In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is ...In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is based on the distribution of acoustic velocity in different directions around rock cores. The heterogeneity of core samples, such as fractures and gravel contained, can also lead to wave velocity anisotropy. Therefore, the corresponding reliability evaluation method is established to exclude some other anisotropy factors caused by non-tectonic stresses. In this paper, the reliability of testing results is evaluated from three aspects, i.e. phase difference, anisotropy index and waveform, to remove the factors caused by non-tectonic stresses.展开更多
It has been known that the error of measuring acoustic veloicities of thin sediment layers by the well-known T2-X2 approach is usually untolerable, and that this approach is unavailable in the case where sea-bed is ha...It has been known that the error of measuring acoustic veloicities of thin sediment layers by the well-known T2-X2 approach is usually untolerable, and that this approach is unavailable in the case where sea-bed is hard because no echo from any subsurface below sea-bottom can be received. Therefore applying the ray-parameter method to thin layers and the refraction method to hard layers need to be considered in an acoustic velocity measurement system composed of a sound source and a towed hydrophone streamer. Some problems of practical importance about the applications of the two methods, such as echo-data processing procedures and error estimations in measuring acoustic veloicities, are discussed, and the effectiveness of theoretical analyses has been verified through computer simulations.展开更多
基金Supported by the PetroChina Company Limited (112002Kt0090001)
文摘In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is based on the distribution of acoustic velocity in different directions around rock cores. The heterogeneity of core samples, such as fractures and gravel contained, can also lead to wave velocity anisotropy. Therefore, the corresponding reliability evaluation method is established to exclude some other anisotropy factors caused by non-tectonic stresses. In this paper, the reliability of testing results is evaluated from three aspects, i.e. phase difference, anisotropy index and waveform, to remove the factors caused by non-tectonic stresses.
文摘It has been known that the error of measuring acoustic veloicities of thin sediment layers by the well-known T2-X2 approach is usually untolerable, and that this approach is unavailable in the case where sea-bed is hard because no echo from any subsurface below sea-bottom can be received. Therefore applying the ray-parameter method to thin layers and the refraction method to hard layers need to be considered in an acoustic velocity measurement system composed of a sound source and a towed hydrophone streamer. Some problems of practical importance about the applications of the two methods, such as echo-data processing procedures and error estimations in measuring acoustic veloicities, are discussed, and the effectiveness of theoretical analyses has been verified through computer simulations.
