摘要
通过对江汉盆地潜江凹陷王场地区王云11井潜江组潜3^3下亚段和潜3^4亚段4个韵律层部分取心样品的全岩热解和有机抽提物分子地球化学分析,将盐间页岩的沉积环境划分为半咸水—咸水湖相和咸水湖相2种类型。前者分布范围相对广泛,沉积水体分层明显,以富含伽马蜡烷和2,3,6-三甲基-芳基异戊间二烯烷烃为特征;后者分布范围相对局限,以较高丰度的3,4,5-三甲基—芳基异戊间二烯烷烃为特征,同时缺少水体分层的分子标志物证据。较高的热解S1含量、S1/w(TOC)比值以及与盐间页岩储层埋藏深度不匹配的萜烷Ts/(Ts+Tm)比值和规则甾烷异构化参数分析揭示,盐间页岩中游离油富集段主要分布在半咸水—咸水环境形成的富有机质纹层发育段,为一定程度的成熟油气沿着顺层微裂缝侧向运移提供了有利场所。通过常规甾萜烷和芳基异戊间二烯烷烃特殊生物标志物组合分析,提出盐间页岩油勘探应关注潜三段和潜四段内几个最大湖泛面,除了继续王场构造区开发试验外,应该加大蚌湖洼陷成熟烃源区的勘探力度。
Fifteen inter-salt shale cores were collected from the well WY 11,Qianjiang Sag,Jianghan Basin,and the sampling intervals include four of the salt cycles in the Eq3 Member of the Eogene Qianjiang Formation.Bulk geochemical data were obtained by whole rock pyrolysis,and gas chromatography-mass spectrometry(GC-MS)analyses were conducted for molecular compositions of saturated and aromatic biomarkers.Our results separated the analyzed samples into two broad categories corresponding to brackish-saline and saline lacustrine settings.Inter-salt shales deposited in the brackish-saline lakes occur over large geographic areas with relatively strong water column stratification,and are characterized by the presence of abundant gammacerane and 2,3,6-trimethyl-aryl isoprenoid alkanes.In contrast,inter-salt shales deposited in saline lakes tend to distribute in small areas,and the presence of abundant 3,4,5-trimethyl-aryl isoprenoid alkanes with lower contents of gammacerane is consistent with relatively shallow water depth.High pyrolysis S1 contents,S1/w(TOC)ratios,Ts/(Ts+Tm),and 20 S/(20 S+20 R)and(αββ/ααα+αββ)ratios of C29 steranes are good indicators for the inter-salt shales that were deposited in the brackishsaline settings and are ideal habitats for lacustrine shale oil enrichment,since the presence of organic rich lamina favor the updip,lateral oil migration along the bedding parallel microfractures.According to the common hopane and sterane parameters as well as aryl isoprenoid biomarker distributions,it is suggested that inter-salt shale oil exploration in the Jianghan Basin should be focused on organic rich shale beds in the Eq3 and Eq4 members deposited during the maximum lake expansion.More efforts were suggested to be invested in the mature source kitchens of the Banghu Sag in addition to the continuing pilot production tests in the Wangchang area.
作者
马晓潇
黎茂稳
刘鹏
李志明
蒋启贵
陶国亮
钱门辉
鲍云杰
曹婷婷
吴世强
MA Xiaoxiao;LI Maowen;LIU Peng;LI Zhiming;JIANG Qigui;TAO Guoliang;QIAN Menhui;BAO Yunjie;CAO Tingting;WU Shiqiang(SINOPEC Petroleum Exploration and Production Research Institute,Beijing 100083,China;State Key Laboratory of Shale Oil Enrichment Mechanisms and Effective Development,Wuxi,Jiangsu 214126,China;Research Institute of Exploration and Development of SINOPEC Jianghan Oilfield Company,Wuhan,Hubei 430223,China)
出处
《石油实验地质》
CAS
CSCD
北大核心
2020年第4期575-585,共11页
Petroleum Geology & Experiment
基金
国家科技重大专项(2017ZX05049)
国家重点基础研究发展计划(973计划)项目(2014CB239100)资助。
