摘要:
四川盆地川中地区震旦系气藏储量规模大,储层分布面积广.在Folk(1959)碳酸盐岩分类方案与张荫本等(1996)对粘结岩分类方案研究的基础之上,结合四川盆地震旦系灯影组的具体情况,提出新的划分方案.研究表明:①高石梯-磨溪地区震旦系灯影组碳酸盐岩岩石类型可分为3个亚类,10个微类.该方案不同之处在于把凝块(石)云岩归位颗粒岩,同时根据藻的形态把藻云岩进一步细分;②沉积岩类的发育和分布受沉积层序的控制.海侵体系域(TST)沉积阶段,以泥-粉晶云岩、微生物岩等正化学岩沉积为主.高位体系域(HST)沉积阶段,以凝块云岩、砂屑云岩等异化颗粒岩沉积为主.纵向上,岩性具有从暗色泥晶云岩→藻云岩→颗粒云岩→浅色泥晶云岩演化的特征,即泻湖亚相→藻丘亚相→颗粒滩亚相→台坪亚相的规律;③凝块云岩、砂屑云岩等颗粒岩是主要的储集岩类;④灯影组碳酸盐岩不同岩类的发育和分布对储层的发育起到控制作用.对灯影组的油气勘探,除了对岩溶作用的研究之外,还需要重视沉积古地貌、岩相展布特征的分析,有助于有效的预测灯影组储层“甜点区”.%The reserves of the Sinian Dengying gas reservoirs in central Sichuan Basin are large and the reservoirs are widely distributed.On the basis of Folk (1959) carbonate classification scheme and Zhang et al.(1996) rock classification scheme,combined with Dengying Formation of Sinian in Sichuan Basin,and the carbonate rocks of the Dengying Formation can be divided into 3 sub-classes,10 kinds of micro-classes.The classification scheme is difference in that thrombolite belongs to grain rock,and microbial carbonate rocks are divided into three sub-classes according to their form.In addition,the development and distribution of sedimentary rocks are controlled by sedimentary sequences.The main sedimentary rock is orthochemical rock in the TST stage,such as micritic dolomite,microbolite and so on.The main sedimnentary rock is allochemical rock,such as thrombolite,dolarenite and so on.In the vertical direction,the evolutionary characteristics of lithology is deep color micrite dolomite→ microbial carbonate→ grain dolomite→light color micrite dolomite,and which is lagoon subfacies→algal mound subfacies→grain beach subfacies→table subfacies.The thirdly,grain rock is the main reservoir rocks,such as tbrombolite and dolarenite.The last,the development and distribution of different rocks in Dengying Formation carbonate rocks play a controlling role in reservoir development.In addition to the study of karstification,it is necessary to pay attention to the analysis of the characteristics of sedimentary palaeogeomorphology and lithofacies distribution,which can help to effectively predict the "reservoir dessert zone" of Dengying Formation.