The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Johann Plank - One of the best experts on this subject based on the ideXlab platform.
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synthesis characterization and performance of a novel phosphate modified fluid loss additive useful in oil Well Cementing
Journal of Natural Gas Science and Engineering, 2016Co-Authors: Thomas Hurnaus, Johann PlankAbstract:Abstract A phosphate-modified terpolymer comprising of 2-acrylamido-2-tert-butyl sulfonic acid (ATBS), N,N-dimethyl acrylamide (NNDMA) and 2-(methacryloxy)ethyl phosphate (MEP) was synthesized by aqueous free radical copolymerization and evaluated as fluid loss additive (FLA) in oil Well cement. Successful incorporation of MEP was confirmed via 1H NMR spectroscopy, and molecular properties of the terpolymer were determined using size exclusion chromatography. It was found that the presence of phosphate anchor groups along the polymer backbone enhances the FLA's performance in cement slurries at high temperatures (up to 140 °C) and in sea water when compared with commonly used ATBS-co-NNDMA or its counterpart composed of ATBS, NNDMA and 2-(methacryloxy)ethanol which bears a hydroxyl instead of the phosphate functionality. The phosphate-modified FLA also revealed better effectiveness and robustness when combined with acetone–formaldehyde–sulfite (AFS) dispersant or ATBS-co-acrylic acid retarder. Adsorption measurements suggest that the superior fluid loss performance is owed to higher adsorption of the phosphated FLA. Measurements of the adsorbed layer thickness on cationic polystyrene particles indicate that the phosphated FLA adsorbs in a train-like conformation which results from the strong affinity of the phosphate anchor groups to the positively charged surface.
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synthesis characterization and working mechanism of a synthetic high temperature 200 c fluid loss polymer for oil Well Cementing containing allyloxy 2 hydroxy propane sulfonic ahps acid monomer
Journal of Applied Polymer Science, 2013Co-Authors: Constantin Tiemeyer, Johann PlankAbstract:A polymer comprising of 2-acrylamido-2-methyl propane sulfonic acid, N, N-dimethyl acrylamide, allyloxy-2-hydroxy propane sulfonic acid (AHPS), acrylic acid, and N, N-methylene bisacrylamide was synthesized by aqueous free radical copolymerization and tested as high temperature performing fluid loss additive (FLA) in oil Well cement. Successful incorporation of AHPS was confirmed and characteristic properties of the copolymer were determined using size exclusion chromatography. The FLA showed excellent water retention in cement at 200°C/70 bar. At this temperature, polymer structure changed from branched to linear and hydrodynamic size decreased by ∼50%, thus indicating potential fragmentation, while performance remained unaffected by these alterations. The FLA copolymer does not viscosify cement slurries which is advantageous in high temperature Well Cementing. The working mechanism of the AHPS-based copolymer was found to rely on reduction of filtercake permeability which is caused by a voluminous coprecipitate of the FLA with tartaric acid retarder, mediated by Ca2+ ions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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co2 stability of portland cement based Well Cementing systems for use on carbon capture storage ccs Wells
Cement and Concrete Research, 2013Co-Authors: Matthias Lesti, Constantin Tiemeyer, Johann PlankAbstract:Abstract Three Portland cement based systems formulated with specific inorganic particles and organic admixtures were tested against conventional API Class G oil Well cement with respect to CO 2 tolerance. Hardened specimens (30 × 50 mm) were prepared and stored under supercritical CO 2 (90 °C/400 bar) for one and six months, respectively. CO 2 ingress was probed via phenolphthalein test and thermogravimetry. In all samples, formation of different CaCO 3 modifications was observed, proving carbonation. Carbonation rates were relatively low and similar, except for one sample. Most detrimental was cracking of specimens as a result of massive CaCO 3 formation which comes along with expansion. Best CO 2 resistance was obtained from a slag cement (CEM III) blended with a reactive filler which can bind large quantities of portlandite, and by providing pore space in the cementitious matrix for growing of CaCO 3 . The addition of latex polymers or of other organic admixtures did not provide much improvement over conventional API oil Well cement.
Alexandre Lavrov - One of the best experts on this subject based on the ideXlab platform.
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effect of eccentric annulus washouts and breakouts on Well Cementing quality laminar regime
Energy Procedia, 2016Co-Authors: Alexandre LavrovAbstract:Abstract Annular Cementing is an essential step in Well construction in underground CO 2 storage projects. The quality of Cementing depends on the quality of mud displacement by the fluids injected into the annulus during the Cementing job. An engineering numerical model of annular fluid displacement in a vertical Well was used in this study to investigate the effect of Well profile on the displacement quality. Annular displacement of the thinner fluid in place by the injected thicker fluid was modelled. The effect of the following factors on the displacement was studied: slightly irregular shape of the Well cross-section; eccentric positioning of the casing in a circular Well; a local washout (enlargement of the Well cross-section); throughgoing breakouts. Random irregularities of the Well cross-section were found to have only a minor effect on the advancement of the displacement front and on the injection pressure. Eccentric positioning of the casing pipe was found to cause flow channelization due to the yield-stress rheology of the fluids. The eccentricity was found to affect the injection pressure as Well. An isolated washout was found to have only a minor influence on the injection pressure and the displacement front propagation. Borehole breakouts were found to cause severe channelization of the injected fluid, and a substantial reduction in the injection pressure. Continuous enlargements of the annulus caused e.g. by borehole breakouts or eccentric positioning of the casing were thus shown to have a more detrimental effect on the annular displacement than a local, isolated enlargement caused e.g. by a washout. Abnormally low injection pressure during a Cementing job might serve as an indication of flow channelization through such a throughgoing enlargement.
