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Accueil > Evénements Scientifiques > Conférences et Séminaires > Conférences et Séminaires 2017 > Séminaire I.Thiagalingam

Séminaire I.Thiagalingam

6 janvier

W1D, a wellbore simulator for geothermal applications.

Séminaire I.Thiagalingam

Post-Doc IMFT

Jeudi 2 février à 16 h 00

Salle Castex rez de chaussée

Résumé :

W1D is a wellbore simulator developed as part of the GEOTREF (GEOThermal energy in Fractured REservoirs) project. It is designed to be effective as a practical tool in the monitoring of geothermal systems. It can be used for instance to interpret PTS (pressure-temperature-spinner) loggings and so collect valuable information (permeability change with depth, in/out flow via well oriented fractures and faults) about the geothermal system and its evolution. It can be also coupled to a reservoir simulator to fully describe and manage a geothermal system. Effectively, when a resource is smartly managed, it can be sustained for decades, avoiding complications such as a reduction of the production or the reservoir depletion.

One of the main objectives of Research and Development investigations in this field is the interpretation of PTS logs so as to associate distinctive features and anomalies to a well-defined physical phenomenon actually occurring within the well, with least uncertainties. In this seminar, we will focus on that particular issue. The first step to achieve the above objective is to assess quantitatively the uncertainties associated to correlations and parameters of the model. Indeed, the theoretical lack in the description of two-phase flows is balanced by ad hoc correlations. Moreover, many parameters such as the wall roughness or the wall heat transfer coefficient are not known initially (due to scaling effect for instance). The impact of these uncertainties on the simulation output (pressure drop for instance) are not negligible and could pollute data interpretation.

Once a confident conceptual model with appropriated set of correlations/parameters had been validated on basic cases, the simulator is upgraded to handle complexities encountered in practice : boiling of complex thermodynamic systems such as “H20-NaCl-CO2” mixture and intricate designs of wellbores (multiple changes of section, deviated wells, multi-feed zones or in/out flows). It is for instance pointed out that pressure and temperature profiles measured within the well, when correctly interpreted, bring to light by specific physical features the existence of multi-feed zones (in or out flow) or the presence of non-condensable gases and dissolved solids (salt for instance). These information are valuables to evaluate the natural state of a geothermal reservoir (before production) and its evolution during the production phase.