摘要
基于JG1井等最新钻井及地震资料,对四川盆地北部茅口组开展了详细的地层层序、沉积特征等方面的研究。结果表明:①JG1井茅口组发育斜坡相,证实了川北地区茅口组沉积的中晚期发生台槽分异,沉积分异时期为茅二b亚段沉积晚期至茅三末期。②JG1井茅二段中上部为下斜坡亚相,以灰黑色泥质灰岩和泥晶灰岩沉积为主,发育风暴沉积、硅质互层及页理;茅三段为上斜坡亚相,以生物碎屑泥晶灰岩和泥晶生物碎屑灰岩沉积为主,反映低能沉积环境,发育生物潜穴、生物碎屑叠瓦状层理。③川北地区斜坡相纵向上构成连续变浅的沉积序列,平面上沿剑阁—阆中一线呈北西向展布,在茅口中晚期形成进积型镶边碳酸盐台地沉积模式。④下斜坡亚相有机质丰度高,其中风暴岩的总有机碳含量可达15%,具有优越的生烃潜力。建立了茅口组旁生侧储、下生上储的成藏模式,这对认识和评价川北地区茅口组的资源潜力具有重要意义。
Recently,a great exploration breakthrough has been made in shoal porous reservoir of Maokou Formation in northern Sichuan Basin.Based on the latest drilling and seismic data,the stratigraphy,sedimentology and geochemistry of Maokou Formation in northern Sichuan Basin has been studied.The results show that:(1)The slope facies is developed in Maokou Formation of Well JG1,which confirms the differentiation of platform and trough occurring in mid-late stage of member-2 to late stage of member-3 of Maokou Formation.(2)The middle and upper part of member-2 of Maokou Formation develops the lower slope subfacies,which is mainly composed of grey-black micrite limestone and silty limestone,with storm deposits,silicon interlayer and lamellation developed.The storm deposition sequences that can be recognized mainly include combination of erosion surface and biodetritus bedding,combination of biodetritus bedding and graded bedding,combination of erosion surface and biodetritus bedding and horizontal bedding,combination of erosion surface and gravel bedding.The member-2 of Maokou Formation develops upper slope subfacies,which consists of bioclastic micritic limestone and micrite bioclast limestone reflecting low-energy sedimentary environment,and the paleontology is a combination of shallow water organisms,with sediment structure of biological burrows and imbricated bedding developed.(3)The slope facies in the northern Sichuan Basin constitutes a continuous shallow sedimentary sequence in the vertical direction,and spreads along the Jiange-Langzhong line in a northwest direction.The slope and platform margin form the progradational sedimentary model of rimmed platform.(4)Organic geochemical analysis shows that the lower slope subfacies have a high abundance of organic carbon,among which tempestite is the best with TOC up to 15%,which has high-quality hydrocarbon generation potential.The study clarifies the period and plane position of platform and trough differentiation,and provids support for expanding the exploration of shoal porous reservoir of Maokou Formation.The discovery of high-quality hydrocarbon source rock in the lower slope subfacies can contribute to establish a variety of reservoir formation mode in the Maokou Formation,which is of great significance to evaluate the resource potential of the Maokou Formation in northern Sichuan Basin.
作者
蒋航
张玺华
陈聪
高兆龙
山述娇
罗平
陈延贵
李天军
胡罗嘉
JIANG Hang;ZHANG Xihua;CHEN Cong;GAO Zhaolong;SHAN Shujiao;LUO Ping;CHEN Yangui;LI Tianjun;HU Luojia
出处
《海相油气地质》
CSCD
北大核心
2023年第4期381-390,共10页
Marine Origin Petroleum Geology
基金
国家科技重大专项“大气田富集规律与勘探关键技术”子课题“四川盆地二叠系-中三叠统天然气富集规律与目标评价”(编号:2016ZX05007-004)资助。
关键词
斜坡相
沉积特征
沉积演化
勘探领域
茅口组
川北地区
slope facies
sedimentary characteristics
sedimentary evolution
exploration field
Maokou Formation
northern Sichuan Basin
