Abstract:

Basic principles and methods are briefly descussed for determining abnor-mal formation pressure and the depth at which it might accur in considerationof the peculiarity of prospecting.Herein seismic seismic prediction before drilling, dc-index detecting in the courae of drilling and well-logging evaluation after drilling etc. are induded. This paper emphasizes on the determining of averpressure strata on the basis of the relationship of sonic transmission time (Δt) versus depth in axgillaceous rocks, and the quick estimating the value of abnormal formation pressate by means of equivalent stress. Finally, an example of a well section cutting through sandstone and mudstone of Tertiary system is given.