Pub Date : 2019-11-22DOI: 10.3997/2214-4609.201903162
A. Chalari, M. Mondanos, T. Coleman, M. Farhadiroushan, A. Stork
Summary Enhanced Geothermal Systems (EGS) offer unique monitoring and characterization challenges. The harsh, high temperature downhole environment and heterogeneous nature of discrete hydraulic features usually governed by discontinuous fractures and faults requires robust measurement technology with advanced resolution capability. Borehole DAS installations are often associated with VSP surveys. However, tomographic seismic, earthquake seismology, and microseismic applications have also been demonstrated at a geothermal field. The spatio-temporal resolution achieved with DTS allows for characterisation of hydrothermal processes as well as estimation of thermal diffusivity with depth. Here we present the use of fibre optic distributed temperature and acoustic systems at both hydrothermal and EGS sites as part of the subsurface geothermal characterisation.
{"title":"Seismic Methods for Geothermal Reservoir Characterization and Monitoring Using Fiber Optic Distributed Acoustic and Temperature Sensor","authors":"A. Chalari, M. Mondanos, T. Coleman, M. Farhadiroushan, A. Stork","doi":"10.3997/2214-4609.201903162","DOIUrl":"https://doi.org/10.3997/2214-4609.201903162","url":null,"abstract":"Summary Enhanced Geothermal Systems (EGS) offer unique monitoring and characterization challenges. The harsh, high temperature downhole environment and heterogeneous nature of discrete hydraulic features usually governed by discontinuous fractures and faults requires robust measurement technology with advanced resolution capability. Borehole DAS installations are often associated with VSP surveys. However, tomographic seismic, earthquake seismology, and microseismic applications have also been demonstrated at a geothermal field. The spatio-temporal resolution achieved with DTS allows for characterisation of hydrothermal processes as well as estimation of thermal diffusivity with depth. Here we present the use of fibre optic distributed temperature and acoustic systems at both hydrothermal and EGS sites as part of the subsurface geothermal characterisation.","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"88 9-10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114009077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-22DOI: 10.3997/2214-4609.201903335
J. Kasahara
To image supercritical water reservoirs, we have proposed to use the distributed acoustic sensing (DAS) in the borehole, surface seismic array, active or passive seismic sources and full-waveform inversion (FWI) method. Through the comparison test of DAS and geophones in a field, we confirmed that the DAS system can be used as an array seismic sensor although it is less sensing the seismic waves perpendicular to the fiber elongation. The sensitivity is almost comparable to the surface seismometers. It can be used as dense seismic array(s). We have also examined the usefulness of full-waveform inversion (FWI) method for imaging of geothermal reservoirs. The FWI result suggests it can be used for geothermal reservoir imaging. To evaluate our approach, we carried out a feasibility study in e Medipolis geothermal field located on Kyushu Island, Japan. We deployed an optical fiber down to a 977 m depth in a borehole. Using distributed temperature sensing (DTS) mode, the measured temperature at the 914 m depth was 264 °C. We obtained four and half days of continuous seismic data via DAS and surface seismometers. The DAS data were obtained every 1 m from a 977 m depth to ground surface. We observed seven natural earthquakes. The DAS sensitivity is comparable to the surface seismometers. This suggest that the optical fiber deployment in the exiting borehole could provide reasonable coupling to the borehole casing. We obtained apparent interval Vp profile along the borehole. There was no distinct seismic attenuation observed, even in the high-temperature zone, and Vp in the high-temperature zone is estimated as 3.0 km/s. The P-to-S converted phase was evident on the surface seismometers, and this could indicate the presence of a conversion zone around the 4 km-depth beneath the Medipolis geothermal field. To image supercritical water reservoirs, we have proposed to use the distributed acoustic sensing (DAS) in the borehole, surface seismic array, active or passive seismic sources and full-waveform inversion (FWI) method. Through the comparison test of DAS and geophones in a field, we confirmed that the sensitivity is almost comparable to the surface seismometers. We have also examined the usefulness of full-waveform inversion (FWI) method for imaging of geothermal reservoirs. We carried out a field study in geothermal field. We deployed an optical fiber down to a 977 m depth in a borehole. Using distributed temperature sensing (DTS) mode, the measured temperature at the 914 m depth was 264 °C. We obtained 4.5 days of continuous seismic data The DAS data were obtained every 1 m from a 977 m depth to ground surface. We confirmed that the optical fiber deployment in the exiting borehole could provide reasonable coupling to the borehole casing. There was no distinct seismic attenuation observed, even in the high-temperature zone, and Vp in the high-temperature zone is estimated as 3.0 km/s. The P-to-S converted phase was evident on the surface seismomete
