Based on rock samples of tight oil reservoirs in the buried hills of North China, conventional gas flooding and high-speed centrifugal experiments at different pressures were carried out. Combined with nuclear magnetic resonance experiments, an evaluation method of oil production potential in fractured porous media was established to quantitatively study the gas flooding potential of target reservoirs. Results indicated that the “gas fingering phenomenon” is serious in conventional gas flooding experiments of fractured cores even under low pressures because of fractures. With an increase in flooding pressure, the changes of T2 (T2 relaxation time) spectrum and displacement percentage are relatively small, which means that the displacement efficiency has not been improved significantly (the flooding pressure for these three cores increased from 0.014 MPa to 2.6 MPa, with an average increase in displacement percentage of 6.3%). High-speed centrifugation can realize “homogeneous displacement” of the cores and overcome the influence of gas channeling. With an increase in the displacement pressure, the T2 spectrum and percentage of displaced oil varied obviously, and the displacement efficiency improved greatly (the flooding pressure for these three cores increases from 0.014 MPa to 2.6 MPa, with an average percentage of displaced oil being increased to 16.16%). Using the method of this study, 13 cores of the target reservoir were evaluated for gas flooding potential. The percentage of available pores in the target reservoir ranges from 17.64% to 58.54%, with an average of 33.84%. Movable fluid controlled by microthroats in the reservoirs larger than 0.1 mD is about 20%, while that in the reservoirs smaller than 0.1 mD is about 5%. This study indicates that the development of fractures and microfractures controls the physical properties and fluid productivity of reservoirs.
REFERENCES
1.
Bai
, B.
, Zhu
, R.
, Wu
, S.
et al, “Multi-scale method of nano(micro)-CT study on microscopic pore structure of tight sandstone
,” Pet. Explor. Dev.
40
(3
), 354
–358
(2013
).2.
Dastvareh
, B.
and Azaiez
, J.
, “Instabilities of nanofluid flow displacements in porous media
,” Phys. Fluids
29
(4
), 044101
(2017
).3.
Datta
, S. S.
, Ramakrishnan
, T. S.
, and Weitz
, D. A.
, “Mobilization of a trapped non-wetting fluid from a three-dimensional porous medium
,” Phys. Fluids
26
(2
), 022002
(2014
).4.
De Paoli
, M.
, Zonta
, F.
, and Soldati
, A.
, “Influence of anisotropic permeability on convection in porous media: Implications for geological CO2 sequestration
,” Phys. Fluids
28
(5
), 056601
(2016
).5.
Fan
, J.
, Yang
, Z.
, Li
, W.
et al, “Assessment of fracturing treatment of horizontal wells using SRV technique for Chang-7 tight oil reservoir in Ordos basin
,” J. China Univ. Pet.
39
(4
), 103
–110
(2015
).6.
Ghanizadeh
, A.
, Clarkson
, C. R.
, Aquino
, S.
et al, “Petrophysical and geomechanical characteristics of Canadian tight oil and liquid-rich gas reservoirs: II. Geomechanical property estimation
,” Fuel
153
(1
), 682
–691
(2015
).7.
Gu
, X.
, Pu
, C.
, Huang
, H.
et al, “Micro-influencing mechanism of permeability on spontaneous imbibition recovery for tight sandstone reservoirs
,” Pet. Explor. Dev.
44
(6
), 1003
–1009
(2017
).8.
Guo
, R. L.
, Chen
, X. D.
, Ma
, X. F.
et al, “Analysis of the characteristics and its influencing factors of horizontal movable fluid in the Chang 7 tight reservoir in Longdong area, Ordos basin
,” Nat. Gas Geosci.
29
(5
), 665
–674
(2018
).9.
Guo
, Y.
, Song
, Y.
, Pang
, X.
et al, “Characteristics and genetic mechanism of near source accumulated accumulation for continuous type tight sand gas
,” Earth Sci.
03
, 433
–440
(2016
).10.
Jafari
, I.
, Masihi
, M.
, and Nasiri Zarandi
, M.
