Jadwiga Jarzyna

X-ray computed microtomography—a useful tool for petrophysical properties determination

The main goal of the research was to employ the unique data delivered by various methods to improve the determination of rock reservoir properties. Results of X-ray computed tomography (XRCMT), one of the newest techniques providing high-resolution images of rocks, were used to show that very precise information from this tool is complementary to results from other methods. Standard laboratory measurements (helium pycnometer, mercury injection porosimetry, permeameter) and sophisticated experiments (X-ray computed tomography and nuclear magnetic resonance spectroscopy) were performed to obtain and compare results. Four types of specimens: typical Miocene sandstone-mudstone-claystone rock samples, artificial corundum specimens, shale gas plugs, and limestone sample were investigated to obtain the porosity, permeability, density, and other parameters used in rock descriptions. Mutual relationships between selected groups of rock material properties were presented to provide an integral picture of rock characteristics. The XRCMT results were in general not influenced by lithology, but there were observed shaliness effects on the shape of pores, cross sections, and the tortuosity of porous channels. An analysis of the average porosity and the standard deviation of each XRCMT plot provided information about differences in the heterogeneity of a formation. Thus, the XRCMT method was recommended in pore space parameter determination for microfracture fluid propagation monitoring. There was also observed equivalence between part of the NMR signal from clay-bound water and the XRCMT volume subgroups in porosity/permeability—structural classes I and II. So, the use of the two-subsample approach in the XRCMT interpretation was promoted.

Rock Reservoir Properties from the Comprehensive Interpretation of Nuclear Magnetic Resonance and Mercury Injection Porosimetry Laboratory Results

AbstractCombination of laboratory measurements res ults of various properties, i.e. porosity, density, permeability and mineral composition, was done to get additional factors useful in fluid flow description in the Miocene sandy-shaly formation. Special computer processing of nuclear magnetic resonance outcomes and mercury injection porosimetry results turned out to be useful in the estimation of the relationships facilitating the reservoir characterization and defining new helpful factors. Determination of the relationships between groups of quantities describing pore space of rock formation was presented as the basis for permeability prediction and for relationships extrapolation into interesting areas.

New Methods for Modeling Laterolog Resistivity Corrections

The paper presents methods for laterolog response modeling. In Coulomb’s charges method, Laplace’s equation is solved for the electric field distribution in rock medium with internal boundaries between different resistivity layers. There, the boundary problem is reduced to Fred-holm integral equation of the second kind. The second method uses a finite element array to model apparent resistivity from laterolog. The task is treated as DC problem and the Laplace equation is solved numerically. The presented methods were applied to borehole data covering a typical stratigraphie section of the Fore-Sudetic Monocline in southwestern Poland. Apparent resistivity was calculated using the Coulomb’s charges method and alternatively modeled using a finite element method which gave similar results. Then, a series of linear corrections for borehole, shoulder bed, and filtration effects for apparent resistivity obtained by the Coulomb’s charges method demonstrated the feasibility of calculating true resistivity of virgin and invaded zones. The proposed methods provide a flexible solution in modeling which can be adapted to other logs.

Elastic Parameters of Rocks from Well Logging Even in Near Surface Sediments

Results of the computer program FalaFWS for processing and interpretation of acoustic full waveforms in deep and shallow rock formations are presented. The goal of the paper is to show a possibility of obtaining correct values of elastic properties of shallow formations on the basis of acoustic waveforms recorded with standard device. Results of measurements with a device constructed for deep wells and results of data interpretation using computer program written for that device provide an interpreter with correct values of dynamic elastic parameters in shallow, poorly consolidated rocks. Field examples are given to confirm the presented analysis.