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U.S. Department of Energy
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In situ stress measurements in inclined holes in the North Sea: Application to water flooding and enhanced oil recovery

Conference ·
OSTI ID:5299567

Water flooding is typical for many North Sea reservoirs and enhanced oil recovery (EOR) projects are being considered for some reservoirs. A knowledge of the in situ stress state is important to reservoir engineers in designing water floods or EOR programs. Eighteen in situ stress measurements were made in two 3.6 km deep wells in an oil reservoir located in the northern Viking Graben region of the North Sea. The wellbores were inclined 60/sup 0/ and 65/sup 0/ from the vertical. The principal in situ stress directions and magnitudes were determined by the anelastic strain recovery method using oriented core immediately after it was retrieved from the wellbore. The maximum principal stress is the overburden, and the average ratios of the maximum and minimum horizontal stresses to the overburden are 0.94 + ..05 and 0.72 + ..07, respectively. The azimuth of the maximum horizontal stress and the direction of potential vertical hydraulic fractures created during a water flood or EOR program is N110/sup 0/E+.22/sup 0/. This hydraulic fracture orientation is nearly perpendicular to the predominant trend of normal faults in the region. In order to achieve maximum efficiency of the areal sweep during a water flood or EOR, production wells should be located perpendicular to the azimuth of hydraulic fractures propagating from the injection wells.

OSTI ID:
5299567
Report Number(s):
CONF-850941-
Country of Publication:
United States
Language:
English