松辽盆地王府断陷火石岭组火山岩成岩作用特征

Diagenesis of volcanic rocks of Huoshiling Formation in Wangfu fault depression,Songliao Basin

为更好分析和预测王府断陷火石岭组火山岩储层,笔者通过岩芯、普通薄片和铸体薄片分析,对火石岭组的岩石类型、成岩作用及其对储层的意义进行了研究。结果表明,王府断陷火石岭组发育火山熔岩、火山碎屑熔岩、火山碎屑岩和沉火山碎屑岩4类,以火山熔岩为主,共经历了早期成岩及晚期成岩阶段的10种主要成岩作用,其中风化淋滤作用、构造作用、交代蚀变作用、充填作用和溶蚀作用在本区更普遍。对研究区火山岩储层的形成演化起建设作用的有挥发分逸出作用、冷凝作用、风化淋滤作用、构造作用和溶蚀作用,且风化淋滤作用和溶蚀作用的贡献更大;而胶结作用、压实作用及充填作用降低储层物性,对火山岩储层具破坏作用,且充填作用具有多期性,破坏性最大。

To make a more accurate analysis and prediction of volcanic reservoirs of Huoshiling Formation in Wangfu fault depression,the rock types,diagenesis and its significance to volcanic reservoirs are studied based on cores,thin sections and casting thin sections.The result shows that rocks of Huoshiling Formation in Wangfu fault depression can be divided into volcanic lavas,pyroclastic lavas,pyroclastic rocks and sedimentary volcaniclasitc rocks,of which volcanic lavas are dominant.Volcanic rocks of Huoshiling Formation have mainly experienced ten types of diagenesis during the early and late diagenetic stages,among which weathering-leaching,tectonism,metasomatic alteration,filling and dissolution are more common.It is found that the escape of volatiles,condensation,weathering-leaching,tectonism,and dissolution play a constructive role in the formation and evolution of volcanic reservoirs,especially,the diagenesis of weathering-leaching and dissolution.Whereas,cementation,compaction and filling reduce the physical properties of reservoirs.Moreover,the process of filling is multi-stage and is the most destructive diagenesis.