Variation of horizontal in situ stress with depth for long-term performance evaluation of the Deep Geological Repository project access shaft

Corkum, A. G.; Damjanac, Branko; Lam, Tom

doi:10.1016/j.ijrmms.2018.04.035

Cited by 25 publications

(13 citation statements)

References 13 publications

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“…Cornet (2016) showed that largescale fluid injections conducted at the Soultz-sous-Forêts site generated large-scale failure zones whose orientation varies with depth. Based on the analyses of borehole failures, considerable stress orientation variations were also highlighted with depth at Rittershoffen (Hehn et al, 2016), at Soultzsous-Forêts (Valley and Evans, 2007b) and at other sites (e.g., Valley and Evans, 2009;Cornet and Röckel, 2012). In this respect, our measurements at the Rittershoffen site confirm the conclusions drawn at many other sites regarding the change in stress orientation.…”

Section: Evaluation Of Stress Magnitude From Breakout Widthsupporting

confidence: 83%

“…11 is the significant rotation of 30 • from NNW to NNE highlighted between the bottom and the top of our analyzed section. Such a rotation with depth has already been shown in the Upper Rhine Graben area in the Basel geothermal boreholes (Valley and Evans, 2009), in potash mines (Cornet and Röckel, 2012) and at the neighboring geothermal site of Soultz-sous-Forêts (Valley and Evans, 2007b). Hehn et al (2016) have also provided evidence of local stress rotations in the sedimentary section of GRT-1 up to the upper Triassic (Keuper) from analyses of DITFs.…”

Section: Evolution Of Breakout Geometry With Depthsupporting

confidence: 52%

“…18 at large depth (below 2250 m). This step occurs at the sediment-basement interface and could be explained by the effect of a stiffness contrast between lithologies (Corkum et al, 2018).…”

Section: Stress Magnitude Evolution With Depthmentioning

confidence: 99%

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Stress characterization and temporal evolution of borehole failure at the Rittershoffen geothermal project

et al. 2019

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Abstract. In the Upper Rhine Graben, several innovative projects based on enhanced geothermal system (EGS) technology exploit local deep-fractured geothermal reservoirs. The principle underlying this technology consists of increasing the hydraulic performances of the natural fractures using different stimulation methods in order to circulate the natural brine at commercial flow rates. For this purpose, knowledge of the in situ stress state is of central importance to predict the response of the rock mass to different stimulation programs. Here, we propose a characterization of the in situ stress state from the analysis of ultrasonic borehole imager (UBI) data acquired at different key moments of the reservoir development using a specific image correlation technique. This unique dataset has been obtained from the open-hole sections of the two deep wells (GRT-1 and GRT-2, ∼2500 m) at the geothermal site of Rittershoffen, France. We based our analysis on the geometry of breakouts and drilling-induced tension fractures (DITFs). A transitional stress regime between strike-slip and normal faulting consistent with the neighboring site of Soultz-sous-Forêts is evident. The time-lapse dataset enables us to analyze both in time and space the evolution of the structures over 2 years after drilling. The image correlation approach developed for time-lapse UBI images shows that breakouts extend along the borehole with time and widen (i.e., angular opening between the edges of the breakouts) but do not deepen (i.e., increase in the maximal radius of the breakouts). The breakout widening is explained by wellbore thermal equilibration. A significant stress rotation at depth is evident. It is shown to be controlled by a major fault zone and not by the sediment–basement interface. Our analysis does not reveal any significant change in the stress magnitude in the reservoir.

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Section: Evaluation Of Stress Magnitude From Breakout Widthsupporting

confidence: 83%

Section: Evolution Of Breakout Geometry With Depthsupporting

confidence: 52%

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Stress characterization and temporal evolution of borehole failure at the Rittershoffen geothermal project

et al. 2019

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“…18 at large depth (below 2250m). This step occurs at the interface sediment basement and could be explained by the effect of stiffness contrast between lithologies (Corkum et al, 2018).…”

Section: Stresses Magnitude Evolution With Depthmentioning

confidence: 99%

Stress Characterization and Temporal Evolution of Borehole Failure at the Rittershoffen Geothermal Project

