7 research outputs found
Model-based characterization of permeability damage control through inhibitor injection under parametric uncertainty
No full textDamage in subsurface formations caused by mineral precipitation decreases the porosity and permeability, eventually reducing the production rate of wells in plants producing oil, gas or geothermal fluids. A possible solution to this problem consists in stopping the production followed by the injection of inhibiting species that slow down the precipitation process. In this work we model inhibitor injection and quantify the impact of a set of model parameters on the outputs of the system. The parameters investigated concern three key factors contributing to the success of the treatment: i) the inhibitor affinity, described by an adsorption Langmuir isotherm, ii) the concentration and time related to the injection and iii) the efficiency of the inhibitor in preventing mineral precipitation. Our simulations are set in a stochastic framework where these inputs are characterized in probabilistic terms. Forward simulations rely on a purpose-built code based on finite differences approximation of the reactive transport setup in radial coordinates. We explore the sensitivity diverse outputs, encompassing the well bottom pressure and space-time scales characterizing the transport of the inhibitor. We find that practically relevant output variables, such as inhibitor lifetime and well bottom pressure, display a diverse response to input uncertainties and display poor mutual dependence. Our results quantify the probability of treatment failure for diverse scenarios of inhibitor-rock affinity. We find that treatment optimization based on single outputs may lead to high failure probability when evaluated in a multi-objective framework. For instance, employing an inhibitor displaying an appropriate lifetime may fail in satisfying criteria set in terms of well-bottom pressure history or injected inhibitor mass
Modelling and simulation of near-wellbore formation damage and inhibition process
No full textLAUREA MAGISTRALEIl fenomeno della riduzione di permeabilità del mezzo poroso nella zona circostante un pozzo (noto come formation damage o scaling) è un problema ben noto nel campo dell’industria petrolifera, del gas e della produzione di energia geotermica. La precipitazione di specie disciolte dà luogo alla formazione di materiali solidi (come calcite, dolomite, asfaltene, paraffina, ecc.) e può provocare danni al giacimento e inconvenienti nel processo di produzione. I danni causati da precipitazioni organiche e inorganiche diminuiscono la porosità e la permeabilità, riducendo così il tasso di produzione. Quando il volume disponibile all’interno del mezzo poroso viene ridotto, il flusso di fluido diminuisce sostanzialmente con conseguente perdita di efficienza di sfruttamento del giacimento. In tal caso, è piuttosto frequente la necessità di installare pompe più potenti o di allungare i tempi di estrazione.
Una possibile soluzione a questo problema consiste nell'arresto della produzione seguita dall'iniezione di sostanze inibitrici che rallentano il processo di precipitazione. L'iniezione dell'inibitore è un metodo ampiamente utilizzato ed efficace per prevenire la formazione di precipitati solidi, ed esso fornisce una protezione affidabile a lungo termine contro il ridimensionamento della formazione.
In questa tesi, l'attenzione è rivolta alla precipitazione di minerali. A partire dalle formulazioni matematiche classiche documentate in letteratura, è stato sviluppato un modello matematico con l’obiettivo di descrivere sia il processo di precipitazione e che il corrispondente processo di inibizione. Per verificare l’efficacia di differenti specie inibenti, è stata eseguita un’analisi di sensitività basata sia sui valori degli indici di saturazione, calcolati tramite simulazione numerica della precipitazione dei minerali, sia sulla variazione delle proprietà delle specie inibenti. Il grado di efficienza del trattamento è determinato dalle proprietà di adsorbimento e desorbimento dell’inibitore e dalla sua concentrazione nel fluido di iniezione.
Nelle simulazioni vengono confrontati due schemi produttivi, vale a dire la normale produzione senza utilizzo di inibitori e la produzione con inibitori. L’indicatore utilizzato per determinare l’efficienza del processo è stata la pressione sul fondo del pozzo: la pressione infatti diminuisce in seguito alla riduzione di permeabilità causata dalle precipitazioni. Le simulazioni evidenziano che, durante la produzione con l'inibitore, questa diminuzione risulta più lenta rispetto alla produzione normale, risultato che consente uno sfruttamento più proficuo del giacimento.
