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Stefan Wiemer - One of the best experts on this subject based on the ideXlab platform.
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the induced earthquake sequence related to the st gallen deep geothermal project switzerland fault reactivation and fluid interactions imaged by microseismicity
Journal of Geophysical Research, 2017Co-Authors: Tobias Diehl, Toni Kraft, E Kissling, Stefan WiemerAbstract:In July 2013, a sequence of more than 340 earthquakes was induced by reservoir stimulations and well-control procedures following a Gas Kick at a deep geothermal drilling project close to the city of St. Gallen, Switzerland. The sequence culminated in an ML 3.5 earthquake, which was felt within 10–15 km from the epicenter. High-quality earthquake locations and 3-D reflection seismic data acquired in the St. Gallen project provide a unique data set, which allows high-resolution studies of earthquake triggering related to the injection of fluids into macroscopic fault zones. In this study, we present a high-precision earthquake catalog of the induced sequence. Absolute locations are constrained by a coupled hypocenter-velocity inversion, and subsequent double-difference relocations image the geometry of the ML 3.5 rupture and resolve the spatiotemporal evolution of seismicity. A joint interpretation of earthquake and seismic data shows that the majority of the seismicity occurred in the pre-Mesozoic basement, hundreds of meters below the borehole and the targeted Mesozoic sequence. We propose a hydraulic connectivity between the reactivated fault and the borehole, likely through faults mapped by seismic data. Despite the excellent quality of the seismic data, the association of seismicity with mapped faults remains ambiguous. In summary, our results document that the actual hydraulic properties of a fault system and hydraulic connections between its fault segments are complex and may not be predictable upfront. Incomplete knowledge of fault structures and stress heterogeneities within highly complex fault systems additionally challenge the degree of predictability of induced seismicity related to underground fluid injections.
João Otavio Leite Nunes - One of the best experts on this subject based on the ideXlab platform.
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Estudo do controle de poços em operações de perfuração em aguas profundas e ultra profundas
2017Co-Authors: João Otavio Leite NunesAbstract:Resumo: O controle de poço sempre foi um assunto muito importante na exploração e explotação de óleo e gás, pois envolve aspectos econômicos, de segurança de pessoas e questões ambientais. O avanço das explorações offshore, particularmente em águas profundas e ultra-profundas, tem aumentado cada vez mais a relevância do controle de Kicks e prevenção de blowouts. Práticas de perfuração largamente utilizadas têm sido otimizadas e reavaliadas, então novas tecnologias têm sido desenvolvidas para tratar problemas relacionados a operações de perfuração em águas profundas, tal como uma prática de controle de poço confiável e eficiente. Este esforço é de grande importância em paises como o Brasil, que tem a maior parte da produção de óleo e gás em campos offshore, sendo que a maioria dos campos localiza-se em águas profundas e ultra-profundas. Considerando-se tal cenário, um modelo matemático foi desenvolvido para simular um Kick de gás e prever a variação de pressão na linha do choke e no espaço anular de um poço, durante uma situação de controle de poço em águas profundas. Considerações sobre o efeito da geometria do poço, perdas de carga por fricção, expansão do influxo e modelagem bifásica foram implementadas. O efeito de algumas variáveis no controle de poço, tais como o pit gain, lâmina d'água, densidade e reologia do fluido de perfuração e vazão de bombeio foram estudadasAbstract: Well control has always been a very important issue in the oi! and Gas exploitation business, since it involves money savings, people safety and environment threatening. The advancement of the exploration frontiers from onshore to offshore fields, particularly, deep and ultra-deep waters, has increased even more the relevance of Kick control and blowout prevention during drilling operations. Widely used drilling practices have been optimized and re-evaluated, so have new technologies been developed to handle specific issues related to deepwater drilling operations, such as reliable and efficient well control practices. This effort has great importance to some countries like Brazil, which have most part of their oil and Gas production concentrated on offshore wells, about of those reserves are located in deepwaters. Regarding such scenario, a mathematical model has been developed to simulate a Gas Kick and predict the pressure variation in the choke line and the annular space of the well during well control situation in deepwater scenarios. Considerations regarding the effects of wellbore geometry, frictional pressure losses, influx expansion, and two-phase flow aspects have been implemented in the present model. The effects of some variables in well control, such as the pit gain, water depth, mud weight and rheology and pump flow rate have been studie
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Estudo do controle de poços em operações de perfuração em aguas profundas e ultra profundas
Universidade Estadual de Campinas. Instituto de Geociencias, 2002Co-Authors: João Otavio Leite NunesAbstract:O controle de poço sempre foi um assunto muito importante na exploração e explotação de óleo e gás, pois envolve aspectos econômicos, de segurança de pessoas e questões ambientais. O avanço das explorações offshore, particularmente em águas profundas e ultra-profundas, tem aumentado cada vez mais a relevância do controle de Kicks e prevenção de blowouts. Práticas de perfuração largamente utilizadas têm sido otimizadas e reavaliadas, então novas tecnologias têm sido desenvolvidas para tratar problemas relacionados a operações de perfuração em águas profundas, tal como uma prática de controle de poço confiável e eficiente. Este esforço é de grande importância em paises como o Brasil, que tem a maior parte da produção de óleo e gás em campos offshore, sendo que a maioria dos campos localiza-se em águas profundas e ultra-profundas. Considerando-se tal cenário, um modelo matemático foi desenvolvido para simular um Kick de gás e prever a variação de pressão na linha do choke e no espaço anular de um poço, durante uma situação de controle de poço em águas profundas. Considerações sobre o efeito da geometria do poço, perdas de carga por fricção, expansão do influxo e modelagem bifásica foram implementadas. O efeito de algumas variáveis no controle de poço, tais como o pit gain, lâmina d'água, densidade e reologia do fluido de perfuração e vazão de bombeio foram estudadasWell control has always been a very important issue in the oi! and Gas exploitation business, since it involves money savings, people safety and environment threatening. The advancement of the exploration frontiers from onshore to offshore fields, particularly, deep and ultra-deep waters, has increased even more the relevance of Kick control and blowout prevention during drilling operations. Widely used drilling practices have been optimized and re-evaluated, so have new technologies been developed to handle specific issues related to deepwater drilling operations, such as reliable and efficient well control practices. This effort has great importance to some countries like Brazil, which have most part of their oil and Gas production concentrated on offshore wells, about of those reserves are located in deepwaters. Regarding such scenario, a mathematical model has been developed to simulate a Gas Kick and predict the pressure variation in the choke line and the annular space of the well during well control situation in deepwater scenarios. Considerations regarding the effects of wellbore geometry, frictional pressure losses, influx expansion, and two-phase flow aspects have been implemented in the present model. The effects of some variables in well control, such as the pit gain, water depth, mud weight and rheology and pump flow rate have been studie
Tobias Diehl - One of the best experts on this subject based on the ideXlab platform.
