摘要
随着油田勘探开发的进程,相当大一批主力油气产层逐步由常规砂岩储层转移到低渗-特低渗致密砂岩储层中,由于低渗致密砂岩储层具有物性差、孔隙结构复杂、层间与层内非均质性强的特点,使得储层电测井响应规律更加复杂,难以厘清,出现许多的“非阿尔奇”现象,导致传统的实验手段及饱和度计算公式适用性不强.本文通过设计多级离心核磁共振实验,在明确核磁特征参数的变化规律基础上,利用核磁与压汞实验的相互刻度,建立低渗致密砂岩储层孔隙结构分类标准,并在孔隙结构分类评价基础上重点分析不同离心转速下的T2几何均值、核磁孔隙度、核磁含水饱和度等数据的衰减规律,通过构建T2谱衰减指数建立其与核磁含水饱和度、核磁孔隙度的关系,从而确定计算饱和度的等效指数,实现了在不具备或者难以开展岩电实验条件下的饱和度定量计算.在实际井资料的应用中,结果表明该方法确定出的饱和度结果相比于常规岩电实验结果更加真实合理,并且与密闭取心数据吻合较好,这种非电法确定饱和度指数的方法不仅扩大了核磁数据的应用范围,也为核磁共振评价复杂低孔渗油气层提供了一种新思路.
With the progress of oilfield exploration and development,a large number of major oil and gas producing layers have gradually shifted from conventional sandstone reservoirs to low-permeability to ultra-low permeability tight sandstone reservoirs.Due to the characteristics of low permeability tight sandstone reservoir,such as poor physical property,complex pore structure,and strong heterogeneity between layers and within layers,the electric logging response law of reservoir is more complex and difficult to be clarified,and many"non-archie"phenomena occur,resulting in the poor applicability of traditional experimental methods and saturation calculation formulas.In this paper,a multistage centrifugal NMR experiment was designed to establish a classification standard for pore structure of low-permeability tight sandstone reservoir by using the mutual scale of NMR and mercury injection experiments on the basis of clarifying the variation rule of the characteristic parameters of NMR.Based on the classification and evaluation of pore structure,the attenuation law of T2 geometric mean,NMR porosity,NMR water saturation and other data at different centrifugal speeds was mainly analyzed.The relationship between T2 spectral attenuation index and NMR water saturation and NMR porosity was established by constructing T2 spectral attenuation index,so as to determine the equivalent index of saturation.The quantitative calculation of saturation is realized under the condition that rock electric experiment is not available or difficult to carry out.In the application of actual well data,the results show that the saturation results determined by this method are more realistic and reasonable compared with the conventional rock electrical test results,and are in good agreement with the closed coring data.This non-electric method to determine saturation index not only expands the application range of NMR data,but also provides a new idea for NMR evaluation of complex low porosity and permeability reservoirs.
作者
曾静波
郑庆伟
谢晓庆
杨帆
程亮
夏阳
ZENG JingBo;ZHENG QingWei;XIE XiaoQing;YANG Fan;CHENG Liang;XIA Yang(Geology Research Institute,China National Logging Corporation,Xi'an 710000,China;Daqing Branch,China National Logging Corporation,Daqing 163412,China)
出处
《地球物理学进展》
CSCD
北大核心
2023年第3期1228-1237,共10页
Progress in Geophysics
基金
中国石油集团重大专项“测井采集处理解释关键技术研究-测井数字岩石技术研究”(2021DJ4003)
“海陆过渡相页岩气勘探开发关键技术研究-海陆过渡相页岩气地震储层预测及测井评价技术研究”(2021DJ2002)
中国石油集团测井有限公司十大科技项目-测井油藏与地质研究(CNLC2022-8B02)联合资助。
关键词
低孔渗储层
孔隙结构
多级离心核磁
饱和度
Low porosity and permeability reservoir
Pore structure
Multistage centrifugal nuclear magnetism
Saturation