Papers by Jens Henrik Hansen
SPE Annual Technical Conference and Exhibition, 2016
The Canadian Journal of Chemical Engineering, 2015
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Polymers for Advanced Technologies, 2015
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Macromolecular Materials and Engineering, 2015
The introduction of surface vinyl groups to PDMS microspheres broadens the latter's applicability... more The introduction of surface vinyl groups to PDMS microspheres broadens the latter's applicability range since the microspheres can be further functionalized or crosslinked into elastomers. Quantification of the surface vinyl concentration of PDMS microspheres is therefore essential. Here, a novel titration method, which is based on efficiently and covalently bonding mono-functional hydride to vinyl, is employed to determine surface vinyl concentration. The titration method exhibits good reproducibility in detection, thereby underlining its potential applicability as a general titration method for cured silicones. Vinyl functional PDMS microspheres are mixed with a hydride crosslinker and non-reactive silicone oil to create a system which allows for extensive crosslinking. Both visual observations and rheological studies show that a robust macroscopic PDMS elastomer is obtained upon crosslinking. Furthermore, the influence of stoichiometric imbalance, and the weight fraction of silicone oil on the terminal storage modulus of the macroscopic PDMS elastomer, is investigated. The wide range of stoichiometries facilitating crosslinking between the PDMS microspheres and the hydride crosslinker found in this study is beneficial for delivering PDMS elastomer to hard-to-reach places, since the sensitivity of the system on concentration fluctuations is small.
RSC Adv., 2014
Schematic diagram of the PDMS network around the microcapsule that leads to the trapping of HMS-3... more Schematic diagram of the PDMS network around the microcapsule that leads to the trapping of HMS-301 in the range 0.8 < r < 1.4.
Macromolecular Materials and Engineering, 2014
Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of... more Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of silicone droplets in a continuous aqueous phase. The commonly used PDMS elastomer, Sylgard 184 from Dow Corning, is used as the dispersed phase. PDMS is polymerized and cross-linked by reacting vinyl end-terminated poly(dimethyl siloxane) oligomers with dimethylmethylhydrogen siloxane cross-linkers via the hydrosilylation reaction using platinum catalyst and heat. Weight ratios of 10:1, 20:1, and 25:1 of the PDMS mixtures are used and emulsified in water using two water-soluble surfactants as stabilizers (sodium dodecyl sulphate and polyvinylalcohol). The temperature is subsequently increased to accelerate the rate of cross-linking and prevent the prepolymer droplets from coalescing. The particle size distribution of cured PDMS microspheres is determined by Mastersizer (laser diffraction). Finally, cured PDMS microspheres are coated with poly(methyl methacrylate) using a chemical process (solvent evaporation technique). Three solvents are used in three different experiments: dichloromethane, tetrahydrofuran, and acetone. The composition and morphology of the cured PDMS microspheres and PMMA coated cured PDMS microspheres are characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy in attenuated-total-reflection mode, optical microscopy, and thermogravimetric analysis. Curing profiles of PDMS elastomer with different ratios between the silicone elastomer base and the silicone elastomer curing agent are obtained. The reactivity of cured PDMS microspheres and PMMA coated cured PDMS microspheres are measured by rheology to evaluate the efficiency of the PMMA coating.
All Days, 2007
In 1999, Mærsk Olie og Gas AS introduced the Controlled Acid Jet (CAJ) completion and stimulation... more In 1999, Mærsk Olie og Gas AS introduced the Controlled Acid Jet (CAJ) completion and stimulation technique and over the last 7 years more than 300 km of reservoir sections have been implemented mainly in the Danish chalk fields (see SPE paper 78318 for a description of the concept). This method allows cost effective single operation acid stimulation of ultra long horizontal wells (15,000+ ft) in carbonate reservoirs. Successful implementation of the CAJ technique requires numerical modelling of the dynamics of the entire stimulation process to ensure equal distribution of the acid, effective control of the wormhole growth rate in all sections of the well, displacement of mud along the entire reservoir section, handling of significant (1,000+ psi) formation pressure gradients along the reservoir section etc. Especially the analysis of the mud displacement process along the horizontal sections has proven to be critical for optimising the completion design. The key to the successful f...
AIChE Journal, 1988
Most crude oils contain high molecular weight components, which at low temperatures may precipita... more Most crude oils contain high molecular weight components, which at low temperatures may precipitate as a wax phase. This may cause plugging of pipes and numerous other problems. This paper presents a solid-liquid equilibrium based model for the description of wax formation. The model for the Gibbs energy contains a contribution based on Flory's theory of multicomponent polymer solutions and a contribution from a metastable subcooled state which oil mixtures may attain. The latter is formulated in terms of the surface tension of the wax phase. Experimental wax appearance points (temperatures), WAP's, are reported for 17 different stabilized North Sea crude oils. The values predicted by the new model are in very good agreement with the experimental WAP's.
All Days, 2014
The present work focuses on experimental evidence of slug mitigation via various devices. The slu... more The present work focuses on experimental evidence of slug mitigation via various devices. The slug mitigation potential of a number of mixers was tested using a laboratory scale air/water setup to compare their effect on the incoming slugs just upstream of the separator inlet. Dedicated methods and key performance indicators were developed to characterize the slug properties and evaluate the mixers effectiveness.Such mitigation is especially interesting for the purpose of producing oil and gas from thin oil rims, in which wells are often drilled following the geological structure of the oil-bearing layer. These wells consequently contain many long, near-horizontal sections, through which the transport of the oil gas mixture often takes the form of slug flow, i.e. large volumes of liquid travelling at the velocity of the gas phase. As the gas cannot bypass the slugs, they are generally produced to the topside facilities, where they have a detrimental effect on the mechanical integrit...
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Papers by Jens Henrik Hansen