BHULLAR, ABID G.¹, and DAG A. KARLSEN¹, HARALD JOHANSEN², KRISTINE HOLM³, and SELAND T. REINERT^4
1Department of Geology University of Oslo, Norway
²Institute for Energy Research, Kjeller, Norway
³Elf Petroleum Norge asa., Stavanger, Norway
⁴Aker Geo Petroleum Services asa, Hillevag, Norway

Abstract: The Filling History of the Rind and Froy Petroleum Accumulations, North Sea - Application of Fluid Inclusions, Core Extracts and Oils to Geological Dating

Petroleum inclusions in authigenic feldspar and quarts cements in the Froy Field and the Rind Discovery are used in combination with reservoir oil and core extracts to determine how and when these structures received their hydrocarbon charges. Analysis of normal alkane and biomarker distributions in the three separate data sets provide us with a unique complex set of time resolved events. Using homogenisation temperatures of fluid inclusions, it was possible to bracket filling time of the main structure of the Rind Discovery. Migration of oil between the main Rind structure and the presently dry neighbouring structure, can based on the relative maturity differences of the oil in these Mo structures be timed relatively. Fault movement between these two compartments disrupted communication and pressure build up blowing the cap on the presently dry structure whilst the oil charge in the main structure was preserved from pressure build up due to lack of communication with the deep generative basin. Numerous petroleum and coexisting water inclusions in this presently dry overpressured structure are found not both to be saturated with respect to gas, whilst some inclusion populations are evidently both saturated. This observation is interpreted to reflect leakage of gas from the system. Information on time for reservoir filling and seal failure, when used to calibrate basin modeling, should provide a better model for understanding movement of hydrocarbon fluids in basins.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas