深部流体对烃源岩发育与再生烃的影响-以塔里木为例

There was giant breakthrough of hydrocarbon exploration in Shunbei Area, Tarim Basin nowadays, but the mechanism of hydrocarbon generation was much more complicated due to the deep-derived activity in this area. The deep-derived fluid can improve the basin’s productivity by inputing various elements, which will fertilize the organism, such as alga, but the most favorite organism and its main controlling factor are still unclear. The main reactivation controlling factor, thermal or material effect, for source rock to generate hydrocarbon needs to be unrevealed, and the research about identification material for such reaction was very rare. Taking source rock in Tarim Basin as example, the project will identify the right source rock sector which was obviously affected by deep-derived fluid by means of geology method. And the special organisms and their combination will also be specialized by means of paleontology, meanwhile, the mechanism of deep-derived fluid promoting excellent source rock development will be proposed. The stable and large space reactor vessel, which was invented to resolve the problem of limited space for golden vessel while unstable for steal vessel, will be used to carry out the experiments for reactivation of high-maturity organic source with CO2-riched and H-riched deep-derived fluid in precise volume. The secret of how deep-derived fluid affect hydrocarbon generation will be answered by means of geochemical analysis. The aromatic matters, especially naphthalene, will be analyzed by FT-ICR-MS in order to identify the specialized matters for recognizing such production. The oil-source correlation will be done in Shunbei Area. The project will consummate the hydrocarbon generation theory in classical petroleum and natural gas geology, and be useful for hydrocarbon exploration practice.

塔里木盆地顺北地区近期油气勘探取得重大进展，但深部流体活动下，该地区的原油成因机理相对复杂。深部流体输入的多种元素可促进藻类等生物的繁育，提高盆地生产力，但主要生物类型及主控因素研究薄弱；烃源岩受深部流体影响再活化生烃的主控因素是热效应还是物质作用，机理不明，产物识别研究极少。本项目以塔里木盆地烃源岩为对象，利用地质学方法，识别深部流体活动影响的层段；利用古生物学方法，厘清特定的成烃生物及组合，提出深部流体促进优质烃源岩发育的机理；自主研发的反应釜，解决了黄金管产物少、不锈钢釜惰性不足、加入的流体物质定量难等问题，用以开展富CO2与富H流体再活化烃源岩生烃的模拟实验；利用有机地化分析，厘清深部流体影响烃源岩生烃的机理；通过FT-ICR-MS等技术，分析产物中的萘等芳烃，建立产物的识别方法。开展顺北地区油源对比。本研究将完善经典石油地质学的生烃机理，指导油气勘探实践，具有理论与应用的双重意义

深层油气是未来油气勘探的主要领域，但深层油气形成的基础-优质烃源岩的形成及深层烃源岩的生烃过程研究较弱。深层具有特殊的温度和压力环境，并且烃源岩成熟度相对较高，与此同时，盆地深层深部流体活动影响更明显。因此，明确深层优质烃源岩在深部流体活影响下的形成机理及其生烃过程，对进一步明确深层油气资源潜力至关重要。本项目依据研究计划书，开展了深部流体向沉积盆地输入的物质，即Fe、Mn、P、N等元素影响成烃生物母质，如小球藻，螺旋藻等繁育的模拟实验、深部流体输入的物质，如氢气和含Zn、Mo盐类对古老烃源岩再次生烃的模拟实验，并开展了针对性分析测试，以建立识别深部流体影响下形成的液态烃类物质。经过研究，初步明确不同的营养元素菌可以促进不同成烃生物的快速繁育，并且影响程度与元素浓度和作用时间呈正相关性，但是，过高的营养元素浓度对成烃生物具有一定的抑制生长作用，这表明深部流体对限制性沉积水体中的成烃生物的促进作用存在一定的阈值。以塔里木盆地玉尔吐斯组烃源岩为代表的古老、高熟烃源岩催化加氢模拟实验表明，盆地深层古老烃源岩在深部流体影响下，可以再次活化生烃，产物以气态烃为主，并且，含Zn盐类的催化效果要优于含Mo盐类。实验气态产物的组分特征表明，实验过程中二氧化碳与甲烷的含量呈负相关关系，同位素分析结果表明，甲烷与二氧化碳的碳同位素组成在高过成熟阶段（500℃及以上）存在一定的相关性，这是由于有机质生烃过程中的二氧化碳在催化条件下与氢气通过FTT反应合成了甲烷，进一步丰富了深部流体影响高演化烃源岩生烃的机理。基于塔里木盆地典型油气田典型样品的质谱和FT-ICR-MS分析结果表明，塔里木盆地奥陶系原油自北向南受深部流体活动比较明显，表现为原油色谱UCM鼓包逐渐升高。并且在顺北不同断裂带之间受影响程度不同，含氮和含硫化合物的类型及其组合，可以很好的指示深部流体活动。本研究进一步丰富了深部流体影响油气从烃源岩到生烃全过程的研究。