南盘江地区二叠系生物礁岩特征、成岩作用及与油气的关系

THE CHARACTERISTICS AND DIAGENESIS OF PERMIAN REEF ROCKS IN NANPANJIANG AREA AND THEIR RELATIONSHIP TO OIL/GAS POOLS

赵泽恒 齐敬文 张孝林

Zhao Zeheng Qi Jinwen Zhang Xiaolin

滇黔桂石油地质科研所

Yunan-Guizhou-Kuangxi Geoscience Research Institute of Petroleum Geology

本区生物礁据其所处的地理位置、出露的平面形态以及礁组合特征,可分为三种类型;台地边缘线状礁、台丘边缘马蹄形礁和点礁。主要的礁岩类型为骨架岩、粘结岩、伟积岩和礁块角砾岩。造礁生物依据其对成礁作用的不同可分为造架生物、联结生物和附礁生物。二叠纪生物礁具有海进成礁,海退消亡,在时间上有多个成礁期,在空间上有多个礁体不断位移之特点。在其发生、发展、演化和消亡的过程中,每一时期的生物礁都基本上经过了定殖、拓殖、泛殖和统殖四个阶段。本区生物礁体位于盆地相区边缘和内部,当生油岩区处于有利的条件和排烃阶段,由于溶蚀作用等又形成聚集期有效孔隙时,这些礁体即近距离捕获油气形成礁型油气藏。然而,由于储集于礁体中的液态烃在地质时期经历了过成熟热演化阶段而裂解成气态烃和固体沥青,因此,只能采取有效的勘探手段在本区以寻找隐伏礁型气藏为目的。

Based on the geographic location,exposed configuration and the com-plex of the reef body,the reef rocks in Nanpanjiang Area can be divided into three types as platform marginal linear reef,platform marginal horse-shoe reef and patch reef.The principal types of the reef rocks are of framestone,bindstone;reef breccia,etc.The reef-building organisms can be divided into framework-building,binding,binding and attaching organisms on the basis of the different effective to the reef formation.Permian reefs are characterized by reef building up at the time of trans-gression,and dying out at the time of regression,as well as the conti-nuously shifting of a number of reefs.The reefs in this area distribute at the margin and interior of basin facies.As the source rocks were under favourable conditions of hydrocar-bon expelling stage,and valid pore formed at right time by solution,these reefs can be formed as reefoid oil/gas pools(in term of short distant oil trapping).However,since the liquid hydrocarbon restored in such reefs has experienced an over-maturation stage and has been pyrolyzed to be gase-ous hydrocarbon and solid bitumen,the subtle reefoid gas pools can be discovered by the valid exploration activities in the area.

https://doi.org/10.11781/sysydz198704332