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Title: Characterization of facies and permeability patterns in carbonate reservoirs based on outcrop analogs. Final report

The primary objective of this research is to develop methods for better describing the three-dimensional geometry of carbonate reservoir flow units as related to conventional or enhanced recovery of oil. San Andres and Grayburg reservoirs were selected for study because of the 13 Bbbl of remaining mobile oil and 17 Bbbl of residual oil in these reservoirs. The key data base is provided by detailed characterization of geologic facies and rock permeability in reservior-scale outcrops of the Permian San Andres Formation in the Guadalupe Mountains of New Mexico. Emphasis is placed on developing an outcrop analog for San Andres strata that can be used as (1) a guide to interpreting the regional and local geologic framework of the subsurface reservoirs (2) a data source illustrating the scales and patterns of variability of rock-fabric facies and petrophysical properties, particularly in lateral dimension, and on scales that cannot be studied during subsurface reservoir characterization. The research approach taken to achieve these objectives utilizes the integration of geologic description, geostatistical techniques, and reservoir flow simulation experiments. Results from this research show that the spatial distribution of facies relative to the waterflood direction can significantly affect how the reservoir produces. Bypassing of unswept oilmore » occurs due to cross flow of injected water from high permeability zones into lower permeability zones were high permeability zones terminate. An area of unswept oil develops because of the slower advance of the water-injection front in the lower permeability zones. When the injection pattern is reversed, the cross-flow effect changes due to the different arrangements of rock-fabric flow units relative to the flow of injected water, and the sweep efficiency is significantly different. Flow across low-permeability mudstones occurs showing that these layers do not necessarily represent flow barriers.« less
Authors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
10175992
Report Number(s):
DOE/BC/14470--10
ON: DE93000150
DOE Contract Number:
AC22-89BC14470
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Jul 1993
Research Org:
Texas Univ., Austin, TX (United States). Bureau of Economic Geology
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; PETROLEUM DEPOSITS; RESERVOIR ROCK; PERMEABILITY; GEOLOGY; OIL WELLS; WATERFLOODING; OPTIMIZATION; PROGRESS REPORT; CARBONATE ROCKS; NEW MEXICO; PETROLOGY; NUMERICAL DATA 020200; 020300; RESERVES, GEOLOGY, AND EXPLORATION; DRILLING AND PRODUCTION