准噶尔盆地及周缘地区石炭系岩相古地理特征及油气基本地质条件

Palaeogeographic characteristics and basic geological conditions of petroleum of the Carboniferous in Junggar Basin and its adjacent areas

准噶尔盆地及周缘地区具前寒武纪变质结晶和褶皱双重基底,石炭系发育有研究区第1套完整且区域对比相对良好的地层。以"构造控盆、盆控相"的思路,对石炭系的沉积相和古地理特征进行了分析:早石炭世发育活动、被动陆缘海相及海陆过渡相沉积盆地,晚石炭世发育海陆过渡相沉积盆地及陆相火山岩。石炭系发育海相、海陆过渡相以及大陆相3个相区,可细分为大陆相、海相火山岩及火山碎屑岩相、次深海—深海相、浅海相、滨海相、三角洲相、河湖相以及冲积扇相等11个相带。从"相控油气基本地质条件"思路出发,认为盆地西北缘克拉玛依—白碱滩地区、南缘巴音沟、乌鲁木齐等地发育的次深海—深海相暗色泥页岩为较好的烃源岩;东北缘如卡拉麦里地区发育的三角洲相为烃源岩、储集岩良好的油气勘探有利相带;三塘湖地区发育的潮坪相与潟湖相、布尔津—富蕴及博格达山地区发育的浅海碳酸盐岩—碎屑岩浅海陆棚相等可形成良好的生储盖组合。这些生、储、盖三位一体分布的相带和地区是今后油气勘探的优选目标和首选地区。

It has the double basement of the Precambrian metamorphic crystallization basement and fold basement in Junggar Basin and its adjacent areas.The Carboniferous was the first full strata and＆amp;nbsp;developed well in the study area.Under the instruction that the tectonic controls a basin＆#39;s development, while the latter controls facies,the sedimentary facies and lithofacies palaeogeographic characteristics in the study area was analyzed as followduring the Early Carboniferous,the sedimentary basins,with active or passive continental marginal marine facies or land-ocean transitional facies,were formed;while in Late Carboniferous,the sedimentary basins of land-ocean transitional facies and the continental volcanic build-ups were developed.Generally,the Carboniferous was divided into three zones of marine,land-ocean transitional,and continental facies;detailedly,8 types of facies were identified,i.e.,continental,marine volcanic and pyroclastic,bathyal-abyssal,neritic,littoral,deltaic,fluvial-lacustrine,and the alluvial-fan facies.Based on the idea that “the sedimentary facies controls the basic geological conditions of petroleum”,the petroleum distribution in Junggar Basin is concluded a（1 ）For the Karamay-Baijiantan areas in the northwestern margin,and the Bayingou and Urumqi in the southern margin,it develops bathyal-abyssal dark muddy shales,which are supposed to be relatively good source rocks;（2） The delta facies which are favorable developed in the southeast-northern margin of Junggar Basin,such as the areas of Karamay are the advantageous zone of oil and gas exploration,and the source rocks and reservoir rocks were developed well.（3）The tidal-flat facies and lagoon facies which are favorably developed in the Santanghu area,as well as the neritic carbonate- clastic shelf facies which are favorably developed in the Burerjin-Fuyun and Bogeda mountain areas can form a relatively good assemblage of source-reservoir-cap. These sedimentary facies and zones where source,reservoir and cap rocks distributed trinity are the optimum targets and the top choice areas.