Advanced NMR core analysis software
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 when working 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 heating sometimes seen during intensive T2 encoded sequences, such as T1- T2 correlation maps, diffusion- T2 correlation maps, spatial T2, and others. 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 the amount of Radio Frequency (RF) power going into the sample by limiting the number of refocusing RF pulses to a constant 512 and then varying the timing of the pulse train so that the same range of T2 values can be integrated. Reducing RF heating is important because localized heating in samples during measurements such as a T2-diffusion map creates thermal currents which can dramatically affect the results, as shown in the figure to the right.
2D Slice Selection
Users looking to select slices of data along a 2D measurement can now do so for images acquired using FSE, SPRITE, or SE-SPI pulse sequences. The resolution of the 2D images has been increased by reducing the averaging over the third dimension.
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, a 30-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.
New Wettability Models
These new models give users the ability to perform wettability modeling 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 models from other technologies, NMR wettability tracking is non-destructive, allowing for wettability monitoring during a single flood (or Enhanced Oil Recovery (EOR) process).
3D T1-T2 Diffusion Maps
Taking the popular 2D correlation maps to the next level, this 3D map adds a third value to the correlation. A user can select T1- T2 correlation maps of specific diffusion values. For example, this would allow users to produce a T1- T2 correlation map of just the oil signal. A processing tool is available to allow users to select the diffusion values on a
collapsed T2-Diffusion map, then plot the T1- T2 map from the selected values.
Subtraction of 2D & 3D Images
During EOR studies, users often wish to examine the effects of surfactant floods and other rock matrix alterations. This examination is made easier with the ability to subtract before and after images to note the changes between the two.
Reprocessing of Spatially Resolved T1 or T2
Examination of spatially resolved relaxation data often requires changing inversion parameters to look at the effects of different parameters. The ability to reprocess relaxation data with varying parameters makes this examination easier.