--> Abstract: The Influence of Bioturbation from the Resource Quality of Low Permeability Gas Charged Reservoirs - A Case Study from the Upper Cretaceous Alderson Member, Southwestern Saskatchewan, Canada, by Ryan T. Lemiski, Murray Gingras, George Pemberton, and Jussi Hovikoski; #90078 (2008)
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The Influence of Bioturbation from the Resource Quality of Low Previous HitPermeabilityNext Hit Gas Charged Reservoirs - A Case Study from the Upper Cretaceous Alderson Member, Southwestern Saskatchewan, Canada

Ryan T. Lemiski1, Murray Gingras1, George Pemberton1, and Jussi Hovikoski2
1Univeristy of Alberta, Edmonton, AB, Canada
2University of Turku, Turku, Finland

Although burrow-associated Previous HitpermeabilityNext Hit is evident in the rock record, it receives little scientific scrutiny. This may be due to the scalar nature of Previous HitpermeabilityNext Hit and that the Previous HitpermeabilityNext Hit of geological media is a bulk character at the reservoir scale. However, the bulk Previous HitpermeabilityNext Hit of sediment dominated by small, macroscopic heterogeneities, such as worm burrows, is exceedingly difficult to observe, assess, and numerically model. Overlooking the potential impact of biogenic structures within a rock body can lead to inaccurate assessments of the Previous HitpermeabilityNext Hit characteristics of a sedimentary rock and possibly the non-recognition of Previous HitpermeabilityNext Hit streaks within a hydrocarbon reservoir. The impact of burrow-hosted porosity and Previous HitpermeabilityNext Hit is especially important in gas-prone reservoirs where slight variations in burrow morphology, distribution and infill can have dramatic effects on the storativity and deliverability of hydrocarbons.

The upper Cretaceous Alderson Member (Lea Park Formation) of western Canada is an example of a giant low Previous HitpermeabilityNext Hit gas-play. Within the Alderson the productive zones are interbedded with the source rock. The gas present within these zones is biogenic in origin and may have been generated recently. Spot Previous HitpermeabilityNext Hit measurements and capillary pressure tests—conducted on hand samples and full diameter core—from the Hatton Gas Pool, show improved porosity and Previous HitpermeabilityNext Hit in association with very small, highly interconnected burrows. In general burrow Previous HitpermeabilityNext Hit is slightly enhanced over matrix Previous HitpermeabilityNext Hit. Typical burrow fabric permeabilities ranged from 0.23 - 30.4 millidarcy while matrix Previous HitpermeabilityTop values were on the order of 0.020 - 0.06 millidarcy. Capillary pressure tests show an increased modality of very fine sand over silt in some ichnogenera, especially in burrows associated with the genus Phycosiphon.

 

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas