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DTSTART:20160407T090000
DTEND:20160407T100000
SUMMARY:CERE-seminar
DESCRIPTION:<h2 style="text-align: center;"><span style="color: rgb(0, 112, 192);">&ldquo;Wettability of chalk and argillaceous sandstones assessed from T<sub>1</sub>/T<sub>2</sub> ratio&rdquo;</span>\n</h2>\n<h2>\n</h2>\n<h2>\n</h2>\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\n<br>\n<p style="text-align: center;"><strong>By</strong></p>\n<h2 style="text-align: center;">Konstantina Katika</h2>\n<p style="margin: 0cm 0cm 0pt; text-align: center;"><strong>&nbsp;</strong></p>\n<p style="margin: 0cm 0cm 0pt;"><strong>&nbsp;</strong></p>\n<p style="margin: 0cm 0cm 0pt;"><strong>Abstract:</strong></p>\n<p style="margin: 0cm 0cm 0pt;">&nbsp;</p>\n<p style="margin: 0cm 0cm 0pt; text-align: justify;"><span>Low field nuclear magnetic resonance (NMR) relaxation of the fluids inside the porous rock is the result of bulk and surface relaxation of the protons inside the pore fluid. Bulk relaxation is a fluid property when the solid-fluid interaction is minimized; and surface relaxation is the result of the solid-fluid interaction and is related to the mineral properties. Thus, longitudinal, <em>T1</em>, and transverse, <em>T2</em>, relaxation times should in principle be similar. However, microscopic magnetic gradients related to minerals can shorten <em>T2 </em>relaxation times as compared to <em>T1 </em>relaxation times provided the saturating fluid has high affinity to the solid. We consequently find that the <em>T1</em>/<em>T2 </em>ratio can quantify the affinity between the rock and wetting pore fluid. </span>The affinity is a measure directly linked to wettability. </p>\n<p style="margin: 0cm 0cm 0pt; text-align: justify;"><span>In order to investigate the <em>T2</em>-shortening, we performed <em>T1</em>-<em>T2 </em>maps NMR experiments on different samples of chalk, Berea sandstone, and chloritic greensand, saturated either with water, oil or oil/water at irreducible water saturation. The <em>T1</em>/<em>T2 </em>ratio obtained from <em>T1</em>-<em>T2 </em>maps reflects the <em>T2 </em>shortening, so we compare the <em>T1</em>/<em>T2 </em>ratio for the same type of rock, saturated with different fluids. The chalk shows high affinity for water, Berea sandstone has no clear preference for oil and water whereas chloritic greensand shows different behaviour for small and large pores as defined in the MICP throat size distribution. Small pores (fast relaxing components) have (<em>T1</em>/<em>T2</em>=2.0) when water saturated, but (<em>T1</em>/<em>T2</em>=3.8) when oil saturated indicating oil-affinity. By contrast large pores (slow relaxing components) have significant preference for water (<em>T1</em>/<em>T2 </em>= 2.2) as compared to oil (<em>T1</em>/<em>T2</em>=1.2-1.4).</span></p>
X-ALT-DESC;FMTTYPE=text/html:<h2 style="text-align: center;"><span style="color: rgb(0, 112, 192);">&ldquo;Wettability of chalk and argillaceous sandstones assessed from T<sub>1</sub>/T<sub>2</sub> ratio&rdquo;</span>\n</h2>\n<h2>\n</h2>\n<h2>\n</h2>\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\n<br>\n<p style="text-align: center;"><strong>By</strong></p>\n<h2 style="text-align: center;">Konstantina Katika</h2>\n<p style="margin: 0cm 0cm 0pt; text-align: center;"><strong>&nbsp;</strong></p>\n<p style="margin: 0cm 0cm 0pt;"><strong>&nbsp;</strong></p>\n<p style="margin: 0cm 0cm 0pt;"><strong>Abstract:</strong></p>\n<p style="margin: 0cm 0cm 0pt;">&nbsp;</p>\n<p style="margin: 0cm 0cm 0pt; text-align: justify;"><span>Low field nuclear magnetic resonance (NMR) relaxation of the fluids inside the porous rock is the result of bulk and surface relaxation of the protons inside the pore fluid. Bulk relaxation is a fluid property when the solid-fluid interaction is minimized; and surface relaxation is the result of the solid-fluid interaction and is related to the mineral properties. Thus, longitudinal, <em>T1</em>, and transverse, <em>T2</em>, relaxation times should in principle be similar. However, microscopic magnetic gradients related to minerals can shorten <em>T2 </em>relaxation times as compared to <em>T1 </em>relaxation times provided the saturating fluid has high affinity to the solid. We consequently find that the <em>T1</em>/<em>T2 </em>ratio can quantify the affinity between the rock and wetting pore fluid. </span>The affinity is a measure directly linked to wettability. </p>\n<p style="margin: 0cm 0cm 0pt; text-align: justify;"><span>In order to investigate the <em>T2</em>-shortening, we performed <em>T1</em>-<em>T2 </em>maps NMR experiments on different samples of chalk, Berea sandstone, and chloritic greensand, saturated either with water, oil or oil/water at irreducible water saturation. The <em>T1</em>/<em>T2 </em>ratio obtained from <em>T1</em>-<em>T2 </em>maps reflects the <em>T2 </em>shortening, so we compare the <em>T1</em>/<em>T2 </em>ratio for the same type of rock, saturated with different fluids. The chalk shows high affinity for water, Berea sandstone has no clear preference for oil and water whereas chloritic greensand shows different behaviour for small and large pores as defined in the MICP throat size distribution. Small pores (fast relaxing components) have (<em>T1</em>/<em>T2</em>=2.0) when water saturated, but (<em>T1</em>/<em>T2</em>=3.8) when oil saturated indicating oil-affinity. By contrast large pores (slow relaxing components) have significant preference for water (<em>T1</em>/<em>T2 </em>= 2.2) as compared to oil (<em>T1</em>/<em>T2</em>=1.2-1.4).</span></p>

URL:https://www.cere.dtu.dk/calendar/2016/04/cere-seminar-by-konstantina-katika
DTSTAMP:20260517T170800Z
UID:{11FE394A-51C8-4A00-AADD-04EBE43908D2}-20160407T090000-20160407T090000
LOCATION: Building 229, room 003
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