{"id":{"repo_id":"reykjavik","oai_identifier":"oai:skemman.is:1946/53773"},"canonical_url":"https://search.dev.ndltd.org/etd/reykjavik/oai:skemman.is:1946/53773","repository":{"repo_id":"reykjavik","name":"Reykjavík University","base_url":"https://skemman.is/oai/request"},"display":{"title":"Natural state modelling of a vapor dominated system : case study Darajat, Indonesia","abstract":"For a mature geothermal field like Darajat, which has been operating for nearly 30 years, re-evaluating the natural state offers an opportunity to evaluate any significant differences revealed by current interpretations from expanded data sets with those presented in the early model. This study also investigates the sensitivity to relative permeability functions for production modelling. However, these cannot be calibrated due to this study being only natural state modelling. The expanded stratigraphy and resistivity models enhance comprehension in lateral distribution of reservoir rocks and cap rock in Darajat conceptual model. Meanwhile, the most recent MEQ distribution suggests the latest delineation of Darajat base of reservoir, which improves the conceptual model’s understanding of vertical extension. The improved conceptual model serves as the main basis to develop numerical model grids and inputs before re-modelling the Darajat steady state. The updated conceptual model is discretized into numerical grids by using PyTOUGH script. The enhanced conceptual model, which contains more information than the early model in 1990, enables the development of finer numerical grids. Then, the refined stratigraphy and fault models are assigned into each rock-type domain in the numerical grids. The natural state model is simulated by using AUTOUGH2 simulator. The numerical model is calibrated to the actual data by adjusting permeability input at each rock-type domain. Natural state calibrations indicate that the temperature models are well matched to the measured temperatures at majority of the pre-production boreholes. The calibrated permeability values appear to control the way heat and mass flow in Darajat system during pre-production era. The effect of linear relative permeability function in the calibrated model shows that in a low residual liquid saturation set-up vapor tends to be more mobile than liquid in single porous medium or within the small pores of rock matrix. The calibrated model, using a low residual liquid saturation set-up of 0.3 in the linear relative permeability function, produces high vapor saturation model of 0.7. If the calibrated model used for single fed production testing in the bottom block of Well G, it provides the estimation of mass flow generated from the tested block. The sensitivity analyses using various PI indicate that higher vapor saturation model from the linear relative permeability function generates higher produced mass flow.","abstract_html":"For a mature geothermal field like Darajat, which has been operating for nearly 30 years, re-evaluating the natural state offers an opportunity to evaluate any significant differences revealed by current interpretations from expanded data sets with those presented in the early model. This study also investigates the sensitivity to relative permeability functions for production modelling. However, these cannot be calibrated due to this study being only natural state modelling. The expanded stratigraphy and resistivity models enhance comprehension in lateral distribution of reservoir rocks and cap rock in Darajat conceptual model. Meanwhile, the most recent MEQ distribution suggests the latest delineation of Darajat base of reservoir, which improves the conceptual model’s understanding of vertical extension. The improved conceptual model serves as the main basis to develop numerical model grids and inputs before re-modelling the Darajat steady state. The updated conceptual model is discretized into numerical grids by using PyTOUGH script. The enhanced conceptual model, which contains more information than the early model in 1990, enables the development of finer numerical grids. Then, the refined stratigraphy and fault models are assigned into each rock-type domain in the numerical grids. The natural state model is simulated by using AUTOUGH2 simulator. The numerical model