, “Numerical simulation of counter-current spontaneous imbibition in water-wet fractured porous media: Influences of water injection velocity, fracture aperture, and grains geometry
,” Phys. Fluids
29
(11
), 113305
(2017
).11.
Jia
, C.
, Zou
, C.
, Li
, J.
et al, “Assessment criteria, main types, basic features and resource prospects of the tight oil in China
,” Acta Petrolei Sin.
33
(3
), 343
–350
(2012
).12.
Jiang
, P.
, Guo
, H.
, Li
, H.
et al, “Experimental study on T2, cutoff in low permeability sandstones
,” Well Logging Technol.
34
(4
), 327
–330
(2010
).13.
Jin
, Y.
and Kuznetsov
, A. V.
, “Turbulence modeling for flows in wall bounded porous media: An analysis based on direct numerical simulations
,” Phys. Fluids
29
(4
), 045102
(2017
).14.
Law
, B. E.
and Curtis
, J. B.
, “Introduction to unconventional petroleum systems
,” AAPG Bull.
86
(11
), 1851
–1852
(2002
).15.
Lei
, Q. H.
, Cheng
, L. B.
, Wang
, C.
et al, “A study on distribution features of movable fluids for Chang 7 tight reservoir in Ordos basin
,” Nat. Gas Geosci.
28
(1
), 26
–31
(2017
).16.
Li
, D.
, Zha
, W.
, Liu
, S.
et al, “Pressure transient analysis of low permeability reservoir with pseudo threshold pressure gradient
,” J. Pet. Sci. Eng.
147
, 308
–316
(2016
).17.
Li
, Z.
, He
, S.
, Yang
, W.
et al, “Physical simulation experiment of water driving by micro-model and fractal features of residual oil distribution
,” J. China Univ. Pet.
30
(3
), 68
–71
(2006
).18.
Li
, Z.
, Liu
, W.
, Sun
, D.
et al, “Experimental study on T2 cutoff value of the movable fluid in high porosity low permeability carbonate rock
,” J. Xi’an Shiyou Univ.
26
(5
), 53
–55
(2011
).19.
Liu
, D. K.
, Sun
, W.
, Ren
, D. Z.
et al, “Features of pore throat structures and movable fluid in tight gas reservoir: A case from the 8th member of Permian Xiashihezi formation and the 1st member of Permian Shanxi formation in the western area of Sulige gasfield, Ordos basin
,” Nat. Gas Geosci.
27
(12
), 2136
–2146
(2016
).20.
Loucks
, R. G.
, Read
, R. M.
, Ruppel
, S. C.
et al, “Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale
,” J. Sediment. Res.
79
, 848
–861
(2009
).21.
Mullen
, J.
, “Petrophysical characterization of the eagle ford shale in south Texas
,” in Canadian Unconventional Resources and International Petroleum Conference, Calgary 19-21 October 2010
(Society of Petroleum Engineers
, 2010
), document SPE-138145-MS.22.
Niu
, X.
, Feng
, S.
, Liu
, F.
et al, “Microscopic occurrence of oil in tight sandstones and its relation with oil sources—A case study from the upper Triassic Yanchang formation, Ordos basin
,” Oil Gas Geol.
V34
(3
), 288
–293
(2013
).23.
Pan
, W. Y.
, Lang
, D. J.
, Lun
, Z. M.
et al, “Experimental study of effective displacement characteristics of different displacing methods in tight oil reservoir
,” Comput. Tomogr. Theory Appl.
25
(6
), 647
–652
(2016
).24.
Qu
, X.
, Fan
, J.
, Chong
, W.
et al, “Impact of fractures on water flooding seepage features of Chang 7 tight cores in Longdong area, Ordos basin
,” J. Xi’an Shiyou Univ.
32
(5
), 55
–60
(2017
).25.
Qu
, X.
, Lei
, Q.
, Gao
, W.
et al, “Experimental study on imbibition of Chang 7 tight oil cores in Erdos basin
,” J. China Univ. Pet.
