摘要
玛湖凹陷风城组受火山活动的影响,在碱湖沉积背景下广泛发育了凝灰岩储层。为明确碱湖背景下的凝灰岩储层成因机理,基于玛湖凹陷15口典型井的209块岩心样品,通过岩心宏观和微观观察、X射线衍射全岩分析、扫描电镜—能谱分析和蒸发结晶实验、元素测试、原位碳氧同位素测试、包裹体测温等手段,总结了储层的基本特征,探讨了储层成因机理。研究认为:(1)凝灰岩储层岩性主要为凝灰岩和沉凝灰岩,储层富含火山碎屑物质和盐类矿物,储集空间类型主要包括晶间孔、溶孔和裂缝,尽管储层致密,但仍发育孔隙度大于6%、渗透率大于0.1×10^(-3)μm^(2)的样品;(2)凝灰岩储层受控于成岩作用的发育,其中脱玻化作用、溶蚀作用、破裂作用和烃类充注是促进储层形成的主要因素;(3)火山碎屑的脱玻化作用发生时间早,形成的晶间孔有效的改善了储层的储集和渗流条件;(4)油气的早期且持续充注形成了异常高压,有效抑制了压实作用和自生矿物的充填,促进早期孔隙的保存;(5)风城组碱湖优质烃源岩持续排出的酸性流体形成了发育的溶蚀作用,并且破裂作用的发育促进了酸性流体的作用范围,溶作用和破裂作用共同促进了碱湖致密储层的发育。
Permian Fengcheng Formation in Mahu Depression is a tuff reservoir formed in alkali lake sedimentation under the influence of volcanic activities.Based on 209 core samples from 15 typical wells in Mahu Depression,this paper summarizes the basic characteristics of the reservoir and discusses the formation mechanism of the reservoir by means of core macroscopic and microscopic observation,whole rock analysis by X-ray diffraction,scanning electron microscopy(SEM),energy spectrum(EDS),evaporation crystallization experiment,element test,in-situ carbon and oxygen isotope test,and inclusions temperature measurement.The study shows that:(1)The tuff reservoir is mainly composed of tuff and tuffite,which are rich in pyroclastic materials and salt minerals.The reservoir space types in the tuff include intercrystalline pores,solution pores and fractures.Though the reservoir is a tight one,samples with porosity greater than 6%and permeability greater than 0.1×10^(-3)μm^(2) are still developed.(2)The tuff reservoir is controlled by the development of diagenesis,in which devitrification,dissolution,fracturing and hydrocarbon charging is the main factor promoting the reservoir formation.(3)Since the devitrification of pyroclastic occurred early,the formation of intergranular pores effectively improved the reservoir and seepage conditions.(4)The early continuous filling of oil and gas formed abnormal high pressure,which effectively inhibited the compaction and authigenic mineral filling,and promoted the preservation of early pores.(5)The acidic fluid continuously discharged from the high-quality Fengcheng Formation source rock formed a relatively developed dissolution effect,and the fracture development expanded the range of the acidic fluid,and the dissolution and fracture jointly promoted the development of the alkali lake tight reservoir in Fengcheng Formation.
作者
何文军
吕正祥
彭妙
肖琳
李响
廖哲渊
徐兵
钱永新
HE Wenjun;LV Zhengxiang;PENG Miao;XIAO Lin;LI Xiang;LIAO Zheyuan;XU Bing;QIAN Yongxin(Erploration and Development Research Institute of PetroChina Xinjiang Oilfield Branch,Karamay,Xinjiang 834000,China;College of Energy,Chengdu University of Technology,Chengdu,Sichuan 610059,China;PetroChina Xinjiang Oilfield Branch,Karamay,Xinjiang 834000,China)
出处
《矿物岩石》
CAS
CSCD
北大核心
2023年第4期109-119,共11页
Mineralogy and Petrology
基金
国家油气重大专项“准噶尔盆地致密油形成条件、资源潜力及有利区优选”(项目编号:2016ZX05046-006)。
关键词
准噶尔盆地
玛湖凹陷
风城组
凝灰岩储层
成因分析
Junggar Basin
Mahu sag
Fengcheng formation
tuff reservoir
reservoir genesis analysis
