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Title: Monitoring compaction and compressibility changes in offshore chalk reservoirs

Journal Article · · SPE Formation Evaluation (Society of Petroleum Engineers); (United States)
DOI:https://doi.org/10.2118/23142-PA· OSTI ID:7306198
;  [1];  [2]
  1. Amerada Hess Ltd., London (United Kingdom)
  2. Amerada Hess, Norge (Norway)

Some of the North Sea's largest and most important oil fields are in chalk reservoirs. In these fields, it is important to measure reservoir compaction and compressibility because compaction can result in platform subsidence. Also, compaction drive is a main drive mechanism in these fields, so an accurate reserves estimate cannot be made without first measuring compressibility. Estimating compaction and reserves is difficult because compressibility changes throughout field life. Installing of accurate, permanent downhole pressure gauges on offshore chalk fields makes it possible to use a new method to monitor compressibility -- measurement of reservoir pressure changes caused by the tide. This tidal-monitoring technique is an in-situ method that can greatly increase compressibility information. It can be used to estimate compressibility and to measure compressibility variation over time. This paper concentrates on application of the tidal-monitoring technique to North Sea chalk reservoirs. However, the method is applicable for any tidal offshore area and can be applied whenever necessary to monitor in-situ rock compressibility. One such application would be if platform subsidence was expected.

OSTI ID:
7306198
Journal Information:
SPE Formation Evaluation (Society of Petroleum Engineers); (United States), Vol. 9:1; ISSN 0885-923X
Country of Publication:
United States
Language:
English