{"title":"Seismic Approach Characterizing Geothermal Reservoirs Using DAS and FWI","authors":"J. Kasahara","doi":"10.3997/2214-4609.201903335","DOIUrl":"https://doi.org/10.3997/2214-4609.201903335","url":null,"abstract":"To image supercritical water reservoirs, we have proposed to use the distributed acoustic sensing (DAS) in the borehole, surface seismic array, active or passive seismic sources and full-waveform inversion (FWI) method. Through the comparison test of DAS and geophones in a field, we confirmed that the DAS system can be used as an array seismic sensor although it is less sensing the seismic waves perpendicular to the fiber elongation. The sensitivity is almost comparable to the surface seismometers. It can be used as dense seismic array(s). We have also examined the usefulness of full-waveform inversion (FWI) method for imaging of geothermal reservoirs. The FWI result suggests it can be used for geothermal reservoir imaging. \u0000To evaluate our approach, we carried out a feasibility study in e Medipolis geothermal field located on Kyushu Island, Japan. We deployed an optical fiber down to a 977 m depth in a borehole. Using distributed temperature sensing (DTS) mode, the measured temperature at the 914 m depth was 264 °C. We obtained four and half days of continuous seismic data via DAS and surface seismometers. The DAS data were obtained every 1 m from a 977 m depth to ground surface. We observed seven natural earthquakes. The DAS sensitivity is comparable to the surface seismometers. This suggest that the optical fiber deployment in the exiting borehole could provide reasonable coupling to the borehole casing. \u0000We obtained apparent interval Vp profile along the borehole. There was no distinct seismic attenuation observed, even in the high-temperature zone, and Vp in the high-temperature zone is estimated as 3.0 km/s. The P-to-S converted phase was evident on the surface seismometers, and this could indicate the presence of a conversion zone around the 4 km-depth beneath the Medipolis geothermal field. \u0000To image supercritical water reservoirs, we have proposed to use the distributed acoustic sensing (DAS) in the borehole, surface seismic array, active or passive seismic sources and full-waveform inversion (FWI) method. Through the comparison test of DAS and geophones in a field, we confirmed that the sensitivity is almost comparable to the surface seismometers. We have also examined the usefulness of full-waveform inversion (FWI) method for imaging of geothermal reservoirs. \u0000We carried out a field study in geothermal field. We deployed an optical fiber down to a 977 m depth in a borehole. Using distributed temperature sensing (DTS) mode, the measured temperature at the 914 m depth was 264 °C. We obtained 4.5 days of continuous seismic data The DAS data were obtained every 1 m from a 977 m depth to ground surface. We confirmed that the optical fiber deployment in the exiting borehole could provide reasonable coupling to the borehole casing. \u0000There was no distinct seismic attenuation observed, even in the high-temperature zone, and Vp in the high-temperature zone is estimated as 3.0 km/s. The P-to-S converted phase was evident on the surface seismomete","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121452319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-22DOI: 10.3997/2214-4609.201903161
Kai Stricker, S. Schimschal, T. Kohl, Jörg Meixner, B. Müller, S. Wessling
Summary Logging while drilling (LWD) borehole images are widely used for the analysis of borehole breakouts. These breakouts develop when the circumferential stress around the borehole exceeds the compressive strength of the rock. The aim of this study was the investigation whether a causal relationship between drilling operations and the development of breakouts exists. For this purpose, we developed a software tool to interpret the data. The observations displayed a general relationship between breakouts and tripping operations as well as events with switched-off pumps. Various pressure reductions have been identified in breakout sections. The pressure reductions of the highest magnitude are caused by the switch-off of pumps during connections. Furthermore, it became visible that the downhole temperature responses negatively to drilling operations. An investigation of the temporal development of breakouts has shown that breakouts tend to grow both azimuthally and depth-wise. Pressure changes between relogs may be an explanation for this behavior. A causal relationship between breakouts and drilling operations could not be proven on the base of the available data. Future research, however, may clarify this relationship by using relog data of higher quantity and quality or data from multiple imaging tools of the same run.
