Capillary Pressures by Fluid Saturation Profile Measurements During Centrifuge Rotation

Fernø, Martin A.; Bull, Øyvind; Sukka, Pål Ove; Graue, A.

doi:10.1007/s11242-009-9355-8

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…During the centrifugal process, the centrifugal force is equal to the driving pressure of the oil saturated in the shale core, which can be obtained by the following equation: , where P is the centrifugal force per cross-sectional area of core, MPa; Δρ is the density difference between air and fluid, kg/m 3 ; ω is the angular velocity, rad/s; r 2 is the distance between the outlet face of the core and the axis of the centrifuge, m; r 1 is the distance between the inlet face of the core and the axis of the centrifuge, m.…”

Section: Results and Discussionmentioning

confidence: 99%

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Experimental Evaluation on the Oil Saturation and Movability in the Organic and Inorganic Matter of Shale

et al. 2020

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Shale oil reservoirs are more complex and difficult to exploit than conventional and tight oil reservoirs because of low porosity, permeability, and rich organic matter. The presence of organic matter has great influence on the flow behaviors of oil in shale and the development methods for shale oil. In this work, the saturation and movability behaviors of oil in organic and inorganic matter of shale were investigated by experimental methods. First, vacuum-imbibition tests were carried out to evaluate the saturated oil amount at different states (in inorganic pores, organic pores, and adsorbed/dissolved in organic matter) in shale cores and to calculate the inorganic/organic saturation and inorganic/organic porosity. The results show that the imbibition volume of oil is 2.4− 5.7 times as much as those of KCl solutions for the several shale cores. The excess of imbibition oil is adsorbed or dissolved into the organic matter and dispersed in the organic pores. The organic saturation of oil in the shale samples is from 58.9 to 82.6%, which is 1.4−4.7 times as much as that in inorganic matter. The inorganic porosity is from 1.9 to 4.4%, while the organic porosity is from 0.3 to 1.3%. Moreover, the oil movability under centrifugation in the organic and inorganic matter of shale was measured by nuclear magnetic resonance. The results show that the content of movable oil in inorganic pores is 20−80%, which is higher than that of organic matter with a value of lower than 10%. The total movable content of oil in shale is influenced greatly by the content of movable oil in organic matter. Therefore, how to displace the oil in organic matter is the main problem to be solved in developing shale oil.

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Section: Results and Discussionmentioning

confidence: 99%

“…During the centrifugal process, the centrifugal force is equal to the driving pressure of the oil saturated in the shale core, which can be obtained by the following equation: 31,32…”

Section: Determination Of Oilmentioning

confidence: 99%

Experimental Evaluation on the Oil Saturation and Movability in the Organic and Inorganic Matter of Shale

et al. 2020

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“…This in turn allows us to start with the exact outflow flux from the right boundary in the third stage. All this indicates the method is a good alternative to existing approaches based on reaching equilibrium several times, as well as for approaches requiring great experimental expertise (for example, electrode placement as in Šimůnek and Nimmo (2005) or direct measurement of properties via radioactive tracers as in Fernø et al 2009). …”

Section: Introductionmentioning

confidence: 99%

A Numerical Model of Transient Unsaturated Flow Under Centrifugation Based on Mass Balance

2011

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Numerical modeling of unsaturated flow in porous media under centrifugation is studied. A precise and numerically efficient approximation is presented for the mathematical model, based on Richards' nonlinear and degenerate equation expressed in terms of effective saturation using the Van Genuchten-Mualem ansatz. The main difference with other methods is the utilization of a nonlocal condition based on mass balance. The method is suitable for determination of soil parameters, including the saturated conductivity, via the solution of an inverse problem in an iterative way. First, the fully saturated sample is centrifugated with a free outflow boundary during some time interval. Next, the output boundary is sealed and the sample is centrifugated for a prescribed time interval, or up to the creation of an equilibrium. Finally, the centrifugation is continued with a free outflow boundary. This procedure can be repeated to increase the information to drive the inverse problem. The application of the present method requires only non-intrusive, cheap measurements: rotational momentum and/or gravitational center of the sample, and optionally, the amount of expelled water.

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“…Additionally, McCartney et al [18] proved that the centrifuge permeameter was successfully implemented as a recent instrument to determine the unsaturated hydraulic characteristics of soils [18]. Developing centrifugal setups has been attempted in several studies [6,13,19,20]. However, steady-state centrifuge methods were generally not adopted for a considerable period of time, especially when unsaturated.…”

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confidence: 99%

Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

Bui

Mori

2021

Water

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If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry a limited amount of soils out of particular regions. We performed a pinhole multistep centrifuge outflow method on three types of soil, which included granite decomposed soil (Masa soil), volcanic ash soil (Andisol soil), and alluvial clayey soil (paddy soil). The experiment was conducted using 2 mL and 15 mL centrifuge tubes in which pinholes were created on the top and bottom for air intrusion and outflow, respectively. Water content was measured at 5, 15, and 30 min after applying the centrifuge to examine the equilibrium time. The results showed that pinhole drainage worked well for outflow, and 15 or 30 min was sufficient to obtain data for each step. Compared with equilibrium data, the retention curve was successfully optimized. Although the curve shape was similar, unsaturated hydraulic conductivities deviated largely, which implied that Ks caused convergence issues. When Ks was set as a measured constant, the unsaturated hydraulic properties converged well and gave excellent results. This method can provide soil hydraulic properties of regions where soil sampling is limited and lacks soil data.

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Capillary Pressures by Fluid Saturation Profile Measurements During Centrifuge Rotation

Cited by 9 publications

References 16 publications

Experimental Evaluation on the Oil Saturation and Movability in the Organic and Inorganic Matter of Shale

Experimental Evaluation on the Oil Saturation and Movability in the Organic and Inorganic Matter of Shale

A Numerical Model of Transient Unsaturated Flow Under Centrifugation Based on Mass Balance

Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

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