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Properties of Well Cement
SpringerBriefs in Petroleum Geoscience & Engineering, 2016Co-Authors: Alexandre Lavrov, Malin TorsæterAbstract:Well Cementing involves pumping a sequence of fluids into the Well. Often these fluids, such as spacers and cement slurries, have non-Newtonian yield-stress rheology. After the cement slurry has been placed in the annulus, it hardens into a low-permeability annular seal. The complexity of these processes and the multitude of materials involved (drilling fluid, spacer, chemical wash, cement, casing, rocks) call for a sufficiently detailed material characterization in order to design and optimize cement jobs. A review of properties describing cements and other materials used in primary Cementing is presented in this chapter. Rheological properties of washes, spacers, and cement slurries that control their flow down the Well and up the annulus are discussed. Basics of non-Newtonian fluid rheology required to understand the subsequent chapters are laid out. Transition properties of cement slurry related to its solidification are reviewed. Mechanical, interfacial, hydraulic, and thermal properties of hardened cement that control e.g. response of cement to thermal stresses, vibrations, etc. are introduced, along with laboratory techniques used for their measurement (Brazilian test, uniaxial test, triaxial test, push-out test).
Helge Hodne - One of the best experts on this subject based on the ideXlab platform.
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potential utilization of class c fly ash based geopolymer in oil Well Cementing operations
Cement & Concrete Composites, 2014Co-Authors: Mahmoud Khalifeh, Arild Saasen, Torbjorn Vralstad, Helge HodneAbstract:Abstract The early age compressive strength development of class C fly ash-based geopolymers under high pressure and high temperatures of curing is considered as an alternative to Well cements. Uniaxial compressive strength (UCS) results show how the curing temperature affects the early compressive strength development. As the temperature rises from 87 to 125 °C, a consecutive reaction seems to take place at the higher concentrations of NaOH, which decrease the compressive strength at the higher temperature. The taken scanning electron microscope (SEM) images show a change in the morphology of the samples at 125 °C with the higher concentrations of NaOH. Ultrasonic cement analyzers (UCA) were employed to investigate the instantaneous strength development of the geopolymeric slurries. As the common cement models were not able to assess the compressive strength development, the custom algorithm option in the UCA software was applied. The developed empirical correlations were not able to accurately estimate the sonic strength of the slurries remarkably at 125 °C. The rheological measurements of the prepared geopolymeric slurries showed a Newtonian like behavior.
Sudong Hua - One of the best experts on this subject based on the ideXlab platform.
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developing high performance phosphogypsum based cementitious materials for oil Well Cementing through a step by step optimization method
Cement & Concrete Composites, 2016Co-Authors: Sudong Hua, Kejin Wang, Xiao YaoAbstract:Abstract In the present study, unprocessed phosphogypsum (PG), a byproduct generated by the phosphorus fertilizer industry, is mixed with conventional oil-Well cement (CM) and ground-granulated blast-furnace slag (GGBFS or SG), along with other activators and admixtures (such as silica fume (SF), retarder (USZ), and fluid loss control additive (BXF200-L)), to form a PGS slurry for oil Well Cementing. The mix proportion was optimized step-by-step according to the key properties of hardened PGS slurry, such as compressive strength, linear expansion, porosity, and permeability. The results indicate that the optimized PGS slurry (PGS-optimal slurry), made with the neat PGS:SF:USZ:BXF200-L (by weight) = 100:6:0.4:2, w/c = 0.44, where the neat PGS is consisting of a ratio of PG:SG:CM = 50:20:30 (by weight), had met major technical requirements for oil Well Cementing operation. Advantageous over the hardened CM slurry, the hardened PGS-optimal slurry generates significant expansion during hydration, thus providing the hardened slurry with excellent shrinkage compensation capability. The hardened PGS-optimal slurry has lower porosity, especially lower amount of harmful pores (>100 nm), than the hardened CM slurry. Consequently, the hardened PGS-optimal slurry also displays much lower permeability.
Mahmoud Khalifeh - One of the best experts on this subject based on the ideXlab platform.
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potential utilization of class c fly ash based geopolymer in oil Well Cementing operations
Cement & Concrete Composites, 2014Co-Authors: Mahmoud Khalifeh, Arild Saasen, Torbjorn Vralstad, Helge HodneAbstract:Abstract The early age compressive strength development of class C fly ash-based geopolymers under high pressure and high temperatures of curing is considered as an alternative to Well cements. Uniaxial compressive strength (UCS) results show how the curing temperature affects the early compressive strength development. As the temperature rises from 87 to 125 °C, a consecutive reaction seems to take place at the higher concentrations of NaOH, which decrease the compressive strength at the higher temperature. The taken scanning electron microscope (SEM) images show a change in the morphology of the samples at 125 °C with the higher concentrations of NaOH. Ultrasonic cement analyzers (UCA) were employed to investigate the instantaneous strength development of the geopolymeric slurries. As the common cement models were not able to assess the compressive strength development, the custom algorithm option in the UCA software was applied. The developed empirical correlations were not able to accurately estimate the sonic strength of the slurries remarkably at 125 °C. The rheological measurements of the prepared geopolymeric slurries showed a Newtonian like behavior.