--> Abstract: Leak-Off Test Analysis to Evaluate Seal: Examples from the Central North Sea, by Najwa Yassir, Peter Winefield, and Amgad Younes; #90039 (2005)

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Leak-Off Test Analysis to Evaluate Seal: Examples from the Central North Sea

Najwa Yassir1, Peter Winefield2, and Amgad Younes1
1 Shell International Exploration and Production, 2288 GS Rijswijk, Netherlands
2 Shell International E&P - Technology Development & Research, Houston, TX

The main control on seal integrity in an overpressured environment is the minimum principal stress, usually the minimum horizontal stress. This is generally defined on a regional basis by using leak-off test data. Methodologies vary, but the lower bound of leak-off test data is commonly used is risking analysis; this is backed by data from rare extended leak-off tests, which plot on the lower bound of a LOT data set. Where overpressures are compartmentalized, however, the minimum bound LOT approach can give inaccurate estimates of minimum stress, leading to under-estimates in risking. The use of leak-off data is reviewed in this paper. Examples of the effects of compartmentalization on pore pressure-minimum stress relationships and seal integrity are given from the Central North Sea.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005