Multistage hydraulic fracturing of horizontal wells continues to be a major technological tool in the oil and gas industry. Creation of multiple transverse fractures in shale gas has enabled production from very low permeability. The strategy entails the development of a Stimulated Reservoir Volume (SRV), defined as the volume of reservoir, which is effectively stimulated to increase the well performance. An ideal model for a shale gas SRV is a rectangle of length equal to horizontal well length and width equal to twice the half length of the created hydraulic fractures. This project focused on using the Multistage Transverse Fractured Horizontal Wells (MTFHW) for two novel applications. The first application considers using the SRV of a shale gas well, after the gas production rate drops below the economic limit, for low grade geothermal heat extraction. Cold water is pumped into the fracture network through one horizontal well drilled at the fracture tips. Heat is transferred to the water through the fracture surface. The hot water is then recovered through a second horizontal well drilled at the other end of the fracture network. The basis of this concept is to use the already created stimulated reservoir volume for heat transfer purposes. This technique was applied to the SRV of Haynesville Shale and the results were discussed in light of the economics of the project. For the second application, we considered the use of a similarly created SRV for producing hydrocarbon products from oil shale. Thermal decomposition of kerogen to oil and gas requires heating the oil shale to 700 degrees F. High quality saturated steam generated using a small scale nuclear plant was used for heating the formation to the necessary temperature. Analytical and numerical models are developed for modeling heat transfer in a single fracture unit of MTFHW. These models suggest that successful reuse of Haynesville Shale gas production wells for low grade geothermal heat extraction and the project appears feasible both technically and economically. The economics of the project is greatly aided by eliminating well drilling and completion costs. The models also demonstrate the success of using MTFHW array for heating oil shale using SMR technology.

Cette recherche vise à étudier les impacts environnementaux d'une technologie émergente de production d’électricité basée sur une source renouvelable, les systèmes géothermiques stimulés (EGS), par l’analyse de leur cycle de vie (ACV).Après avoir analysé plusieurs études de cas, nous avons développé un modèle ACV paramétré capable de caractériser les performances environnementales de la filière EGS. Nos résultats montrent que les émissions de gaz à effet de serre des EGS sur leur cycle de vie sont bien inférieures à celles des centrales utilisant des combustibles fossiles.Dans un deuxième temps, nous avons mis au point un cadre méthodologique pour appliquer l'analyse de sensibilité globale (GSA) à l’ACV des technologies émergentes comme les EGS, prenant en compte les incertitudes élevées liées à leur caractère innovant. Nous avons appliqué notre nouvelle approche GSA pour développer un modèle ACV simplifié, à destination des décideurs, permettant une estimation rapide des impacts des EGS à partir de seulement cinq paramètres clefs: capacité installée, profondeur de forage, nombre de puits, débit géothermal et durée de vie.L'approche méthodologique développée dans cette thèse est applicable à d'autres technologies et ouvre de larges perspectives de recherche dans le domaine de l'évaluation environnementale. / This thesis investigates the environmental impacts of an emerging renewable energy technology, the enhanced geothermal systems (EGS), using a life cycle assessment (LCA) approach.Following the analysis of several EGS case studies, we developed a parameterized LCA model able to provide a global overview of the life cycle impacts of the EGS technology. The greenhouse gas emissions of EGS are found comparable with other renewable energy systems and far better than those of power plants based on fossil fuels.In a second stage, we developed a methodological framework for the application of global sensitivity analysis (GSA) to the LCA of emerging technologies like the EGS, taking into account the high uncertainties related to their description. We applied our new GSA approach to generate a simplified LCA model, aimed at decision makers, allowing a rapid estimation of the life cycle impacts of EGS from only five key parameters: installed capacity, drilling depth, number of wells, flow rate and lifetime.The methodological approach developed in this thesis is applicable to other technologies and opens large research perspectives in the field of environmental assessment.

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Rapporten handlar om att jämföra fyra olika värmesystem med varandra. Dessa värmesystem är bergvärmesystem, sjövärmesystem, markvärmesystem och akvifersystem. Strukturen på rapporten ser ut på följande: Först beskrivs varje systemför sig, alltså hur hela systemet fungerar och sedan beskrivs nackdelar samt fördelar för varje system. Vid val av rätt värmesystem är det olika för olika villor eftersom alla har olika förutsättningar. Vid diskussion jämförs dessa fyra värmesystem med varandra utifrån just dessa förutsättningar.  De förutsättningar som jämförs med varandra om de olika systemen går att hitta under rubriken målformulering längre fram. / This rapport is about evaluating four different heating systems. These systems are first, each system is described, how it works and then pros and cons with each system. Choosing the right heating system is different for different buildings since they all have different conditions. In the discussion these four systems are compared to each other considering all these conditions. The Conditions examined can be found in the beginning of the report.