摘要
近年来,通过加大深层—超深层碎屑岩晚期油气成藏地质认识研究,在河套盆地临河坳陷实现了超深层碎屑岩油气勘探的重大发现。基于对临河坳陷古近系烃源岩热模拟、钻录试井资料及成储成藏演化分析,主要形成3点地质认识:(1)临河坳陷北部古近系发育富含树脂体(陆源)和藻类体(水生)的优质烃源岩,该烃源岩在低演化阶段开始大量生排烃,具有生烃强度大、生烃窗口宽的特点,淖西洼槽带超深层热演化程度相对较高,油气资源潜力大;(2)发育远源水浅坡缓大型辫状河三角洲沉积,砂体广覆式分布,受低地温、晚深埋、高石英含量、弱压实、弱胶结等弱成岩因素影响,形成了以弱成岩保孔主导、叠加后生超高压改造扩缝的成储新机制,储层物性好,极大拓展了超深层油气勘探空间;(3)生烃期早充注、持续沉降深埋热演化、加速生排烃和持续充注形成过饱和与超高压油气藏,而超高压一旦超过储源交互体破裂压力,形成缝孔连通、源储同聚、连续型大面积展布的常规油气成藏新认识,有力提高了超深层常规油气藏勘探潜力。临河坳陷北部古近系临河组超深层油气成藏条件优越,有利勘探区规模大,展现了良好的勘探前景,同时进一步丰富了超深层碎屑岩晚期油气成藏理论认识,对类似盆地尤其是万米超深层的源内勘探具有重要指导意义。
In recent years,the geological understanding of late hydrocarbon accumulation in deep to ultra-deep clastic rocks has been deepened,and a major oil and gas discovery has been achieved in ultra-deep clastic rocks in Linhe Depression in Hetao Basin.Based on the thermal simulation of the Paleogene source rock,well drilling,logging and testing data,and analysis of reservoir formation and hydrocarbon accumulation evolution,the new geological understanding has been formed in three aspects:(1)The high-quality source rocks rich in resinite(terrestrial)and algae(aquatic)were developed in the Paleogene in the northern Linhe Depression,which generated and expulsed a large amount of hydrocarbon in the low thermal evolution stage,and showed characteristics of high intensity and wide window of hydrocarbon generation.The source rock in ultra-deep Naoxi trough has a high thermal evolution degree and great potential of oil and gas resources.(2)The large-scale braided river delta deposits were developed in the far-source shallow and gentle slope,with sand body widely distributed.Affected by weak diagenetic factors such as low formation temperature,late deep burial,high quartz content,weak compaction and weak cementation,a new reservoir formation mechanism is formed,which is dominated by weak diagenesis for pore maintenance,and superimposed by epigenetic ultra-high pressure transformation and fracture expansion.The reservoir has good physical properties,greatly expanding the space for petroleum exploration in ultra-deep formations.(3)A new understanding of hydrocarbon accumulation is put forward,which includes the initial oversaturated and ultra-high pressure oil and gas reservoirs in hydrocarbon generation period formed by the early hydrocarbon charging,continuous subsidence,deep burying and thermal evolution,accelerated hydrocarbon generation,expulsion,and continuous charging,and ultimately the late hydrocarbon accumulation of conventional oil and gas reservoirs once the fracture pressure of reservoir-source rock interaction body is broken through by ultra-high pressure,with characteristics of fracture-pore connection,accumulation in both source rock and reservoir,and continuous and large-area distribution,greatly improving the exploration potential.The hydrocarbon accumulation conditions in the ultra-deep Paleogene Linhe Formation in the northern Linhe Depression are superior,and the favorable exploration area is large,showing promising exploration prospects.Meanwhile,the new theoretical understanding of late hydrocarbon accumulation in the ultradeep clastic rocks has important guiding significance for the exploration in similar basins,especially for the inside-source exploration in ultradeep formations with a burial depth of 10000 meters.
作者
张锐锋
陈树光
冯广业
师玉雷
胡延旭
孙瑞娜
万照飞
武函
田思思
张宇飞
汪关妹
周然然
罗玉财
王孝超
张晰蒙
Zhang Ruifeng;Chen Shuguang;Feng Guangye;Shi Yulei;Hu Yanxu;Sun Ruina;Wan Zhaofei;Wu Han;Tian Sisi;Zhang Yufei;Wang Guanmei;Zhou Ranran;Luo Yucai;Wang Xiaochao;Zhang Ximeng(PetroChina Huabei Oilfield Company;PetroChina Oil,Gas&New energies Company;North China Research Center,BGP Inc.,CNPC;Academician Workstation,CNPC Logging Co.,Ltd.)
出处
《中国石油勘探》
CAS
CSCD
北大核心
2024年第1期119-129,共11页
China Petroleum Exploration
基金
中国石油天然气股份有限公司“攻关性、应用性”重大科技专项“超深层碎屑岩油气规模增储上产与勘探开发技术研究”(2023ZZ14)。
关键词
临河坳陷
古近系
超深层
超高压
千吨井
Linhe Depression
Paleogene
ultra-deep formation
ultra-high pressure
oil well with a flow rate of thousand tons
