Fundamental Understanding Of CH -CO O Interactions In .

Fundamental Understanding of CH 4-CO2H2O Interactions in Shale Nanoporesunder Reservoir ConditionsPRESENTED BYYi f e n g Wa n g , Tu a n A n h H o , G u a n g p i n g X u , P h i l i p p e We c k(SNL)S h i k h a S h a r m a ( We s t Vi r g i n i a U n i v e r s i t y)NETL Manager: Bruce Brown1Sandia National Laboratories is a multimissionlaboratory managed and operated by NationalTechnology & Engineering Solutions of Sandia, LLC,a wholly owned subsidiary of HoneywellInternational Inc., for the U.S. Department ofEnergy’s National Nuclear Security Administrationunder contract DE-NA0003525.

Unlock Nanopores In Shale MatrixUnlockingnanoporesFracturingNanopores accounts for 90% of total porosity inshale. This work aims to understand fluid behaviorsin shale nanopores and explore possible engineeringapproaches to unlocking these nanopores such thata long-term performance of a well can be improved(i.e. the slope of a decline curve can be minimized).Production rateImprovement of productiondecline curveTimeWhat makes unconventional reservoirsunconventional? Fluid properties in shalenanopores are different those in conventionalreservoirs (i.e. in bulk systems).Akkutlu, 2013

Publications3 Xiong, Y., Wang, Y. & Olivas, T. (2015) Experimental Determination of P-V-T-X Properties andSorption Kinetics in the CO2-CH4-H2O System under Shale Gas Reservoir Conditions: Part One, PV-T-X Properties, Sorption Capacities and Kinetics of Model Materials for CO2-CH4 Mixtures to125oC , High Temperature Aqueous Chemistry, HiTAC-II Workshop, Heidelberg, April 16,2015.Ho, T. A., Criscenti, L. J. & Wang, Y. (2016) Nanostructural control of methane release in kerogenand its implications to wellbore production decline. Scientific Reports 6, 28053; doi:10.1038/srep28053.Weck, P. F., Kim, E. & Wang, Y. (2016) van der Waals forces and confinement in carbonnanopores: Interaction between CH4, COOH, NH3, OH, SH and single-walled carbon nanotubes.Chem. Phys. Lett. 62, 22-26.Cristancho, D., Akkutlu, I.Y., Criscenti, L.J., Wang, Y. (2016) Gas storage in model kerogen poreswith surface heterogeneities, SPE-180142-MS, DOI: 10.2118/180142-MS.Wang, Y. (2017) On subsurface fracture opening and closure. J. Petrol. Eng. 155, 46-53.Weck, P. F. Kim, E., Wang, Y. et al. (2017) Model representation of kerogen structures: An insightfrom the density functional theory. Scientific Reports, 7, DOI:10.1038/s41598-017-07310-9.Ho, T. A., Greathouse, J. A., Wang, Y, and Criscenti, L. J. (2017) Atomistic structure of mineralnano-aggregates from simulated compaction and dewatering. Scientific Reports, 7, 15286.Ho, T. A., Wang, Y., Criscenti, L. J. & Xiong, Y. (2017) Differential retention and release of CO 2and CH4 in kerogen nanopores: Implications to gas extraction and carbon sequestration. Fuel, 220,1-7.Ho, T. A. Wang, Y. and Criscenti, L. J. (2018) Chemo-mechanical coupling in kerogen gasadsorption/desorption. Phys. Chem. Chem. Phys., 20, 1239.Ho, T. A, Wang, Y. et al. (2018) Supercritical CO2-induced atomistic lubrication for water in arough hydrophilic nanochannel. Nanoscale, 10, 19957.Ho, T. A., Wang Y. (2019) Enhancement of oil flow in shale nanopores by manipulating frictionand viscosity. Phys. Chem. Chem. Phys., 21, 12777.Wang, Y. (2019) From nanofluidics to basin-scale flow in shale: Tracer investigations, In: ShaleSubsurface Science and Engineering, https://doi.org/10.1002/9781119066699.ch3 (bookchapter).Ho, T. A., Wang, Y. (2020) Pore size effect on selective gas adsorption and transport in shalenanopores, J. Natural Gas Sci. Engineering (available online).Ho, T. A., Wang, Y., Jove-Colon, C. F., Coker, E. N. (2020) Fast Advective Water Flow in ClayInterlayers, ACS Nano (in revision).Xu et al. (2020) Interaction of kerogen with brine-saturated supercritical carbon dioxide (CO2) andits implications to geologic carbon sequestration and enhanced oil/gas recovery. Inter. J. CoalGeol. (in revision).Xu, G., Wang, Y., Ho, T. A. (2020) Non-elastic behavior of kerogen upon gasadsorption/desorption, Scientific Reports (ready for submission)

Integrated method for construction of kerogen molecular on ofmineralinterferenceMDAIMDElimination ofunphysical bondsXRD4

Effect of pyrite on NMR measurementsMarK samplewith 49% pyritePyrite in nano-meter scale crystals are closely inter-associatedwith kerogen (dark color) which makes harder to remove pyritefrom kerogen completely, thus the interference of pyrite cannotbe ignored.