Azzola¹,

Valley²,

Schmittbuhl³

et al. 2019

Preprint

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Abstract. In the Upper Rhine Graben, several innovative projects based on the Enhanced Geothermal System (EGS) technology exploit local deep fractured geothermal reservoirs. The principle underlying this technology consists of increasing the hydraulic performances of the natural fractures using different stimulation methods in order to circulate the natural brine with commercially flow rates. For this purpose, the knowledge of the in-situ stress state is of central importance to predict the response of the rock mass to the different stimulation programs. Here, we propose a characterization of the in-situ stress state from the analysis of Ultrasonic Borehole Imager (UBI) data acquired at different key moments of the reservoir development using a specific image correlation technique. This unique dataset has been obtained from the open hole sections of the two deep wells (GRT-1 and GRT2, ~ 2500 m) at the geothermal site of Rittershoffen, France. We based our analysis on the geometry of breakouts and of drilling induced tension fractures (DITF). A transitional stress regime between strike-slip and normal faulting consistently with the neighbour site of Soultz-sous-Forêts is evidenced. The time lapse dataset enables to analyse both in time and space the evolution of the structures over two years after drilling. The image correlation approach developed for time lapse UBI images shows that breakouts extend along the borehole with time, widen (i.e. angular opening between the edges of the breakouts) but do not deepen (i.e. increase of the maximal radius of the breakouts). The breakout widening is explained by wellbore thermal equilibration. A significant stress rotation at depth is evidenced. It is shown to be controlled by a major fault zone and not by the sediment-basement interface. Our analysis does not reveal any significant change in the stress magnitude in the reservoir.

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“…According to such a relation, it was found that the mininginduced stress showed an increasing trend with the face length [15]. With respect to the relationship between the stress magnitude and cover depth, the mining-induced stress increased linearly and the ratio between horizontal and vertical stresses decreased nonlinearly from a large value of 3.5 to 1.0 with an increase in the cover depth [16,17].…”

Section: Introductionmentioning

confidence: 99%

Ground Response and Mining‐Induced Stress in Longwall Panel of a Kilometer‐Deep Coal Mine

Wang

Yang

et al. 2021

Shock and Vibration

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In order to improve ground control of the longwall mining, ground response and mining-induced stress in the longwall panel of a kilometer-deep coal mine are investigated in this study. Field measurements on abutment stress, roof displacement, and fracture development indicate that the region influenced by the longwall mining reaches 150 m ahead of the longwall face. Failure scope of the coal seam, where mining-induced fractures are well developed, ranges from 10 to 13 m inward the face line. Vertical stress concentration coefficient reaches 2.2. Based on the field measurements, a numerical model is moreover developed and utilized to examine the response of the principal stress to the longwall mining. The concentration coefficient, peak point location, and influence scope of the principal stress gradually become stable with an increase in face advancement. Regarding the major principal stress, the concentration coefficient and influence scope are 2.4 and 152 m, respectively, and the peak point locates 13 m inward the face line, which are consistent with the field measurements. With respect to the minor principal stress, the referred coefficient and scope are 1.5 and 172 m, respectively, and its peak point location is 21 m ahead of the face line. The major principal stress in the coal seam rotates from vertical to horizontal direction in the vertical plane parallel with face advance direction. The maximum rotation angle reaches 20°. The minor principal stress first rotates into the referred vertical plane and then it rotates from horizontal to vertical direction at the same speed with the major principal stress in the same plane. Rotation angle of the principal stress in roof strata is greatly enlarged, the rotation trace of which is influenced by the longwall mining and vertical distance above the seam. Based on the relation between rotation trace of the principal stress and face advance direction, the influence of stress rotation on the stability of roof structure is discussed.

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Variation of horizontal in situ stress with depth for long-term performance evaluation of the Deep Geological Repository project access shaft

Cited by 25 publications

References 13 publications

Stress characterization and temporal evolution of borehole failure at the Rittershoffen geothermal project

Stress characterization and temporal evolution of borehole failure at the Rittershoffen geothermal project

Stress Characterization and Temporal Evolution of Borehole Failure at the Rittershoffen Geothermal Project

Ground Response and Mining‐Induced Stress in Longwall Panel of a Kilometer‐Deep Coal Mine

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