摘要
充满流体的裂缝其声阻抗与岩石声阻抗具有显著区别,当声波通过裂缝时,必然引起声波的能量衰减。为有效识别致密砂岩气藏单井裂缝发育段,首先利用鄂尔多斯盆地K区EXDT全波列数据经过一系列处理得到阵列声波幅度衰减曲线,然后应用岩心分析、薄片鉴定、微电阻率成像资料标定阵列声波幅度衰减曲线,明确了裂缝发育段的声波幅度衰减明显增大的响应特征,确定了裂缝发育段阵列声波幅度衰减曲线的界限值:纵波幅度衰减曲线值大于12.5db/m、横波幅度衰减曲线值大于13db/m、斯通利波幅度衰减曲线值大于5.6db/m,较好地实现了单井裂缝段的识别。鄂尔多斯盆地K区实例井分析表明,千5、盒2、盒4和盒6段对应的阵列声波幅度衰减大,裂缝较为发育,是研究区的主力产层。裂缝较大地改善了致密砂岩储层的渗透率,对产能起到了积极贡献,因此单井裂缝发育段的准确划分对于射孔开发具有指导意义。
The acoustic impedance of fluid-filled fractures has a significant difference with that of rocks.The energy of the sound wave decays when the acoustic wave passes the fractures.In order to effectively identify the single-well fracture sections in tight sandstone gas reservoirs,based on the EXDT full wave processing data in Area K of Ordos Basin,the array acoustic wave amplitude attenuation features were analyzed and calibrated by the core analysis,thin slice observation and micro-resistivity imaging data.The response characteristics of the increment of the acoustic amplitude attenuation values were clarified,and the cutoff values were determined as:the compressional amplitude attenuation value is more than 12.5 db/m,the shear amplitude attenuation value is more than 13 db/m,and the Stoneley wave amplitude attenuation value is more than 5.6 db/m.As a result,the identification of single-well fracture sections was well achieved.The case analysis of Area K in Ordos Basin shows that the fractures in Layer Qian5,He2,He4 and He6 relatively develop corresponding to a significant amplitude attenuation of array acoustic wave,and have a good correspondence with the main producing interval.The fractures improve the permeability of tight sandstone reservoirs obviously and contribute positively to reservoirs productivity.Therefore the accurate identification of the single-well fracture section has a guiding significance for the perforation.
作者
韩刚
何峰
张孝珍
王立华
祝彦贺
雷克辉
HAN Gang;HE Feng;ZHANG Xiaozhen;WANG Lihua;ZHU Yanhe;LEI Kehui(Beijing Research Center of CNOOC(China)Co.,Ltd.,Beijing City,100027,China;PST Service Corp.,Beijing City,100094,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2019年第3期63-69,共7页
Petroleum Geology and Recovery Efficiency
关键词
致密储层
裂缝识别
阵列声波
声波幅度衰减曲线
鄂尔多斯盆地
tight reservoir
fracture identification
array acoustic waves
amplitude attenuation curve
Ordos Basin
