1、第30卷第1期油气地质与采收率Vol.30,No.12023年1月Petroleum Geology and Recovery EfficiencyJan.2023收稿日期：2022-03-14。作者简介：张钰祥（1994），男，山东东营人，博士，从事油气渗流理论与应用方向的研究。E-mail：。通信作者：杨胜来（1961），男，河北辛集人，教授，博士。E-mail：。基金项目：国家自然科学基金项目“超深层碎屑岩油气藏渗流物理基础研究”（51774300），国家科技重大专项“深层碳酸盐岩气藏高效开发技术”（2016ZX05015-003）。文章编号：1009-9603（2023）01-0049
2、-11DOI：10.13673/37-1359/te.202203041应力对超深层碳酸盐岩气藏孔喉结构的影响张钰祥1，2，3，杨胜来1，李强1，王蓓东1，邓惠4，鄢友军4，闫海军2，陈掌星3（1.中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249；2.中国石油勘探开发研究院，北京 100083；3.加拿大卡尔加里大学 化学与石油工程系，卡尔加里 T2N1N4；4.中国石油西南油气田分公司 勘探开发研究院，四川 成都 610041）摘要：超深层碳酸盐岩气藏埋藏深，应力状态复杂，非均质性极强，应力变化前后孔喉结构的变化规律尚不明确。选取高石梯-磨溪区块台内灯四气藏储层岩心，通过
3、CT扫描得到应力实验和压裂实验前后不同类型储层的孔喉尺寸分布、缝洞占比和连通性等，研究应力和压裂对超深层碳酸盐岩储层孔喉结构的影响规律。结果表明：在受压恢复后，孔洞型和缝洞型岩心的孔隙和喉道个数均大幅度下降且主要集中在半径在1 mm以下的微孔、中孔和0.04mm以下的微喉，孔隙平均半径、喉道平均半径和喉道平均长度均大幅度增加，缝洞比例大幅度增加，孔隙和喉道总体积趋于减小；孔洞型岩心连通孔喉体积占比大幅下降，而缝洞型岩心由于裂缝发育，其连通孔喉体积占比维持原有水平。压裂后，孔洞型岩心孔隙个数大幅度下降，减少的孔隙半径主要集中在0.5 mm以下的微孔和中孔，孔隙平均半径大幅度上升，增加的孔隙半径主
4、要集中在0.50.8 mm，孔隙体积总体呈上升趋势，喉道个数、喉道平均半径、喉道平均长度和喉道总体积均趋于增加，缝洞比例大幅度增加，连通孔喉体积大幅度提高。实验表明超深层碳酸盐岩储层受压恢复后，渗流能力不降反而大幅度提升，压裂主要通过提高孔喉空间中裂缝占比来改善孔喉连通性。关键词：碳酸盐岩气藏；灯影组；应力；压裂；缝洞结构；孔喉结构中图分类号：TE122.2+3文献标识码：AEffects of stress on pore and throat structuresof ultra-deep carbonate gas reservoirsZHANG Yuxiang1，2，3，YANG Sh
5、englai1，LI Qiang1，WANG Beidong1，DENG Hui4，YAN Youjun4，YAN Haijun2，CHEN Zhangxing3（1.State Key Laboratory of Petroleum Resources and Prospecting，China University of Petroleum（Beijing），Beijing City，102249，China；2.Research Institute of Petroleum Exploration&Development，PetroChina，Beijing City，100083，Ch
6、ina；3.Department of Chemicaland Petroleum Engineering，University of Calgary，Calgary，T2N1N4，Canada；4.Exploration and Development ResearchInstitute of PetroChina Southwest Oil&Gasfield Company，Chengdu City，Sichuan Province，610041，China；）Abstract：Ultra-deep carbonate gas reservoirs are deeply buried，wi
7、th complex stress states and extremely strong heterogeneity，and the change laws of pore and throat structures before and after stress changes is not clear.In this paper，the coresfrom Deng4 gas reservoir in Gaoshiti-Moxi block were selected，and CT experiments were conducted to obtain the size distrib
8、ution of pores and throats，the proportion of pores and vugs，and the connectivity of various reservoirs before and afterthe stress experiment and fracturing experiment.In addition，the effects of stress and fracturing on the pore and throat structures of ultra-deep carbonate reservoirs were studied.Th
9、e research results reveal that the pores and throats in the pore-vugand fracture-vug cores decrease obviously after recovery from stress，and most of them are the micropores and mesoporeswith a radius of less than1 mm and the micro-throats with a radius of less than 0.04 mm.The average pore radius，av
10、eragethroat radius，average throat length，as well as the proportion of fractures and vugs all rise significantly，while the total vol 50 油气地质与采收率2023年1月ume of pores and throats tends to decline.The volume ratio of connected pores and throats in the pore-vug cores decreasessignificantly，while the volum
11、e ratio of connected pores and throats in the fracture-vug cores remains at the original leveldue to the development of fractures.After fracturing，the pores in the pore-vug cores decrease sharply and the reducedpores are mainly micropores and mesopores with a radius below 0.5 mm.The average pore rad
12、ius greatly increases，whilethe most increased pore radii are in 0.5-0.8 mm.There is an upward trend in the pore volume，the throats，average throat radius，average throat length as well as total throat volume，and the proportion of fractures and vogs and the volume of connected pores and throats increas
13、e drastically.The experiments indicate that after recovery from stress，the flow capacity ofthe ultra-deep carbonate reservoir does not decrease but greatly increases，and fracturing mainly improves the connectivityof pores and throats by increasing the proportion of fractures in the pore-throat space
14、.Key words：carbonate gas reservoir；Dengying Formation；stress；fracturing；fracture and vug structure；distribution of poresand throats已有学者通过CT扫描方法来研究应力对碳酸盐岩样品储集空间变化的影响。SALIMIDELSHAD等利用声波速度和CT扫描分析来研究循环压力作用于碳酸盐岩储层，岩石物理性质的变化、多孔介质中孔隙结构的变化和储层中流体运移的变化1。YANG等通过CT扫描技术从不同类型碳酸盐岩岩心中提取数字岩心模型，并在此基础上进行孔隙级流动模拟，研究应力加载
15、和卸载循环过程中裂缝形态的变化以及对岩样流动特性的影响2-3。WANG等利用CT扫描技术对基质型、裂缝型和孔洞型碳酸盐岩样品的物性进行分析，研究裂缝和孔洞对孔渗关系、岩心孔喉结构的非均质性、渗透率和孔隙度应力敏感性以及油层相对渗透率的影响4。FU等利用X射线断层扫描，在加压和减压过程中获得孔隙型、裂缝-孔隙型和裂缝-孔洞型碳酸盐岩的数字岩心，并采用格子玻尔兹曼方法和孔隙网络模型模拟不同围压下的渗透率和气水两相流5。目前针对超深层碳酸盐岩在承受应力及压裂前后孔喉结构影响规律的研究较少。超深层碳酸盐岩气藏储层承受的地层应力巨大，与中浅层的应力条件相差甚大，生产过程中的应力状态“巨变”，可能导致承受
16、应力前后储层孔喉结构参数测定结果存在差异6-9。因此通过CT扫描，对应力实验和压裂实验前后的超深层碳酸盐岩岩心样品进行研究，得到实验前后孔喉分布特征及连通性变化的规律，从而为现场气藏开发提供理论支持。1应力实验及压裂实验1.1实验样品选取高石梯-磨溪区块台内灯四气藏4块全直径岩心进行CT扫描，4块岩心的岩石物性及扫描参数见表1，4块岩心实验前后如图1所示，其中DS4对应压裂实验，其余3块岩心对应应力实验。表1实验岩心基本物性参数Table1Basic physical property parameters of core samples岩心编号DS2DS4DS5DS6长度/cm7.87310.256.0427.134直径/cm6.684 56.956.513 56.495 5实测孔隙度/%5.6455.99611.19111.993实测渗透率/mD0.046 90.03141.9942.9岩心类型孔洞型孔洞型缝洞型缝洞型4块全直径岩心均为中-细晶云岩，XRD分析结果表明，其矿物组分非常接近，白云石占 95.7%99.1%，萤石占0.2%3.9%，石英占0.4%3.2%，方解石含量在0
