邓少贵^1,2,,
袁习勇^1,2,
王正楷^1,2,
梁盛煜^1,2,
张盼^1,2
1. 中国石油大学(华东)地球科学与技术学院, 青岛 266580
2. 海洋国家实验室海洋矿产资源评价与探测技术功能实验室, 青岛 266071

基金项目: 国家自然科学基金（41174099，41574118），中央高校基本科研业务费专项资金（17CX06044），山东省自然科学基金（ZR2013DM015），中国石油科技创新基金（2015D-5006-0303）和国家科技重大专项（2017ZX05009-001）联合资助


详细信息

作者简介: 邓少贵, 男, 1970年生, 博士, 教授, 主要从事电测井方法、岩石物理方面的研究.E-mail:dengshg@upc.edu.cn

中图分类号: P631

收稿日期:2017-04-20
修回日期:2018-06-20
上线日期:2018-08-05

Numerical simulation of azimuthal laterolog response in fractured formation

DENG ShaoGui^1,2,,
YUAN XiYong^1,2,
WANG ZhengKai^1,2,
LIANG ShengYu^1,2,
ZHANG Pan^1,2
1. School of Geosciences, China University of Petroleum, Qingdao 266580, China
2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China


MSC: P631

--> Received Date: 20 April 2017
Revised Date: 20 June 2018
Available Online: 05 August 2018


摘要
摘要:为研究井周裂缝发育特征，本文提出一种新型方位侧向测井方法，利用三维有限元法，模拟裂缝的方位侧向测井响应.结果显示，深浅侧向电阻率幅度差异受裂缝倾角的控制，低角度缝为负差异，高角度缝为正差异；倾斜裂缝张开度的增大使测井响应值减小，方位电阻率差异增大；井周方位电阻率可反映裂缝方位产状，单一缝或裂缝密度较小时，沿裂缝走向的方位电阻率小，沿裂缝倾向的方位电阻率大；裂缝发育地层的测井响应显示宏观各向异性特征，但方位电阻率的差异显示发生反转现象，即沿裂缝走向/层理方向的方位电阻率大，沿裂缝倾向/垂直层理方向的方位电阻率小；对方位电阻率测井响应进行井周成像，直观显示了裂缝的产状和发育特征.
关键词: 方位侧向测井/
三维有限元/
裂缝性地层/
裂缝产状/
各向异性

Abstract:A new azimuthal laterolog logging method is proposed to reveal the characteristics of fractures around boreholes. The azimuthal laterolog response in fractured formation is numerically simulated using a three-dimensional finite element method. Simulation results show that amplitude difference between deep and shallow laterolog resistivity is mainly controlled by fracture dipping angle. A negative separation between the deep and shallow resistivity appears in low-angle fractures while the positive appears in high-angle conditions. For dipping fractures, log response values decrease and the variation of the azimuthal resistivity becomes larger when fracture aperture increases. With the same fracture aperture, the deep and shallow laterolog resistivity exhibit small values with negative separations in low-angle fractures, while azimuthal resistivity has large variations with positive separations in high-angle fractures. Azimuthal resistivity around the borehole can reflect the azimuthal attitude of fractures. In conditions of single fractures or low fracture density, the azimuthal resistivity is low in fracture strike direction and is high in fracture dipping direction. Log response presents macroscopic anisotropy when fracture density is large enough. But there happens a reversal in the variation of the azimuthal resistivity:the azimuthal resistivity is high in fracture strike/bedding plane direction and is low in fracture dipping/vertical to the bedding plane direction. It is exactly opposite to the reality. So it is essential to do some 'convert it to the true' work if we want to use azimuthal resistivity to evaluate anisotropic formations. The azimuthal resistivity image around the borehole visually displays the attitude and developmental characteristics of fractures. Research presented in this paper will contribute to the evaluation of fractured formation.
Key words:Azimuthal laterolog logging/
3D finite element/
Fractured formation/
Fracture attitude/
Anisotropy



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