摘要
致密气储层微观结构复杂,物性与压裂产能相关性不明显,仅从物性上难以进行准确的压后效果评价及压裂选层。为了找出有效的储层分级评价方法,利用压汞实验结果标定核磁数据,区分不同类型孔隙大小,进行分形后,确定不同孔隙尺寸界限,建立与产能的对应关系;为了建立孔渗参数进行孔隙类型表征方法,采用R i的相关系数法表征不同进汞饱和度下孔喉半径与孔渗的相关性,建立渗透率的预测公式,然后将大孔含量及R i投影到同一个图版中,确定R i的分类界限。结果表明,对标定后的120多个核磁数据进行分形,形成以0.1μm和1.0μm为界限的大、中、小孔隙结构划分标准;大孔隙含量与渗透率关系最好,而小孔隙与渗透率关系最差;当小孔隙含量占到总孔隙度50%及以上时孔隙度与渗透率之间的关系发生偏离;对39个样品的进汞饱和度为5%~40%时所对应的孔喉半径分析,R_(15)与渗透率和孔隙度之间的关系最好;通过将大孔隙含量投影到R_(15)图版中,确定Ⅰ类储层R_(15)大于2.00μm,Ⅱ类储层R_(15)为0.40~2.00μm,Ⅲ类储层R_(15)为0.05~0.40μm,Ⅳ类储层R_(15)小于0.05μm。应用该研究成果可以根据孔渗参数计算R_(15),从而进行储层分级评价,指导压裂效果评价以及压裂选层。
Due to complex microstructure of tight gas reservoirs,the correlation between physical properties and fracturing productivity is unobvious,and it’s hard to carry out accurate evaluation of post-compression effect and fracturing layer selection only from physical properties.In order to make sure an effective method for reservoir classification and evaluation,nuclear magnetic resonance data was calibrated by using the mercury injection experiment results,and different types of pore sizes were distinguished.After fractal analysis,different pore size boundaries were determined,and then the relationship with productivity was established.To establish pore permeability parameters for characterizing pore types,the correlation coefficient method of R i was used to characterize the correlation between pore throat radius and pore permeability under different mercury saturation,and then a prediction formula for permeability was established.When the macropore content and R i was projected onto the same chart,the classification boundary of R i was determined.The results showed that fractal analysis was performed on more than 120 calibrated nuclear magnetic data,resulting in the classification criteria for large,medium,and small pore structures with boundaries of 0.1μm and 1.0μm.The ones with macropores has the best relationship with permeability,the worst relationship with small pores.When the small pores content accounts for 50%or more,the relationship between porosity and permeability will deviate.The pore throat radius analysis of 39 samples with mercury saturation with 5%~40%showed that R_(15)had the best relationship with permeability and porosity.By projecting the macropore content onto the R_(15)chart,it is determined that the R_(15)of TypeⅠ,Ⅱ,ⅢandⅣreservoirs is greater than 2.00μm,0.40~2.00μm,0.05~0.40μm and less than 0.05μm respectively.The application can be used to calculate R_(15)based on porosity and permeability parameters,furthermore,reservoir classification evaluation can be carried out to provide guidance for fracturing effect evaluation and fracturing layer selection.
作者
刘子雄
李啸南
李凡
寇双燕
陈玲
魏志鹏
LIU Zixiong;LI Xiaonan;LI Fan;KOU Shuangyan;CHEN Ling;WEI Zhipeng(Oilfield Production Research Institute of China Oilfield Services Limited,Tianjin 300450,China;Shenzhen Company of CNOOC(China)Co.,Ltd.,Shenzhen 518000,Guangdong,China)
出处
《石油地质与工程》
CAS
2023年第5期50-55,共6页
Petroleum Geology and Engineering
关键词
大孔隙
微观结构
核磁共振
压汞实验
分级评价
macropore
microstructure
nuclear magnetism
mercury injection
grading evaluation
