对渤海BZ19-6区块变质岩潜山数口钻井的铸体薄片、常规物性等数据展开综合分析,依据矿物组成和岩石结构、构造等建立该区块变质岩的岩性划分方案.研究结果表明:除黑云二长片麻岩、黑云斜长片麻岩和黑云钾长片麻岩外,其余变质岩的浅色矿物(石英、长石为主)含量均较高,暗色矿物(黑云母等)含量较低;有效储集空间主要为构造运动产生的未充填裂缝和斜长石的粒内溶孔;当石英含量为25%~35%(体积分数)、斜长石比率为0.4~0.6时,物性最好;碎裂岩、二长片麻岩、二长混合花岗岩、斜长混合花岗岩的浅色矿物含量高,孔隙度和渗透率高,是形成优势储层最有利的变质岩岩性.但是,各岩性之间的浅色矿物含量、物性、抗压强度等相差不显著,指示岩性确实起到基础作用,但是构造作用可能是有利储层形成最主要的控制因素之一.
All the rock thin sections,conventional physical properties and other data from more than ten wells in BZ19-6 block,Bohai sea were comprehensively analyzed.The lithology division scheme of metamorphic rock in this block,including granitic gneiss,cataclastic rock and granulite was constructed.The results show that the content of light minerals(mainly quartz and feldspar)of this lithology is very high,and the content of dark minerals(biotite,etc.)is low,respectively.The effect reservoirs contain micro-cracks and intragranular dissolved pores.When the content of quartz is between 25%and 35%,and the ratio of plagioclase/(plagioclase+alkali feldspar)is between 0.4 and 0.6;The cataclastic rock,monzonitic gneiss,monzonitic mixed granite and plagioclase mixed granite are the best metamorphic rocks forming good reservoirs,based on the high content of light minerals,high values of porosity and permeability.It shows that the superior lithology sequence is influenced by lithology in basically,but tectonic movement is also one of the main controlling factors.