Abstract
Direct 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 0.015m2/g to 0.5m2/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.