is calibrated to the actual data by adjusting permeability input at each rock-type domain. Natural state calibrations indicate that the temperature models are well matched to the measured temperatures at majority of the pre-production boreholes. The calibrated permeability values appear to control the way heat and mass flow in Darajat system during pre-production era. The effect of linear relative permeability function in the calibrated model shows that in a low residual liquid saturation set-up vapor tends to be more mobile than liquid in single porous medium or within the small pores of rock matrix. The calibrated model, using a low residual liquid saturation set-up of 0.3 in the linear relative permeability function, produces high vapor saturation model of 0.7. If the calibrated model used for single fed production testing in the bottom block of Well G, it provides the estimation of mass flow generated from the tested block. The sensitivity analyses using various PI indicate that higher vapor saturation model from the linear relative permeability function generates higher produced mass flow.","abstract_has_math":false,"creators":["Hanna Melati Tampubolon 1990-"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Háskólinn í Reykjavík"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-06-12T11:38:30Z","date_published":"2026-06-12T11:38:30Z","updated_at":"2026-07-27T20:42:37Z","subjects":["Meistaraprófsritgerðir","Verkfræði","Endurnýjanleg orka","Jarðhitasvæði","Engineering","Sustainable energy","Geothermal fields"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1946/53773","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Háskólinn í Reykjavík"]},{"key":"dc:creator","label":"Author","values":["Hanna Melati Tampubolon 1990-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-06-12T11:38:26Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2026-06-12T11:38:26Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-06-12T11:38:30Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Meistaraprófsritgerðir","Verkfræði","Endurnýjanleg orka","Jarðhitasvæði","Engineering","Sustainable energy","Geothermal fields"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1946/53773"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["For a mature geothermal field like Darajat, which has been operating for nearly 30 years, re-evaluating the natural state offers an opportunity to evaluate any significant differences revealed by current interpretations from expanded data sets with those presented in the early model. This study also investigates the sensitivity to relative permeability functions for production modelling. However, these cannot be calibrated due to this study being only natural state modelling. The expanded stratigraphy and resistivity models enhance comprehension in lateral distribution of reservoir rocks and cap rock in Darajat conceptual model. Meanwhile, the most recent MEQ distribution suggests the latest delineation of Darajat base of reservoir, which improves the conceptual model’s understanding of vertical extension. The improved conceptual model serves as the main basis to develop numerical model grids and inputs before re-modelling the Darajat steady state. The updated conceptual model is discretized into numerical grids by using PyTOUGH script. The enhanced conceptual model, which contains more information than the early model in 1990, enables the development of finer numerical grids. Then, the refined stratigraphy and fault models are assigned into each rock-type domain in the numerical grids. The natural state model is simulated by using AUTOUGH2 simulator. The numerical model is calibrated to the actual data by adjusting permeability input at each rock-type domain. Natural state calibrations indicate that the temperature models are well matched to the measured temperatures at majority of the pre-production boreholes. The calibrated permeability values appear to control the way heat and mass flow in Darajat system during pre-production era. The effect of linear relative permeability function in the calibrated model shows that in a low residual liquid saturation set-up vapor tends to be more mobile than liquid in single porous medium or within the small pores of rock matrix. The calibrated model, using