CAJ | 학술논문

通过岩心分析、显微镜下观察（常规、铸体薄片和扫描电镜）、岩石地球化学分析测试等技术手段，以准噶尔盆地西北缘下二叠统油气储层为实例，研究了火山岩、火山碎屑岩和火山岩屑质砂砾岩中的火山玻璃、火山碎屑、长石以及辉石、角闪石等火山物质的低温-埋藏蚀变作用。镜下观察发现，在含火山物质油气储层中，常见对储集空间具有重要影响的自生矿物主要有绿泥石、沸石（包括方沸石、片沸石和浊沸石）、方解石、钠长石和自生的石英。结合共生关系、元素组成和元素迁移，分析了自生矿物的微观特征和成因，建立了火山物质蚀变的成岩演化序列，可以概括为：①火山玻璃水化-蒙脱石化-沸石化及各种沸石的转化---钠长石化；②铁镁矿物影响的绿泥石化；③长石蚀变向绿泥石和方解石转化，后期发生钠长石化。在研究区，火山物质的蚀变和自生矿物的析出与中-基性的母岩物质组成密切相关，并受地层温度、压力、孔隙水的化学性质控制。研究火山物质蚀变的产物、蚀变过程及控制因素，能够明确含火山物质的油气储层质量差异机理，为优质储层预测提供科学的依据。
통과암심분석、현미경하관찰（상규、주체박편화소묘전경）、암석지구화학분석측시등기술수단，이준갈이분지서북연하이첩통유기저층위실례，연구료화산암、화산쇄설암화화산암설질사력암중적화산파리、화산쇄설、장석이급휘석、각섬석등화산물질적저온-매장식변작용。경하관찰발현，재함화산물질유기저층중，상견대저집공간구유중요영향적자생광물주요유록니석、비석（포괄방비석、편비석화탁비석）、방해석、납장석화자생적석영。결합공생관계、원소조성화원소천이，분석료자생광물적미관특정화성인，건립료화산물질식변적성암연화서렬，가이개괄위：①화산파리수화-몽탈석화-비석화급각충비석적전화---납장석화；②철미광물영향적록니석화；③장석식변향록니석화방해석전화，후기발생납장석화。재연구구，화산물질적식변화자생광물적석출여중-기성적모암물질조성밀절상관，병수지층온도、압력、공극수적화학성질공제。연구화산물질식변적산물、식변과정급공제인소，능구명학함화산물질적유기저층질량차이궤리，위우질저층예측제공과학적의거。
Based on observations of available cores ,thin-sections and SEM and analysis of rock geochemistry ,we studied low-temperature-burial metamorphism ( alteration ) of volcanics in the Lower Permian at northwestern margin of Junggar Basin .These volcanics include volcanic glass , volcanic clasts , feldspar , and mafic minerals such as pyroxene and horn-blende,etc.,which originate from lavas,pyroclastic rocks,and volcaniclastic sandstones or conglomerates .In oil/gas reservoirs containing volcanics ,the authigenic minerals that are common but important to pore spaces include chlorite ,ze-olites(like analcime,heulandite,and laumontite),calcite,albite,and authigenic quartz.Based on the paragenetic relation-ship of minerals and the composition and migration of elements ,we analyzed the microscopic characteristics and origins of authigenic minerals ,and established diagenetic evolution models during volcanic alteration .The alteration can be summa-rized as follows:①volcanic glasses hydrolysis-montmorillization-zeolitization-albitization;②chloritization related to mafic minerals and smectites;③transformation of feldspar to chlorite,calcite,and finally to albite.The alteration of volcanics and the formation of authigenic minerals in the study area were controlled by various factors such as the precipitation of authigenic minerals ,composition of neutral-basic host rocks ,temperature and pressure ,and the chemical behaviors of pore water.The study on alteration process,alteration products,and control factors is helpful to understand the mechanisms that cause the differences of volcanics-bearing reservoir qualities , so as to provide a scientific geological foundation for the predication of high-quality reservoirs .