基于模糊层次分析方法的泥质有效低熟气源岩评价

在特定地质背景下,低熟气可以聚集成藏。由于沉积盆地的古环境、母质类型及有机质演化程度的不同,仅以低熟气源岩物理化学性质为侧重点的烃源岩评价方法很难对不同沉积盆地中的烃源岩的生烃潜力进行相对优劣排序。因此,为了快速有效评价低熟气源岩的生烃潜力,分析了w(TOC)、I_H、w("A")等10个因素对气源岩生气能力的影响,建立有效低熟气源岩评价指标体系。并运用层次分析法和模糊数学,建立低熟气源岩生烃潜力评价模型。应用此模型对乌连戈伊气田进行了生烃潜力评价,评价结果表明:Achimov气藏、Bazhenov气藏、Vasyugan气藏、Pokur气藏烃源岩是低熟气源岩;Neocomian气藏和Tyumen气藏烃源岩介于低熟气源岩和常规气源岩之间;Tampey气藏烃源岩属于常规气源岩。这与Galimov所得结论是完全吻合的,说明模型的评价结果是可靠的,可以实现低熟气源岩的综合评价,值得推广应用。

Evaluation Method of Terrestrial Low-Mature Gas Source Rocks by Fuzzy AHP

Under certain geological conditions ,low‐mature gas can accumulate to a gas reservoir .In the past ,the evaluation of terrestrial low‐mature gas source rock was only focused on the study of the physical and chemical properties . Due to the limitation of the current exploration and analyzing techniques ,it is difficult to objectively evaluate the potential of the low‐mature gas source rocks and their relative merits as source rocks . After reviewing the current research status of terrestrial low ‐mature gas source rocks , we build a new evaluation index system through analyzing 10 influencing factors and the range of each parameter .Based on the above ,we build a new evaluation model for the terrestrial low‐mature gas source rock by fuzzy analytic hierarchy process (AHP ) . With this new evaluation model ,we can avoid the paradox in the evaluation of the low‐mature gas source rocks and the blindness of selecting parameters ;also we can improve the evaluation efficiency .The evaluation results agree with the analysis in Urengoy gas field .Based on the evaluation ,the source rocks of Achimov , Bazhenov ,Vasyugan ,and Pokur are low‐mature ;Neocomian’s and Tyumen’s are in between of low‐mature and mature ;while Tampey’ s is mature . The method is provedto be practical and reliable in application .