GIT Systems Version 11
Advanced NMR Rock Core Analysis Software

GeoSpec

GIT Systems Version 11 introduces a major update to the user interface,presenting users with an intuitive and configurable experience. Version 11
also provides improved performance and responsiveness, particularly whenworking with large datasets or computationally intense measurements.
New Measurements
This latest version of the GIT Systems software
suite adds several new measurements. The
highlights of these additions will be discussed
below.

Variable Tau CPMG
This innovative CPMG pulse sequence
addresses the problems of sample heatingsometimes seen during intensive T2 encoded
sequences, such as T1- T2 correlation maps,diffusion- T2 correlation maps, spatial T2 andothers. In higher field instruments (12 MHz +) RF
heating during signal intensive measurements
can heat a sample by 10° to 100° C. The
variable tau CPMG sequence reduces theThe GIT Systems user interface has been updated to allow users to efficiently create
and view their data with scalable, user defined window layout and clear, intuitive
colour schemes and layouts.

amount of Radio Frequency (RF) power going
into the sample by limiting the number of
refocusing RF pulses to a constant 512, andthen varying the timing of the pulse train
so that the same range of T2 values can beintegrated. Reducing RF heating is importantbecause localized heating in samples
during measurements such as a T2-diffusion
map creates thermal currents which candramatically affect the results, as shown in thefigure to the right .

In the figure above, the NMR volume of a brine saturated sandstone is calculated
from a CPMG experiment repeated many times. The volume drops by 7% using theconventional CPMG train (blue). The red line is using the variable tau CPMG sequence.

GIT Systems Version 11
Advanced NMR Rock Core Analysis Sotware

GeoSpec

3D T1-T2-Diffusion Map

2D Slice Selection

Taking the popular 2D correlation maps to the next level,

Users looking to select slices of data along

this 3D map adds a third value to the correlation. A user can

a 2D measurement can now do so for images acquired

select T1- T2 correlation maps of specific diffusion values.

using FSE, SPRITE or SE-SPI pulse sequences. The resolution

For example, this would allow users to produce a T1- T2of the 2D images has been increased by reducing thecorrelation map of just the oil signal. A processing tool isaveraging over the third dimension.

available to allow users to select the diffusion values on acollapsed T2-Diffusion map, then plot the T1- T2 map fromthe selected values.

Saturation Recovery T1-T2 Maps
To reduce the acquisition times for T1 - T2 correlation maps,
the option is now available to use a saturation recovery
method instead of the inversion recovery. For example, a30-step inversion recovery T1 - T2 correlation map with 16
averages and a maximum T1 and T2 of 500ms takes 43
minutes. The same measurement with the same parameters
but using saturation recovery takes just 24 minutes.

Inversion Recovery Spin Echo T1
For samples with high ferrite content (thus short T2*),
traditional free induction decays are too short to acquire
adequate T1 data following inversion recovery. Users can
now use a spin echo inversion recovery to acquire adequate
signal for a T1 measurement.

Subtraction of 2D and 3D images
During EOR studies, users often wish to examine the effectsof surfactant floods and other rock matrix alterations. This
examination is made easier with the ability to subtract before
The figure above shows an example of the T1-T2-Diffusion 3D mapinterface.

and after images to note the changes between the two.

Reprocessing of Spatially Resolved T1 or T2

New Wettability Models
These new models give users the ability to performwettability modelling from either T2 or T1- T2 measurements.
The T2 method is based on Looyestijn’s method, while the T1- T2 method is based on the Valori method. Unlike wettability

Examination of spatially resolved relaxation data often
requires changing inversion parameters to look at the effectsof different parameters. The ability to reprocess relaxation
data with varying parameters makes this examination easier.

models from other technologies, NMR wettability tracking is
non-destructive, allowing for wettability monitoring during asingle flood (or Enhanced Oil Recovery (EOR) process).

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