Modeling of Compositional Grading in Heavy Oil Fields

2021 ◽  
Author(s):  
Andre Vinhal ◽  
Jawad Azeem ◽  
Karen Pedersen
Keyword(s):  
Relative Rate ◽  
Petroleum Reservoirs ◽  
Oil Fields ◽  
Compositional Variation ◽  
Fluid Viscosity ◽  
Compositional Gradient ◽  
Aromatic Components ◽  
Lower Temperature ◽  
Compositional Grading ◽  
The Impact

Abstract Field data for the compositional variation with depth in five petroleum reservoirs have been analyzed including one rich in asphaltenes with a very high compositional gradient. The data follows the well-known pattern with an increasing concentration of heavy components with depth. The observed compositional variation is higher than what could be explained by gravity segregation alone. An enthalpy term was added to take into account that the components have different preferences for residing at a higher or a lower temperature. It was found necessary to modify the enthalpy term to account for the impact of fluid viscosity and concentration of aromatic components on the relative rate at which smaller and larger molecules move in a fluid column. With this modification, a good match was seen of the compositional variation in the five reservoirs initially analyzed. The method was successfully tested on three other reservoirs, not part of the initial analysis, one of which had a fluid column of 970 m.

Viscosity Measurements for Various Mixed Fluids Used to Enhance Oil Recovery

2017 ◽  
Author(s):  
Mahmoud O. Elsharafi ◽  
Cody Chancellor ◽  
Denzel Kinyua ◽  
Reuben Denwe
Keyword(s):  
Oil Recovery ◽  
Oil Fields ◽  
Effect Of Temperature ◽  
Fluid Viscosity ◽  
Water Mobility ◽  
Reservoir Rocks ◽  
Viscosity Measurements ◽  
Different Types ◽  
Enhance Oil Recovery ◽  
The Impact

In mature reservoirs, the goal is to increase oil mobility and decrease water mobility. As a result, oil production will be increased and unwanted water production will be decreased. Surfactant and alkaline are widely used to change the wettability of reservoir rocks from oil wet to water wet. Viscosity measurements are important in finding out the impact viscous fluids on enhanced oil recovery (EOR). This project focuses on the viscosity measurements of various mixed fluids used in oil-fields to enhance oil recovery. Two types of surfactants (A and B) and one type of alkaline were utilized throughout the work. In addition, different types of oil obtained from different areas were implemented. The viscosity of these mixed fluids was measured while observing the implications of using varying surfactant and alkaline concentrations. Lastly, the effect of temperature on fluid viscosity was monitored.

A Novel Design of Landing Gear Oleo Strut Damper Using MR Fluid for Aircraft and UAV’s

2012 ◽  
Vol 225 ◽  
pp. 275-280
Author(s):  
Chandra B. Asthana ◽  
Rama B. Bhat
Keyword(s):  
Shock Absorber ◽  
Fluid Viscosity ◽  
Simulation Approach ◽  
Body Frame ◽  
Mr Fluid ◽  
Orifice Area ◽  
Aerial Vehicle ◽  
Impact Kinetic Energy ◽  
The Impact ◽  
Novel Design

Most landing gears used in aircraft employ very efficient oleo-pneumatic dampers to absorb and dissipate the impact kinetic energy of the aircraft body frame. A single-acting shock absorber is most commonly used in the oleo strut that has a metering pin extending through the orifice, which can vary the orifice area upon compression and extension of the strut. This variation is adjusted by shaping the metering pin so that the strut load is fairly constant under dynamic loading. In this paper, it is proposed to further change the damping coefficient as a function of time in order to achieve a semi-active control of the aircraft vibrations during landing by using Magnetorheological (MR) fluid in the Oleo. With the metering pin designed for a nominal flight condition, further variation in the fluid viscosity would help achieve the optimal performance in off-nominal flight conditions. A simulation approach is employed to show the effect of different profiles for viscosity variation in the MR fluid. The utility of such a damper can be very well exploited to include different criteria such as the landing distance after touchdown. This type of system can be used also in Unmanned Aerial Vehicle (UAV) application where the focus of design may be to accomplish the task without the consideration of passenger comfort.