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the induced earthquake sequence related to the st gallen deep geothermal project switzerland fault reactivation and fluid interactions imaged by microseismicity
Journal of Geophysical Research, 2017Co-Authors: Tobias Diehl, Toni Kraft, E Kissling, Stefan WiemerAbstract:In July 2013, a sequence of more than 340 earthquakes was induced by reservoir stimulations and well-control procedures following a Gas Kick at a deep geothermal drilling project close to the city of St. Gallen, Switzerland. The sequence culminated in an ML 3.5 earthquake, which was felt within 10–15 km from the epicenter. High-quality earthquake locations and 3-D reflection seismic data acquired in the St. Gallen project provide a unique data set, which allows high-resolution studies of earthquake triggering related to the injection of fluids into macroscopic fault zones. In this study, we present a high-precision earthquake catalog of the induced sequence. Absolute locations are constrained by a coupled hypocenter-velocity inversion, and subsequent double-difference relocations image the geometry of the ML 3.5 rupture and resolve the spatiotemporal evolution of seismicity. A joint interpretation of earthquake and seismic data shows that the majority of the seismicity occurred in the pre-Mesozoic basement, hundreds of meters below the borehole and the targeted Mesozoic sequence. We propose a hydraulic connectivity between the reactivated fault and the borehole, likely through faults mapped by seismic data. Despite the excellent quality of the seismic data, the association of seismicity with mapped faults remains ambiguous. In summary, our results document that the actual hydraulic properties of a fault system and hydraulic connections between its fault segments are complex and may not be predictable upfront. Incomplete knowledge of fault structures and stress heterogeneities within highly complex fault systems additionally challenge the degree of predictability of induced seismicity related to underground fluid injections.
Xiangfang Li - One of the best experts on this subject based on the ideXlab platform.
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multiphase transient flow model in wellbore annuli during Gas Kick in deepwater drilling based on oil based mud
Applied Mathematical Modelling, 2017Co-Authors: Xiangfang LiAbstract:Abstract Transient-state Gas and oil-based mud (OBM) two-phase flow in wellbore annuli will occur during Gas Kick. The phase behavior of influx Gas and OBM will make the Gas Kick during OBM drilling more complicated. There are three possible cases in an annulus: only liquid flow in the entire annulus, Gas and liquid two-phase flow in part of the annulus, and Gas and liquid two-phase flow in the entire annulus. First, the phase behaviors of Gas and OBM in wellbore annuli are studied based on the phase behavior of methane and diesel. A multiphase transient-flow model in annuli during Gas Kick based on OBM is then established based on Gas–liquid two-phase flow theory and on flash theory in annuli. The influences of phase behavior in annuli and annular geometry are taken into account. The local flow parameters are predicted by the hydrodynamic models and the local thermodynamic parameters are predicted by the heat-transfer models in the corresponding flow pattern. The proposed model has a better performance, compared with two other models, against the published experimental data. Finally, the variation of pit gain, well-bottom hole pressure, and Gas void fraction are obtained, leading to a better understanding of the occurrence and evolution mechanism of Gas Kick during deepwater drilling.
Zhaopeng Zhu - One of the best experts on this subject based on the ideXlab platform.
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development of a transient non isothermal two phase flow model for Gas Kick simulation in hthp deep well drilling
Applied Thermal Engineering, 2018Co-Authors: Xianzhi Song, Zhaoyu Pang, Zhaopeng ZhuAbstract:Abstract The simulation of Gas/liquid two-phase flow, considering the heat transfer between the annulus fluid and the surrounding environment, is of significance in predicting temperature and pressure distributions after a Gas Kick in HTHP deep well drilling. This paper presents the development of a transient non-isothermal two-phase flow model for the dynamic simulation of multiphase flow in the wellbore after a Gas Kick. The drift-flux model is used to describe Gas/liquid two-phase flow, and multiple transient energy conservation equations are used for predicting temperature profiles of fluids in the drillpipe, drillpipe, the fluid in the annulus, casing string, and formation. As for numerical scheme of this strongly coupled model, the advection upstream splitting model (AUSMV) hybrid scheme is adapted for solving flow equations, while the finite difference approach is adapted for simultaneously solving energy conservation equations of the wellbore-formation system. Physical properties of Gas and liquid phases are updated at each timestep. Predicted temperature and pressure distributions are validated against the field data. Flow behaviors predicted by the models with and without the heat transfer effect are compared. The effects of some major parameters (reservoir pressure, choke pressure, geothermal gradient, liquid mass flow rate) on temperature, pressure, and Gas fraction distributions along the wellbore are investigated.