{"title":"Drilling Induced Borehole Breakouts - New Insights From LWD Data Analysis","authors":"Kai Stricker, S. Schimschal, T. Kohl, Jörg Meixner, B. Müller, S. Wessling","doi":"10.3997/2214-4609.201903161","DOIUrl":"https://doi.org/10.3997/2214-4609.201903161","url":null,"abstract":"Summary Logging while drilling (LWD) borehole images are widely used for the analysis of borehole breakouts. These breakouts develop when the circumferential stress around the borehole exceeds the compressive strength of the rock. The aim of this study was the investigation whether a causal relationship between drilling operations and the development of breakouts exists. For this purpose, we developed a software tool to interpret the data. The observations displayed a general relationship between breakouts and tripping operations as well as events with switched-off pumps. Various pressure reductions have been identified in breakout sections. The pressure reductions of the highest magnitude are caused by the switch-off of pumps during connections. Furthermore, it became visible that the downhole temperature responses negatively to drilling operations. An investigation of the temporal development of breakouts has shown that breakouts tend to grow both azimuthally and depth-wise. Pressure changes between relogs may be an explanation for this behavior. A causal relationship between breakouts and drilling operations could not be proven on the base of the available data. Future research, however, may clarify this relationship by using relog data of higher quantity and quality or data from multiple imaging tools of the same run.","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124843214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3997/2214-4609.201903160
W. Bauer
{"title":"Borehole Measurements in Geothermal Wells: Why One Should Measure and Know Certain Parameters","authors":"W. Bauer","doi":"10.3997/2214-4609.201903160","DOIUrl":"https://doi.org/10.3997/2214-4609.201903160","url":null,"abstract":"","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126330224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3997/2214-4609.201903165
H. von Hartmann, C. Kunkel, H. Buness, S. Wadas, T. Schintgen, V. Shipilin, M. Fadel, J. Bauer
{"title":"Utilization of Well Logs for Geothermal Prospect Evaluation on Reservoir and Regional Scale","authors":"H. von Hartmann, C. Kunkel, H. Buness, S. Wadas, T. Schintgen, V. Shipilin, M. Fadel, J. Bauer","doi":"10.3997/2214-4609.201903165","DOIUrl":"https://doi.org/10.3997/2214-4609.201903165","url":null,"abstract":"","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"367 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116362909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3997/2214-4609.201903164
N. Cuevas
{"title":"Surface-Borehole Electromagnetic Method - A Review on the Technology Development and Potential for Geothermal Applications","authors":"N. Cuevas","doi":"10.3997/2214-4609.201903164","DOIUrl":"https://doi.org/10.3997/2214-4609.201903164","url":null,"abstract":"","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121066152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3997/2214-4609.201903163
Ó. Eidesgaard
{"title":"Shallow Geothermal Energy System in Fractured Basalt; A Case Study From Kollafjør∂ur, Faroe Islands, NE-Atlantic Ocean","authors":"Ó. Eidesgaard","doi":"10.3997/2214-4609.201903163","DOIUrl":"https://doi.org/10.3997/2214-4609.201903163","url":null,"abstract":"","PeriodicalId":198000,"journal":{"name":"EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy","volume":"310 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121165701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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