42
(2
), 102
–109
(2018
).26.
Quan
, H.
, Zhu
, Y.
, Zhang
, H.
et al, “Reservoir pore structure and micro flow characteristics of water flooding: A case study from Chang6 reservoir of Wangyao block in Ansai oilfield
,” Oil Gas Geol.
32
(54
), 952
–956
(2011
).27.
Rezaei Niya
, S. M.
and Selvadurai
, A. P. S.
, “The estimation of permeability of a porous medium with a generalized pore structure by geometry identification
,” Phys. Fluids
29
(3
), 037101
(2017
).28.
Rokhforouz
, M. R.
and Akhlaghi Amiri
, H. A.
, “Phase-field simulation of counter-current spontaneous imbibition in a fractured heterogeneous porous medium
,” Phys. Fluids
29
(6
), 062104
(2017
).29.
Shahnazari
, M. R.
, Ashtiani
, I. M.
, and Saberi
, A.
, “Linear stability analysis and nonlinear simulation of the channeling effect on viscous fingering instability in miscible displacement
,” Phys. Fluids
30
(3
), 034106
(2018
).30.
Shi
, J. C.
, Qu
, X. F.
, Lei
, Q. H.
et al, “Distribution characteristics and controlling factors of movable fluid in tight oil reservoir: A case study of Chang 7 reservoir in Ordos basin
,” Nat. Gas Geosci.
27
(5
), 827
–834
(2016
).31.
Suleimanov
, B. A.
, Abbasov
, E. M.
, and Sisenbayeva
, M. R.
, “Mechanism of gas saturated oil viscosity anomaly near to phase transition point
,” Phys. Fluids
29
(1
), 012106
(2017
).32.
Uth
, M. F.
et al, “A direct numerical simulation study on the possibility of macroscopic turbulence in porous media: Effects of different solid matrix geometries, solid boundaries, and two porosity scales
,” Phys. Fluids
28
(6
), 065101
(2016
).33.
Wang
, R.
and Chen
, M.
, “Characteristics and influencing factors of movable fluid in ultra-low permeability sandstone reservoir
,” Acta Petrolei Sin.
29
(4
), 558
–561
, 566
(2008
).34.
Wang
, R.
, Shen
, P.
, Song
, Z.
et al, “Characteristics of micropore throat in ultralow permeability sandstone reservoir
,” Acta Petrolei Sin.
30
(4
), 560
–563
(2009
).35.
Wang
, Y. D.
, Yang
, Y. S.
, Liu
, K. Y.
et al, “Quantitative and multi-scale characterization of pore connections in tight reservoirs with micro-CT and DCM
,” Bull. Mineral., Petrol. Geochem.
34
(1
), 86
–91
(2015
).36.
Wei
, Q.
, Li
, Z.
, Wang
, X.
et al, “Mechanism and influence factors of imbibition in fractured tight sandstone reservoir: An example from Chang8 reservoir of Wuqi area in Ordos basin
,” Pet. Geol. Recovery Effic.
32
(5
), 103
–107
(2016
).37.
Wei
, X.
, Ok
, J. T.
, Feng
, X.
et al, “Effect of pore geometry and interfacial tension on water-oil displacement efficiency in oil-wet microfluidic porous media analogs
,” Phys. Fluids
26
(9
), 093102
(2014
).38.
Wu
, G.
, Fang
, H.
, Han
, Z.
et al, “Growth features of measured oil initially in place and gas initially in place during the 12th five-year plan and its outlook for the 13th five-year plan in China
,” Acta Petrolei Sin.
37
(9
), 1145
–1151
(2016
).39.
Wu
, S.
, Zou
, C.
, Zhu
, R.
et al, “Reservoir quality characterization of upper triassic Chang 7 shale in Ordos basin
,” Earth Sci.-J. China Univ. Geosci.
11
, 1810
–1823
(2015
).40.
Wu
, Z.
and Mirbod
, P.
, “Experimental analysis of the flow near the boundary of random porous media
,” Phys. Fluids
30
(4
), 047103
(2018
).41.
