<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0122-5383</journal-id>
<journal-title><![CDATA[CT&F - Ciencia, Tecnología y Futuro]]></journal-title>
<abbrev-journal-title><![CDATA[C.T.F Cienc. Tecnol. Futuro]]></abbrev-journal-title>
<issn>0122-5383</issn>
<publisher>
<publisher-name><![CDATA[Instituto Colombiano del Petróleo (ICP) - ECOPETROL S.A.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0122-53832021000200017</article-id>
<article-id pub-id-type="doi">10.29047/01225383.366</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[LOW FIELD NMR AS AN ALTERNATIVE TECHNIQUE TO ESTIMATE OF DENSITY AND VISCOSITY IN TOLUENE-HEAVY OIL MIXTURES]]></article-title>
<article-title xml:lang="es"><![CDATA[RMN DE BAJO CAMPO COMO UNA TÉCNICA ALTERNATIVA PARA ESTIMAR LA DENSIDAD Y VISCOSIDAD EN MEZCLAS DE TOLUENO-ACEITE PESADO]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sandoval M]]></surname>
<given-names><![CDATA[María]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Valderrama P]]></surname>
<given-names><![CDATA[Herin]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sánchez M]]></surname>
<given-names><![CDATA[Miranda]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Molina V]]></surname>
<given-names><![CDATA[Daniel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Muñoz N]]></surname>
<given-names><![CDATA[Samuel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Grupo de investigación Recobro Mejorado, Escuela de Petróleos  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Industrial de Santander  ]]></institution>
<addr-line><![CDATA[Bucaramanga ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2021</year>
</pub-date>
<volume>11</volume>
<numero>2</numero>
<fpage>17</fpage>
<lpage>26</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0122-53832021000200017&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0122-53832021000200017&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0122-53832021000200017&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[ABSTRACT The success of low field Nuclear Magnetic Resonance (LF-NMR) to estimate heavy oil properties depends on a good selection of mathematical models and fitting parameters. Since the correlations proposed are not universally applicable, in this study, a NMR published model was chosen and tuned to determine the density and viscosity of several mixtures of a Colombian heavy oil with toluene. The process began by mixing toluene with heavy oil to obtain several measuring points with properties similar to those of heavy oils. Each mixture was taken to a 7.5 MHz spectrometer at 40°C, where NMR parameters were acquired and used in the five pre-selected mathematical models. The reliability of viscosity measurements was analysed with the root mean square error (RMSE) and maximum absolute error (MAE). After the NLS regression process, the most accurate prediction was reached through the Burcaw model, with RMSE values of 40.55 cP. On the other hand, the density was estimated with the Wen correlation with results showing a relative error percentage of less than 1%. According to such error values, the tuned models are considered a starting point to extend the NRM technique use to other Colombian heavy oils with low uncertainty levels.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN El éxito de la RMN para estimar las propiedades del petróleo pesado depende de una buena selección de los modelos matemáticos y los parámetros de ajuste. Dado que las correlaciones propuestas no han resultado ser de aplicación universal, en el estudio actual, se eligió un modelo de RMN publicado y se ajustó para determinar la densidad y viscosidad de varias mezclas de un a crudo pesado colombiano con tolueno. El proceso comenzó mezclando tolueno con el crudo pesado para obtener varios puntos de medición con propiedades similares a los crudos pesados. Cada mezcla se llevó a un espectrómetro de 7,5 MHz a 40 ° C, donde se adquirieron los parámetros de RMN y se emplearon en los cinco modelos matemáticos preseleccionados. La contabilidad de las mediciones de viscosidad se analizó con la raíz del error cuadrático medio (RMSE) y el error absoluto máximo (MAE). La predicción más precisa se alcanzó con el modelo de Burcaw, después del proceso de regresión NLS, con valores de RMSE de 40,55 cP. Por otro lado, la densidad se estimó con la correlación de Wen y los resultados mostraron un porcentaje de error relativo menor al 1%. De acuerdo con esos valores de error, los modelos ajustados en este trabajo se consideran un punto de partida para extender el empleo de la técnica NRM a otros petróleos pesados de Colombia con bajos niveles de incertidumbre.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[NMR]]></kwd>
<kwd lng="en"><![CDATA[Heavy oil]]></kwd>
<kwd lng="en"><![CDATA[Liquid solvents]]></kwd>
<kwd lng="en"><![CDATA[Viscosity]]></kwd>
<kwd lng="en"><![CDATA[Density]]></kwd>
<kwd lng="es"><![CDATA[RMN]]></kwd>
<kwd lng="es"><![CDATA[Crudo pesado]]></kwd>
<kwd lng="es"><![CDATA[Solvente líquido]]></kwd>
<kwd lng="es"><![CDATA[Viscosidad]]></kwd>
<kwd lng="es"><![CDATA[Densidad]]></kwd>
</kwd-group>
</article-meta>
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