摘要
深层低渗-致密气层孔隙结构复杂,孔渗相关性差,为提高气层渗透率测井解释精度,以东海盆地N气田深层花港组三段气层为例,采用压汞、CT扫描、核磁测试等手段,量化了不同孔径的孔隙对渗透率贡献的差异性,以压汞平均孔径分布区间刻度核磁T2谱,求取不同核磁T2谱区间所对应的孔隙对渗透率的贡献因子,建立基于孔径分布的低渗-致密气层渗透率核磁测井计算新模型,并通过烃类校正消除了含气对核磁测井的影响.研究结果表明:研究区孔径0.40μm以下的孔喉占比最高,超过44%,但对渗透率的贡献不足0.64%,孔径1.0~6.3μm的孔喉对渗透率的累积贡献超过90%,对应的核磁T2弛豫时间为30~310 ms,取心段和试气段验证了新建立的渗透率核磁测井解释方法有效且提高了渗透率参数的解释精度.
Pore structures in deep low permeability and tight gas reservoirs are complex and the correlation between porosity and permeability is poor. In order to improve the accuracy of permeability in well logging interpretation, a case study is carried out in N gas field, East China Sea basin. The study layer is the 3 rd member of Huagang formation. Reservoir test techniques such as the mercury intrusion method, CT scanning and nuclear magnetic are used. The difference of permeability contribution of pores with different pore sizes is quantified. Nuclear magnetic T2 spectrum of different pores is calibrated in the mercury intrusion test. Permeability-contribution factors of pores with different nuclear magnetic T2 spectrum intervals are obtained. Based on the pore-throat distribution, a new permeability interpretation model for low permeability and tight gas reservoirs with nuclear magnetic logging is established. A hydrocarbon correction method is built to eliminate gas-bearing effects in nuclear magnetic logging. In the study area, it can be concluded that pore throats with diameters smaller than 0.4 μm occupy the highest proportion, exceeding 44%, but their contribution to permeability is less than 0.64%;the pore throats with diameters between 1.0 and 6.3 μm, whose nuclear magnetic T2 relaxation times are 30 to 310 ms, contribute more than 90% to the cumulative permeability. It is also proved in sections with drilling cores and gas test that this new presented method improves the accuracy of permeability in well logging interpretation.
作者
张宪国
刘玉从
林承焰
张涛
黄鑫
段冬平
ZHANG Xianguo;LIU Yucong;LIN Chengyan;ZHANG Tao;HUANG Xin;DUAN Dongping(Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Shandong Provincial Key Laboratory of Reservoir Geology,Qingdao,Shandong 266580,China;CNPC Key Laboratory for Oil and Gas Reservoirs,Qingdao,Shandong 266580,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;Research Institute of Shanghai Branch,CNOOC,Shanghai 200035,China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2019年第6期1266-1275,共10页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(41672129,41602135)
中央高校基本科研业务费专项项目(19CX02001A)
关键词
低渗-致密气层
孔隙结构
孔径分布
渗透率
核磁测井
low permeability and tight gas reservoirs
pore structure
pore size distribution
permeability
nuclear magnetic resonance logging
