基于核磁共振的CO 2驱喉道动用界限——以朝阳沟油田为例  

Producing limit of CO_(2) flooding throat based on nuclear magnetic resonance

作　　者：白振强 皮彦夫[1] 王清华 宋文波 朱琦 BAI Zhenqiang;Pi Yanfu;WANG Qinghua;SONG Wenbo;ZHU Qi(College of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,Heilongjiang,China;Exploration&Development Research Institute of Daqing Oilfield Company,PetroChina,Daqing 163000,Heilongjiang,China)

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318 [2]中国石油大庆油田勘探开发研究院,黑龙江大庆163000

出　　处：《石油地质与工程》2024年第4期90-94,100,共6页Petroleum Geology and Engineering

摘　　要：依据核磁共振基本原理,通过孔隙的简化,推导出核磁共振T_(2)驰豫时间与孔隙喉道半径关系,利用数值差值和最小二乘基本方法,结合高压压汞岩心孔喉分布,将核磁共振T_(2)图谱转换为岩心孔喉半径分布。在此基础上,利用岩心驱替过程中含油饱和度的变化,信号幅度同步变化的基本规律,分析水驱和CO_(2)驱不同孔喉半径的信号幅度变化曲线,判断出不同开发方式下的最小孔喉动用界限。研究表明,朝阳沟油田特低渗透区块为亲水特性,低压水驱岩样采出程度28.0%,高压水驱岩样采出程度30.0%,非混相气驱岩样的采出程度为48%,混相气驱岩样的采出程度为64%;水驱主要动用孔隙中喉半径大于1.00μm孔的可动油,非混相驱替不可动用的最小孔喉半径为0.15μm,混相驱没有提高喉道动用界限,但是驱替效率却大幅度提高;CO_(2)驱替出原油中的轻质组分,残余油黏度变大,不可动流体在原有的基础上增加了1/3~3/4,核磁共振图谱发生左移现象。研究结论为CO_(2)驱开发方案提供重要的参考依据。According to the basic principle of NMR,the relation between NMR T_(2)relaxation time and pore throat radius was deduced through pore simplification.NMR T_(2)map was converted into core pore throat radius distribution by using numerical difference and least square method combined with high-pressure mercury injection core pore throat distribution.On this basis,the change of oil saturation and the synchronous change of signal amplitude in the process of core flooding are used to analyze the change curve of signal amplitude of different pore-throat radius of water flooding and CO_(2) flooding,and the minimum orifice throat production limit under different development modes is determined.The shows that the ultra-low permeability block of Chaoyanggou Oilfield is hydrophile,the recovery degree for low and high pressure water drive is 28.0% and 30.0%respectively,48% and 64% for immiscible and miscible gas drive respectively.In water flooding,movable oil is mainly used in pores with pore throat radius greater than 1μm.In immiscible flooding,the maximum pore throat radius is 0.15μm.Miscible flooding does not improve the throat limit,but the displacement efficiency is greatly improved.The light components in crude oil are displaced by CO_(2),the viscosity of residual oil increases,and the immovable fluid increases by 1/3~3/4 on the original basis,and the NMR spectrum shifts to the left.The conclusion provides a good reference for development plan of CO_(2) flooding.

关 键 词：CO_(2)驱 核磁共振 高压压汞 喉道半径 动用界限 

分 类 号：TE357[石油与天然气工程—油气田开发工程]