Gli obiettivi di questo lavoro sono stati proposti dalla società TEA SISTEMI S.p.A., azienda nella quale è stato svolto il tirocinio di tesi. I dati di laboratorio e di campo sono invece stati condivisi con l'autrice da CHIMEC S.p.A., azienda partner di TEA SISTEMI, impegnata nella progettazione e produzione di additivi per il settore petrolifero e del gas.The phenomenon of permeability reduction in the zone near a well (called formation damage or scaling) is a well-known problem in oil & gas and geothermal energy industry. Precipitation of dissolved species (such as calcite, dolomite, asphaltene, paraffin, etc.) can result in formation damage and failure in production during processing of the reservoir. Damage in the subsurface formation caused by organic and inorganic precipitation decreases the porosity and permeability, eventually reducing the production rate. When the flow pathways and pore spaces are plugged, fluid flow decreases substantially resulting in loss of efficiency in the reservoir exploitation. Quite frequently larger pumps need to be installed or the operation period is extended to meet demand.
A possible solution to this problem consists in stopping the production followed by the injection of inhibiting species that slow down the precipitation process. Inhibitor injection is widely used and is an effective method to prevent the precipitation which provides a reliable long-term protection against formation scaling.
In this thesis, the focus is given to the mineral precipitation. A mathematical model is built to express the precipitation and the corresponding inhibition process, starting from classical model formulations proposed in the literature. Sensitivity analysis is performed with various values for saturation index of precipitating mineral and inhibitor properties to test the efficiency of the inhibiting species. The efficiency is determined by adsorption and desorption properties of the inhibitor, and its concentration in the injection fluid.
Two scenarios, namely, normal production and production with inhibitors are compared. As the key output the pressure in the well-bottom is monitored. Well-bottom pressure decreases as a result of permeability damage by the precipitation, and from the simulation it is obtained that during the production with the inhibitor this decrease is slower with respect to the normal production, which allows longer exploitation of the reservoir.
The objectives of this work were suggested by the company TEA SISTEMI S.p.A., which hosted the thesis internship. Laboratory and field data are shared with the Author by CHIMEC S.p.A., a partner of TEA SISTEMI, a company designing and producing additive for the oil & gas sector
MyFutures: Imagining speculative care and support futures in The Netherlands
No full textIn many Western societies, decisions about leaving home and spending your last years in a care home are often taken suddenly. Immediate health issues force family, friends and neighbours who offer informal support to ask for immediate formal support. Such urgent situations do not lead to the best solutions.Design Conceptualization and Communicatio
Kohliella anula Pulawski. We 1991
No full textKohliella anula Pulawski, 1991 (Figs 1–9) Kohliella anula Pulawski 1991:295, ♀, ³. Holotype: ♀, Sri Lanka: Mannar District: 0.8 km northeast of Kokmotte in Wilpattu National Park at about 8°32’N 80°02’E (NMNH). Material Examined. 2 ³, INDIA: Kerala, Kannur district, Kannapuram (11°58’45.768’’N, 75°18’25.884’’E), 17.iii.2019, Coll. C. Charesh, ZSIK Regd. Nos. ZSI/ WGRC /IR/INV/14903 & 14904. Comparison with Sri Lankan Specimens.The Indian specimens agree well with the original description (Pulawski 1991), except in the male examined, the apical sternum is only slightly pointed apically (Fig. 9), whereas in the Sri Lankan male the apical sternum has a prominent apical point. This minor difference seems to be due to individual difference in geographically separated populations. We are grateful to Dr. Kailash Chandra, Director, Zoological Survey of India, Kolkata for providing facilities and encouragements. We thankfully acknowledge C. Charesh, Laboratory Assistant, Western Ghat Regional Centre, Zoological Survey of India, Kozhikode for collecting this rare specimens. Authors thank the authorities at Smithsonian National Museum of Natural History of Washington DC, USA for the digital image of holotype of Kohliella anula Pulawski. We also thankful to Dr. W. Pulawski, California Academy