Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures
Abstract Fractures in oil and gas reservoirs have been the topic of many studies and have attracted reservoir research all over the world. Because of the complexities of the fractures, it is difficult to use fractured reservoir core samples to investigate true underground conditions. Due to the dive...
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KeAi Communications Co., Ltd.
2017
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oai:doaj.org-article:739daa4708ba4396ba1d36e4b59a9c152021-12-02T02:29:16ZExperiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures10.1007/s12182-017-0173-21672-51071995-8226https://doaj.org/article/739daa4708ba4396ba1d36e4b59a9c152017-07-01T00:00:00Zhttp://link.springer.com/article/10.1007/s12182-017-0173-2https://doaj.org/toc/1672-5107https://doaj.org/toc/1995-8226Abstract Fractures in oil and gas reservoirs have been the topic of many studies and have attracted reservoir research all over the world. Because of the complexities of the fractures, it is difficult to use fractured reservoir core samples to investigate true underground conditions. Due to the diversity of the fracture parameters, the simulation and evaluation of fractured rock in the laboratory setting is also difficult. Previous researchers have typically used a single material, such as resin, to simulate fractures. There has been a great deal of simplifying of the materials and conditions, which has led to disappointing results in application. In the present study, sandstone core samples were selected and sectioned to simulate fractures, and the changes of the compressional and shear waves were measured with the gradual increasing of the fracture width. The effects of the simulated fracture width on the acoustic wave velocity and amplitude were analyzed. Two variables were defined: H represents the amplitude attenuation ratio of the compressional and shear wave, and x represents the transit time difference value of the shear wave and compressional wave divided by the transit time of the compressional wave. The effect of fracture width on these two physical quantities was then analyzed. Finally, the methods of quantitative evaluation for fracture width with H and x were obtained. The experimental results showed that the rock fractures linearly reduced the velocity of the shear and compressional waves. The effect of twin fractures on the compressional velocity was almost equal to that of a single fracture which had the same fracture width as the sum of the twin fractures. At the same time, the existence of fractures led to acoustic wave amplitude attenuations, and the compressional wave attenuation was two times greater than that of the shear wave. In this paper, a method was proposed to calculate the fracture width with x and H, then this was applied to the array acoustic imaging logging data. The application examples showed that the calculated fracture width could be compared with fractures on the electric imaging logs. These rules were applied in the well logs to effectively evaluate the fractures, under the case of no image logs, which had significance to prospecting and development of oil and gas in fractured reservoirs.Bao-Zhi PanMing-Xin YuanChun-Hui FangWen-Bin LiuYu-Hang GuoLi-Hua ZhangKeAi Communications Co., Ltd.articleFractured rockAcoustic wave velocityAcoustic wave amplitudeExperimental measurementFracture widthScienceQPetrologyQE420-499ENPetroleum Science, Vol 14, Iss 3, Pp 520-528 (2017) |
| institution |
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| topic |
Fractured rock Acoustic wave velocity Acoustic wave amplitude Experimental measurement Fracture width Science Q Petrology QE420-499 |
| spellingShingle |
Fractured rock Acoustic wave velocity Acoustic wave amplitude Experimental measurement Fracture width Science Q Petrology QE420-499 Bao-Zhi Pan Ming-Xin Yuan Chun-Hui Fang Wen-Bin Liu Yu-Hang Guo Li-Hua Zhang Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| description |
Abstract Fractures in oil and gas reservoirs have been the topic of many studies and have attracted reservoir research all over the world. Because of the complexities of the fractures, it is difficult to use fractured reservoir core samples to investigate true underground conditions. Due to the diversity of the fracture parameters, the simulation and evaluation of fractured rock in the laboratory setting is also difficult. Previous researchers have typically used a single material, such as resin, to simulate fractures. There has been a great deal of simplifying of the materials and conditions, which has led to disappointing results in application. In the present study, sandstone core samples were selected and sectioned to simulate fractures, and the changes of the compressional and shear waves were measured with the gradual increasing of the fracture width. The effects of the simulated fracture width on the acoustic wave velocity and amplitude were analyzed. Two variables were defined: H represents the amplitude attenuation ratio of the compressional and shear wave, and x represents the transit time difference value of the shear wave and compressional wave divided by the transit time of the compressional wave. The effect of fracture width on these two physical quantities was then analyzed. Finally, the methods of quantitative evaluation for fracture width with H and x were obtained. The experimental results showed that the rock fractures linearly reduced the velocity of the shear and compressional waves. The effect of twin fractures on the compressional velocity was almost equal to that of a single fracture which had the same fracture width as the sum of the twin fractures. At the same time, the existence of fractures led to acoustic wave amplitude attenuations, and the compressional wave attenuation was two times greater than that of the shear wave. In this paper, a method was proposed to calculate the fracture width with x and H, then this was applied to the array acoustic imaging logging data. The application examples showed that the calculated fracture width could be compared with fractures on the electric imaging logs. These rules were applied in the well logs to effectively evaluate the fractures, under the case of no image logs, which had significance to prospecting and development of oil and gas in fractured reservoirs. |
| format |
article |
| author |
Bao-Zhi Pan Ming-Xin Yuan Chun-Hui Fang Wen-Bin Liu Yu-Hang Guo Li-Hua Zhang |
| author_facet |
Bao-Zhi Pan Ming-Xin Yuan Chun-Hui Fang Wen-Bin Liu Yu-Hang Guo Li-Hua Zhang |
| author_sort |
Bao-Zhi Pan |
| title |
Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| title_short |
Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| title_full |
Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| title_fullStr |
Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| title_full_unstemmed |
Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| title_sort |
experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures |
| publisher |
KeAi Communications Co., Ltd. |
| publishDate |
2017 |
| url |
https://doaj.org/article/739daa4708ba4396ba1d36e4b59a9c15 |
| work_keys_str_mv |
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| _version_ |
1718402476532563968 |