a low residual liquid saturation set-up of 0.3 in the linear relative permeability function, produces high vapor saturation model of 0.7. If the calibrated model used for single fed production testing in the bottom block of Well G, it provides the estimation of mass flow generated from the tested block. The sensitivity analyses using various PI indicate that higher vapor saturation model from the linear relative permeability function generates higher produced mass flow.","Fyrir þroskað jarðhitasvæði á borð við Darajat, sem hefur verið í rekstri í nær þrjátíu ár, felur endurmat á náttúrulegu ástandi í sér tækifæri til að meta hvort marktækur munur komi fram milli núverandi túlkunar, byggðrar á stækkuðum gagnasöfnum, og þeirrar sem sett var fram í upphaflega líkaninu. Jafnframt er í þessari rannsókn kannað næmi framleiðslulíkana fyrir hlutfallslegum gegndræpisföllum. Ekki reyndist þó unnt að kvarða þau, þar sem rannsóknin takmarkast eingöngu við líkanagerð á náttúrulegu ástandi. Útvíkkuð jarðlagaskipan og viðnámslíkön bæta skilning á láréttri dreifingu geymisbergs og þekjubergs í hugmyndalíkani Darajat. Jafnframt bendir nýjasta dreifing smáskjálfta (MEQ) til nýjustu afmörkunar botns jarðhitageymisins í Darajat, sem eykur skilning hugmyndalíkansins á lóðréttri útbreiðslu þess. Endurbætt hugmyndalíkan myndar meginstoð við uppbyggingu talnalíkanets og inntaksgagna áður en stöðugt ástand Darajat er endurlíkanað. Uppfærða hugmyndalíkaninu er skipt niður í talnagrindur með notkun PyTOUGH-forritsskriftu. Hið endurbætta hugmyndalíkan, sem inniheldur meiri upplýsingar en upphaflega líkanið frá árinu 1990, gerir kleift að þróa fíngerðari talnagrindur. Að því loknu eru endurbætt jarðlagalíkön og misgengislíkön úthlutuð hverju berggerðarsvæði innan talnagrindarinnar. Líkan af náttúrulegu ástandi er hermt með AUTOUGH2-herminum. Talnalíkanið er kvarðað að raunmælingum með því að stilla gegndræpisgildi fyrir hvert berggerðarsvæði. Kvörðun náttúrulega ástandsins sýnir að hitastigslíkön samræmast vel mældum hita í meirihluta borhola frá tímabilinu fyrir vinnslu. Kvarðuð gegndræpisgildi virðast stjórna því hvernig varmi og massi streymdu um Darajat-kerfið á tímabilinu fyrir vinnslu. Áhrif línulegs hlutfallslegs gegndræpisfalls í kvarðaða líkaninu sýna að við lága afgangsvatnsmettun hefur gufa tilhneigingu til að vera hreyfanlegri en vökvi í einsleitum gljúpmiðli eða innan smárra hola í bergfylki. Kvarðaða líkanið, þar sem notast er við afgangsvatnsmettunina 0,3 í línulega hlutfallslega gegndræpisfallinu, gefur gufumettunarlíkan upp á 0,7. Ef kvarðaða líkanið er notað til einsfæðrar framleiðsluprófunar í neðsta reit holu G, fæst mat á því massastreymi sem myndast úr prófuðum reit. Næmnigreiningar með mismunandi framleiðnivísitölu (PI) benda til þess að hærri gufumettun samkvæmt línulega hlutfallslega gegndræpisfallinu leiði til meira framleidds massastreymis."]},{"key":"dc:title","label":"Title","values":["Natural state modelling of a vapor dominated system : case study Darajat, Indonesia"]}]}],"canonical_facts":{"dc:contributor":["Háskólinn í Reykjavík"],"dc:creator":["Hanna Melati Tampubolon 1990-"],"dc:date.accessioned":["2026-06-12T11:38:26Z"],"dc:date.available":["2026-06-12T11:38:26Z"],"dc:date.issued":["2026-06-12T11:38:30Z"],"dc:description.abstract":["For a mature geothermal field like Darajat, which has been operating for nearly 30 years, re-evaluating the natural state offers an opportunity to evaluate any significant differences revealed by current interpretations from expanded data sets with those presented in the early model. This study also investigates the sensitivity to relative permeability functions for production modelling. However, these cannot be calibrated due to this study being only natural state modelling. The expanded stratigraphy and resistivity models enhance comprehension in lateral distribution of reservoir rocks and cap rock in Darajat conceptual model. Meanwhile, the most recent MEQ distribution suggests the latest delineation of Darajat base of reservoir, which improves the conceptual model’s understanding of vertical extension. The improved conceptual model serves as the main basis to develop numerical model grids and inputs before re-modelling the Darajat steady state. The updated conceptual model is discretized