基于核磁共振动态截止值理论的致密砂砾岩储层渗透率评价方法  

Permeability evaluation method of tight glutenite reservoir based on NMR dynamic cutoff theory

作　　者：张啸[1] 陈国军[1] 肖华 张文芊 张帆[1] 高明[1] ZHANG Xiao;CHEN Guojun;XIAO Hua;ZHANG Wenqian;ZHANG Fan;GAO Ming(Research Institute of Exploration and Development,Xinjiang Oilfield Branch,PetroChina,Urumqi 830013,Xinjiang;China Petroleum Logging Co.Ltd.,Xi’an 710077,Shaanxi)

机构地区：[1]中国石油新疆油田分公司勘探开发研究院,新疆乌鲁木齐830013 [2]中国石油测井有限公司,陕西西安710077

出　　处：《长江大学学报（自然科学版）》2024年第2期52-59,共8页Journal of Yangtze University(Natural Science Edition)

基　　金：国家科技重大专项“准噶尔盆地岩性地层油气藏分布规律与目标评价”(2017ZX05001-004)。

摘　　要：准噶尔盆地南缘深层清水河组致密砂砾岩储层为该区的重要勘探领域,渗透率是评价致密砂砾岩储层的关键参数。为提高此类储层渗透率计算精度,基于核磁共振实验,分析致密砂砾岩岩心饱和水及离心核磁共振横向弛豫时间(T_(2))谱,明确致密砂砾岩孔隙中流体的赋存形态及渗流规律,提出常规核磁共振渗透率计算方法的不足,并且提出核磁共振动态截止值的概念。基于核磁共振动态截止值,将储层孔隙空间划分为3类:自由流体孔、毛细管半束缚孔、完全束缚孔;分析了渗透率与不同孔隙类型之间的相关关系:致密砂砾岩储层渗透率与自由流体孔孔隙度、核磁总孔隙度、毛细管半束缚孔的T_(2)几何平均值呈正相关关系,与完全束缚孔流体饱和度呈负相关关系。构建基于不同孔隙类型渗透率模型,计算渗透率与岩心实验渗透率之间的相对误差小于9.0%。该方法提高了致密砂砾岩储层渗透率的计算精度,且在准噶尔盆地南缘深层清水河组致密砂砾岩储层评价中具有广泛的应用前景。The tight glutenite reservoir of Qingshuihe Formation in deep southern margin of Junggar Basin is an important exploration area,and permeability is a key parameter to evaluate tight glutenite reservoir.In order to improve this kind of reservoir permeability calculation accuracy,this article is based on nuclear magnetic resonance experiment,analyse saturated water of tight glutenite core and centrifugal state nuclear magnetic resonance(NMR)transverse relaxation time(T_(2))spectrum,made clear occurrence pattern of fluid and fluid seepage rule in tight glutenite pore,put forward the deficiency of conventional NMR permeability calculation method,and propose the concept of dynamic cut-off value of NMR.Based on the NMR dynamic cut-off value,the reservoir pore space was divided into three parts:free fluid pore,capillary semi-bound pore and complete bound pore.Analyze the correlation of permeability and different pore types.The permeability of tight glutenite reservoirs is positively correlated with the free fluid porosity,the total porosity of nuclear magnetic,the geometric mean of T_(2) in capillary semi-bound pores,and negatively correlated with the fluid saturation of completely bound pores.A permeability model based on different pore types was constructed,and the relative error between the calculated permeability and the permeability of the core experiment was less than 9.0%.This method improves the accuracy of the permeability calculation of tight glutenite reservoirs,and has wide application prospects in the evaluation of tight glutenite reservoirs of Qingshuihe Formation in deep southern margin of Junggar Basin.

关 键 词：准噶尔盆地 南缘深层 致密砂砾岩 核磁共振 动态截止值 渗透率 

分 类 号：P681.84[天文地球—地质学] TE132.14[石油与天然气工程—油气勘探]