Effect of shape factor, characteristic length, and boundary conditions on spontaneous imbibition

Yildiz, Hasan O.; Gokmen, Melih; Cesur, Yusuf

doi:10.1016/j.petrol.2006.06.002

Cited by 80 publications

(49 citation statements)

References 36 publications

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“…Zhang et al (1996) and Ma et al (1997) reported that the modified characteristic length could closely correlate the imbibition data for cylindrical cores with different sizes and boundary conditions. However, further experiments showed that the modified characteristic length could not closely correlate the imbibition data for irregular cores (Standnes, 2004;Yildiz et al, 2006). The shape of production curves could be different for SI in cores with different geometry shape and boundary condition (Babadagli, 2002;Standnes, 2004;Mason Fig.…”

Section: Completely Counter-current Imbibitionmentioning

confidence: 94%

A critical review on fundamental mechanisms of spontaneous imbibition and the impact of boundary condition, fluid viscosity and wettability

Meng

Liu

Wang

2017

Adv. Geo-Energ. Res.

111

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Spontaneous imbibition (SI) is one of the primary mechanisms of oil production from matrix system in fractured reservoirs. The main driving force for SI is capillary pressure. Researches relating to SI are moving fast. In the past few years, amount of literature on the development of SI with respect to many variables, such as mechanism of imbibition, scaling of imbibition data and wettability of matrix blocks. In this review, we first introduced the fundamental physics mechanism of SI through capillary tube models and micromodels. Then both conventional and more novel experimental methods of measuring oil production are discussed thoughtfully. This is followed by reviewing the oil production performance under various boundary conditions and the characteristic length in scaling equations that have been used to account for different cores shape and boundary conditions. The effect of fluid viscosity on the rate of oil production and final oil recovery as well as the development of viscosity term in the scaling equation are reported. The commonly used methods to quantitatively evaluate the wettability of cores and the SI under mix-and oil-wet conditions are introduced. And last but not least, the methods and mechanism of wettability alteration for enhanced oil recovery in mix-or oil-wet fractured reservoirs are presented.Keywords: Spontaneous imbibition, fractured reservoirs, boundary condition, viscosity ratio, wettability.Citation: Meng, Q., Liu, H., Wang, J. A critical review on fundamental mechanisms of spontaneous imbibition and the impact of boundary condition, fluid viscosity and wettability.

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Section: Completely Counter-current Imbibitionmentioning

confidence: 94%

A critical review on fundamental mechanisms of spontaneous imbibition and the impact of boundary condition, fluid viscosity and wettability

Meng

Liu

Wang

2017

Adv. Geo-Energ. Res.

111

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“…The correlation appears to work quite well (Yildiz et al 2006). For a cylinder open on all faces this equation gives (Zhang et al 1996)…”

