海洋地质前沿2025，Vol.41Issue(6)：68-77,10.DOI:10.16028/j.1009-2722.2024.109
川北古中坳陷飞仙关组鲕粒灰岩沉积分布模式及其油气地质意义
Sedimentary distribution model and oil&gas geological significance of oolitic limestone in Feixianguan Formation of the Paleo-Central Depression in Northern Sichuan
摘要
Abstract
The Feixianguan Formation in the Paleo-Central Depression of the Northern Sichuan Basin hosts high-yield quality natural gas reservoirs in the dolomitized oolitic limestone under the control of sedimentary facies.Understanding the sedimentary characteristics and distribution patterns of the oolitic limestone could help guide the exploration and development of natural gas in this area.Specific sedimentary facies zones of the Feixianguan Formation were distinguished using rock core from Well Q1 in the study area via microscopic thin-section obser-vation.Results indicate that the study area contains 6 types of ooids,mainly surface ooids and calcitic-metacrystic ooids,followed by true ooids,"negative ooids"(or hollow ooids due to selective dissolution after oolite forma-tion),dolomitic-metacrystic ooids,and some complex ooids.Various types of ooids were mixed and deposited at different depths,enriched in mainly micritic-oolitic limestone,micritic dolomictic-oolitic limestone,and oolitic sparite.The analysis on the occurrence and microscopic characteristics of ooids suggested that the ooids were de-posited in a platform environment with barrier coasts,and their sedimentary microfacies include 6 types:ooid beach,oolitic biological reef,tidal channel,bioclastic beach,lagoon ooze,and stagnant water ooze.Ooids were found in 3 types of microfacies:ooid beach,oolitic biological reef,and tidal channel.Classification of sediment-ary facies showed that metacrystic ooids were deposited near wave base in open platform,and enriched mostly in micritic dolomictic-oolitic limestone.The oolitic sparite contains all types of ooids,while the micritic dolomictic-oolitic limestone contains only calcitic-metacrystic oolites and"negative oolites",indicating tidal channel micro-facies and restricted platform facies.The metacrystic ooids in the dolomictic-oolitic limestone are characteristic of dolomitic metacrysts,representing open platform facies.The establishment of sedimentary facies is beneficial for paleogeographic reconstruction of the study area,thereby determining the location of quality productive reser-voirs,and providing reliable basis for logging data interpretation and evaluation for effective oil and gas extraction.关键词
鲕粒灰岩/台地相带/古中坳陷/飞仙关组/沉积模式Key words
oolitic limestone/platform facies/Paleo-Central Depression/Feixianguan Formation/sedimentary model分类
石油、天然气工程引用本文复制引用
都忠建,倪子尧,殷楠,胡鳕茹,赵彦舟,梁斌,吴伟..川北古中坳陷飞仙关组鲕粒灰岩沉积分布模式及其油气地质意义[J].海洋地质前沿,2025,41(6):68-77,10.基金项目
中国石油天然气股份有限公司项目"四川省四川盆地中部仪陇-营山地区油气勘查"(0200002030130) （0200002030130）
