ABSTRACT: Borehole Electrical Images And Dipmeter Patterns Of Fluvial-Deltaic Reservoirs: Outcrop Examples From Arkansas

KEAR, GEORGE R., CHARLES E. STELTING, SCOTT E. TURNER, and CHARLES G. STONE

Stratigraphic interpretation and modeling of sedimentary successions and characterization of reservoir intervals have benefited from development of borehole electrical imaging technology. The ability to resolve individual bedding features and faults has made this technology a valuable subsurface tool. While a complete analysis combines integration of images and core data, core is often not available. This paper bridges the gap by presenting the results of an outcrop-logging program and provides new information on recognizing sedimentary and dip features in the most common fluvial-deltaic reservoir sand bodies.

Gamma ray, induction, and FMI data collected during this study are compared to 3-D exposures of Pennsylvanian meanderbelt, distributary mouth bar, and delta- front deposits exposed at several quarry localities in the Arkansas Valley.

The value of these data is that they: (1) provide a practical correlation of images to the physical bedding in three dimensions: (2) point out the complexity of natural conditions as opposed to the simplified conditions shown by published depositional models and (3) establish the merit of hand-picked dip patterns in defining reservoir stacking pattern and geometry.

The significance of this work to the oil industry is that the relationships established between outcrops and log data provide guidelines for improved stratigraphic interpretation of borehole images. This facilitates the prediction of reservoir geometry and lateral and vertical variations.

AAPG Search and Discovery Article #90941©1997 GCAGS 47th Annual Meeting, New Orleans, Louisiana