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塔里木盆地西北缘震旦系奇格布拉克组 微生物白云岩发育特征及储集意义

作    者:杨翰轩1,2,3, 沈安江2,3, 郑剑锋2,3, 胡安平2,3
单    位:1中国石油勘探开发研究院; 2中国石油杭州地质研究院; 3中国石油集团碳酸盐岩储层重点实验室
基金项目:本文受国家科技重大专项“大型油气田及煤层气开发”项目下属课题等资助
摘    要:
塔里木盆地震旦系奇格布拉克组发育一套厚层微生物白云岩,对其微生物岩类型、分布规律和储层成因等方面的认识仍不清楚。基于野外剖面实测及薄片观察,对该套白云岩的发育特征及油气储集意义进行了研究。奇格布拉克组发育规模不等的多种类型微生物白云岩,包括叠层石白云岩、凝块石白云岩、泡沫绵层石白云岩及与微生物相关颗粒白云岩,以微生物丘和微生物白云岩坪建造的形式产出。奇格布拉克组由SQ1和SQ2 2个三级层序构成,不同沉积建造发育于层序格架内的特定阶段:微生物丘主要发育于三级层序的TST和HST早期,微生物白云岩坪则主要发育于三级层序的HST中晚期;叠层石白云岩集中发育于SQ1,环境条件的改变导致SQ2以发育泡沫绵层石白云岩为主。奇格布拉克组微生物白云岩储层具有相控性,位于向上变浅旋回顶部的丘坪和微生物白云岩坪是储层发育的有利相带。泡沫绵层石白云岩发育多种类型孔隙,纵向上频繁叠置、累计厚度大,横向上分布稳定,是奇格布拉克组储集性能最好的储集岩,具备成为规模优质储层的潜力。
关键词:微生物白云岩; 微生物白云岩坪; 奇格布拉克组; 震旦纪; 塔里木盆地

Sedimentary characteristics and reservoir significance of the microbial dolomite of Sinian Qigebrak Formation in the northwest margin of Tarim Basin

Author's Name: ANG Hanxuan, SHEN Anjiang, ZHENG Jianfeng, HU Anping
Institution: PetroChina Hangzhou Research Institute of Geology
Abstract:
Microbial carbonate is a new field and hot spot for petroleum exploration. The Sinian Qigebrak Formation of Tarim Basin develop a set of thick microbial dolomite, and its type, distribution rule, and reservoir genesis are still unclear. Based on the outcrop measurement and thin section observation, the sedimentary and reservoir characteristics of the microbial dolomite in Sinian Qigebrak Formation in the northwest margin of Tarim Basin were studied. Various types and scales of microbial dolomites, including stromatolite dolomite, thrombolite dolomite, spongiostromata dolomite, and microbe-related granular dolomite were found in microbial flat and microbial mound of Qigebrak Formation. There are two third-order sequences in Qigebrak Formation, in which microbial mounds develop during the TST and the early stage of HST, while microbial flats mainly develop during the mid-late stage of HST. Stromatolite dolomite is enriched in SQ1, and spongiostramata dolomite is enriched in SQ2 due to the change of environment. The microbial dolomite reservoir in the Qigebrak Formation is controlled by facies, and the mound and microbial dolomite flat on the top of the upward shallowing cycle are favorable facies zones for reservoir development. Spongiostromata dolomite could be a large-scale high-quality reservoir, which contains various types of pore space, overlays frequently in vertical and distributes stably in horizon.
Keywords: microbial dolomites; microbial dolomite flat; Qigebrak Formation; Sinian; Tarim Basin
投稿时间:2019-05-29  
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