Estimation of effective permeabilities in the lower Stevens Formation of the Paloma Field, San Joaquin Valley, California

Journal Article · Tue Nov 01 00:00:00 EST 1988 · SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States)

DOI:https://doi.org/10.2118/15907-PA· OSTI ID:6546477

Desbarats, A ^[1]

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1. Geological Survey of Canada, Ottawa (CA)

Simulation programs used in reservoir studies require effective gridblock permeability values representing spatial averages over large volumes of formation. Within such volumes, most reservoir rocks exhibit a considerable degree of heterogeneity, with permeability measurements often varying over several orders of magnitude. A satisfactory method for averaging permeabilities must consider not only the magnitude of permeability variations, but also the variations of permeability in space. Using experimental histograms and variograms to describe the heterogeneous permeability field within gridblocks, a Monte Carlo technique is used to estimate effective permeability. The method is illustrated by an example with actual permeability data from the lower Stevens formation of the Paloma field in Kern County, CA. Experimental downhole variograms of permeability showed a large nugget effect at short lags and a longer correlation structure with a range of 100 ft (30 m). For the particular distribution and spatial correlation structure of these data, effective horizontal and vertical permeabilities were found to be respectively higher and lower than the geometric mean. Calculated effective permeabilities were found to be relatively insensitive to assumptions regarding the horizontal range of spatial correlation. This lack of sensitivity is caused by the large nugget effect or random short-range correlation structure. Effective permeabilities obtained with an approximate analytical relation were compared with effective permeabilities calculated numerically.

• OSTI ID: 6546477
• Journal Information: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Vol. 3:4
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
CALIFORNIA
OIL FIELDS
MONTE CARLO METHOD
PERMEABILITY
CALCULATION METHODS
RESERVOIR ROCK
HETEROGENEOUS EFFECTS
BOREHOLES
DATA ANALYSIS
EVALUATION
EXPERIMENTAL DATA
SIMULATION
VARIATIONS
CAVITIES
DATA
FEDERAL REGION IX
GEOLOGIC DEPOSITS
INFORMATION
MINERAL RESOURCES
NORTH AMERICA
NUMERICAL DATA
PETROLEUM DEPOSITS
RESOURCES
USA
020200* - Petroleum- Reserves
Geology
& Exploration
020300 - Petroleum- Drilling & Production