Incorporating gout guideline advice into urate reports is associated with reduced hospital admissions: results of an observational study

Rheumatology ◽  
2021 ◽  
Author(s):  
Philip L Riches ◽  
Laura Downie ◽  
Carol Thomson
Keyword(s):  
Hospital Admissions ◽  
Relative Rate ◽  
Primary Diagnosis ◽  
Relative Increase ◽  
Local Data ◽  
Improved Outcomes ◽  
Significant Difference ◽  
Prescription Rates ◽  
The Impact ◽  
Health Boards

Abstract Objective To evaluate the impact of incorporating treatment guidance into reporting of urate test results. Methods Urate targets for clinically confirmed gout were added to urate results above 0.36 mmol/l requested after September 2014 within NHS Lothian. Scotland-wide data on urate-lowering therapy prescriptions and hospital admissions with gout were analysed between 2009 and 2020. Local data on urate tests were analysed between 2014 and 2015. Results Admissions with a primary diagnosis of gout in Lothian reduced modestly following the intervention from 111/year in 2010–2014 to 104/year in 2015–2019, a non-significant difference (P = 0.32). In contrast there was a significant increase in admissions to remaining NHS Scotland health boards (556/year vs 606/year, P < 0.01). For a secondary diagnosis of gout the number of admissions in NHS Lothian reduced significantly (58/year vs 39/year, P < 0.01) contrasting with a significant increase in remaining Scottish health boards (220/year vs 290/year, P < 0.01). The relative rate of admissions to NHS Lothian compared with remaining Scottish boards using a 2009 baseline were significantly reduced for both primary diagnosis of gout (1.06 vs 1.25, P < 0.001) and secondary diagnoses of gout (0.64 compared with 1.4, P < 0.001) after the intervention; however, there was no difference before the intervention. A relative increase in the prescription rates of allopurinol 300 mg tablets and febuxostat 120 mg tablets may have contributed to the improved outcomes seen. Conclusion Incorporation of clinical guideline advice into routine reporting of urate results was associated with reduced rates of admission with gout in NHS Lothian, in comparison with other Scottish health boards.

A Novel Gemini Cationic Viscoelastic Surfactant-Based Fluid for High Temperature Well Stimulation Applications

2021 ◽  
Author(s):  
Dawn Friesen ◽  
Brian Seymour ◽  
Aaron Sanders
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Chain Length ◽  
Surfactant Concentration ◽  
Gemini Surfactant ◽  
Alkyl Chain ◽  
Friction Reduction ◽  
Fluid Viscosity ◽  
Viscoelastic Surfactant ◽  
The Impact

Abstract Viscoelastic surfactant (VES)-based fracturing fluids can reduce the risk of formation damage when compared with conventional polymer-based fracturing systems. However, many VES systems lose viscoelasticity rapidly under high-temperature conditions, leading to high fluid leakoff and problems in proppant placement. A gemini cationic VES-based system offering thermal stability above 250°F and its efficiency in friction reduction is presented in this paper. Rheology measurements were conducted on viscoelastic cationic gemini surfactant fluids as a function of temperature (70 – 300°F) and surfactant concentration. The length of surfactant alkyl chain was varied to investigate the impact of surfactant chain length on VES fluid viscosity at elevated temperatures. The effect of flow rate on friction reduction capability of the surfactant fluid was measured on a friction flow loop. Foam rheology measurements were conducted to evaluate the VES fluid's ability to maintain high temperature viscosity with reduced surfactant concentration. A gemini cationic surfactant was used to prepare a viscoelastic surfactant system that could maintain viscosity over 50 cP at a shear rate of 100 s−1up to at least 250°F. With this system, viscoelastic gel viscosity was maintained without degradation for over 18 hours at 250°F, and the fluid showed rapid shear recovery throughout. Decreasing the average alkyl chain length on the surfactant reduced the maximum working temperature of the resulting viscoelastic gel and showed the critical influence of surfactant structure on the resulting fluid performance. The presence of elongated, worm-like micelles in the fluid provided polymer-like friction reduction even at low surfactant concentrations, with friction reduction of over 70% observed during pumping (relative to fresh water) up to a critical Reynolds number. Energized fluids could also be formulated with the gemini surfactant to give foam fluids suitable for hydraulic fracturing or wellbore cleanouts. The resulting viscoelastic surfactant foams had viscosities over 50 cP up to at least 300°F with both nitrogen and carbon dioxide as the gas phase. The information presented in this paper is important for various field applications where thermal stability of the treatment fluid is essential. This will hopefully expand the use of VES-based systems as an alternative to conventional polymer systems in oilfield applications where a less damaging viscosified fluid system is required.

