main geomorphic units.The plain can be divided into slope and river floodplain.The slope mouth was formed between the palaeo-valley and its plain.Conclusion The pre-Jurassic palaeogeomorphic characteristics had a great control on the sedimentary facies types and sand-body distribution in the lower Jurassic.The north margin of the palaeo-valley and the slop of secondary valley are the location where oil and gas distribute.The slop of secondary valley should be paid attention to in the future exploration.By the recheck of the old well data,the new oil and gas will be found of lower Jurassicperiod.