Mechanism underlying initiation of migration of film-like residual oil

Han, Xu; Wang, Lihui; Xia, Huifen; Han, Peng; Cao, Renyi; Liu, Huan

doi:10.1080/01932691.2021.1883440

“…The elastic effect of a compound solution is mainly investigated through experiments that have attracted substantial attention. Gogarty and Levy studied the flow of viscoelastic polymer solutions in a porous medium [ 29 , 30 , 31 , 32 , 33 ]. Several comparison schemes confirmed that the total pressure drop in the flow is affected by the viscosity and elasticity.…”

Section: Introductionmentioning

confidence: 99%

Influence of Polymer Viscoelasticity on Microscopic Remaining Oil Production

Yan

¹

,

Wang

²

,

Sang

³

et al. 2022

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To investigate the impact of polymer viscoelasticity on microscopic remaining oil production, this study used microscopic oil displacement visualisation technology, numerical simulations in PolyFlow software, and core seepage experiments to study the viscoelasticity of polymers and their elastic effects in porous media. We analysed the forces affecting the microscopic remaining oil in different directions, and the influence of polymer viscoelasticity on the displacement efficiency of microscopic remaining oil. The results demonstrated that the greater the viscosity of the polymer, the greater the deformation and the higher the elasticity proportion. In addition, during the creep recovery experiment at low speed, the polymer solution was mainly viscous, while at high speed it was mainly elastic. When the polymer viscosity reached 125 mPa·s, the core effective permeability reached 100 × 10−3 μm2, and the equivalent shear rate exceeded 1000 s−1, the polymer exhibited an elastic effect in the porous medium and the viscosity curve displayed an ‘upward’ phenomenon. Moreover, the difference in the normal deviatoric stress and horizontal stress acting on the microscopic remaining oil increased exponentially as the viscosity of the polymer increased. The greater the viscosity of the polymer, the greater the remaining oil deformation. During the microscopic visualisation flooding experiment, the viscosity of the polymer, the scope of the mainstream line, and the recovery factor all increased. The scope of spread in the shunt line area significantly increased, but the recovery factor was significantly lower than that in the mainstream line. The amount of remaining oil in the unaffected microscopic area also decreased.

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“…Under the same conditions of displacement phase viscosity, as the interfacial tension decreases, the oil-water interface deformation amplitude in the oil-wet pore channel and the wetting angle increases [ 46 , 47 , 48 ]. The oil saturation cloud diagram shows that the remaining oil in the corners varies as the interfacial tension decreases and that the continuous oil phase migrates to the outlet end, increasing the degree of production of the corner residual oil.…”

Section: Resultsmentioning

confidence: 99%

Study on Micro Production Mechanism of Corner Residual Oil after Polymer Flooding

Sun

¹

,

Zhao

²

,

Fan

³

et al. 2022

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To study the microscopic production mechanism of corner residual oil after polymer flooding, microscopic visualization oil displacement technology and COMSOL finite element numerical simulation methods were used. The influence of the viscosity and interfacial tension of the oil displacement system after polymer flooding on the movement mechanism of the corner residual oil was studied. The results show that by increasing the viscosity of the polymer, a portion of the microscopic remaining oil in the corner of the oil-wet property can be moved whereas that in the corner of the water-wet property cannot be moved at all. To move the microscopic remaining oil in the corners with water-wet properties after polymer flooding, the viscosity of the displacement fluid or the displacement speed must be increased by 100–1000 times. Decreasing the interfacial tension of the oil displacement system changed the wettability of the corner residual oil, thus increasing the wetting angle. When the interfacial tension level reached 10−2 mN/m, the degree of movement of the remaining oil in the corner reached a maximum. If the interfacial tension is reduced, the degree of production of the residual oil in the corner does not change significantly. The microscopic production mechanism of the corner residual oil after polymer flooding expands the scope of the displacement streamlines in the corner.

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“…Wang et al [13][14][15] have made a high-temperature blocking agent capable of resisting 250 °C by mixing sulfonated tannin extract with phenol, formaldehyde, or paraformaldehyde. Fangeng et al [16] used tannin extract as raw material to react with phenol and formaldehyde and then used transition metal salts such as inorganic salts MnSO 4 , TiCl 4 , and tannin extract.…”

Section: Introductionmentioning

confidence: 99%

Plugging Performance of a New Sulfonated Tannin Gel System Applied in Tight Oil Reservoir

Xu

¹

,

Wang

²

,

Bai

³

et al. 2022

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In this study, based on the high-temperature characteristics of Western China tight oil reservoirs, a phenolic-larch tannin, temperature-resistant, plugging agent was synthesized by changing the mass fractions of larch tannin, double cross-linking agent, and accelerator. Young’s modulus of the dispersed gel was directly measured by an atomic force microscope, and the macroscopic plugging performance was evaluated by a physical simulation experiment of the artificially fractured natural core from Western China tight oil oilfield, thereby establishing a mapping relationship between the two. Research indicates that the formula of the high-temperature-resistant tannin system optimized by the experiment is 3.0 % sulfonated tannin + 3.0 % formaldehyde cross ‐ linking agent + 1.0 % phenol cross ‐ linking agent + 0.05 % MnS O 4 accelerator ; the mechanical strength of the tannin gel and its plugging performance have a linear relationship. When Young’s modulus rises from 18.74 to 63.89 KPa, the plugging rate rises from 94.11% to 97.44%.

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Mechanism underlying initiation of migration of film-like residual oil

Cited by 5 publications

References 41 publications

Influence of Polymer Viscoelasticity on Microscopic Remaining Oil Production

Influence of Polymer Viscoelasticity on Microscopic Remaining Oil Production

Study on Micro Production Mechanism of Corner Residual Oil after Polymer Flooding

Plugging Performance of a New Sulfonated Tannin Gel System Applied in Tight Oil Reservoir

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