Geochemical Fingerprinting in Multi-Stacked Deltaic Reservoirs — Opportunities and Challenges

Herwig Ganz¹, Vincent Okpoto¹, Seye Ososanya¹, Isaac Olabimtan¹, Elijah Ukpabio¹, Ray Berhitoe², Rob Kreulen³, and Bart van den Haven^3
1SPDC, Shell, Port Harcourt, Nigeria
²SIEP, Shell, The Hague, Netherlands
³Isolab B.V., Neerijnen, Netherlands

Fingerprinting technology is probably best known for its capability to monitor co-mingled production. But there are many more applications of geochemical fingerprinting in production and exploration:

● Identify connectivity/compartmentalisation in the field
● Identify corrosion problems
● Identify which formations are actively producing and where inadvertently co-mingling may happen without knowing due to mechanical problems
● Identify potential candidates for co-mingled production (surface and subsurface co-mingling)
● Support solving allocation problems
● Provide a better understanding/improve of the reservoir model
● Determine amount of mud-contamination in PVT samples to derive more accurate PVT data
● Identify oils which have similar fingerprints and whose PVT data could therefore be used to substitute oils where such PVT/compositional data are not available
● Identify origin of oils in litigation cases
● Reconstruct field-filling history and predict hydrocarbon type in near field prospects

In this paper we will present three case histories from Nigeria (Tunu-Kanbo, Soku and Cawthorne Channel Fields). Particular emphasis will be on challenges to properly interpret geochemical fingerprints in multi-stacked deltaic reservoirs. Most oils in Nigeria are the result of complex migration/leakage/spillage/remigration and are actually hybrid oils. The picture is further complicated by the combined effect of multiple transformation processes such as gas/water washing and biodegradation.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery