experimental and numerical study of multiphase flow phenomena and models in oil gas industry

n/

Development and application of an innovative tool to automate the process of results extraction from the thermo-hydraulic simulator Olga

Abstract This paper presents the development and application of an innovative code to extract in an automated way data from the thermo-hydraulic simulator Olga. The results show that the tool can significantly reduce the time needed for the data extraction procedure and increase the reliability of results due to the fact that there is no more the need of the human operator. Moreover, during the data extraction phase, the Olga code is available for running different simulations allowing to optimize the use of this resource

Sand transport in multiphase flow mixtures in a horizontal pipeline: An experimental investigation

An inherent problem with both oil and natural gas production is the deposition of sand particles in pipeline, which could lead to problems such as excessive pressure drops, equipment failure, pipeline erosion, and production decline. The characterization of sand particles transport and sedimentation in different flow systems such as sand–multiphase mixtures is vital to predict the sand transport velocity and entrainment processes in oil and gas transportation pipelines. However, it seems that no model exists able to accurately characterize the sand transport and deposition in multiphase pipeline. In fact, in the last decade several researchers tried to extend the modeling of liquid-solid flow to gas-liquid-solid flow, but no significant results have been obtained, especially in slug flow condition due to the complexity of the phenomenon. In order to develop and validate a mathematical model properly formulated for the calculation of the sand critical deposition velocity in gas-liquid flow, more and more experimental data are necessary. This paper presents a preliminary experimental study of three phase flows (air-water-sand) inside a horizontal pipe and the application of the sand-liquid models present in literature. Significant observations were made during the experimental study from which several conclusions were drawn. Different sand flow regimes were established by physical observation and data analysis: fully dispersed solid flow, moving dunes and stationary bed. The critical deposition velocities were determined at different sand concentrations. It was concluded that sand transport characteristics and the critical deposition velocity are strongly dependent on the gas-liquid flow regime and on sand concentration. Keywords: Sand transport, Multiphase flow, Minimum transport condition, Deposition, Experimental investigation, Oil and ga

Design and Optimisation of a Steam Assisted Gravity Drainage (SAGD) Facility for Improved Recovery from Canadian Oil Sands

La sempre più limitata disponibilità di olio prodotto da fonti convenzionali sta valorizzando la produzione di combustibili da fonti non convenzionali quali le sabbie bituminose. Le sabbie bituminose sono una combinazione di sabbia, argilla, acqua e bitume, ovvero petrolio. Il più grande accumulo conosciuto si trova nella regione dell’Alberta (Canada). Numerose tecniche di estrazione di olio da sabbie bituminose sono state sviluppate negli ultimi decenni. La tecnica “Steam Assisted Gravity Drainage” è la più promettente tra quelle utilizzate per la produzione di oli viscosi. La tecnologia SAGD si basa sulla riduzione della viscosità delle sabbie bituminose operata attraverso la diluizione con vapor d’acqua in combinazione con il drenaggio per gravità che utilizza una coppia di lunghi pozzi orizzontali, configurata in modo che dal pozzo superiore si possa iniettare il vapore e da quello inferiore produrre l’olio diluito. L’obiettivo generale di questo lavoro di Tesi è di presentare un dettagliato studio di ottimizzazione di un ipotetico impianto, di scala industriale, di recupero di bitume da oil sands canadesi tramite SAGD, chiamato ipoteticamente LINK. Tutti i dati relativi all’impianto LINK sono stati ricavati da un’attenta analisi della letteratura relativa ad impianti SAGD esistenti oppure coerentemente ipotizzati. L’impianto LINK permette di estrarre una miscela multifase di bitume, acqua, vapore e gas e di recuperarne il bitume in un CPF (Central Processing Facility). Scopo principale di questo lavoro di Tesi è una dettagliata ottimizzazione tecnica del sistema di pipeline dell’impianto ipotizzato basata sulla disciplina della Flow Assurance. Lo studio di “Flow Assurance” è stato condotto tramite l’utilizzo del software OLGA (SPT) for quattro sistemi principali: il sistema emulsione, quello vapore, quello gas naturale ed il sistema acqua. Una linea aggiuntiva è stata considerata per il trasporto del gas naturale da una stazione erogatrice (considerata privata e chiamata NGS) all’impianto LINK. Sulla base dei dati raccolti e delle assunzioni fatte e dopo una corretta caratterizzazione termodinamica dei fluidi studiati tramite l’utilizzo del software PVTsim (Calsep), lo studio di Flow Assurance è stato condotto per mezzo di simulazioni in condizioni stazionarie e transitorie. Dall’analisi svolta, sono stati ottenuti i seguenti risultati: configurazione dei sistemi, diametri delle pipeline, comportamento termico, idraulico e chimico dei sistemi, integrità meccanica, performance del sistema e possibili problematiche relative ad alcune operazioni transitorie. Secondo obiettivo della presente Tesi è la valutazione economica del sistema studiato secondo il metodo dei Flussi di Cassa Attualizzati, condotto su un foglio Excel opportunamente sviluppato. I costi (di investimento e operativi) di impianti basati sulla tecnologia SAGD già esistenti sono stati trovati in letteratura. Gli indici di valutazione della redditività degli investimenti calcolati mostrano che l’investimento relativo all’impianto LINK è economicamente conveniente. Terzo ed ultimo obiettivo della presente Tesi è un’analisi di tipo ambientale dell’impianto studiato. Al fine di valutare le emissioni di gas serra (GHG) dell’impianto LINK, un ulteriore file Excel è stato sviluppato basandosi su dati di letteratura. Dalla comparazione dei risultati ottenuti con i valori di emissioni di olio prodotto da fonti convenzionali e tramite tecnologia in situ è evidente che la tecnologia SAGD è molto promettente anche dal punto di vista ambiental

