True porosity

SWS are useful to obtain direct indications of hydrocarbons (under UV light) and to differentiate between oil and gas. The technique is applied extensively to sample microfossils and pollen for stratigraphic analysis (age dating, correlation, depositional environment). Qualitative inspection of porosity is possible, but very often the sampling process results in a severe crushing of the sample thus obscuring the true porosity and permeability. 

If the two porosities match, the formation is saturated with a liquid, water or oil, and the porosities are true porosities. 

If the neutron porosity is low and the density porosity is high, the formation contains gas and the true porosity can be determined with charts. 

Since the true porosity has been determined, formation water saturation can be determined by... 

The true porosity <1> is determined with the neutron-density Pe logs. R is generally given by the deep investigation resistivity curve. R equals R, in the water formations. It increases rapidly in hydrocarbon saturated formations. 

A high neutron porosity and low density porosity occur in the shale zones 2256-2274 and 2356-2388 ft. In the clean zone, around 2280-2290 ft, the cleanest part reads = 18% and = 13%. Plotting the point in the CNL chart of Figure 4-303, the rock matrix appears to be a dolomitized limestone and the true porosity is 17%. 

Oxide Powder liquid, gcm Wet compressive Strain at failure, % True porosity, %... 

Figure 17.17 Evaluation of the separation area of the Troger s base enantiomers. Solid line Anal5Ttical Solution with the Henry coefficients derived from the analytical chromatograms. Dashed line Analytical Solution with the Best Fit Langmuir Isotherm Data. Symbols +, calculated Umits of the separation area based on the correct isotherm and the true porosity of each column o calculated limits of the separation area based on the average column porosity experimental conditions of the experiments performed. K. Mihlbachler, A. Seidel-Morgenstem, G. Guiochon, AlChE J., 50 (2004) 611 (Fig. 6). Reproduced by permission of the American Institute of Chemical Engineers. 1997 AlChE. All rights reserved.

ISO 5016 1997 Shaped insulating refractory products - determination of bulk density and true porosity... 

True Porosity. The ratio of the total volume of the open and sealed pores to the bulk volume, expressed as a percentage. 

True Porcelain, hard porcelain (q.v.). True Porosity. See under porosity. 

The apparent porosity, which is the ratio of the volume of the open pores to the bulk volume (expressed as a percentage), is of importance in that it gives an indication of the resistance of the refractory to attack by liquid and gaseous phases. The sealed pores — which together with the open pores constitute the true porosity -are not very important from the viewpoint of performance of the material. 

BS 1902-3.8. Determination of bulk density, true porosity and apparent porosity of dense shaped products (method 1902-308). 

BS EN 993-1 1995, BS 1902-3.8 1995. Methods of test for dense shaped refractory products. Determination of hulk density, apparent porosity and true porosity. 

The definition for an unshaped refractory is given in ISO 1927 (5) and EN 1402-1 It is a mixture, which consists of an aggregate and a bond or bonds, prepared ready for use either directly in the condition in which it is supplied or after the addition of a liquid that satisfies the requirements on refractoriness given in ISO R 836. They may contain metallic, organic, or ceramic fiber material. This mixture is either dense or insulating. An insulating mixture is one whose true porosity is not less than 45% when determined in accordance with EN 1094-4, using a test piece prefired to specified conditions. 

True porosity is then calculated from the results of the evacuation and pycnometer methods ... 

Bulk density/ apparent porosity/true porosity... 

A dried sample is required to carry out MIP measurements. Drying methods are known to modify the porosity as it exists in nondried samples. Thus, the users should keep in mind that MIP porosity might not exactly reflect the true porosity of cementitious materials. 

---