Hydraulic fracturing in a sedimentary geothermal reservoir: Results and implications

Legarth, Björn; Huenges, Ernst; Zimmermann, Günter

doi:10.1016/j.ijrmms.2005.05.014

Cited by 165 publications

(94 citation statements)

References 18 publications

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“…Borehole breakouts, borehole fractures (Brudy et al, 1997;Zoback et al, 2003;Haimson, 2007), microseismic events (Shapiro et al, 1997;Baisch & Harjes, 2003;Bohnhoff et al, 2004;Michelet & Toksöz, 2007) and stimulation pressures (Zoback & Harjes, 1997;Legarth et al, 2003;Legarth et al, 2005) have been evaluated to confine the orientation and amplitude of the principal stress components.…”

Section: General Conceptsmentioning

confidence: 99%

“…Johnson et al, 1993;Legarth et al, 2005;Zimmermann et al, 2009). These gels enclose a so called breaker to undo the cross-linking after the proppants are placed in the fracture.…”

Section: Gel-proppant Treatmentsmentioning

confidence: 99%

“…These hydraulic fracturing stimulations can be categorized as waterfracs, gel-proppant fracs, and a combination of both called hybrid fracs (Sharma et al, 2004). The procedures are well known in the hydrocarbon industry (Shaoul et al, 2007a(Shaoul et al, , 2007b as well as in Hot Dry Rock (HDR) technology Baumgärtner et al, 2004;Schindler et al, 2008) and have also been applied in hydrothermal systems (Legarth et al, 2003;Legarth et al, 2005;Huenges et al, 2006). Compared to hydrocarbon reservoir stimulation, the application for hydrothermal reservoirs requires a technique that is able to produce considerably higher amounts of fluids (Economides & Nolte, 2000).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results

et al. 2011

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Section: General Conceptsmentioning

confidence: 99%

“…Johnson et al, 1993;Legarth et al, 2005;Zimmermann et al, 2009). These gels enclose a so called breaker to undo the cross-linking after the proppants are placed in the fracture.…”

Section: Gel-proppant Treatmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results

et al. 2011

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“…After the release of the pumping pressure, the induced fractures remain open under the highly confining stress due to the proppant and therefore greatly enhance the permeability of the reservoir [1]. Other applications of hydraulic fracturing include heat production from geothermal reservoirs [2] and measurements of in situ stresses [3]. A model to predict the hydraulic fracturing process can be used to optimize these processes.…”

Section: Introductionmentioning

confidence: 99%

The enhanced local pressure model for the accurate analysis of fluid pressure driven fracture in porous materials

Remij

Remmers

Huyghe

et al. 2015

Computer Methods in Applied Mechanics and Engineering

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“…The fault pattern analysis of a 3D structural model 8 indicates normal to strike slip faulting for the Lower Permian sediments. The formation pore 9 pressure (pp) is 43.8 MPa, determined by p-T logs at stationary conditions of the geothermal 10 target horizon (Legarth et al 2005). According to the stress relation of normal faulting the 11 effective mean stress (σ meff ) was calculated as 42.9 MPa (Blöcher et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Long-term Petrophysical Investigations on Geothermal Reservoir Rocks at Simulated In Situ Conditions

Milsch

Seibt²,

Spangenberg

2008

Transp Porous Med

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Abstract. In the course of stimulation and fluid production the chemical fluid-rock equilibrium of a geothermal reservoir may become disturbed by either temperature changes and/or an alteration of the fluid chemistry. Consequently, dissolution and precipitation reactions might be induced that result in permeability damage. In connection with the field investigations at a deep geothermal doublet, complementary laboratory based research is performed to address these effects. The reservoir is located at a depth of 4100 to 4200 m near Groß Schönebeck within the Northeast German Basin, 50 km north of Berlin, Germany. Within the reservoir horizon, an effective pressure of approximately 45 MPa and a temperature of 150°C are encountered. Furthermore, the Lower Permian (Rotliegend) reservoir rock is saturated with a highly saline Ca-Na-Cl type formation fluid (TDS ≈ 255 g/L). Under these conditions we performed two sets of long-term flow-through experiments. The pore fluid used during the first and the second experiment were a 0.1 molar NaClsolution and a synthetic Ca-Na-Cl type fluid with the specifications as above, respectively. The maximum run duration was 186 days. In detail, we experimentally addressed: (1) the effect of long-term flow on rock permeability in connection with possible changes in fluid chemistry and saturation; (2) the occurrence and consequences of baryte precipitation; and (3) potential precipitations related to oxygen-rich well water invasion during water-frac stimulation. In all sub-studies petrophysical experiments related to the evolution of rock permeability and electrical conductivity were complemented with microstructural investigations and a chemical fluid analysis. We also report the technical challenges encountered when corrosive fluids are used in long-term in-situ petrophysical experiments. After it was assured that experimental artifacts can be excluded, it is demonstrated that the sample permeability remained approximately constant within margins of ± 50 % for nearly six months. Furthermore, an effect of baryte precipitation on the rock permeability was not observed. Finally, the fluid exchange procedure did not alter the rock transport properties. The results of the chemical fluid analysis are in support of these observations. In both experiments the electrical conductivity of the samples remained unchanged for a given fluid composition and constant p-T conditions. This emphasizes its valuable complementary character in determining changes in rock transport properties during long-term flow-through experiments when the risk of experimental artifacts is high.

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Hydraulic fracturing in a sedimentary geothermal reservoir: Results and implications

Cited by 165 publications

References 18 publications

Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results

Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results

The enhanced local pressure model for the accurate analysis of fluid pressure driven fracture in porous materials

Long-term Petrophysical Investigations on Geothermal Reservoir Rocks at Simulated In Situ Conditions

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