1、Pore Structure and Hydrocarbon Recovery in Fractured Shales1(Max) Qinhong Hu胡钦红maxhuuta.eduDepartment of Earth and Environmental SciencesUniversity of Texas, Arlington2http:/www.eia.gov/pub/oil_gas/natural_gas/analysis_publications/maps/maps.htm20002008200420063http:/www.eia.gov/todayinenergy/detail
2、.cfm?id=2170Updated June 1, 20114Low gas recovery factor 15-30% for Barnett Shale (King, 2012)5Pore Structure and Low Hydrocarbon Production Amount of gas in place Free vs. adsorbed gas Tortuous transport pathways Gas deliverability from nanoporesto well borePore structureRPSEA project: “Integrated
3、experimental and modeling approaches to studying the fracture-matrix interaction in gas recovery from Barnett shale”Porosity: 5.5%k:nanodarcys(10-21 m2)Median pore dia.: 5 nmBarnett Shale (7,219 ft)Pore Geometry and TopologyPore structure: shape, volume, size, size-distribution, connectivity, and su
4、rface area 6Dead EndsBackboneInfinite ClusterEdge PorosityIsolated Porosity Connected PorosityTotal PorosityFractureMatrix InteractionMy work on fracture transport starts with this rock 7Rock milling in 1998Field observation (preferential flow in a fracture network)of dye distribution in unsaturated
5、 fractured tuff at Yucca Mt.8Louckset al. (2009)Intraparticleorganic nanoporesAr-ion-beam milling and field-emission-gun SEM: resolve pores as small as 5 nmelliptical to completely rounded angularrectangularWhere is the porosity?9CH4 size: 0.375 nm10http:/ nm1112Fluid Flow and Mass Transport in Stim
6、ulated Reservoir Volume3106 m3 for one fracstage (Curtis et al., 2012)13http:/ R. 2010. Key Considerations for Hydraulic Fracturing of Gas Shales. Manager, Shale Gas Technology, BJ Services Company, September 9, 2010. www.pttc.org/aapg/lafollette.pdf1 m/yrmovement (advection vs. diffusion ?)中海油以151亿
7、美元收购加拿大Nexen公司, 并承担该公司约43亿美元债务Ewing and Horton (2002)Pore Connectivity and Diffusion Same mathematics for diffusion and imbibition: Affected the same way by pore connectivity:=xcDxtcs )(q =xDxtqqq )(Pore connectivity:Time-dependence:Distance to frontDiffusion coefficientDistance-dependence:Diffusion
8、 coefficientHight 0.5constantconstantLowt 0.263t -0.48t -1.8315Percolation Theoryp = 0.5 p = 0.66percolation threshold0.5 =cccff nbhhhh1/ paMultiple Approaches to Studying Pore Structure Imbibition with samples of different shapes Edge-accessible porosity Liquid and gas diffusion Mercury injection porosimetry N2 adsorption/desorption isotherms Vapor absorption Nuclear Magnetic Resonance Cryoporometry SEM imaging after Woods metal impregnation Microtomography (high-resolution, synchrotron) Focused Ion Beam/SEM imaging Small-Angle Neutron Scattering (SANS) Pore-scale network modeling 30
