Application of nuclear magnetic resonance measurements in the evaluation of two coal seam gas wells in the Pedirka Basin*
Adrian Manescu A and Stewart Bayford BA Baker Hughes Level 7, 256 St George Terrace, Perth WA 6000 Australia. Email: adrian.i.manescu@bakerhughes.com
B Central Petroleum Suite 3, Level 4 Southshore Centre. Email: StewartBayford@centralpetroleum.com.au
The APPEA Journal 50(2) 733-733 https://doi.org/10.1071/AJ09097
Published: 2010
Abstract
In 2008, Central Petroleum was involved in an extended exploration campaign in the Pedirka Basin. The main targets were conventional oil and coal seam gas (CSG). A comprehensive logging program including nuclear magnetic resonance (NMR) measurements was acquired, with the scope of evaluating both targets in two wells.
NMR tools measure the magnetisation of hydrogen protons present in the flushed-zone of the formation pore space. By calibrating this measurement in a water tank, NMR tools provide formation porosity independent of lithology, while classical methods for deriving porosity (density, neutron, etc.) are lithology dependent. While in conventional plays (clastics, carbonates) porosity is needed for evaluating the reservoir storage capacity, in coal beds porosity is needed for evaluating the surface areas of the pores. As methane in coal is bound to the coal surface, total pore surface affects the coal bed methane producing capacity.
NMR measurements also provide information about porosity/grain size distribution, permeability and hydrocarbon saturation in conventional formations. This information can be very useful for evaluating coal seam gas, provided the conventional models can be converted and applied in coal beds.
Evaluation of coal seam gas prospects using nuclear magnetic resonance is an industry first. This presentation highlights the benefits and difficulties of nuclear magnetic resonance evaluation of CSG prospects in these two wells.
Keywords: coal seam gas (CSG), nuclear magnetic resonance logging (NMR), petrophysical evaluation
Adrian Manescu received his MSc degree from the University of Bucharest, Faculty of Geology and Geophysics, in 1991. He graduated with a diploma in Petrophysics. From 1991 to 1997 Adrian worked for Romanian oil company Petrom, as a petrophysicist. In 1997 he joined Western Atlas. He is currently Staff Petrophysicist in Perth, Australia. His areas of interest are: nuclear magnetic resonance; borehole acoustic; and, resistivity anisotropy. Member: SPWLA, SEG and FESAus. |
Stewart W. Bayford received a BSc from the University of Western Australia. After graduating in 1975 he worked in seismic processing for 3 years and then joined Conoco, where he gained worldwide experience as a geophysical interpreter. In 1986 he joined WMC, becoming Timor Sea Regional Exploration Manager. In 1992 he returned to a technical role as a consultant working throughout Australia and New Zealand. He joined Hardy Petroleum in 1997 and stayed with the company as it merged with both British Borneo and then Eni. In 2007 he joined Centurion Petroleum in Egypt. In 2009 he was appointed Exploration Manager for Central Petroleum. |
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