NMR Core-Analysis in Unconventional Resource Plays Rice University Consortium on Processes in Porous Media Department of Chemical & Biomolecular Engineering Philip M. Singer George J. Hirasaki Walter G. Chapman Dilipkumar N. Asthagiri Zeliang Chen Jinlu Liu 4/22/20151

2 Outline 1.NMR Background 2.Porosity Models in Shale 3.Answer-Products in Shale 4.Equipment & Computational Tools 5.Challenges to Investigate

4/22/20153 NMR Background B0B0 NN B1B1 T1T1 T2T2 Logging: detect fluids only Core-analysis: fluids & solids H H H H H H C C H H H H HH H O H H S H C H H H H

44/22/2015 NMR Log Porosity Model TETE Kerogen Structural Water Bitumen Clay Bound Water Irreducible Oil Movable Light Oil

Kerogen Structural Water Bitumen 54/22/2015 NMR Core Porosity Model TETE Irreducible Oil T 2-cutoff Gaussian decay Solid Exponential decay Liquid Clay Bound Water Movable Light Oil

Current: 1.Total porosity: Kerogen (from porosity deficit) 2.Movable fluid porosity: T 2-cutoff (calibrated from core) Research (validate & calibrate with core): 1.Fluid typing (saturation): T 1 / T 2 ratio 2.Pore-size distribution:  T 2 3.Wettability: Restricted D(T 2 ) 4.Permeability transform 4/22/20156 NMR Answer-Products 0.3 T 2 (ms) 5000 E. Rylander et al. SPE (2013)

4/22/20157 Eagle-Ford Tight-Oil Log Calibration with Core 42 API 1500 scf/bbl 2 MHz 100 C T e ~ 0.4 ms P.M. Singer et al. SCA-18 (2013)

Core Re-Saturation 4/22/20158 Zoning As-ReceivedOil Re-Saturated (2000 psi) R. Kausik et al. SCA-73 (2014)

4/22/20159 Pore-Size Distribution T. Jiang et al. SPWLA-LL (2013)  = 5 nm/ms

4/22/ Bulk Crude-Oils Z. Yang et al. JMR-192 (2008) Theory Experiment

4/22/ NMR Core Equipment Low-field 2 MHz Core dia.: 0.5”, 1.0”, 1.5” T E (ms): 0.03, 0.06, 0.1 T 1 - T 2, D - T 2, Profile - T 2 1.0” dia., 0.1 ms 5,000 psi confining 4,500 psi differential 100 C

4/22/ Model hydrocarbon phase-behavior & storage in nano-pores, requires: 1.Hydrocarbon composition 2.Pressure & temperature 3.Pore-size from NMR core data 4.Wettability from NMR core data Model hydrocarbon transport in nano-pores using: In-situ NMR core-flooding data Real-time monitoring of core-flood front Saturated pore-size distribution across core C H H H H C C H H H H HH C H H H H C H H H H C H H H H Kerogen Computational Chemistry

4/22/ Theory and Modeling Atomic length scale Ab initio quantum chemical & empirical force-field based simulations Quasi-chemical theory to interpret simulation results Atomic-to-pore length scale Empirical force-field based simulations + accelerated sampling techniques iSAFT (interfacial Statistical Associating Fluid Theory) Pore-to-core length scale Density functional theory for modeling phase-behavior

1.Surface relaxation with nano-pore confinement 2.Exponential (fluid) versus Gaussian (solid) decay 3.Deviations from theory at long correlation times (solid-like) 4.Internal gradients in the motional averaging regime 5.Hydrocarbon phase-behavior and storage in shale 6.Hydrocarbon transport (non-Darcy flow) in shale 7.Permeability transforms in shale 4/22/ Challenges to Investigate