A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Hydraulic Fracturing In Situ Stress Estimations in a Potential Geothermal Site, Seokmo Island, South Korea
Abstract We conducted hydraulic fracturing (HF) in situ stress measurements in Seokmo Island, South Korea, to understand the stress state necessary to characterize a potential geothermal reservoir. The minimum horizontal principal stress was determined from shut-in pressures. In order to calculate the maximum horizontal principal stress (SHmax) using the classical Hubbert–Willis equation, we carried out hollow cylinder tensile strength tests and Brazilian tests in recovered cores at depths of HF tests. Both tests show a strong pressure rate dependency in tensile strengths, from which we derived a general empirical equation that can be used to convert laboratory determined tensile strength to that suitable for in situ. The determined stress regime (reverse-faulting) and SHmax direction (ENE–WSW) at depths below ~300 m agrees with the first order tectonic stress. However the stress direction above ~300 m (NE–SW) appears to be interfered by topography effect due to a nearby ridge. The state of stress in Seokmo Island is in frictional equilibrium constrained by optimally oriented natural fractures and faults. However, a severe fluctuation in determined SHmax values suggests that natural fractures with different frictional coefficients seem to control stress condition quite locally, such that SHmax is relatively low at depths where natural fractures with low frictional coefficients are abundant, while SHmax is relatively high at depths where natural fractures with low frictional coefficients are scarce.
Hydraulic Fracturing In Situ Stress Estimations in a Potential Geothermal Site, Seokmo Island, South Korea
Abstract We conducted hydraulic fracturing (HF) in situ stress measurements in Seokmo Island, South Korea, to understand the stress state necessary to characterize a potential geothermal reservoir. The minimum horizontal principal stress was determined from shut-in pressures. In order to calculate the maximum horizontal principal stress (SHmax) using the classical Hubbert–Willis equation, we carried out hollow cylinder tensile strength tests and Brazilian tests in recovered cores at depths of HF tests. Both tests show a strong pressure rate dependency in tensile strengths, from which we derived a general empirical equation that can be used to convert laboratory determined tensile strength to that suitable for in situ. The determined stress regime (reverse-faulting) and SHmax direction (ENE–WSW) at depths below ~300 m agrees with the first order tectonic stress. However the stress direction above ~300 m (NE–SW) appears to be interfered by topography effect due to a nearby ridge. The state of stress in Seokmo Island is in frictional equilibrium constrained by optimally oriented natural fractures and faults. However, a severe fluctuation in determined SHmax values suggests that natural fractures with different frictional coefficients seem to control stress condition quite locally, such that SHmax is relatively low at depths where natural fractures with low frictional coefficients are abundant, while SHmax is relatively high at depths where natural fractures with low frictional coefficients are scarce.
Hydraulic Fracturing In Situ Stress Estimations in a Potential Geothermal Site, Seokmo Island, South Korea
Chang, Chandong (author) / Jo, Yeonguk (author) / Oh, Yangkyun (author) / Lee, Tae Jong (author) / Kim, Kwang-Yeom (author)
2013
Article (Journal)
Electronic Resource
English
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
| British Library Online Contents | 2014
In situ stress measurement using hydraulic fracturing for shallow tunnel in Korea
| British Library Conference Proceedings | 1997
Borehole AE monitoring during in-situ hydraulic fracturing stress measurements
| British Library Conference Proceedings | 2000
On the stimulation of geothermal reservoir by downward hydraulic fracturing
| Tema Archive | 1977