--> Abstract: Characterization of Oil-Filled Fluid Inclusions in the Trenton-Black River Limestones, Albion-Scipio Area, Michigan, by V. C. Granath and R. K. McLimans; #91004 (1991)

Datapages, Inc.Print this page

Characterization of Oil-Filled Fluid Inclusions in the Trenton-Black River Limestones, Albion-Scipio Area, Michigan

GRANATH, VICTORIA, C., Conoco, Inc., Ponca City, OK, and ROGER K. McLIMANS, E. I. Du Pont De Nemours and Co., Deepwater, NJ

The Albion-Scipio and Stoney Point fields in southern Michigan are examples of fracture controlled dolomite reservoirs in the Ordovician Trenton and Black River groups. Oil and mixed aqueous-oil filled fluid inclusions are ubiquitous in the dolomites and late-stage fracture filling calcite cements. The inclusions in the dolomite occur primarily along healed microfractures that crosscut grain boundaries, thus postdating the bulk of the dolomitization.

Fluorescence spectra collected from oil inclusions are of two types characterized as blue green and yellow green. Inclusions that fluoresce blue green are present in both the dolomite and the calcite cements, but yellow green fluorescence is found only in the calcite. Produced oil from the Trenton also shows blue green fluorescence. The yellow green fluorescence of inclusions in calcite suggests entrapment of a less mature or altered oil. Oils in inclusions were analyzed by pyrolysis/gas chromatography and show odd-number carbon preference and pristane/phytane ratios similar to Ordovician oils in the basin; constant with a carbonate/evaporite source environment.

Geothermometry of the oil inclusions yields mean homogenization temperatures of 102 degrees C (n = 87) in the dolomites, and approximate maximum temperatures predicted by the burial history model for the southern Michigan basin. Mean homogenization temperatures of 76 degrees C (n = 34) and 77 degrees C (n = 35) for the oil and mixed aqueous-oil inclusions in the calcite, respectively, suggest entrapment at shallower depths following erosion of overlying strata.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)