Fluid typing and NMR
- 1. INDIAN INSTITUTE OF TECHNOLOGY ROORKEE Advanced fluid typing and pore estimation using NMR logging technique Shivam Yadav
- 2. 2 Introduction • NMR- Nuclear Magnetic Resonance is a type of advanced logging technique which basically work on the principle of response of nuclei to a external magnetic field. • It is one technique that provide quickest and reliable information about rock and fluid characterization such as; quantity of fluid, physical property of fluid and size and distribution of the pores in the rock volume. Isidor Isaac Rabi (1898 – 1988)was an American physicist who won the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance imaging.
- 3. 3 Principle Mechanism Echo decay, x-axis as time and y-axis as amplitude Source:commons.wikimedia.org/wiki/File:GWM _HahnEchoDecay.gif Proton spin, x-axis as time and y-axis as magnetic moment. With the decrease in area of rotation Mxy decreases and increases in My because of increase intensity of moment. Source:commons.wikimedia.org/wiki/File:GWM_Hahn EchoDecay.gif
- 4. 4 Principle Outputs NMR fuild typing. Source:petrowiki.org/File:Vol5_Page_0326_Image_0001 .png Typical NMR properties for pore fluids. Source: petrowiki.org/File:Vol5_Page_0327_Image_0001.png Typical NMR-related fluid properties for Gulf of Mexico sandstones. Source:petrowiki.org/File:Vol5_Page_0295_Im age_0002.png
- 5. 5 Methods Involved • There are two general types, or sets, of CMPG acquisitions that are associated with each mechanism: • T1 contrast between the hydrocarbon and brine phases (i.e., a water- wet formation containing light hydrocarbons) • T2 contrast between the gas and oil phases Dual TW (T1-weighted mechanism ) • To achieve full polarization (long TW) in one acquisition channel • To acquire the small signal amplitudes associated with the short Methods using T1-weighting for hydrocarbon typing Source:petrowiki.org/File:Vol5_Page_0330_Image_0001.png
- 6. 6 Methods Involved (continues….) • Dual TE (Diffusion-weighted mechanism) The identification of viscous oil is very difficult by dual-TW acquisition because there is little T1 contrast between water and viscous oil. A significant difference in the diffusion characteristics of water and viscous oil is used to create a T2 contrast that separates the two NMR signals. The inter-echo spacing, TE, is chosen long enough that the water and oil signals are fully separated in the T2-domain. Variation in CPMG pulse sequence Source: petrowiki.org/File:Vol5_Page_0326_Image_0002.png
- 7. 7 References • Xie Ranhong and Xiao Lizhi , 2011. “Advanced fl uid-typing methods for NMR Logging”. • Robert Freedman, 2006. “Advances in NMR logging”. • Ajay Kumar, Ramesh Babu, Ravindra Kumar et al, 2015. “Benefits by Integrating Core, Image and NMR Data for Shale Reservoir Characterization - A Case Study in Cambay Basin, India
- 8. 8 Thank you