It is well known that shale can be considered as transverse isotropy (TI) materials, which can be described by 5 independent elastic constants. Usually, shale is saturated water, so the elastic constants derived from saturated shale should be more appropriate than that derived from dry shale. In this study, Ultrasonic measurements were performed to investigate the effects of water saturation and diagenetic pressure on elastic anisotropy of synthetic shale. To reduce the number of unknown factors caused by multiple minerals, we made 6 samples each with a different diagenetic pressure: 25MPa, 50MPa, 75MPa, 100MPa, 125MPa, 150MPa, named A1-A6. The results show that with the same mineral content and cementation, synthetic shale with higher diagenetic pressure shows higher elastic constants and higher degree of anisotropy. It suggests that the preferred orientation of clays depends mostly on the degree of compaction, which is related to the diagenesis. In the water saturation case, , and increase largely compared to that of dry samples, yet and decrease slightly. Anisotropy parameters are also influenced by the saturated water, which resulted in significant decrease of ? and d; while the effect of water saturation on S-wave anisotropy is unclear.
Presentation Date: Tuesday, October 18, 2016
Start Time: 1:25:00 PM
Location: 166
Presentation Type: ORAL