of Sciences, San Francisco, USA, for editing the first version of the manuscript, Dr. Yuriy Danilov, subject editor (Apoid Wasps) and two anonymous reviewers for their valuable and helpful comments on the manuscript. The first author is also thankful to UGC for providing financial support and the authorities of University of Calicut for providing facilities and encouragements.Published as part of Mawadda, N. V. Ayisha, Kumar, P. Girish & Sureshan, P. M., 2020, First report of the genus Kohliella Brauns, 1910 (Hymenoptera: Crabronidae Crabroninae) from India with the species K. anula Pulawski, 1991 from Kerala, pp. 148-150 in Zootaxa 4890 (1) on page 148, DOI: 10.11646/zootaxa.4890.1.10, http://zenodo.org/record/430153
A Study of Two Nationalistic Puerto Rican Compositions: Hector Campos Parsi's Sonatina No. 2 for Violin and Piano, and Jack Delano's Sonata for Violin and Piano
No full textabstract: Puerto Rican composers Hector Campos Parsi (1922-1998) and Jack Delano (1914-1997) form an integral part of the nationalistic school of composition that revolutionized the island during the mid to late twentieth century. They both sought to combine Western Classical composition techniques with folkloric and traditional musical elements from Puerto Rico. In doing so, not only did they transform the way Western Classical music was made on the island, but they also brought validation and recognition to Puerto Rico’s culture as well as folkloric and popular musical heritage. Furthermore, both of these composers wrote works for violin and piano that form an important part of Puerto Rico’s musical legacy.
This research document presents biographical studies of both composers, as well as studies of Hector Campos Parsi’s Sonatina No. 2 for Violin and Piano, and Jack Delano’s Sonata for Violin and Piano. In addition, this document includes the first ever printed edition of Jack Delano’s Sonata for Violin and Piano, as well as a copy of the out of print Peermusic edition of Campos Parsi’s Sonatina No. 2 for Violin and Piano. This document also presents detailed charts of discrepancies and corrections to both scores.
With the gathering and presentation of this biographical and musical information, this research document seeks to bring international recognition to two important Puerto Rican nationalistic composers, Hector Campos Parsi and Jack Delano; spark an interest in their two little-known works for violin and piano (Campos Parsi’s Sonatina No.2 for Violin and Piano and Jack Delano’s Sonata for Violin and Piano); as well as make these two works more accessible to performers, educators, and the general public alike.Dissertation/ThesisDoctoral Dissertation Music 201
Liberal theory and Islam: (re)imagining the interaction of religion, law, state and society in Muslim contexts
No full textWithin the global phenomenon of the (re)emergence of religion into issues of public debate, one of the most salient issues confronting contemporary Muslim societies is how to relate the legal and political heritage that developed in pre-modern Islamic polities to the political order of the modern states in which Muslims now live.
This study seeks to develop a framework for addressing this issue by drawing upon two sources. The first is an interpretative understanding of the history of Muslim contexts emphasising, in particular, the diversity of views about what Islam mandates that have always been a part of Muslim experience and the distinction between political and religio-legal authority that developed in practice in these environments. The second source is a variety of contemporary liberal theory which this study develops and calls ‘justice as discourse’.
The central argument is that liberal theory, and justice as discourse in particular, though it may have emerged in a different social and cultural milieu, can be normatively useful in Muslim contexts for relating, religion, law, state and society. It is argued first, that Muslim contexts are facing issues similar to those out of which liberal theory emerged. Additionally, it is argued that both Muslim contexts and liberal theory are dynamic and continually developing and that this shared dynamism means that there may be space for convergence of the two. Just as Muslim contexts have developed historically (and continue to develop today) the same is the case with the requisites of liberal theory and this may allow for liberal choices to be made in a manner that is not a renunciation of Muslim heritage