scholarly journals Relative Rates of Gluten Digestion by Nine Commercial Dietary Digestive Supplements

2021 ◽  
Vol 8 ◽  
Author(s):  
Gregory John Tanner
Keyword(s):  
Amino Acids ◽  
Celiac Disease ◽  
Initial Rate ◽  
Relative Rate ◽  
Elisa Method ◽  
Fasting Stomach ◽  
The Mean ◽  
Stomach Volume ◽  
The Impact

Endopeptidases containing supplements may digest gluten and reduce the impact on celiac and gluten-sensitive subjects who inadvertently consume gluten. We investigated the relative rate of disappearance of coeliac relevant epitopes in extracts of nine commercial supplements, using two competitive enzyme-linked immunosorbent assays (ELISAs)—Ridascreen (detects QQPFP, QQQFP, LQPFP, and QLPFP) and Gluten-Tec (detects Glia-α20 and PFRPQQPYPQ). All epitopes are destroyed by cleavage after P and Q amino acids. Rates at pH 3.5 and pH 7.0 were measured. These experiments were designed to measure relative rates of epitope digestion not to mimic in vivo digestion. The supplements were: 1 GluteGuard, 2 GlutenBlock, 3 GliadinX, 4 GlutnGo, 5 GlutenRescue, 6 Eat E-Z Gluten+, 7 Glutenease, 8 Glutezyme, and 9 Gluten Digest. The mean initial rate and half-lives of epitope digestion were deduced and extrapolated to rates at the recommended dose of one supplement in a fasting stomach volume. At pH 7, supplement 1 was the fastest acting of the supplements, with Ridascreen ELISA, more than twice as fast as the next fastest supplements, 5, 6, 7, and 8. Supplements 2, 3, and 4 showed little activity at pH 7.0. Supplement 1 was also the fastest acting at pH 7 with Gluten-Tec ELISA, more than three times the rate for supplements 2 and 3, with supplements 4–9 showing minimal activity. At pH 3.5, supplement 1 acted more than five times as fast as the next fastest supplements, 2 and 3, when measured by Ridascreen, but supplements 2 and 3 were over two times faster than supplement 1 when measured by Gluten-Tec. Supplements 4–9 demonstrated minimal activity at pH 3.5 with either ELISA. Supplement 1 most rapidly digested the key immuno-reactive gluten epitopes identified by the R5 antibody in the Codex-approved competitive Ridascreen ELISA method and associated with the pathology of celiac disease.

Comparative Analysis of Autoxidation of Haemoglobin

2001 ◽  
Vol 204 (11) ◽  
pp. 2029-2033
Author(s):  
Frank B. Jensen
Keyword(s):  
Temperature Sensitivity ◽  
Oxidation Rate ◽  
Protective Role ◽  
Yellowfin Tuna ◽  
Histidine Residue ◽  
River Lamprey ◽  
Different Temperatures ◽  
Lower Temperature ◽  
The Impact

