【摘要】 受震旦纪末期桐湾运动影响,四川盆地震旦系灯影组白云岩因遭受大气降水岩溶作用而发育了丰富的溶蚀孔隙。虽然经历了漫长的埋藏成岩演化过程,深层灯影组白云岩中仍见有丰富的储集空间未被成岩矿物充填而保存下来。通过对钻井及野外剖面进行系统岩石矿物学研究发现,储集空间保存段是灯影组上部的沥青显示段;而没有沥青的下部白云岩中的孔隙空间多被白云石等成岩矿物所充填。对林1井研究发现,上部沥青发育段白云岩储层孔隙度多大于3.0%,最高可达10.6%,平均为4.0%;但下部沥青不发育的自生白云石充填段孔隙度一般都小于3.0%,平均为1.95%。下部白云岩段溶蚀孔洞中自孔洞边缘向中心,所充填的白云石中流体包裹体均一温度从120℃逐渐增加至238℃;电子探针分析Fe、Mn平均含量从0.063%和0.025%逐渐升高至0.35%和0.108%;氧同位素组成δ18 OVPDB从-6.8‰逐渐降低至-11.2‰;表明了下部沥青未充填段成岩充填作用在埋藏过程中持续进行。油气充注改变了白云岩储层中的成岩流体环境并抑制了成岩矿物的形成;在后期埋藏过程,油逐渐转变成沥青覆盖在孔洞壁周围,也抑制了成岩矿物的沉淀形成;因而在现今沥青存在的深层白云岩储层中仍有丰富的孔隙空间保存下来。更多还原

【Abstract】 Dolomitic rock of Sinian Dengying Formation in the Sichuan basin developed abundant dissolution pores due to meteoric karstifcation during the Tongwan tectonic uplift at the end of Sinian period.Many pores were found unfilled and well preserved in the deep dolomite reservoirs even though the dolomite reservoirs had experienced long burial diagenetic process.Detail petrology and mineralogy analyses of the samples from wells and outcrop profiles reveal that many pores have been well preserved within the upper part of the Dengying Formation dolomite reservoirs with bitumen and the pores in the lower part without bitumen are heavily filled by diagenetic dolomite minerals.Research on the Lin 1 well suggests that porosity in the upper part is generally more than 3.0%,at most to 10.6% and 4.0%in average;but that in the lower part is commonly less than 3.0% and 1.95% in average.From edge to central of the dissolution pores in the lower part,homogenization temperature of the fluid inclusions in the dolomite minerals filled in the dissolution pores increases from 120℃ to 238℃;Average concentrations of Fe and Mn increase from 0.063% and 0.025%to 0.35% and 0.108%,respectively;andδ18 OVPDBvalues decrease from-6.8‰ to-11.2‰.Our results above indicate that the diagenetic cementation in the dolomite reservoirs without bitumen proceeded continuously during deep burial stage.Oil charge alters fluid environment in the dolomite reservoir and thus inhibits precipitation of diagenetic minerals.During deep burial stage,oil is gradually altered into bitumen that sticks on the walls of pores and then inhibit precipitation of diagenetic minerals.Therefore,abundant dissolution pores have been preserved in the deep dolomite reservoirs with bitumen until present day.更多还原