Green Imaging Technologies offers a patented, exclusive NMR capillary pressure (Pc) measurement called GIT-CAP. Capillary pressure is a critical parameter for the oil exploration and production industry and is a common measurement performed in core analysis laboratories worldwide. However, traditional techniques for measuring capillary pressure such as porous plate, centrifugation and mercury injection are laborious, time consuming and expensive.
The GIT-CAP method directly measures the water saturation distribution down the core plug after centrifugation using a one-dimensional NMR profile. This allows users to collect 30-40 data points per spin. This technique is as accurate as porous plate and is five times faster than traditional centrifuge capillary pressure measurements.
The advantages to the GIT-CAP method of capillary pressure measurement include:
- Data rich
- Highly accurate
- Up to 10 times faster than other methods of measuring Pc
- Non-destructive
- Does not require the use of any dangerous chemicals
- Direct measurement, not modelled
The GIT-CAP NMR capillary pressure measurement has several advantages over more traditional methods for the measurement as are shown in the table below.
| GIT-CAP Advantages | |
|---|---|
| Mercury Injection | Uses representative fluids Non-destructive Direct measurement Simpler sample handling procedures |
| Traditional Centrifuge | Speed (GIT-CAP takes days, centrifuge takes weeks) Accuracy/more data (GIT-CAP provides 30-40 data points per centrifuge speed) Simpler centrifuge set-up (no costly upgrades required) |
| Porous Plate | Speed (GIT-CAP takes days, porous plate takes weeks or months) More data points |
Capillary pressure measurements using the GIT-CAP method are substantially faster than those made by traditional techniques, particularly for low permeability samples with longer equilibrium times. They also provide significantly more data points, allowing more accurate prediction of additional parameters, such as pore throat distributions, wettability, and relative permeability. With the inherent time and accuracy advantage, the GIT-CAP NMR measurement can help laboratories increase their sample throughput without sacrificing accuracy.
GIT Systems Advanced software allows users to perform the patent protected GIT-CAP capillary pressure measurement on a gradient enhanced GeoSpec NMR instrument. Various field strengths can be used. Contact our sales team to find out more information about our NMR software and hardware products.
More detailed information on how GIT-CAP works can be found in the application note entitled Rapid Non-destructive Capillary Pressure Measurements with NMR.