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Title: Stress-sensitive permeability in a high-permeability sandstone reservoir--The Kuparuk field. [Alaska]

Conference · · Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:5571388

Buildup test analyses for wells in the Kuparuk field, Alaska, give permeability values that are two to seven times higher than values from drawdown test analyses. Often buildup skins indicate extreme formation damage, while drawdown skins indicate minimal damage. This sandstone reservoir exhibits the characteristics of stress-sensitive permeability. The existence of stress-sensitive permeability was demonstrated using well test analyses, simulation studies, core analyses, and laboratory flow experiments. Comparisons were made for most wells in the field, with significant differences between buildups and drawdowns evident in a majority of the analyses. Simulation of well tests required stress-sensitive permeability to match both buildup and drawdown tests. Core analyses and laboratory flow tests were done to determine the cause and magnitude of the stress-sensitive permeability. Evidence points to open vertical fractures as the cause of this stress-sensitive permeability. These fractures are small-scale, with characteristic heights on the order of inches, and apparently randomly distributed in the reservoir. Because of the fractures' size and distribution, the reservoir behaves as a homogeneous porous medium with stress-sensitive permeability rather than as a classical naturally fractured reservoir. Well tests show no typical fractured reservoir behavior (i.e., linear flow). The extreme effects of stress-sensitive permeability, as seen in this reservoir, can seriously impact field operations.

Research Organization:
ARCO Oil and Gas Co.
OSTI ID:
5571388
Report Number(s):
CONF-830312-
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Vol. SPE 11718; Conference: SPE California regional meeting, Ventura, CA, USA, 23 Mar 1983
Country of Publication:
United States
Language:
English