eprintid: 1831 rev_number: 13 eprint_status: archive userid: 6 dir: disk0/00/00/18/31 datestamp: 2017-03-02 10:25:35 lastmod: 2017-05-16 12:21:20 status_changed: 2017-03-02 10:25:35 type: article metadata_visibility: show creators_name: Jeanne, Pierre creators_name: Rutqvist, Jonny creators_name: Dobson, Patrick F. creators_name: Garcia, Julio creators_name: Walters, Mark creators_name: Hartline, Craig creators_name: Borgia, Andrea corp_creators: Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA corp_creators: Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA corp_creators: Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA corp_creators: Calpine Corporation, Middletown, California, USA corp_creators: Calpine Corporation, Middletown, California, USA corp_creators: Calpine Corporation, Middletown, California, USA corp_creators: Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA title: Geomechanical simulation of the stress tensor rotation caused by injection of cold water in a deep geothermal reservoir subjects: MP6 subjects: RU1_1 subjects: SG divisions: SHEER-5 full_text_status: none abstract: We present a three-dimensional thermohydromechanical numerical study of the evolution and distribution of the stress tensor within the northwest part of The Geysers geothermal reservoir (in California), including a detailed study of the region around one injection well from 2003 to 2012. Initially, after imposing a normal faulting stress regime, we calculated local changes in the stress regime around injection wells. Our results were compared with previously published studies in which the stress state was inferred from inverting the focal plane mechanism of seismic events. Our main finding is that changes in stress tensor orientation are caused by injection-induced progressive cooling of the reservoir, as well as by the seasonal variations in injection rate. Because of the gravity flow and cooling around a liquid zone formed by the injection, the vertical stress reduction is larger and propagates far below the injection well. At the same time, the horizontal stress increases, mostly because of stress redistribution below and above the cooling area. These two phenomena cause the rotation of the stress tensor and the appearance of a strike-slip regime above, inside, and below the cooling area. The cooling and the associated rotation of the stress regime can play a significant role in the observed long-term deepening of the microseismicity below active injection wells. date: 2015 date_type: published publication: Journal of Geophysical Research: Solid Earth volume: 120 number: 12 publisher: John Wiley & Sons pagerange: 8422-8438 id_number: doi:10.1002/2015JB012414 issn: 2169-9313 official_url: http://doi.org/10.1002/2015JB012414 access_IS-EPOS: limited owner: Publisher citation: Jeanne, Pierre and Rutqvist, Jonny and Dobson, Patrick F. and Garcia, Julio and Walters, Mark and Hartline, Craig and Borgia, Andrea (2015) Geomechanical simulation of the stress tensor rotation caused by injection of cold water in a deep geothermal reservoir. Journal of Geophysical Research: Solid Earth, 120 (12). pp. 8422-8438. DOI: https://doi.org/10.1002/2015JB012414