液硫沉积吸附影响下高含硫气藏储层精细定量表征  

Fine quantitative characterization of high-H2S gas reservoirs under the influence of liquid sulfur deposition and adsorption

作　　者：李童 马永生 曾大乾 李倩 赵光[4] 孙宁 LI Tong;MA Yongsheng;ZENG Daqian;LI Qian;ZHAO Guang;SUN Ning(School of Earth and Space Science,Peking University,Beijing 100871,China;Sinopec Petroleum Exploration and Production Research Institute,Beijing 102206,China;China Petrochemical Corporation,Beijing 100728,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国石化石油勘探开发研究院,北京102206 [3]中国石油化工集团有限公司,北京100728 [4]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《石油勘探与开发》2024年第2期367-379,共13页Petroleum Exploration and Development

基　　金：国家自然科学基金“海相深层油气富集机理与关键工程技术基础研究”(U19B6003);中国石化科技攻关项目“礁滩相高含硫气藏储层精细表征及剩余气分布规律研究”(P20077kxjgz)。

摘　　要：为明确液硫沉积吸附对高含硫气藏储层的影响规律,选取代表3种典型碳酸盐岩孔隙结构的天然岩心,以高温高压岩心驱替实验为基础,综合采用核磁共振横向弛豫时间谱与成像技术、全直径岩心X射线CT扫描技术、基础物性测试和场发射扫描电镜成像等手段,对原始状态、注硫后和气驱后3个稳定状态的岩心进行精细定量表征。研究表明:硫沉积吸附引起的孔隙体积损失主要来源于1000μm以上的中大孔;液硫在较小孔隙空间中的吸附沉积能力更强,对原始孔隙结构较差的储层伤害更大;3类碳酸盐岩储层的孔隙结构呈现多重分形特征,孔隙结构越差,液硫沉积吸附引起的内部空间孔隙分布改变越大,非均质性越强;液硫沉积吸附引起岩石孔径分布、孔隙连通性和非均质性变化,进而改变储层物性,注硫及气驱后物性较好的Ⅰ类储层渗透率下降16%,而物性较差的Ⅱ、Ⅲ类储层渗透率下降90%以上,伤害程度极大,说明初始物性越差,液硫沉积吸附伤害越大;液硫以絮状、蛛网状或网膜状吸附沉积于不同类型的孔隙空间,引起储层孔隙结构和物性的改变。In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of Type I reservoirs with good physical properties decreased by 16%,and that of Types II and III reservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.

关 键 词：高含硫气藏 液硫 吸附沉积 孔隙结构 物性特征 储层表征 

分 类 号：TE122.2[石油与天然气工程—油气勘探]