海相碳酸盐烃源岩生烃潜力模糊评价方法

The Evaluation Method of Marine Carbonate Source Rocks' Hydrocarbon Potential by Fuzzy AHP

烃源岩主要包括泥岩、页岩和碳酸盐岩。因此,海相碳酸盐岩烃源岩也是油气成藏和含油气系统的基础。对于海相碳酸盐岩烃源岩的评价,通常只侧重于物理化学性质的研究。由于不同的沉积盆地在沉积古环境,母质类型的输入以及有机质所经历的热演化程度等方面差异较大,仅以烃源岩物理化学性质为侧重点的烃源岩评价方法很难评价不同沉积盆地中烃源岩的生烃潜力。因此,为了快速有效评价碳酸盐烃源岩生烃能力,对有机质丰度、有机质类型、有机质成熟度和生烃过程4个方面因素进行分析研究,确定了海相碳酸盐岩烃源岩生烃潜力评价指标体系。并运用层次分析法和模糊数学,建立烃源岩生烃潜力评价新模型;避免了在碳酸盐岩烃源岩评价过程中由于参数过多而导致的矛盾现象,避免了选取参数时的盲目性,提高了烃源岩评价效率。在渤海湾盆地进行了生烃潜力评价,实际应用表明该方法快速、实用、可靠,具有一定的推广价值。

Source rocks include mudstone, shale and carbonate rocks. And carbonate source rocks are also the basis for oil or gas accumulation and petroleum system. The evaluation of marine source rock in the past is only focused on the study of the physical and chemical properties. Because different basins have different marine sedimentary environments, the entrance material types and degree of thermal evolution are different. If only the physical and chemical properties are considering, it is difficult to objectively evaluate hydrocarbon potentiality and to rank the hydrocarbon generation potentiality of the carbonate source rocks. So, to quickly and efficiently evaluate hydrocarbon potentialitY of carbonate source rocks, we investigate and survey the current research data, build a new evaluation index system and ensure the range of each parameter. In this paper, there are four factors being considered, the abundance of organic matter, organic matter type, organic maturitY and hydrocarbon generation. With the criteria, we have built a new evaluation model of marine carbonate source rock which is based on fuzzy AHP mathematics. Using this model, we can avoid the paradox in the evaluation process of the carbonate source rocks and blindness in selecting parameters. It also helps to improve efficiency of carbonate source rocks evaluation. It is found that the method is rapid, practical and reliable in the application of Bohai Bay Basin, so it is worth promoting.