1,149 research outputs found
Brigadier General Thomas W. Sherman portrait
No full textCarte de visite portrait of Brigadier General Thomas W. Sherman, collected as part of the Howard Rossen Collection. Sherman (1813-1879) was born in Rhode Island and served in United States Army during the Second Seminole War, Mexican-American War and American Civil War. He held commands in the 3rd U.S. Artillery Regiment; the 1st Division, Army of the Ohio; and the 2nd Division, XIX Corps
Injectivity in Non-Newtonian two-phase flow
No full textA recent study [Rossen et al., 2011] developed a fractional-flow model (an extension of the Buckley-Leverett theory for a waterflood) for non-Newtonian two-phase flow (surfactant solution and gas) around a well. In this fractional-flow model two effects are represented: the decrease in water saturation Sw during gas injection in a SAG process and the non-Newtonian mobility with respect to radial position in the near-wellbore region, respectively. An important implication of this model is the relationship between these effects and injectivity. In this paper we create a model which determines injectivity as a function of time from data for water saturation and radial position, for shear thinning foam, modeled as a power-law fluid, in the near-wellbore region. We take the results generated by Rossen et al. and recast them in a form from which injectivity can be calculated. We compare the results, with both changing water saturation and non-Newtonian rheology, to two simpler cases: the effect of non-Newtonian rheology alone (effective viscosity changes with radial distance but Sw is assumed uniform) and the effect of water saturation alone (Sw varies with radial position but non-Newtonian effects are ignored) on injectivity. From these results we analyse whether or not it is essential to model both effects as in Rossen et al. We observe that the effects of non-Newtonian rheology on injectivity are far greater than those due to changing water saturation Sw in the near-wellbore region and that it is therefore not necessary to model both effects; one only needs to account for shear thinning. One limitation of this fractional flow model is that it disregards foam collapse. We found that this collapse of foam near the well has a much larger effect on injectivity than shear-thinning behavior. In order to determine how much the non-Newtonian rheology and nonuniform water saturation really affect injectivity, the foam model needs to be extended to include foam collapse. Furthermore, the factor (rw/re) in dimensionless position xD should not be disregarded in the MOC calculations, as it was in Rossen et al. [2011]. Doing so affects mobilities very close to the well and therefore affects injectivity. The model described in this paper focuses on non-Newtonian “strong” (shear thinning) foam flow; however, the approach could also be extended to polymer injection.Geoscience & EngineeringCivil Engineering and Geoscience
Model for gas sweep with foam
No full textIn this BSc-thesis a Surfactant-Alternating-Gas (SAG) foam displacement is represented by an idealized model. Shan and Rossen show in the article ‘Optimal Injection Strategies for Foam IOR’ (2004) that this model, though greatly simplified, is a useful representation of a foam displacement in the physical world, where pressure gradient is the most important factor in controlling gravity override. The process of building the model and numerical problems and solutions are discussed. The foam displacement is extended beyond the range computed by Shan and Rossen, to an dimensionless position XD of 4. The following cases are considered: kv = kh, 0<kv<kh and kv = 0. A comparison shows that the smaller the kv, the less convex the foam displacement front is. Ironically, in this case, increasing vertical permeability reduces the extent of gravity segregation of gas and increases vertical sweep.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Freeliving and plant parasitic nematodes from Spitzbergen, collected by Mr. H. van Rossen
No full textt. Eudorylaimus subjunctus ÇPublished as part of P.A.A. LOOF, 1971, FREELIVING AND PLANT PARASITIC NEMATODES FROM SPITZBERGEN, COLLECTED BY MR. H. VAN ROSSEN, pp. 1-86 in Mededelingen Landbouwhogeschool Wageningen 71 on page 69, DOI: 10.5281/zenodo.815298
Foam Generation with Flow Rate: Effect of Surfactant Concentration and Gas Fraction
No full textAbstract
The propagation of foam in an oil reservoir depends on the creation and stability of the foam in the reservoir, specifically the creation and stability of foam films, or lamellae. As the foam propagates far from in injection well, superficial velocity and pressure gradient decrease with distance from the well. Experimental (Friedmann et al., 1994) and theoretical (Ashoori et al., 2011) studies relate concerns about foam propagation at low superficial velocity to the minimum velocity for foam generation near the well (Rossen and Gauglitz, 1990; Gauglitz et al., 2002). The objective of this work is to measure the impact of surfactant concentration and gas fractional flow on foam generation. Theory (Rossen and Gauglitz, 1990; Kam and Rossen, 2003) relates foam generation to gas fractional flow and, indirectly, to the stability of foam films, or lamellae, which in turn depends on surfactant concentration (Apaydin and Kovcsek, 2001). However, the link between foam generation and surfactant concentration has not been established experimentally.
