Petrophysical Properties of a Synthetic Model Rock for Validation of Micro-CT Based Calculation

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDirect calculations of petrophysical properties from micro-CT imaging have been reported in the literature to accurately predict single phase and multiphase flow transport properties respectively. These predictions are usually validated with experimental data available in the literature. The properties of rocks that are usually used (Berea, Benthiemer and Fontainbleau), even though have been assumed to be homogenous but vary in terms of pore pattern. Data from the literature which were obtained from different rock samples may introduce an error if the same rock sample is not used in the micro-CT imaging for direct computations or network model simulations. For proper validation of predictive capability of CT-imaging and its computational techniques with negligible variation, there is need to use porous media with same pore patterns in both CT-imaging and laboratory measurements. This paper presents laboratory measurements made on synthetic model rock (ROBU) with uniform pore patterns. The result from these measurements will be handy for validation of micro-CT based direct computation of petrophysical properties. Petrophysical properties measured in this paper include porosity, permeability and calculated formation resisitivity factors.Four different samples with BET surface area range 0.015m 2 /g to 0.5m 2 /g. were used. The experiments were repeated thrice for reproducibility check.The results from the measurements show the porosity and permeability are in the range of 0.3 to 0.4 and 2.5 to 300 Darcy, respectively for all samples (0, 1, 3 and 4). Formation resistivity factors are in the range of 4.5 to 8.5 for the four samples. The porosity values of all the samples are considered moderate but the permeability values of samples 3 and 4 are comparable to some homogenous model rocks (Kirby and Briarhill sandstones). The results from the measurements show that more reliable and consistent data can be obtained from the synthetic model rocks used. In general, the samples used are said to be homogenous within the limit of experimental error and the data obtained can be used for validation of both direct computations and network model predictions. The use of this synthetic model rock for initial model calibration in studies related to multiphase flow transport properties will give a more realistic, accurate and representative results than the presently used natural occurring model rock.

3D printing sandstone porosity models

“…Recent advances in X-ray CT imaging technology make it possible to reconstruct 3D pore networks by penetrative scanning of rock fragments (Ketcham and Carlson, 2001;Riepe et al, 2011;Lopez et al, 2012;Mohammed et al, 2012;Blunt et al, 2013). Visualization of CT data provides the capability to extract pores and grain matrix selectively and displays them as isosurfaces, which represent 3D contours with constant X-ray attenuation values within a CT volume (Hansen and Johnson, 2005).…”

3D printing porous proxies as a new tool for laboratory and numerical analyses of sedimentary rocks

“…Recent advances in x-ray CT imaging technology make it possible to reconstruct 3D pore networks by using penetrative scanning of rock fragments Riepe et al, 2011;Blunt et al, 2012;Lopez et al, 2012;Mohammed et al, 2012). Visualization of CT data provides the capability to extract pores and grain matrix selectively and display them as isosurfaces, which represent 3D contours with constant x-ray attenuation values within a CT volume (Hansen and Johnson, 2005).…”