Technical and economic analysis of different cogeneration systems for energy production from biomass

none3This paper compares the results of a techno-economic performance analysis of seven plants for energy production from biomass with the aim of identifying the most effective solution. Small ( ≤ 250 KWe) and micro ( ≤ 100 KWe) size plants were investigated: 50 kWe diesel internal combustion engine coupled with a gasifier and 35 kWe Stirling engine coupled with a gasifier with an overall efficiency of 41.1% and 87.5% respectively, two biomass cogenerators, one of 25 kWe and the other of 100 kWe, 250 kWe Otto internal combustion engine coupled with a gasifier and 250 kWe diesel internal combustion engine coupled with a gasifier and 238 kWe biomass ORC plant. The technical analysis provided calculations for specific biomass consumption, electricity generation, heat produced and overall system efficiency. The economic evaluation was carried on through a discounted cash flow analysis. Data were provided by literature, analysis of case study at Italian and European level, and directly by the manufacturers of cogeneration systems. The results showed that a combined heat and power (CHP) generator is the best solution because it is economically viable with a high NPV and a PBP of five years and also technically performing with a global efficiency of 78.2% and a low biomass consumption.mixedGiacchetta G; Leporini M; Marchetti BGiacchetta, G; Leporini, M; Marchetti, Barbar

Economic and environmental analysis of a Steam Assisted Gravity Drainage (SAGD) facility for oil recovery from Canadian oil sands

As conventional oil production becomes limited, transportation fuels are being produced from other unconventional fossil resources such as oil sands. Oil sands are a combination of clay, sand, water and bitumen. Vast quantities of oil sands resources have been found worldwide. The largest known reservoir of oil sands in the world is located in the province of Alberta (Canada). Several techniques for the extrac- tion of the oil from oil sands have been developed in recent decades. Steam-Assisted Gravity Drainage (SAGD) is the most promising approach for recovering heavy and viscous oil resources. In SAGD, two clo- sely-spaced horizontal wells, one above the other, form a steam-injector and producer pair. The reservoir oil is heated by the injected steam and drains to the producer under the effect of gravity. First aim of this work is an economic optimization and evaluation of an hypothetical industrial scale facility (named LINK), located in Alberta. All data relating to LINK plant have been obtained from a review of the existing literature references or have been assumed. A Discounted Cash Flow Analysis (DCFA) of LINK plant has been performed. Costs of existing projects have been found in literature. The results show that the hypo- thetical plant LINK is a profitable investment and that the investment cost has a significant effect on the competitiveness of the LINK facility. Second purpose of the present work is an environmental analysis of the LINK plant: in order to evaluate GHG emissions from LINK plant, a LCA analysis has been carried out. The calculated emissions from oil sand production by SAGD technology have been compared with values relating to conventional crude oil pathways and to recovery and extraction of bitumen through surface mining from literature. The comparison demonstrated that SAGD is a promising technology also from an environmental point of view. An economic–environmental model for SAGD technology optimization has been developed

Technical and economic analysis of different cogeneration systems for energy production from biomass

This paper compares the results of a techno-economic performance analysis of seven plants for energy production from biomass with the aim of identifyng the most effective solution

Development of an innovative and sustainable model for integrating river maintenance with energy production from residual biomass

This study aims to develop an innovative model for managing territory maintenance in which the productive function is linked with the protective one and that integrates environmental and economic development aspects, combining the energetic valorization with an effective territory maintenance program. The strong innovation consists in the creation of an agro-energy environment chain based on the maintenance of river basins and small waterways made by single farmers or associations that will use residual biomass to produce electrical and thermal bio-energy. The maintenance activities include the control of aquatic weeds, grass cutting on river banks, and tree/bush management. If left unmanaged, they can block the flow of watercourses and increase the risk of flooding. The implementation of this virtuous model to the rivers maintenance aims to provide management and conservation means based on the territory characteristics. In fact, the new model has been applied to an existing site in the Marche region (Italy) located near a river characterized by a poor state of maintenance. A real commercial system for residual biomass exploitation was chosen, and both the technical and economic feasibility of the model implementation have been demonstrated