Pyrite interference causes underestimate aliphatic fraction.CP/MAS 13C NMR spectra of the same kerogen before pyrite removal (blue) and after theremoval of pyrite (red) from Bazhenov Shale. Modified from Galukhin et al. (2017)

C13 NMR data using multi-contact cross polarization (MC-CP) methodWoodford Sh MAR-1 #10.63%0.7%Vitrinite Reflectance (VR0)bSh MAR #2 SDR MAR (CPD) SDR Mar (201321252) San Mar #1 San MAR #2 San MAR #3 San MAR #4 MarK0.7%1.4%1.4%2.2%2.2%2.2%2.2%2.2%Sulfur by IC analysisSulfur by elemental analysisSulfur from pyrite calculated from 9.6%3.2%7.7%1.6%36.3%1.4%5.3%0.7%Iron 0.460.11905aTotalPyriteH/C atomic ratioO/C atomic ratioMIP-3H MT2.9%26.3%86.0%3.4%5.9%1.6%96.8%0.470.05NMR structural parametersTotal Aromatic carbon (%)Total Aliphatic carbon (%)Total Alkyl (%)rangeChemical shift (ppm)(90 – 165)25.049.0(0 – de and ketone (%)Carboxy and amide .30.700.5O-substituted aromatic (%)(150-165)1.71.51.211.4111.1Alkyl substituted aromatic ted aromatic rotonated aromatic dgehead aromatic carbon (%)O-substituted alkyl (%)-CH, -CH2 (%)-CH3 (aliphatic aromatic) 31.90.95.35.833.91.24.25.429.20.97.2660335Mole fraction of bridgehead carbon0.440.320.320.350.340.360.380.340.67Fraction of aromatic carbons with rage aliphatic carbon chain length12.14.95.51.71.21.21.211.360.22a sulfur content using elemental measurement if available, if not using value by IC measurement; b Bousige et al. (2016); c calcuated from elemental sulfur content; d Agrawal and Sharma (2020)Using MC-CP method eliminates the pyrite interference.89100.37150.85d

Kerogen XRD as a new structural/maturity indicator?SAN Mar #4Sulfur: 0.7%VRo: 2.5SDR Mar (201321252)Sulfur: 11.5%VRo: 1.4SDR Mar (CPD)Sulfur: 1.6%VRo: 1.4Sh Mar-1 #2Sulfur: 26%VRo: 0.7Sh Mar-1 #1Sulfur: 7.2%VRo: 0.7Increasing maturitySAN Mar #3Sulfur: 4.8%VRo: 2.5WoodfordSulfur: 3.4%VRo: 0.6XRD curve calculatedover-mature kerogenfrom MD simulations

Non-elastic swelling of over-mature kerogenMD simulationPeak shift:A A' A'' A''', B B' B'' B''', C C' C''and D D' Experiments: Expose kerogen to 1 atmCO2 and then measure pore size changes. Strong mechano-chemical coupling.Kerogen is mechanically compliant andswelling is irreversible. Mechanical propertiesImplications to reservoir engineering,especially, for organic carbon-rich ductileplays.

Multicomponent gas permeation in clay nanopores: A MD studyPure gas orCH4/C2H6 1:1Ho and Wang (2020)CH4/C2H6 ?Knudsendiffusion 𝐷𝑘 𝑃𝐽𝑘 𝑅𝑇 𝐿𝑤 8𝑅𝑇𝐷𝑘 3 𝜋𝑀10

Selective gas permeation: Pore size – 0.8 nm11

Selective gas permeation: Pore size – 1.8 nm12

Implications Long puzzling observation: Shalegas rich in CH4 but depleted inCO2. Preferential CO2 expulsionduring kerogen maturation Continuum-scale modeling Inadequacy of existingapproaches: Knudsen diffusion Accounting for surface sorptionand surface diffusion. Monitoring Use compositional evolution tomonitor reservoir status.Ho et al. (2018)ClaysCO2KerogenCH2O 0.5 CH4 0.5 CO2Table 1. Apparent transport diffusion coefficients 𝐷𝑖𝑎𝑡 (m2/s)Pore size8Å13 Å18 ÅPure 2.045E-7Binary 8E-82.164E-713

Water transport in clay interlayers 𝑃 𝑀𝑃𝑎 135.02 ln 𝑅𝐻Relative humidityDarcy’s law still applies!14

