准噶尔盆地东部石钱滩凹陷石炭系石钱滩组烃源岩特征及其生烃潜力分析

Characteristics and Hydrocarbon Generation Potential for Source Rock of Carboniferous Shiqiantan Formation in Shiqiantan Depression,Eastern Junggar Basin

石钱滩组烃源岩为准噶尔盆地石钱滩凹陷石炭系的主力生烃层位。在充分调研其空间展布的基础上,选取最新发现的双井子地质探槽剖面及石钱1井、石钱2井与钱1井进行系统的烃源岩总有机碳、热解、族组分组成、有机显微组分、镜质体反射率及饱和烃色质等有机地球化学分析测试。结果表明,石钱滩组烃源岩为一套典型的海湾泻湖相沉积,呈NW–SE向展布于石钱滩凹陷,局部地区厚度巨大,可达370 m,沉积厚度中心位于凹陷东南隅。富有机质层段主要集中在石钱滩组下部,次为上部。整体具有较高的有机质丰度,可达到好等级及以上,有机质类型以Ⅱ2-Ⅲ为主,且已进入到高成熟生气阶段。综合研究认为,石炭系石钱滩组烃源岩具有良好的生烃条件,能够为石钱滩凹陷提供充足的油气源。

The source rock of Shiqiantan formation is a main hydrocarbon−generation bed of the carboniferous for Shiqiantan depression in Junggar basin.Based on the detailed investigation on spatial distribution of forma-tion,the newly found Shuangjingzi geological trench section,Shiqian 1 well,Shiqian 2 well and Qian 1 well can be selected for systematic organic geochemistry analysis and testing of total organic carbon,pyrolysis,group composition,organic macerals,vitrinite reflectance,and chromatogram−mass spectrometry of saturated hydro-carbon for source rock samples,the results show that the source rock of the Shiqiantan formation is a set of typi-cal bay lagoon deposits,which is mainly distributed in the Shiqiantan depressionin with northwest−southeast di-rection.Besides,the local thickness is huge,even up to 370 m.The center of sediment thickness is located in the southeastern corner.The organic rich strata are mainly concentrated in the lower part of formation,and the up-per part comes second.The overall organic matter content is relatively high,and can reach the good grade or above,the main type of organic matter is II2-III,and has entered the high mature gas generation stage.It is con-cluded that the source rock of carboniferous Shiqiantan formation is characertized by good hydrocarbon genera-tion condition and can provide sufficient resources for Shiqiantan depression.