A key input for log evaluation is the measurement and interpretation of the Archie parameters for formation resistivity, 'm' and 'n'. The relationships between the resistance of the rock and porosity or brine saturations can be determined in our laboratory.

PanTerra can measure capillary pressure by porous plate method, air-mercury (HPMI) or ultra-centrifuge. Capillary pressure is measured on core plugs and can be used to: 1. Evaluate reservoir rock quality, pore throat size distributions and wetting characteristics; 2. Predict fluid saturations in the reservoir vs. height; 3. Estimate the thickness of the transition zone; 4. Quantify sealing capacity of overlying rock;

Wettability tests can be performed on fresh / native, clean and restored state core samples, at ambient or elevated temperatures. The different methods available are: Amott wettability: relies on spontaneous imbibition of the wetting fluid. From this, the Amott-Harvey Displacement Index is calculated to express wettability with a single number. The Amott wettability test is insensitive near neutral wetting conditions. USBM: measures the wettability by determination of drainage and imbibition multi-speed capillary pressure curves using an ultra-centrifuge. Comparison of the areas under the drainage and imbibtion Pc curves gives an insight of the wettability characteristics. This technique is more sensitive for neutral wetting conditions.

The main application for doing NMR analysis on rock samples is to calibrate the downhole NMR logs and to obtain total and effective porosities. Other petrophysical information such as pore size distributions, effective porosity, capillary bound water, clay bound water, drilling mud invasions studies and monitor fluid redistribution during wettability restoration/aging can be extracted.

Various methods to determine relative permeability curves are available. These tests are often complex and there is no single best method. Depending on lithology, rock properties and budget, PanTerra can recommend an analytical program suitable for your samples. Methods available: Unsteady-state relative permeability by core flooding or centrifuge.

Our test setup can apply axial and radial stress of up to 10,000 psi on the sample. The transducers, with frequency responses of nominal 590-700 kHz, are used in conjunction with a matching CNS PUNDIT system, which provides the pulse excitation and a digital timing unit with a resolution of up to 0.1msec and a digital oscilloscope with a time-axis resolution of up to 0.0625 msec.