In our experiments, nitrogen foam is generated in a core of Bentheimer sandstone. The foamgeneration experiments consist of measuring the critical velocity for foam generation as a function of gas fractional flow at three surfactant concentrations well above the critical micelle concentration. Experimental results show that critical velocity decreases with increasing liquid fraction, as shown by previous foam generation studies (Rossen and Gauglitz, 1990; Friedmann et al., 1991). Additionally, our results show that the critical velocity decreases with increasing surfactant concentration, far above the CMC. We also propose a workflow for screening out the experimental artifacts that can distort the trigger velocity.</jats:p
Injectivity errors in foam EOR
No full textSimulators play a crucial role in EOR reservoir modeling. One of the big problems with the simulation of gas injection in SAG foam processes, is that foam collapse near the injection well is poorly represented in the simulator well model. This paper focusses on the question whether a simulator using the Peaceman equation for a homogeneous reservoir is accurate enough to simulate the increase in injectivity as foam near an injection well collapses at decreasing water saturation S_w. Four scenarios are examined; they have different foam-strength parameters and different wellbore grid-block radii. As a comparison to the simulation model, fractional-flow theory [Buckley and Leverett, 1941, Rossen et al., 2011] is used to represent the same scenarios. The differences, which represent errors in the simulator case with the Peaceman equation, are discussed. This comparison shows that the Peaceman equation gives very inaccurate injectivity for foam SAG processes.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Enterovirus and human Parechovirus infections in children: clinical symptoms, diagnosis and prognosis
No full textTutu-Furth, A.M. van [Promotor]Obihara, C.C. [Copromotor]Rossen, J.W.A. [Copromotor
Simulation models for the minimum velocity for foam generation and propagation
No full textFoam injection is a promising means of reducing the relative mobility of gas, and hence improving the sweep efficiency of gas, in CO2 and H2 storage, soil-contaminant removal in aquifer remediation, enhanced oil recovery, and matrix-acid well stimulation. Theory (Rossen and Gauglitz, 1990; Ashoori et al., 2012) and experiments (Gauglitz et al., 2002; Yu et al., 2019, 2020) indicate that both foam generation and propagation in steady flow in porous media require the attainment of a sufficiently large superficial velocity or pressure gradient ∇P. Here we examine several foam-simulation models for their ability to represent a minimum velocity, or trigger, for foam generation. We define criteria for representation of such a trigger. For simplicity, we assume a homogeneous porous medium and absence of an oleic phase. We examine the Population-Balance (PB) models of Kam and Rossen (2003) and one of its variants (Kam, 2008), and the PB model of Chen et al. (2010); and the implicit-texture (IT) models in CMG-STARS (Computer Modeling Group, 2017) and of Lotfollahi et al. (2017). Our result show that the PB models of Kam and Rossen and its variant, and the IT models of CMG-STARS and of Lotfollahi et al. do represent a minimum velocity for foam generation. They achieve this by modeling an abrupt decrease in gas mobility with increasing pressure gradient over some range of ∇P. The model of Chen et al. (2010) is based on the model of Kovscek and Radke (1996), which was not intended to represent a trigger for foam generation (Kovscek and Radke, 1993). We cannot say categorically whether it could predict a trigger for any set of model parameter values. Instead, we derive criteria that must be satisfied by the choice of parameters to represent a trigger for foam generation. In simulations of radial foam propagation the STARS foam model predicts that foam propagation fails at the radius at which local ∇P cannot maintain strong foam, not at a greater velocity and ∇P as seen in experiments (Yu et al., 2020). In addition, we identify a fundamental challenge in representing foam generation at the large ∇P at the wellbore in a numerical simulation: conventional simulators do not represent ∇P at the wellbore. Foam generation at the very high superficial velocity at the well radius is not represented in the absence of truly exceptional grid refinement.Reservoir Engineerin
Coreflood Study of Non-Monotonic Fractional-Flow Behavior with Foam: Implications for Surfactant-Alternating-Gas Foam EOR
No full textFoam is able to increase gas’s sweep efficiency in Enhanced-Oil-Recovery applications. A surfactant-alternating-gas, or SAG, process is usually preferred for placing foam in the reservoir. During a SAG process, foam is generated away from the wellbore, offering both good injectivity and good mobility control at the leading edge of the foam bank. Scale-up of laboratory data for SAG to field applications remains a challenge. Direct scale-up of dynamic SAG coreflood results is unreliable because of the dominance of core-scale artifacts. Steady-state coreflood data can be scaled up using fractional-flow theory (Kibodeaux and Rossen, 1997; Rossen and Boeije, 2015). However, about half the published laboratory studies of foam fractional-flow curves report non-monotonic behavior, where at some point liquid saturation Sw increases with decreasing liquid fractional flow fw. Rossen and Bruining (2007) warn that such behavior would result in foam collapse during injection of the gas slug in a SAG process at the field scale. Here we report and analyse a series of steady-state and dynamic coreflood experiments to investigate the occurrence of non-monotonic fractional-flow behavior. These corefloods vary surfactant concentration, injected gas fraction (foam quality) and total superficial velocity and are supported by CT measurements. The CT data confirm that in these cases, as foam weakens with decreasing fw, liquid saturation increases, confirming the non-monotonic fw(Sw) behaviour. In our results, every case of non-monotonic fractional-flow behavior begins with propagation of foam from the inlet, followed by eruption of a much-stronger foam at the outlet of the core and backwards propagation of the stronger foam state to the inlet, similar to behavior reported by Apaydin and Kovscek (2001) and Simjoo et al. (2013). This suggests that there may be more than one stable local-equilibrium (LE) foam state. The initial creation of the stronger foam near the outlet is at least in part due to the capillary end effect. It is thus not clear which LE foam state controls behaviour in a SAG process in the field. In our results, the subsequent transition from a stronger- to a weaker-foam state, leading to non-monotonic fw(Sw) behavior, coincides with conditions for weaker foam (lower surfactant concentration, lower fw) and less-vigorous foam generation (lower superficial velocity); this agrees with the theory of foam propagation of Ashoori et al. (2012). We discuss the implications of these findings, if confirmed to apply generally, for design of SAG foam processes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin
- …
