DBPapers
DOI: 10.5593/SGEM2016/HB14/S01.011

COMPARISON OF THE EFFICIENCY OF 1H NMR AND µCT FOR DETERMINING THE POROSITY OF THE SELECTED ROCK CORES

A. T. Krzyzak, L. Kaczmarek
Friday 11 November 2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, SGEM Vienna GREEN Extended Scientific Sessions, www.sgemviennagreen.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-80-3 / ISSN 1314-2704, 2 - 5 November, 2016, Book 1 Vol. 4, 81-88pp, DOI: 10.5593/SGEM2016/HB14/S01.011

ABSTRACT

1H low field NMR relaxometry 1D and 2D and μCT techniques were applied for determination of porosity for selected rock cores from oil and gas deposits in Poland. The issue is significant in many geological and geophysical fields of science and industry. The 1H NMR CMPG imaging measurements with a short echo time TE equal to 60 μs were carried out on a 0.05T Low Field NMR scanner. This approach enabled the registration of T1, T2 distribution, T1-T2 maps together with the petrophysical parameters of water saturated and dried rock cores like: PSD - the pore size distribution, total and effective NMR porosities. In addition the different water content types in pores like: (Free Fluid Index (FFI), Bulk Volume Irreducible (BVI), Clay-bound Water (CBW), capillary-bound water) were determined. Appling theoretical models, the NMR PSD was estimated. The T1-T2 maps allowed us to estimate the different types of water mobility in the samples. The porosity changes within the samples were observed due to the T2 relaxation time distribution and μCT calculations. Special attention was focused on the pore size limitation as it was possible to register by both methods.
The second approach was based on an analysis of the variability of X-ray absorption coefficient. The μCT approach enables internal structure analysis with pores distribution in 3-D space. Hence pore and fracture determination can be distinguished. Furthermore different zones of various density can be indicated. According to technical settings of μCT tests the voxel side size is 25 μm. During the study, a tungsten cone radiation source was used.
The results of the petrophysical parameters obtained by both approaches will be presented and compared. The feasibility of the techniques, as well as their limitations, will be discussed.

Keywords: Nuclear Magnetic Resonance, T1, T2, μCT, pore size distribution, porosity, rock cores.

PAPER DOI: 10.5593/SGEM2016/HB14/S01.011, COMPARISON OF THE EFFICIENCY OF 1H NMR AND µCT FOR DETERMINING THE POROSITY OF THE SELECTED ROCK CORES

35 EURO ADD TO CART


Your cart ( items)

Subtotal:
Tax cost ():
Shipping cost:
Total:
Checkout Empty