Predicting correct pore-pressure is important for drilling applications. Wellbore stability
problems, kicks, or even blow-outs can be avoided with a good estimate of porepressure.
Conventional pore-pressure estimation methods are based on one-dimensional
compaction theory and depend on a relationship between porosity and vertical effective
stress. Strike-slip or reverse faulting environments especially require a different way to
determine pore-pressure, since the overburden is not the maximum stress.
This study proposes a method which better accounts for the three-dimensional nature of
the stress field and provides improved estimates of pore-pressure. We apply the mean
total stress estimate to estimate pore-pressure. Pore pressure is then obtained by
modifying EatonâÂÂs pore-pressure equations, which require either resistivity or sonic log
data.
The method was tested in the Snorre Field in the Norwegian North Sea, where the field
changes from strike-slip to reverse stress state. EatonâÂÂs resistivity and sonic equations were used to predict pore-pressure in this region by replacing the vertical stress by the
mean total stress estimate. Results suggest that the modified Eaton method with
resistivity log data gives better results for the area than the conventional method. The
ratio of maximum horizontal stress to minimum horizontal stress throughout each well
should be known for best results.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4762 |
| Date | 25 April 2007 |
| Creators | Ozkale, Aslihan |
| Contributors | Schubert, Jerome |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 1888267 bytes, electronic, application/pdf, born digital |
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