渤海沙垒田凸起带地层流体特征及其形成机制  

Formation Fluid Properties and Mechanism of Shaleitian Uplift Zone in Bohai Sea

作　　者：时梦临 张成[1] 解习农[1] Shi Menglin;Zhang Cheng;Xie Xinong(China University of Geosciences(Wuhan),Wuhan,Hubei 430000,China)

机构地区：[1]中国地质大学(武汉),湖北武汉430000

出　　处：《特种油气藏》2020年第2期78-86,共9页Special Oil & Gas Reservoirs

基　　金：国家自然科学基金“断陷湖盆陆源碎屑-碳酸盐混积岩成因及优质储层发育机制——以渤海湾盆地渤中凹陷为例”(41772111)。

摘　　要：盆地流体动力学研究是当前油气勘探的焦点问题,针对沙垒田凸起带流体化学特征及压力系统特征认识不清等问题,通过对沙垒田凸起及其周缘地区上百个地层流体化学数据和实测地层压力数据的系统分析,查明了研究区平面上和垂向上的地层流体特征,进而讨论了水-岩相互作用过程。研究结果表明:沙垒田凸起及其周缘地区新生界分为3个水化学作用带,包括地层水交替自由带、地层水交替阻滞带和地层水交替停滞带;地层水蒸发浓缩作用和泥岩压实排水作用发生在1 300 m以浅的交替自由带,而黏土矿物淡化作用主要发生在2 300 m以深的地层水交替停滞带,地层压力系统也与之有一定联系;地层水矿化度呈现出随地层埋深而增大的趋势,在3 000 m处出现峰值;膏盐溶解是交替自由带和交替阻滞带Na+富集的主要因素,碳酸盐胶结物的形成、斜长石的钠长石化、钠长石的高岭石化是研究区地层水交替停滞带的主要水-岩相互作用。通过地层水化学和压力特征以及两者之间耦合关系的研究,揭示了地层流体的形成机制,可指示油气赋存的层位,对于沙垒田凸起带的油气勘探有一定借鉴作用。Basin fluid dynamics is considered as a hotspot in the current hydrocarbon exploration. Hundreds of formation fluid chemical data and measured formation pressure data in the Shaleitian Uplift and its peripheral area were systematically analyzed to clarify the chemical properties and pressure system in this zone. The formation fluid properties along the longitudinal and lateral directions were gained to further discuss the water-rock interaction process. Research indicates that The Cenozoic in the Shaleitian Uplift and its peripheral area can be divided into three hydro-chemical zones,including formation water alternation free zone,formation water alternation blocking zone and formation water alternation stagnation zone. Formation water evaporation-concentration and mudstone compaction drainage effect are dominant in the formation water alternation free zone that is shallower than 1 300 m.The clay mineral desalination is mainly in the formation water alternation stagnation zone that is deeper than 2 300 m,which is also related to the formation pressure. Formation water salinity shows a tendency to increase with the increase of burial depth and a peak at 3 000 m. Gypsum-salt dissolution is the key factor for Na+enrichment in the formation water alternation stagnation zone. The carbonate cement formation,plagioclase albitization and albitekaolinization are considered as the major water-rock interactions in the formation water alternation stagnation zone. The water formation mechanism was revealed through formation water chemical properties,pressure pattern and their coupling relationship,which could indicate the hydrocarbon enrichment layers. This research could provide certain reference for the hydrocarbon exploration in the Shaleitian uplift zone.

关 键 词：地层流体 压力场 化学场 沙垒田凸起 

分 类 号：TE122.2[石油与天然气工程—油气勘探]