Shale research progress and achievements in seal appraisal technology

Shales form a large proportion of sedimentary basin fill worldwide and they have not been studied in great detail to date due to the lack of preserved specimens, clay mineral dilation and shrinkage, small granular, timing taken to perform tests. Understanding shale behavior is critical to a range of issues confronting petroleum industry, such as wellbore stability, top seal, predicting overpressure for low-permeability shale, understanding the effects of anisotropy on depth conversion, shale mechanics and petrophysical response on logs. It is also necessary for the exploration of shale gas. A series of progress has been made in shale research and seal appraisal at home and abroad.