摘要
为了明确准噶尔盆地东部石钱滩凹陷石炭系上统石钱滩组致密砂岩储层特征及主控因素,采用铸体薄片鉴定、扫描电镜、电子探针、X射线衍射及流体包裹体分析等实验手段,结合层序格架与沉积相分析,系统开展了相关研究。研究结果表明:①该区石钱滩组储层岩石类型复杂,扇三角洲平原—扇前缘岩性主要发育粒度相对较粗的砂岩,杂基含量相对较少,物性较好,而滨浅海沉积物岩性跨度大,以砂岩、含生屑粉砂质泥岩、砂质生屑灰岩为主,粒度细、成分复杂、碳酸盐含量高,物性较差;②石钱滩组储层主要储集空间为次生溶孔(长石/岩屑粒内溶孔、浊沸石填隙物溶孔)与微裂缝(构造缝/溶蚀缝);③石钱滩组储层受成岩作用影响明显,压实作用是造成孔隙度降低的主要原因,各类方解石胶结对孔隙主要起破坏作用,绿泥石、伊蒙混层等黏土矿物虽有利于微孔隙发育但却明显降低渗透率;④与构造作用伴生的深部热液溶蚀作用对储层物性改善最为显著,次生溶孔与构造破裂作用等产生的微裂缝搭配可增加孔隙连通性、提高渗透率,靠近断层附近的同沉积相带砂岩储层物性相对较好。结论认为,该区扇三角洲前缘粗粒砂岩与构造—热液复合改造区为优质储层发育区,烃源岩生烃产生的酸性流体与深部热液共同控制次生孔隙的形成。
To clarify the characteristics and controlling factors of the Upper Carboniferous tight sandstone reservoirs in Shiqiantan Sag,eastern Junggar Basin,a systematic study was conducted by using analysis techniques such as cast thin section,scanning electron microscope(SEM),electron probe microanalyzer,X-ray diffraction(XRD),and fluid inclusion,together with the sequence stratigraphic framework and sedimentary facies analysis.Results show that(i)Shiqiantan Formation reservoirs are complex in rock types.The delta plain–front lithology mainly develops sandstone with relatively coarse grain size and relatively low content of impurities,with good physical properties.However,the littoral-neritic deposits exhibit a wide range of lithologies,mainly consisting of sandstones,bioclastic silty claystones and arenaceous bioclastic limestones,with fine grain size,complex composition,high carbonate content and poor physical properties;(ii)the main storage spaces of Shiqiantan Formation reservoirs are secondary dissolved pores(e.g.feldspathic/lithic intragranular dissolved pores and laumontite interstitial dissolved pores)and microfractures(e.g.structural fractures and dissolved fractures);(iii)Shiqiantan Formation reservoirs are significantly controlled by diagenesis.Specifically,compaction served as the primary driver to reduce porosity,cementation of various calcites played a critical role in destructing pores,and clay minerals like chlorite and illite-smectite mixed layer severely impeded the permeability regardless of their benefits for micropore development;and(iv)deep hydrothermal dissolution associated with tectonic activities has the most significant effect on improving reservoir properties.Secondary dissolved pores and structure-fracturing-induced micropores are configured to enhance the pore connectivity and the permeability,and sandstone reservoirs in synsedimentary facies belts near the faults show relatively good physical properties.In conclusion,the delta front coarse-grained sandstones and the hydrothermal-tectonic alternation zones are targets with high-quality reservoirs,and acidic fluids formed during hydrocarbon generation of source rocks and deep hydrothermal process jointly controlled the creation of secondary pores.
作者
肖冬生
林潼
刘小洪
马强
杨润泽
李攀
曹娟
XIAO Dongsheng;LIN Tong;LIU Xiaohong;MA Qiang;YANG Runze;LI Pan;CAO Juan(Research Institute of Exploration and Development,PetroChina Tuha Oilfield Company,Hami,Xinjiang 839009,China;PetroChina Research Institute of Exploration and Development,Beijing 100083,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China)
出处
《天然气勘探与开发》
2025年第4期27-40,共14页
Natural Gas Exploration and Development
基金
中国石油股份有限公司“十四五”前瞻性基础性重大科技项目“不同类型大气田(区)成藏主控因素及领域评价”(编号:2021DJ0605)。
关键词
准噶尔盆地东部
石炭系上统石钱滩组
致密砂岩
储层特征
成岩作用
热液溶蚀
次生孔隙
Eastern Junggar Basin
Upper Carboniferous Shiqiantan Formation
Tight sandstone
Reservoir characteristic
Diagenesis
Hydrothermal dissolution
Secondary pore
