四川盆地坡西地区长兴组——飞仙关组礁滩体发育特征与储集性  

Development Characteristics and Reservoir Properties of Reef and Oolitic Shoal of Changxing and Feixianguan Formation,Poxi Area,Sichuan Basin

作　　者：王坤[1] 王明磊[1] 梁坤[1] 林世国[1] Wang Kun;Wang Minglei;Liang Kun;Lin Shiguo(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083)

机构地区：[1]中国石油勘探开发研究院,北京100086

出　　处：《中外能源》2022年第12期40-49,共10页Sino-Global Energy

基　　金：国家重大科技专项“下古生界—前寒武系碳酸盐岩油气成藏规律、关键技术及目标评价”(编号:2016ZX05004)。

摘　　要：晚二叠世长兴组生物礁与早三叠世飞仙关组鲕粒滩是四川盆地天然气勘探的重要层系,已发现普光、龙岗等多个大型气田。本文以开江—梁平海槽东侧坡西地区为研究区,利用钻井、地震资料对生物礁和鲕粒滩的发育特征及储集物性进行了研究。结果显示生物礁具有岩电特征和地震反射特征,易于识别和刻画,井震资料揭示研究区发育三期生物礁,经历了由退积到加积的生长过程,呈三排展布。鲕粒滩以残余鲕粒白云岩为主要岩石类型,地震剖面上呈断续反射,研究区共发育两期叠置型鲕粒滩,呈加积生长。通过礁滩体储层特征的分析对储层发育主控因素进行了讨论。坡西地区礁滩总体发育低孔—低渗型储层,礁盖微相和鲕粒滩微相的储集性最好。缓坡地貌背景下的水动力条件、溶蚀改造条件和充分的白云石化作用是坡西地区礁滩储层发育的主要控制因素,其中飞仙关组鲕粒滩储层具备大面积展布的地质条件,具有较好的勘探前景。Late Permian Changxing Formation reefs and early Triassic Feixianguan Formation oolitic shoals are the important strata for natural gas exploration in Sichuan Basin,and several large gas fields such as Puguang and Longgang have been discovered.In this paper,the development characteristics and reservoir physical properties of the reefs and oolitic shoals in Poxi area of the east of Kaijiang-Liangping Trough are studied by using drilling and seismic data.The results show that the organic reef has the characteristics of litho-electricity and seismic reflection,which are easy to be identified and characterized.The well seismic data reveal that the organic reef developed in three stages in the study area,which experienced the growth process from retrogradation to accretion and distributed in three rows.The oolitic shoals are mainly composed of residual oolitic dolomite,which shows intermittent reflection on seismic profile.Two-stage overlapping oolitic shoals developed in the study area,showing accretion growth.The main controlling factors of reservoir development are discussed by analyzing reservoir characteristics of reef and oolitic shoal.Low porosity and low per-meability reservoirs generally developed in the reef-shoals in Poxi area,and reef cover microfacies and oolitic shoal microfacies have the best reservoir property.Hydrodynamic conditions,dissolution reconstruction conditions and sufficient dolomitization under the gentle slope geomorphology background are the main controlling factors for the development of reef-shoal reservoirs in Poxi area,among which the oolitic shoal reservoirs of Feixianguan Formation have the geological conditions for a large-scale distribution with good exploration prospect.

关 键 词：坡西地区 生物礁 鲕粒滩 迁移演化规律 储层特征 主控因素 

分 类 号：P618.13[天文地球—矿床学]