碎屑岩储集层中绿泥石包膜的研究现状

An overview on study of chlorite films in clastic reservoirs

绿泥石包膜在国内外碎屑岩储集层中常有发现,其对石英次生加大的抑制及对储集层物性的影响一直是国内外学者的研究热点。本文回顾了绿泥石包膜的研究历史,总结了其研究成果,包括微观赋存状态、形成时间和机理、控制因素、对石英次生加大的抑制和对储集层物性的影响等。结果表明:(1)储集层中绿泥石包膜主要偏富铁,具连续生长的双层结构,符合"Ostwald"熟化过程,始于早期富铁黏土包膜,早成岩期转化为平行或斜切颗粒表面的内层包膜,逐渐向外生长为垂直颗粒表面的孔隙衬里绿泥石,并可在埋藏成岩过程持续生长;(2)富含铁镁矿物的火山物质(火山岩岩屑和火山灰)及暗色矿物(黑云母和角闪石等)是形成绿泥石包膜的主要物质来源,并主要富集在三角洲入海(湖)的高能水动力相带,如三角洲前缘水下分流河道及河口坝等沉积微相中,烃类充注影响孔隙衬里绿泥石的生长形态;(3)中低温环境绿泥石包膜明显抑制石英次生加大的生长,高温环境抑制效果减弱;(4)绿泥石包膜的发育有利于粒间孔隙的保护,但易降低孔隙喉道的连通性。最后指出了绿泥石包膜在目前研究中存在的问题和今后的研究趋势。

Abstract：Chlorite films were common in clastic rock reservoirs,and their inhibiting overgrowth of quartz and influence on reservoir properties are research focus at home and abroad. Study history of chlorite films was reviewed and the current research results were summarized,including micro-morphological occurrence,timing and mechanism of chlorite growth,controlling factors,their inhibiting overgrowth of quartz and influence on reservoir properties. Results show that： （1）Most of the discovered chlorite films are Fe-rich with ＂two layers structure＂following Ostwald processes. The inner part adjacent to grain is finer-crystalline chlorite which is mainly parallel to the grain surface,and the outer part near pore space is coarser-crystalline which is generally perpendicular to the grain surface. Fe-rich clay films,precursor minerals of the inner part,will recrystallize in the eogenetic stage,and continue to precipitate based on the incipient chlorite films. （2）Ferromagnesian minerals,like volcanic materials（volcanic debris and ash）and dark minerals（biotite and amphibole）,are the main sources of chlorite films,and their enrichment are closely related to hydrodynamic facies,such as the subaqueous distributary channel and mouth bar in the deltaic front. （3）The growth morphology of pore-lining chlorite films is affected by hydrocarbon injection in diffident places. （4）Chlorite films help to protect the intergranular pore,but easily damage the pore-throat connectivity. Finally,existing problems and research trend on chlorite films were proposed.