Advective water flow in clay interlayers15

Fast advective water flow in clay interlayers Evaporation ( 700 MPa) can drive fast advectivewater flow through a clay interlayer the channel.Flow velocity 0.88 m/s for a 4.6 nm long channel For 2 m particle: 95 m/sViscosity of water confined in narrow channel is 3 times higher than bulk viscosity16

Fast advective water flow in clay interlayersImplications: Water imbibition duringhydrofracturing Well treatment (removal ofwater skin) Dry supercritical CO2?Dehydration of 2 μm bentonite measuredwith thermo-gravimetric (TGA) analysis.Liu et al. (2015)17

18Emergent transport properties in nanopores:Isotopic fractionation-20-25-30-35δD (‰)-40-45-50-55-60-65-70-10-9-8-7δ18O (‰)ConventionalreservoirShale formationSPE 124253 (2009)𝑘𝑎𝑝𝑝 2𝑟 8𝑅𝑇 1/23𝑅𝑇 𝜋𝑀 1 8𝜋𝑅𝑇 1/2 𝜇 2𝑀𝑝𝑟 𝛼 1𝑐𝑟 28𝜇M - Molecular weightWang (2019)Mass dependent transport-6-5-4

Effect of nanoconfinement & Ultrafiltration in Shale Gas/oil Field:Isotopic Evidence19

20Nonlinear dynamics of fluid flow in deformable low permeabilitymedia: Porosity waves“Burping” effect (𝑘𝑓 2 𝑃) 𝑡Continuity for fluid 𝑅𝑑 𝐸 [ 2 𝜏 2 𝑃 𝐼 0 𝐸] 𝑡2𝐺𝑑xShear induced dilatancy𝛽𝛼𝜏 𝑛 𝑚𝑓 1 𝛼𝜏 𝑛 𝑚𝜏 𝐺𝑑 𝐽𝐺𝑑 (𝑓 𝛽 2 𝑓)(𝐺𝑑 𝐺𝑤 )Wang et al. (2020)PeriodicStableChaoticStress partitioning/fluidinduced weakening02 𝜏 2𝑓 New mechanism that can potentially change ourgeneral perception (and therefore manipulation) offluid flow in unconventional reservoirs.

Work flow forpredicting productiondecline curve Non-elastic swelling of kerogen upon gas adsorption/desorption. Strong mechano-chemical coupling must be taken into account in a reservoirscale simulation.Reservoir-scalesimulation Kerogen characterization and development of a new paradigm forstructural model reconstruction “Realistic” kerogen models, benchmarked and verified with experimentalmeasurements, are critical to predict gas-in-place. New indicators for kerogen maturity (e.g. XRD) Fluid flow model forfracture networksCritical for prediction of gas-in-place and locating potential production sites. Selective gas permeation in clay nanochannelsClays are a dominant component in shale. This result help mechanisticallyunderstand gas migration in shale matrix and provide a means for fieldmonitoring of a production well for its recovery rate. Fast water advection in clay interlayers Predict water imbibition during stimulation and develop a new well treatmentmethod for removal of water skins. Ultrafilitration and isotopic fractionation in shale gas production Develop a novel field monitoring method for shale gas production; relate fieldscale observation to fluid flow processes in shale nanopores. Nonlinear dynamics of fluid flow in low-permeability media Help develop a new stimulation strategy for shale gas production.Addressed by this work Fluid flow model forshale matrixNanoscaleunderstanding of fluidflow in shale matrixDevelopment of high-fidelity predictive modelResults and implications

22FY21 WorkTheme: Continue nanoscale understanding w/ focus on fluid flow; Extend to include other hydrocarbon components; Upscale fluid/material properties from nanoscale to continuum scale. Complete model constructions for two representative kerogens (mature and less mature).Update gas adsorption and release MD calculations with new kerogen structure models.Initiate experiments on differential gas adsorption/release from kerogen and shale samples.Extend MD simulations to include other chemical components (one LNG, one liquidhydrocarbon). Competitive sorption Fluid phase separation and transport.Develop EOS for one to two fluids in nanoconfinement and up-scaling the EOS.Understand isotope fractionation in nanoconfinement (SNL-WVU)Develop the nonlinear dynamic model for fluid flow in shale and related experimentalcapability.Synergistics: SANS, fracture network modeling and reservoir scale simulations(LANL)Lattice Boltzmann simulations (LANL)Redox properties of kerogen (NETL)

P R E S E N T E D B Y. Unlock Nanopores In Shale Matrix e Time g es Improvement of production decline curve . Sulfur by elemental analysis 2.73% 6.8% 25.7% 3.0% 8.7% 26.3% . c calcuated from elemental sulfur content; d Agrawal and Sharma (2020) C13 NMR data using multi-contact cross pola