SUMMARY Autoxidation of oxyhaemoglobin (oxyHb) to methaemoglobin was measured at different temperatures in haemoglobin solutions from Atlantic hagfish, river lamprey, common carp, yellowfin tuna and pig. The aims were to evaluate the impact of the absent distal histidine in hagfish haemoglobin, the importance of oxyHb being either monomeric (hagfish and lamprey) or tetrameric (carp, tuna and pig) and to gain information on the temperature-sensitivity of autoxidation. The rate of autoxidation was lower in hagfish than in carp, yellowfin tuna and lamprey haemoglobins at any given temperature. Substitution of the distal histidine residue (His E7) with glutamine in hagfish haemoglobin was therefore not associated with an accelerated autoxidation, as might be expected on the basis of the normal protective role of His E7. Glutamine may have similar qualities to histidine and be involved in the low susceptibility to autoxidation. The low oxidation rate of hagfish haemoglobin, together with an oxidation rate of lamprey haemoglobin that did not differ from that of carp and yellowfin tuna haemoglobins, also revealed that autoxidation was not accelerated in the monomeric oxyhaemoglobins. Pig haemoglobin was oxidised more slowly than fish haemoglobins, demonstrating that fish haemoglobins are more sensitive to autoxidation than mammalian haemoglobins. The rate of autoxidation of hagfish haemoglobin was, however, only significantly greater than that of pig haemoglobin at high temperatures. Autoxidation was accelerated by rising temperature in all haemoglobins. Arrhenius plots of carp and yellowfin tuna haemoglobin revealed a break at 25°C, reflecting a lower temperature-sensitivity between 5 and 25°C than between 25 and 40°C.

scholarly journals Blowout Accident Impact Analysis Method for the Siting of Offshore Floating Nuclear Power Plant in Offshore Oil Fields

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Zhigang Lan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Impact Analysis ◽  
Oil Spills ◽  
Oil Field ◽  
Oil Fields ◽  
Offshore Oil ◽  
The Impact

Focused on the utilization of nuclear energy in offshore oil fields, the correspondence between various hazards caused by blowout accidents (including associated, secondary, and derivative hazards) and the initiating events that may lead to accidents of offshore floating nuclear power plant (OFNPP) is established. The risk source, risk characteristics, risk evolution, and risk action mode of blowout accidents in offshore oil fields are summarized and analyzed. The impacts of blowout accident in offshore oil field on OFNPP are comprehensively analyzed, including injection combustion and spilled oil combustion induced by well blowout, drifting and explosion of deflagration vapor clouds formed by well blowouts, seawater pollution caused by blowout oil spills, the toxic gas cloud caused by well blowout, and the impact of mobile fire source formed by a burning oil spill on OFNPP at sea. The preliminary analysis methods and corresponding procedures are established for the impact of blowout accidents on offshore floating nuclear power plants in offshore oil fields, and a calculation example is given in order to further illustrate the methods.

Numerical and experimental investigation on the effect of the two-phase flow pattern on heat transfer of piston cooling gallery

2019 ◽  
Vol 20 (5) ◽  
pp. 507 ◽  
Author(s):  
Lijun Deng ◽  
Jian Zhang ◽  
Guannan Hao ◽  
Jing Liu
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Unstable Wave ◽  
Fluid Viscosity ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Process ◽  
The Impact ◽  
Piston Cooling

To study factors affecting the formation and conversion of two-phase flow pattern as well as the heat transfer of piston cooling gallery, a transient visual target test bench was set up to research the oscillatory flow characteristics in the cooling gallery under idle condition of the engine. The computational fluid dynamics (CFD) was employed while dynamic mesh technology, SST k–ω turbulence model and volume of fluid (VOF) two-phase flow model were applied to simulate the flow process of piston cooling gallery so as to predict the distribution pattern of two-phase flow. Simulation results were in good agreement with that experimentally obtained. It was observed that in the reciprocating movement of the piston, the action of two-phase flow oscillation was severe, forming some unstable wave flows and slug flows. Results show that under the same pipe diameter, the increase of fluid viscosity results in the decrease of amplitude and the increase of the liquid slugs number as well as the enhancement on heat transfer effect. In addition, it was revealed that injection pressure has little effect on the two-phase flow pattern. However, when the pressure is reduced, the change of the liquid phase is weakened and the locations of flow pattern transition move towards to the behind, thus the impact on the heat transfer is also faint.

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