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

Online Access: Get full text
doi: 10.1002/jgrb.50086
Author(s): 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
Author Affiliation(s): Primary:
Tohoku University, Institute of Fluid Science, Sendai, Japan
OYO Company, Japan
Japan Agency for Marine-Earth Science and Technology, Japan
Universite Joseph Fourier, France
University of Massachusetts at Amherst, United States
Kyoto University, Japan
Pennsylvania State University, United States
University of Southampton, United Kingdom
University of Connecticut, United States
Volume Title: Journal of Geophysical Research
Source: Journal of Geophysical Research, 118(3), p.1203-1215. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227
Note: In English. 28 refs.; illus.
Summary: In situ test of hydraulic fracturing (HF) provides the only way to observe in situ stress magnitudes directly. The maximum and minimum horizontal stresses, SHmax and Shmin, are determined from critical borehole pressures, i.e., the reopening pressure Pr and the shut-in pressure Ps, 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 Pr. For effective measurement of Pr, 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 SHmax determination from Pr was developed. Furthermore, a new method for stress measurement not restricted by the system compliance and Pr is herein proposed. In this method, the magnitudes and orientations of SHmax and Shmin are determined from (i) the cross-sectional shape of a core sample and (ii) Ps 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 ∼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.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Accretionary wedges; Boreholes; Cores; Crust; Expedition 319; Fracture zones; Hydraulic fracturing; IODP Site C0010; IODP Site C0011; Integrated Ocean Drilling Program; Mid-ocean ridges; NanTroSEIZE; North Pacific; Northwest Pacific; Ocean floors; Oceanic crust; Pacific Ocean; Physical properties; Pressure; Shikoku Basin; Stress; West Pacific
Coordinates: N331236 N331236 E1364112 E1364112
N324944 N324945 E1365256 E1365254
Record ID: 2013046062
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom