摘要
为研究不同孔隙结构对声波时频特性的影响,将不同孔隙结构的碳酸盐岩岩心切割成边长60 mm的立方体,利用自主研发的多频超声波测试仪测量岩心轴向纵波首波传播时间,同时利用Ultrascope软件采集接收端探头声波波形,对不同孔隙结构碳酸盐岩中传播纵波的波速、时域波形及频谱特征进行研究。结果表明:声波时域及频域波形特征主要与岩心孔洞尺寸及胶结情况有关,而与孔隙度的大小无关;随着孔洞尺寸的增大,碳酸盐岩对声波中高频谐波过滤作用逐渐增强;垂直裂缝传播的声波时域波形含有大量尾随信号,频域波形中高频信号强度显著变弱且谱峰数量多,振荡强烈;平行裂缝传播的声波时频特征与垂直裂缝传播明显不同。碳酸盐岩声波时频特征研究,拓宽了声波预测岩心信息的方法,对该类储层特征预测及评价具有重要的意义。
To acquire the law of different pore structures′ influence on acoustic propagation time and frequency characteristics,carbonate cores of different pore structures were cut into 60 mm cube. Then the self-developed multi-frequency ultrasonic tester was used to measure the longitudinal wave propagation time of core axial. Meanwhile, Ultra Scope software was used to collect acoustic waveform of receiver probe to investigate the longitudinal wave velocity, time domain waveform and spectrum characteristics of carbonate rocks with different pore structures. The results show that acoustic time domain and frequency domain waveform characteristics mainly relate to the core hole size and cementation, which have nothing to do with the size of the porosity; with the increase of hole size, the filtering effect of carbonate rocks on high frequency harmonic increases; time domain waveform of sound waves propagating in the vertical direction of fractures contains lots of following wave signals, and the strength of high frequency harmonic weakens significantly with the increasing quantity of spectrum peaks and strong oscillation; there are distinct differences between the waveforms of acoustic waves propagating in vertical and parallel direction of fractures. The study of acoustic wave time and frequency characteristic broadens the methods of core information prediction, which has important significance for reservoir prediction and evaluation.
出处
《断块油气田》
CAS
北大核心
2016年第6期825-828,共4页
Fault-Block Oil & Gas Field
关键词
碳酸盐岩
声波
时频特性
孔隙结构
频谱分析
carbonate rock
acoustic wave
time and frequency characteristics
pore structure
spectrum analysis
