T1 and T2 correlation for fluid typing and quantification

Application Note 4

In recent years, lab based NMR core analysis researchers have begun to take advantage ofenhanced signal-to-noise ratios (SNR) and shorter tau values to implement more data richmeasurement techniques. In the past, extremely long acquisition times for T1-T2 maps, orcorrelation plots, made them next to impossible to obtain. Current SNR levels have eliminated thislimitation and have allowed researchers to begin exploring what can be learned from these maps.
Here, we show how T1-T2 maps can be used to differentiate(Figure 1, left panel). The samples were then placed in

fluids with different viscosities. We demonstrate howbrine under 2,000 psi of pressure for 48 hours to fullywater and bitumen can be discriminated with T1-T2 maps

saturate the samples and the inversion recovery CPMG T1-T2

in representative shale formations. Further, we show how

measurements were repeated. (Figure 1, center panel). All

measuring T1 and T2 at different temperatures allows us tomeasurements were performed on an Oxford Instruments

differentiate between components of varying viscosity.

GeoSpec2 2/75 2 MHz spectrometer with a 40 mm probe.
The as received T1-T2 measurement was then subtracted fromMethod

the fully saturated T1-T2 measurement to give the net T1-T2

Initial inversion recovery CPMG T1-T2 measurements weremeasurement (Figure 1, right panel).

obtained on six shale samples in the as received state.
Figure 1: T1-T2 maps of shale core in various conditions

As received

Fully saturatedNetT1 and T2 correlation for fluid typing and quantification

ResultsThe T1/T2 ratio can be used todetermine the origins of the signal innet T1-T2 maps [1]. In fluids with lowviscosities, T1 and T2 are similar, but
as viscosity increases T1 and T2 will
deviate [2]. Higher ratios indicate moreviscous materials such as bitumen
while lower ratio contributions arelikely due to water. In the T1-T2 mapsof Figure 1, high signal intensity is red
while low intensity is shown in blue.
The white diagonal line represents aT1/T2 ratio of 1:1.

Temperature studies
Solid Wax
An initial measurement was taken ona solid wax sample at 35ºC. Figure 2shows T1-T2 maps of wax at different
temperatures. The T1-T2 map shows signal
at a high T1/T2 ratio indicating a highly
viscous material. When the sample washeated to 45ºC the signal spread to lower
T1/T2 ratios. At a temperature of 70ºC the35ºC

sample was liquefied and the signal waspresent around the 2:1 line.
Figure 2: T1-T2 maps of wax
at various temperatures.

45ºC.

70ºC

Application Note 4Ozocerite
Figure 3 shows similar studies performed on ozocerite, a naturally occurring bitumen. At 35ºC, signal
appeared along the 20:1 line and at 70ºC an extended signal area appeared near the 1:1 line. When thematerial becomes less viscous the T1/T2 ratio shifts to lower values.
Figure 3: T1-T2 maps of ozocerite at various temperatures.

35ºC.

70ºC

T1 and T2 correlation for fluid typing and quantification

Figure 4: T1-T2 maps of shale atvarious temperatures.

Further temperature studies
were performed on a groupof eight shale samples. Aswith the previous studies, T1-T2Oxford Instruments Magnetic Resonance
For more information: magres@oxinst.com
www.nmr.oxinst.com

maps were acquired but inUK

this study the temperatures

Tubney Woods, Abingdon, Oxfordshire, OX13 5QX, UK

were 350C, 650C, and 1100C.

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Figure 4 shows a representative
shale sample at these three

35ºC

Application Note 4USA

temperatures. In the top panel,

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we see the results at 350C

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with the bitumen populations
appearing in the 10:1 to 100:1
ratio range and the water peak

China
Floor 1, Building 60, No.461, Hongcao Road,nearer the 1:1 ratio line. InShanghai, 200233, China

the middle panel, the results at

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650C are shown. The two peaks
begin to separate but show
very little change. At 1100C,(bottom panel) the water has

65ºC

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drying. The bitumen peak also

Canadadecreases, moving towards

520 Brookside Drive, Suite B, Fredericton, NB, E3A 8V2,

change in viscosity.
References[1] E. Rylander, P. M. Singer, T. Jiang, R.
Lewis, R. McLin, S. Sinclair, SPE-164554(2013).
[2] N. Bloembergen, E. M. Purcell and R.
V. Pound, Nature, 160, 475-476 (1947).

4567

For more information: info@greenimaging.com

begun to dissipate indicating

the 1:1 ratio line, indicating a110ºC

Green Imaging Technologies[3] Ali Tinni, 2013, personalcommunication. Work was supportedby the Unconventional Shale Gas
Consortium at the Mewbourne
School of Petroleum and GeologicalEngineering, the University ofOklahoma.

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