秘鲁乌卡亚利盆地油气勘探潜力分析  

Evaluation of Petroleum Exploration Potential in Ucayali Basin,Peru

作　　者：张申[1] 田世存[1] 郭建宇[1] 肖芳锋[1] 

机构地区：[1]中化石油勘探开发有限公司,北京100031

出　　处：《天然气地球科学》2012年第2期268-278,共11页Natural Gas Geoscience

基　　金：国土资源部"全球油气地质综合研究与区域优选"课题"南美北部地区油气地质综合研究与区域优选"项目(编号:GT-YQ-QQ-2008-4-10)资助

摘　　要：秘鲁乌卡亚利盆地是油气资源丰富的南美安第斯前陆盆地的子盆地之一。该盆地油气潜力巨大,勘探程度低,已发现12个油气田,可采储量约6×108t。根据大量物探、钻井和实验分析资料,系统分析乌卡亚利盆地的烃源岩、储集层、盖层及圈闭等基本石油地质条件,并提出勘探有利区域和潜力。研究表明,乌卡亚利盆地自奥陶纪形成以来,长期沉降接受沉积。从古生代到中生代沉积3套主要烃源岩,即三叠系—侏罗系Pucara组烃源岩、二叠系Ene组烃源岩和石炭系Ambo群烃源岩,这些烃源岩有机质含量高,处于成熟阶段,分别向盆地的北部、中部和南部运移供油;盆地内有多套储盖组合,主要储集层为白垩系Cushabatay组和Vivian组;晚二叠世以来的多次构造运动特别是晚白垩世以来的构造运动形成多种类型的圈闭,圈闭类型主要为挤压背景下形成的推覆背斜、断背斜和断块等构造圈闭,也存在大量地层和岩性隐蔽圈闭。盆地勘探前景广阔,最有利的勘探区域是盆地东南部的Urubamba次盆和构造发育的西部褶皱逆冲带。已经发现的油气藏全部是构造油气藏而且多数位于逆冲断层的上盘,对下盘圈闭的勘探很少。勘探潜力包括2个方面:一是要继续寻找构造圈闭,特别要加强对逆冲断裂下降盘的勘探力度;二是要重视隐蔽油气圈闭勘探,特别是要加大二叠系Ene组古潜山圈闭、三叠系—侏罗系Pucara组生物礁圈闭和白垩系岩性(河道砂体)圈闭的勘探。Ucayali basin in the Peru is one of the greatest abundance petroleum Sub Andean foreland basins in the South America.Although the degree of petroleum exploration is now low,it is highly prospective with 12 oil and gas fields and about 4.7 billion proved oil equivalent reserves.Based on seismic integration,drilling and core analysis data,we evaluate the general petroleum geological conditions in the Ucayali basin,including source rock,reservoir rock,cap rock and trap;and then we point out the favorable exploration area and potential goal.The results indicate that there are three sets of source rocks with high organic carbon and mature stage in the Ucayali basin,i.e.Triassic-Jurassic Pucara,Permian Ene and Carboniferous Ambo.Three sets of source rocks provided the petroleum toward the north,middle and south,respectively.The main exploration targets are Cretaceous Cushabatay and Vivian sandstones.The trap types are anticline,faulted anticline and fault nose formed under compressional tectonic background,as well as lithologically subtle traps.The basin has wide exploration domains and huge potential,the most favorable area for exploration is Urubamba subbasin in the southeast of the basin and folding and thrusting belt in the west of the basin.All oil and gas fields are discovered in the structural traps and most of them are located in the hanging wall of thrusting fault.The exploration to the footwall of thrusting fault is poor.Therefore,the exploration targets in the basin should focus on the following two aspects： structural traps（especially footwall traps） and subtle traps.In the subtle trap,the lithological traps should be paid more attention,such as Permin Ene Formation buried hill,Triassic-Jurassic Pucara bio-reef and Cretaceous channel sands.

关 键 词：乌卡亚利盆地 石油地质 勘探潜力 隐蔽圈闭 前陆盆地 秘鲁 

分 类 号：TE122.3[石油与天然气工程—油气勘探]