摘要:
川东地区五百梯构造带上二叠统长兴组为川东地区天然气藏的主要产层,也是邻区寻找新气源的最有利层位之一。根据野外剖面、岩心和室内镜下岩石薄片鉴定分析,并结合岩石学、测井及地震等沉积相标志研究,确定五百梯构造带长兴组发育有台内海槽(深水盆地)、台地前缘缓斜坡、台地边缘生物礁滩和开阔台地4个沉积相带,进一步划分出若干亚相和微相。研究认为,岩石类型、沉积环境和成岩作用对储集层具有明显的影响,长兴组台地边缘生物礁滩相地层为最重要的油气勘探层段,骨架礁、黏结礁和生屑滩为最有利储层发育的微相,储层岩性主要为颗粒白云岩、晶粒白云岩和礁白云岩。在此基础上,综合考虑各种因素,以结合地质资料预测的沉积相平面分布图叠合地震反演预测的生物礁滩岩隆带,最终圈定出有利储集相带发育区。
Abstract:
The characteristics and genesis of the reservoirs in Changxing Formation in the Wubaiti area are studied. The Changxing Formation of Permain is the major pay zone of the gas fields in the eastern Sichuan Basin and also one of the most favorable targets for gas exploration in the adjacent areas. Based on outcrop observation, core description and thin section analysis in combination with lithological, palaeontological and logging data, the Changxing Formation is divided into four main sedimentary facies, i.e. the facies of intratrough platform (deep water basin), platform slope, platform edge and open platform. Various subfacies and microfacies could be further recognized. The reservoir properties of the Changxing Formation are generally controlled by microfacies and diagenesis. Reef flat deposits, reef framework and bindstones are favorable microfacies for reservoir space. The rock types of reservoir mainly consist of grained dolomite, reef dolomite and sparry dolomite. It is conclued that favorite reservoirs could be predicted by the integrated study of all factors, in particular the spatial distribution pattern of depositional facies, the detailed facies framework of the bioreef deposits and the thickness distribution of dolomite inferred from seismic data.
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