Xueling
, Z.
, Weiyao
, Z.
, Qiang
, C.
et al, “Compressible liquid flow in nano- or micro-sized circular tubes considering wall–liquid Lifshitz–van der Waals interaction
,” Phys. Fluids
30
(6
), 062002
(2018
).42.
Yang
, H.
, Li
, S.
, and Liu
, X.
, “Characteristics and resource prospects of tight oil and shall oil in Ordos basin
,” Acta Petrolei Sin.
34
(1
), 1
–11
(2013
).43.
Yang
, W.
, Zhu
, Y.
, Chen
, S.
et al, “Characteristics of the nanoscale pore structure in northwestern Hunan shale gas reservoirs using field emission scanning electron microscopy, high-pressure mercury intrusion, and gas adsorption
,” Energy Fuels
28
(2
), 945
–955
(2014
).44.
Yang
, X.
, Zhao
, W.
, Zou
, C.
et al, “Origin of low permeability reservoir and distribution of favorable reservoir
,” Acta Petrolei Sin.
28
(4
), 57
–61
(2007
).45.
Yang
, Y.
, Birmingham
, T.
, and Kremer
, A.
, “From hydraulic fracturing, what can we learn about reservoir properties of tight sand at the Wattenberg field in the Denver-Julesburg basin
,” in SPE Rocky Mountain Petroleum Technology Conference, Denver, CO, 14-16 April 2009
(Society of Petroleum Engineers
, 2009
), document SPE-123031-MS.46.
Yang
, Z.
, Guo
, H.
, Liu
, X.
et al, Characteristic Experimental Technology of an Extra-Ultra Low Permeability Reservoir
(Petroleum Industry Press
, Beijing
, 2012
).47.
Yao
, J.
, Deng
, X.
, Zhao
, Y.
et al, “Characteristics of tight oil in triassic Yanchang formation, Ordos basin
,” Pet. Explor. Dev.
40
(2
), 161
–169
(2013
).48.
Yao
, C. C.
and Yan
, P. Y.
, “A diffuse interface approach to injection-driven flow of different miscibility in heterogeneous porous media
,” Phys. Fluids
27
(8
), 083101
(2015
).49.
Yu
, B.
, Luo
, X.
, Qiao
, X.
et al, “Influential factor and characteristics of Shan-2 member of shanxi formation in Yanchang oil-gas field, Ordos basin
,” J. Cent. South Univ.
43
(10
), 3931
–3937
(2012
).50.
Zhang
, X. S.
, Wang
, H. J.
, Ma
, F.
et al, “Classification and characteristics of tight oil plays
,” Pet. Sci.
13
(1
), 18
–33
(2016
).51.
Zhao
, H.
, Ning
, Z.
, Wang
, Q.
et al, “Petrophysical characterization of tight oil reservoirs using pressure-controlled porosimetry combined with rate-controlled porosimetry
,” Fuel
154
, 233
–242
(2015
).52.
Zhong
, D.
, Zhou
, L.
, Sun
, H.
et al, “Influences of petrologic features on diagenesis and pore development: An example from the triassic Yanchang formation in Longdong area, Ordos basin
,” Oil Gas Geol.
33
(6
), 890
–895
(2012
).53.
Zhou
, B.
et al, “General slip regime permeability model for gas flow through porous media
,” Phys. Fluids
28
(7
), 072003
(2016a
).54.
Zhou
, S.
, Liu
, H.
, Yan
, G.
et al, “NMR research of movable fluid and T2 cutoff of marine shale in South China
,” Oil Gas Geol.
37
(4
), 612
–616
(2016b
).55.
Zou
, C.
, Zhu
, R.
, Wu
, S.
et al, “Types, characteristics, genesis and prospects of conventional and unconventional hydrocarbon accumulation: Taking tight oil and tight gas in China as an instance
,” Acta Petrolei Sinica
33
(2
), 173
–187
(2012
).© 2019 Author(s).
2019
Author(s)
You do not currently have access to this content.