一裂隙发育对低孔低渗含气地层声传播特征的影响中国石油大学学报.pdf

2013年摇 第37卷摇 摇 摇 摇 摇 摇 中国石油大学学报(自然科学版)摇 摇 摇 摇 摇 摇 摇 摇 Vol.37摇 No.4 摇 第4期摇 摇 摇 摇 摇 摇 摇 摇 Journal of China University of Petroleum摇 摇 摇 摇 摇 摇 摇 摇 Aug.2013 摇 摇 文章编号:1673鄄5005(2013)04鄄0088鄄06摇 摇 摇 doi:10.3969/ j.issn.1673鄄5005.2013.04.013 一裂隙发育对低孔低渗含气地层声传播特征的影响 陈雪莲,钱玉萍,唐晓明 (中国石油大学地球科学与技术学院,山东青岛266580) 摘要:在含孔、裂隙介质弹性波动统一理论的基础上,研究裂隙发育对低孔含气地层弹性波速度的影响。 针对岩心 测量的纵横波速度,探讨估算岩心裂隙密度的方法。 结果表明:随着裂隙密度的增加,弹性波的速度降低明显;地 震、测井和实验室岩心测量频率下的波速变化明显,显示出了较强的频散特性;在孔隙度为1郾1%时,裂隙发育岩石 在饱含气时的纵波速度与饱含水相比明显降低,裂隙密度为0郾15 和0郾35 时,500 kHz 下的纵波速度分别下降了 7郾6%和27%;井孔模式波的衰减与速度相比对含气的敏感性更高,这为利用声波测井方法识别孔隙流体性质提供 了思路。 关键词:声波测井;岩石物理;裂隙;气层;频散;衰减 中图分类号:TE 19摇 摇 摇 文献标志码:A Infuence of crack on acoustic propagation characteristics in low porosity and low permeability gas reservoir CHEN Xue鄄lian,QIAN Yu鄄ping,TANG Xiao鄄ming (School of Geosciences in China University of Petroleum,Qingdao266580,China) Abstract:Basedontheunifiedelasticwavetheorywhichdescribestheeffectofbothporesandcracks,theinfluenceofcrack strength on the acoustic velocity of cracked low鄄porous gas reservoir was studied. According to the compressional and shear wavevelocityobtainedbymeasuringthecoresamples,theestimationmethodofformationcrackdensitywasinvestigated. The results of numerical calculation show that the elasticwave velocities decreasewith the crack density increasing,and the ve鄄 locity dispersionsbecomeobvious. Whentheporosity is1郾1%,thecompressionalvelocityof gas鄄saturatedrockislowerthan that of water鄄saturatedrock. Whenthe crack density is0郾15 and0郾35,the compressional velocityfor500 kHz decreasesby 7郾6% and27% respectively. The attenuation of borehole mode waves is more sensitive to gas saturation than the velocity, which provides a new way of identifying pore鄄fluid nature by acoustic log