靖边潜台北部奥陶系风化壳储层研究  

Ordovician karst weathering crust reservoirs on the northern Jingbian buried platform in the Ordos Basin

作　　者：李杰[1] 张振文[1] 刘顺治[2] 冷丹凤 张道峰[4] 何亚宁[1] 吕利刚[1] 

机构地区：[1]长庆油田分公司第一采气厂,陕西榆林718500 [2]延长石油集团油气勘探公司,陕西延安716000 [3]延长油田勘探开发技术研究中心,陕西延安716000 [4]长庆油田分公司勘探开发研究院,陕西西安710021

出　　处：《沉积与特提斯地质》2013年第1期79-85,共7页Sedimentary Geology and Tethyan Geology

摘　　要：根据靖边气田、乌审旗气田以往的勘探经验,岩溶作用改造的白云岩储层是制约下古生界天然气勘探成功率的关键。本文在大量岩心、薄片观察的基础上,对研究区风化壳储层类型与发育特征进行了分析。结果表明:潜台北部马五4、马五5不同种类的白云岩储层的储集类型有别,主要为裂缝-溶孔(洞)型、裂缝-孔隙型及孔隙型等。岩溶台地带马五4、马五5白云岩储层剥露,上古生界煤系烃源岩成为白云岩储集体成藏的直接有效的气源;岩溶斜坡带发育的沟槽一般深切马家沟组顶面,有利于地表水岩溶作用的进行,使得马五4有利储层大多沿沟槽展布。白云岩化及岩溶作用是形成该地区隐蔽的岩性及地层-岩性复合圈闭气藏的关键,在今后勘探过程中马五段中、下部地层仍将是该地区工作重点。Judged from the pre-existing exploration history of the Jingbian and Wushenqi Gas Fields,the key factors for the successful exploration of the Lower Palaeozoic natural gas depend on the dolostone reservoirs modified by karstification.It is apparently important to the refinement of the interpretation of the genesis of the dolostone reservoirs in the study area.The examination of the types and development of the weathering crust reservoirs within the Jingbian buried platform has disclosed that the porosity types in Ma-54 and Ma-55 strata contain the fissure-solution openings(pore caves) type,fissure-pore space type and pore space type.Because of the exhumation of the Ma-54 and Ma-55 strata,the source rocks in the Upper Palaeozoic coal measures became direct and effective gas source for the hydrocarbon accumulation in the dolostone reservoirs.The gullies and grooves widespread in the karst slope zone tend to penetrate into the uppermost part of the Majiagou Formation,and thus allow the alignment of the Ma-54 reservoirs along these gullies and grooves.The dolomitization and karstification are interpreted to be the key factors for the formation of the concealed lithologic and stratigraphic-lithologic traps.The middle and lower parts of the Ma-5 reservoirs will still be the target horizons in the future exploration.

关 键 词：风化壳储层 储层类型 奥陶系 靖边潜台 鄂尔多斯盆地 

分 类 号：P618.130.2[天文地球—矿床学]