into numerical grids by using PyTOUGH script. The enhanced conceptual model, which contains more information than the early model in 1990, enables the development of finer numerical grids. Then, the refined stratigraphy and fault models are assigned into each rock-type domain in the numerical grids. The natural state model is simulated by using AUTOUGH2 simulator. The numerical model is calibrated to the actual data by adjusting permeability input at each rock-type domain. Natural state calibrations indicate that the temperature models are well matched to the measured temperatures at majority of the pre-production boreholes. The calibrated permeability values appear to control the way heat and mass flow in Darajat system during pre-production era. The effect of linear relative permeability function in the calibrated model shows that in a low residual liquid saturation set-up vapor tends to be more mobile than liquid in single porous medium or within the small pores of rock matrix. The calibrated model, using a low residual liquid saturation set-up of 0.3 in the linear relative permeability function, produces high vapor saturation model of 0.7. If the calibrated model used for single fed production testing in the bottom block of Well G, it provides the estimation of mass flow generated from the tested block. The sensitivity analyses using various PI indicate that higher vapor saturation model from the linear relative permeability function generates higher produced mass flow.","Fyrir þroskað jarðhitasvæði á borð við Darajat, sem hefur verið í rekstri í nær þrjátíu ár, felur endurmat á náttúrulegu ástandi í sér tækifæri til að meta hvort marktækur munur komi fram milli núverandi túlkunar, byggðrar á stækkuðum gagnasöfnum, og þeirrar sem sett var fram í upphaflega líkaninu. Jafnframt er í þessari rannsókn kannað næmi framleiðslulíkana fyrir hlutfallslegum gegndræpisföllum. Ekki reyndist þó unnt að kvarða þau, þar sem rannsóknin takmarkast eingöngu við líkanagerð á náttúrulegu ástandi. Útvíkkuð jarðlagaskipan og viðnámslíkön bæta skilning á láréttri dreifingu geymisbergs og þekjubergs í hugmyndalíkani Darajat. Jafnframt bendir nýjasta dreifing smáskjálfta (MEQ) til nýjustu afmörkunar botns jarðhitageymisins í Darajat, sem eykur skilning hugmyndalíkansins á lóðréttri útbreiðslu þess. Endurbætt hugmyndalíkan myndar meginstoð við uppbyggingu talnalíkanets og inntaksgagna áður en stöðugt ástand Darajat er endurlíkanað. Uppfærða hugmyndalíkaninu er skipt niður í talnagrindur með notkun PyTOUGH-forritsskriftu. Hið endurbætta hugmyndalíkan, sem inniheldur meiri upplýsingar en upphaflega líkanið frá árinu 1990, gerir kleift að þróa fíngerðari talnagrindur. Að því loknu eru endurbætt jarðlagalíkön og misgengislíkön úthlutuð hverju berggerðarsvæði innan talnagrindarinnar. Líkan af náttúrulegu ástandi er hermt með AUTOUGH2-herminum. Talnalíkanið er kvarðað að raunmælingum með því að stilla gegndræpisgildi fyrir hvert berggerðarsvæði. Kvörðun náttúrulega ástandsins sýnir að hitastigslíkön samræmast vel mældum hita í meirihluta borhola frá tímabilinu fyrir vinnslu. Kvarðuð gegndræpisgildi virðast stjórna því hvernig varmi og massi streymdu um Darajat-kerfið á tímabilinu fyrir vinnslu. Áhrif línulegs hlutfallslegs gegndræpisfalls í kvarðaða líkaninu sýna að við lága afgangsvatnsmettun hefur gufa tilhneigingu til að vera hreyfanlegri en vökvi í einsleitum gljúpmiðli eða innan smárra hola í bergfylki. Kvarðaða líkanið, þar sem notast er við afgangsvatnsmettunina 0,3 í línulega hlutfallslega gegndræpisfallinu, gefur gufumettunarlíkan upp á 0,7. Ef kvarðaða líkanið er notað til einsfæðrar framleiðsluprófunar í neðsta reit holu G, fæst mat á því massastreymi sem myndast úr prófuðum reit. Næmnigreiningar með mismunandi framleiðnivísitölu (PI) benda til þess að hærri gufumettun samkvæmt línulega hlutfallslega gegndræpisfallinu leiði til meira framleidds massastreymis."],"dc:identifier.uri":["https://hdl.handle.net/1946/53773"],"dc:language.iso":["en"],"dc:subject":["Meistaraprófsritgerðir","Verkfræði","Endurnýjanleg orka","Jarðhitasvæði","Engineering","Sustainable energy","Geothermal fields"],"dc:title":["Natural state modelling of a vapor dominated system : case study Darajat, Indonesia"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T20:42:37Z"}