Section: Of All-faces-open Imbibition With Results From Linear and Ramentioning

confidence: 87%

Spontaneous Counter-Current Imbibition into Core Samples with All Faces Open

et al. 2008

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Counter-current imbibition occurs when brine spontaneously displaces oil from a very strongly water-wet rock. Experiments are usually carried out on cylindrical core plugs which have all of their faces open, mainly because this is easiest to do and also because it appears to give the most reproducible results. The flow patterns are complex, but a reasonable approximation can be obtained by assuming piston-like advance of fronts from the radial outer face and both flat ends. This separates the flow pattern into two types: linear imbibition into cones and radial imbibition into the surrounding toroid ring. Production versus time curves have been calculated for cylinders of varying aspect ratios and other core shapes. The analytical results confirm the experimental observation that sample shape does not have much effect on the shape of the production versus time curves. Bearing in mind the inherent variability of experimental results for individual core samples, the differences would be difficult to detect in experiments. The time for imbibition to be completed scales as the characteristic length. The function given by Ma et al. (J Pet Sci Eng 18:165-178, 1997) requires only a small correction factor for agreement with the analytical result. The present analysis makes straightforward the comparison of results from the complex flow condition 123 200 G. Mason et al. of all-faces-open imbibition with results from linear and radial experiments. A comparison is made with published results. Nomenclature a L toroid − L cone (m) A Area (m 2 ) A f Area of the displacement front (m 2 ) A i Area open to imbibition in the ith direction (m 2 ) A R Area of the cylinder at a general radius, R(m 2 ) b L cone /R max C spread Factor determined by the breadth and shape of the pore size distribution d Core diameter (m) f Fraction of the core filled K Permeability (m 2 ) k rnw Relative permeability of the non-wetting phase k rw Relative permeability of the wetting phase L c Characteristic length (m) L cone Length of a cone (m) L core Core length (m) L c,Ma Characteristic length calculated from Ma's equation (m) L f Distance from the open face to the front for the cone (m) L max Length of the core for linear imbibition (m) L toroid Length of the toroid (m) M Mobility factor (Pa −1 s −1 )n Total number of surfaces open to imbibition P c Capillary pressure (Pa) P cf Capillary pressure at the imbibition front (Pa) P co Capillary pressure at the open face (Pa) P nw Pressure in the non-wetting phase (Pa) P w Pressure in the wetting phase (Pa) q nw Flow of non-wetting phase (m 3 /s) q w Flow of wetting phase (m 3 /s) q R w Flow passing through the surface of the cylinder, radius R (m 3 /s) R f Radial distance of the front from the axis (m) R end Radius of the final position of the front for the shorter toroid (m) R core Core radius (m) R sphere Radius of spherical core (m) S wf Wetting phase saturation behind the front S wi Initial wetting phase saturation t Time (s) t D Dimensionless time t end Time when imbibition ceases (s) t f Time when ...

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“…Makhanov et al [19] demonstrated that the SI rate in a tight oil reservoir would depend on fluid and shale properties, fracture-matrix interface, and soaking time. Yildiz et al [20] investigated the effects of shape factor, characteristic length, and boundary conditions on the rate of SI. Because of the invisible nature of the core, previous studies on SI measured macroscopic parameters such as oil saturation, oil output, and electrical resistivity to speculate the microscopic process of imbibition.…”

Section: Introductionmentioning

confidence: 99%

Nuclear Magnetic Resonance Measurement of Oil and Water Distributions in Spontaneous Imbibition Process in Tight Oil Reservoirs

Nie

Chen

2018

Energies

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Spontaneous imbibition of water into tight oil reservoirs is considered an effective way to improve tight oil recovery. We have combined testing techniques such as nuclear magnetic resonance, mercury injection capillary pressure, and magnetic resonance imaging to reveal the distribution characteristics of oil and water during the spontaneous imbibition process of tight sandstone reservoir. The experimental results were used to describe the dynamic process of oil–water distribution at the microscopic scale. The water phase is absorbed into the core sample by micropores and mesopores under capillary forces that dry away the original oil phase into the hydraulically connected macropores. The oil phase entering the macropores will drive away the oil in place and expel the original oil from the macropores. The results of magnetic resonance imaging clearly show that the remaining oil accumulates in the central region of the core because a large amount of water is absorbed in the late stage of spontaneous imbibition, and the water in the pores gradually connects to form a “water shield” that blocks the flow of the oil phase. We propose the spontaneous imbibition pathway, which can effectively explain the internal mechanisms controlling the spontaneous imbibition rate. The surface of the core tends to form many spontaneous imbibition pathways, so the rate of spontaneous imbibition is fast. The deep core does not easily form many spontaneous imbibition pathways, so the rate of spontaneous imbibition is slow. This paper reveals the pore characteristics and distribution of oil and water during the spontaneous imbibition process, which is of significance for the efficient development of tight oil.

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Effect of shape factor, characteristic length, and boundary conditions on spontaneous imbibition

Cited by 80 publications

References 36 publications

A critical review on fundamental mechanisms of spontaneous imbibition and the impact of boundary condition, fluid viscosity and wettability

A critical review on fundamental mechanisms of spontaneous imbibition and the impact of boundary condition, fluid viscosity and wettability

Spontaneous Counter-Current Imbibition into Core Samples with All Faces Open

Nuclear Magnetic Resonance Measurement of Oil and Water Distributions in Spontaneous Imbibition Process in Tight Oil Reservoirs

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