准噶尔盆地石炭系火山岩油气藏烃源示踪研究

The Carboniferous source rocks widely occur in the Junggar basin with variable sedimentation environments and high thermal maturities. Molecular parameters and carbon isotopic compositions of individual n-alkanes will be analyzed on bitumen A, bitumen C, and oil components released from kerogen during confined pyrolysis with gold capsules and hydropyrolysis for these source rocks. Based on molecular and isotopic parameters,in combination with basin tectonic and sedimental facies, the critalia of molecular and isotopic parameters to distinguish the Carboniferous source rocks from the other source rocks will be established. In addition, the Carboniferous volcanic rocks are of important reservoir rocks with large oil reserve proportion in the Junggar basin. For this type of oil containing reservoir rocks,the free oil, adsorbed oil, inclusion oil and oil components released from asphaltenes by confined pyrolysis and mild chemical oxidation will be obtained and analysed for the molecular parameters and carbon isotopic compositions of individual n-alkanes.Based on these geochemical data, oil source correlation and reconstruction of oil filling histories for some typical oil reservoirs within volcanic rocks will be performed.

针对准噶尔盆地石炭系烃源岩分布范围广、沉积环境差异大和成熟度高的特征，系统研究烃源岩沥青A、沥青C、干酪根金管热解和加氢催化热解油气组分的分子和正烷烃单体碳同位素组成及其与盆地构造和沉积环境演变的关系，建立盆地不同区域石炭系烃源岩分子和同位素地球化学判识指标。石炭系火山岩油气藏的储量在该盆地占有较大的比重，通过对含油火山储集岩自由态组分、束缚态组分、油气包裹体和沥青质热解和氧化降解释放的油气组分的分子和正烷烃单体碳同位素组成分析，精细判识代表性火山岩油气藏的油源，揭示油气藏的成藏过程。

石炭系是准噶尔盆地重要烃源岩和储集岩。本项研究的主要目标：(1)揭示石炭系烃源岩分子与同位素地球化学特征；(2)准东克拉美丽气田油气来源及准噶尔盆地主要勘探区块的原油是否含有石炭系烃源的成分。本项目主要研究内容为：(1) 准噶尔盆地东部下石炭统滴水泉组(C1d)和上石炭统巴山组(巴塔玛依内山组， C2b)有机质丰度、类型、分子地球化学和正构烷烃单体碳同位素地球化学特征；(2)准噶尔盆地东部克拉美丽气田上石炭统巴山组火山岩储层的原油及含油储集岩连续抽提研究，揭示原油和自由态组分、束缚态组分及油气包裹体分子地球化学和正构烷烃单体碳同位素组成特征；(3)准噶尔盆地西北缘、西南缘石炭系火山岩储层、上覆二叠系、三叠系及侏罗系砂岩储层原油和储集岩连续抽提研究，揭示原油和自由态组分、束缚态组分及油气包裹体分子地球化学和正构烷烃单体碳同位素组成特征；(4)准噶尔盆地二叠系烃源岩生烃动力学特征研究。根据实验分析结果，结合地质资料得到以下主要认识：(1) 准噶尔盆地东部下石炭统滴水泉组(C1d)和上石炭统巴山组(C2b)烃源岩在生物标志物含量、组成和正构烷烃单体碳同位素组成存在明显差异；(2) 油源对比结果表明准东克拉美丽气田原油主要来源于下石炭统滴水泉组(C1d)烃源岩；(3) 盆地西北缘玛湖凹陷中－北部、克－乌断裂带中－北部、达巴松凸起和夏盐凸起西部的原油来源于下二叠统风城组烃源岩，而玛湖凹陷南部、克－乌断裂带南部、莫索湾凸起、莫北凸起和夏盐凸起东部原油主要来源于中二叠统下乌尔和组烃源岩；(4) 在盆地西南缘已明确检测出来源于下二叠统风城组、中二叠统下乌尔和组、侏罗系、二叠系与侏罗系烃源岩混合和侏罗系与白垩系和古近系烃源岩混合的原油；(5) 在盆地西北缘、腹部和西南缘主要勘探区块没有检测出来源于石炭系烃源岩的原油；(6) 二叠系烃源岩具有生油量高、排油效率高和生气量低的特征。