Ito, Takatoshi; Funato, Akio; Lin, Weiren; Doan, Mai-Linh; Boutt, David F.; Kano, Yasuyuki; Ito, Hisao; Saffer, Demian; McNeill, Lisa C.; Byrne, Timothy; Moe, Kyaw Thu (2013): Determination of stress state in deep subsea formation by combination of hydraulic fracturing in situ test and core analysis; a case study in the IODP Expedition 319. American Geophysical Union, Washington, DC, United States, Journal of Geophysical Research, 118 (B3), 1203-1215, georefid:2013-046062

Abstract:
In situ test of hydraulic fracturing (HF) provides the only way to observe in situ stress magnitudes directly. The maximum and minimum horizontal stresses, S (sub Hmax) and S (sub hmin) , are determined from critical borehole pressures, i.e., the reopening pressure P (sub r) and the shut-in pressure P (sub s) , etc, observed during the test. However, there is inevitably a discrepancy between actual and measured values of the critical pressures, and this discrepancy is very significant for P (sub r) . For effective measurement of P (sub r) , it is necessary for the fracturing system to have a sufficiently small compliance. A diagnostic procedure to evaluate whether the compliance of the employed fracturing system is appropriate for S (sub Hmax) determination from P (sub r) was developed. Furthermore, a new method for stress measurement not restricted by the system compliance and P (sub r) is herein proposed. In this method, the magnitudes and orientations of S (sub Hmax) and S (sub hmin) are determined from (i) the cross-sectional shape of a core sample and (ii) P (sub s) obtained by the HF test performed near the core depth. These ideas were applied for stress measurement in a central region of the Kumano fore-arc basin at a water depth of 2054 m using a 1.6 km riser hole drilled in the Integrated Ocean Drilling Program (IODP) Expedition 319. As a result, the stress decoupling through a boundary at 1285 m below seafloor was detected. The boundary separates new upper layers and old lower ones with an age gap of approximately 1.8 Ma, which is possibly the accretionary prism. The stress state in the lower layers is consistent with that observed in the outer edge of accretionary prism. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.
Coverage:
West: 136.4112 East: 136.5256 North: 33.1236 South: 32.4944
Relations:
Expedition: 319
Site: 319-C0010
Site: 319-C0011
Expedition: 322
Site: 322-C0011
Expedition: 332
Site: 332-C0010
Expedition: 333
Site: 333-C0011
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.1002/jgrb.50086 (c.f. for more detailed metadata)
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