Stochastic characterization of gridblock permeabilities

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · SPE Formation Evaluation (Society of Petroleum Engineers); (United States)

DOI:https://doi.org/10.2118/22187-PA· OSTI ID:6994146

Gomez-Hernandez, J J; Journel, A G ^[1]

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1. Stanford Univ., CA (United States)

Permeability is generally measured at the core scale and only at a few sites. By using geostatistical techniques, one can generate alternative high-resolution images of the reservoir at the measurement scale. These images will honor both the data values at the data sites and some prior structural information as modeled, for example, by a covariance function. However, these images must be averaged to the scale of the flow-simulation gridblocks. Two questions arise: (1) how should averaging be carried out and (2) could the gridblock values be generated directly from the core or log without the intermediary step of small-scale imaging This paper proposes avenues to answer both questions. First, the authors propose an averaging technique from point to block permeabilities, accounting for the tensorial character of permeability. Second, they propose a method to infer the covariances and cross-covariances among the different components of the block permeability tensor, and the cross-covariances between these block values and the point measurements. This set of covariances and cross-covariances is then used to generate directly multiple, equally likely spatial realizations of gridblock permeability tensors conditioned to the point measurements. The method is not constrained by small variability of the underlying point permeability distribution, nor does it require a multi-Gaussian-related hypothesis.

• OSTI ID: 6994146
• Journal Information: SPE Formation Evaluation (Society of Petroleum Engineers); (United States), Journal Name: SPE Formation Evaluation (Society of Petroleum Engineers); (United States) Vol. 9:2; ISSN 0885-923X; ISSN SFEVEG
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CALCULATION METHODS
GEOLOGIC DEPOSITS
GEOLOGIC MODELS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PERMEABILITY
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
STOCHASTIC PROCESSES