--> Abstract: Influence of Diagenetic Illite on the Permeability of a North Sea Sandstone Reservoir: An Image Analysis-Based Approach, by S. Belin, Y. Anguy, J. B. Ferm, and B. Fritz; #90937 (1998).

Datapages, Inc.Print this page

Abstract: Influence of Diagenetic Illite on the Permeability of a North Sea Sandstone Reservoir: An Image Analysis-Based Approach

BELIN, S., Centre de Geochimie de la Surface; Y. ANGUY, Laboratoire Energetique et Phenomenes de Transfer, J.B. FERM, Perception and Decision Systems, Inc., and B. FRITZ, Centre de Geochimie de la Surface

Abstract

The objective of this work is to quantify the relationship between the permeability and the micro-geometry of a set of samples from a North Sea sandstones reservoir showing different degrees of illite diagenesis. The approach is based on image analysis. Back-scattered electrons images are digitized in gray level images. Images consist of 5x5 elementary overlapping views (512x512 pixels ; pixel edge: 5.208 m) binarized and merged into mosaics. The approach consists in characterizing a set of binary images of the micro-geometry by a few 3-D objects, or Pore-Types (P.T.) interpreted as the consequence of the initial depositional fabric and/or post depositional diagenetic events. Using pattern recognition algorithms, P.T.s are derived from the distributions of sizes and shapes of closed patches of porosity (PORe Elements; porels) exposed in the set of binary images. Each P.T. is expressed by the distribution of sizes and shapes of the collection of porels it yields in two-dimensions.

Multiple regression analysis procedures applied to P.T.s data combined with capillary pressure (Pc) curves allows for a series of discrete Pc intervals to quantify the relative amount of pores of the kth type connected by a throat size representative a ith Pc interval. Numerous case studies have revealed that the pore-type/throat sizes relationship is not random. The structured nature of the pore-type/throat sizes relation is a strong argument to interpret P.T.s as the fundamental elements of a hierarchy of structures and is interpreted; for sandstones, as the consequence of a general structural model e.g. as the consequence of ‘... the ongoing influence of a well-sorted depositional fabric coupled with the presence of clasts resistant to dissolution or recrystallization'. Such observed relation is used to express much of the flow variability as an indirect function of the variations in the relative abundance of the P.T.s associated to the largest throat sizes.

The target of this contribution is an illustration of this approach in the case of a North Sea Sandstones Reservoir (deltaic-, channel infilling- and deposit-facies) for a set of samples representative of the different stages of illite diagenesis.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah