A Flow Assurance Assessment Of Possible Low Temperature Excursions Within A Flowline/Pipeline System

2011 ◽  
Author(s):  
Chris Mcdermott ◽  
Brad Dewalt
Keyword(s):  
Low Temperature ◽  
Flow Assurance ◽  
Pipeline System

Thermal Insulation With Latent Energy Storage for Flow Assurance in Subsea Pipelines

2015 ◽  
Author(s):  
Mohammad Parsazadeh ◽  
Xili Duan
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Insulation ◽  
Phase Change Materials ◽  
Heat Transfer Analysis ◽  
Flow Assurance ◽  
Pipeline System ◽  
Fluid Temperature ◽  
Latent Energy ◽  
Subsea Pipelines

Flow assurance is critical in offshore oil and gas production. Thermal insulation is an effective way to reduce heat loss from subsea pipelines and avoid the formation of hydrates or wax deposits that could block the flowlines. This paper presents heat transfer analysis from a subsea flowline with different insulation materials, particularly with nano-enhanced phase change materials (NPCMs) that allow thermal energy storage in the pipeline system. The phase change materials (PCMs) can effectively regulate fluid temperature during production fluctuations or increase the cool-down time during production shutdown. This paper considers a pipe in pipe configuration with different insulation methods; the cool-down times are calculated and compared. The results show that thermal insulation can greatly delay the fluid cool-down process. A significant improvement of cool-down time can be achieved with PCM energy storage under a good conventional insulation layer. Moreover, with nanoparticles in a PCM, the latent energy storage is enhanced thus it takes even longer time for the internal fluid to reach its hydrate formation temperature.

Effect of Low-Temperature Cleaning of Milking Equipment on the Microbiological Quality of Raw Milk

1983 ◽  
Vol 46 (1) ◽  
pp. 58-60 ◽  
Author(s):  
J. B. STONE ◽  
A. N. MYHR ◽  
I. DAVIE
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Negative Slope ◽  
Plate Count ◽  
Pipeline System ◽  
Standard Plate Count

Effect on the microbiological quality of milk of using a special cleaning detergent (Diversey-Wyandotte, Inc.) for low-temperature (initial 43.8°C, end of wash 35.4°C) washing in a milking parlor pipeline system was compared to regular high-temperature (initial 73°C, end of wash 43.8°C) wash of the system. Microbiological quality of the milk was determined by standard plate count (SPC) and psychrotrophic bacterial count (PBC). Cleanliness of equipment was evaluated by measurement of calcium deposits and visual inspection. Statistical analysis of data over time (June 5 to September 16, 1980) indicated no difference in SPC and PBC of milk between low-and high-temperature washing and, although there was a significant negative slope of PBC with time, this was due to factors other than treatment. Calcium soil deposition and visible evaluation of the equipment were not different for the wash temperatures.

scholarly journals Flow Assurance Study on Offshore Marginal Oil Field Development in Vietnam: The Case of Ca Ngu Vang Oil Field

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Van Thinh Nguyen ◽  
Thi Hai Yen NGUYEN
Keyword(s):  
Region Of Interest ◽  
Oil Field ◽  
Oil Fields ◽  
Flow Assurance ◽  
Pipeline System ◽  
Wax Deposition ◽  
Daily Production ◽  
Subsea Pipeline ◽  
Field Development ◽  
Method Of Production

Over the last few years, PetroVietnam has discovered and exploited several marginal oil fields such as Ca Ngu Vang, Te Giac Trang, Hai Su Den, Hai Su Trang, etc. however the reserves are modest. Test results received during drilling exploratory wells within these fields indicated that the maximum total daily production rate from the wells could promisingly range to about 20,000 barrels of oil per day (BOPD). Unfortunately, the optimum development of these offshore oil fields still offers numerous challenges to oil engineers due to the limitations of equipment and technology. Oil production activities worldwide show that if the daily production of an offshore oilfield is less than 20,000 BOPD, a connection of the marginal fields to their nearest larger oil field should be taken into consideration in order to efficaciously recover more crude oil. Often, this method of production requires a long subsea pipeline system. Besides, the transportation of the fluids from these fields to the processing platform will undergo several serious problems caused by the deposition of wax. All these matters should be handled to guarantee the performance of transportation. A number of models using PIPESIM, PIPEPHRASE and OLGA have been applied to design and examine the operations of the subsea pipeline in different working conditions. Results of the simulations proposed the use of passive insulation to economically eliminate wax deposition and recommended proper pipeline shutdown operations to minimize several problems related to flow assurance issues in the region of interest.

Dry tree well flow assurance challenges and solutions for offshore gas condensate field development

2014 ◽  
Vol 54 (2) ◽  
pp. 522
Author(s):  
Jeff Zhang ◽  
Ian Kopperman
Keyword(s):  
Low Temperature ◽  
Gas Condensate ◽  
Flow Assurance ◽  
Field Development ◽  
Start Up ◽  
Modelling Uncertainties ◽  
Operating Constraints ◽  
Operating Window ◽  
The Impact ◽  
Management Issues

Offshore field developments usually conceive that the dry tree wells (DTW) have less flow assurance challenges when compared with subsea development options. The relatively short vertical flow path for the DTW production risers causes fewer issues with respect to hydrate and wax management; however, the DTWs have particular flow assurance challenges due to dry tree well platforms design constraints. This extended abstract presents the various flow assurance challenges associated with the design and operation of DTWs for deepwater gas-condensate field developments, including: the impact of production riser annulus thermal behaviour and soil modelling uncertainties on the topsides materials selection; the coupling of low temperature propagation and cold liquid management issues topsides during cold well start-up; and, the narrow operating window to establish the forward flow for the downstream systems following cold well start-up. The absence of the capacity provided by subsea pipelines and flowlines, thus, leads to the requirement for integrated consideration of the DTWs and downstream topsides and potentially pipeline systems. The coupling for low temperature and liquid management issues, particularly for transient operations, requires rigorous flow assurance analysis. This extended abstract summarises the analytical solutions developed, applying the advanced flow assurance tools available, by considering the operating constraints, with the downstream process and export systems, to determine practical design solutions and operating philosophies.

Material Challenges in Arctic Areas

2007 ◽  
Author(s):  
Agnes Marie Horn ◽  
Per Egil Kvaale ◽  
Mons Hauge
Keyword(s):  
Low Temperature ◽  
Oil And Gas ◽  
Material Selection ◽  
Low Cost ◽  
Cost Effective ◽  
Structural Steels ◽  
Cold Climate ◽  
International Standards ◽  
Pipeline System ◽  
Oil And Gas Exploration

There is a lack of rules and standards that provide guidelines for material selection and qualification of materials for offshore and onshore structures in arctic areas. Many current standards for low temperature applications such as cryogenic piping and process systems do not reflect the need for low-cost bulk materials for large volume applications such as pipelines and production facilities. The growing focus on oil and gas exploration in arctic areas has raised the need for new standards and industry practice that supports cost effective and safe installation and operation of production and transport facilities in the cold climate. There are materials today that are applicable for low temperature conditions. The grades are often highly alloyed (typically 3–9% Ni) with good toughness properties, but these alloys are expensive compared to conventional steel material grades. Such materials may not be applicable in pipelines, structures and process plants. This challenge can be met in two ways. First, structural steels that are capable of being welded and operated in the cold climate should be developed and qualified. Second, materials for forged and casted components that can be welded to the structural steels should be developed and qualified to fit into the integrated structure or pipeline system. Some actions have been taken to develop new standards e.g. within ISO19906, and actions are being taken in Russia to harmonize their specifications with the international standards, but this is a comprehensive job and the work must be executed in parallel with the development of new steels and welding technology.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Field ion microscopy

1988 ◽  
Vol 46 ◽  
pp. 434-435
Author(s):  
Gert Ehrlich
Keyword(s):  
Low Temperature ◽  
Sample Surface ◽  
Low Pressure ◽  
Radius Of Curvature ◽  
Field Ion Microscopy ◽  
Phosphor Screen ◽  
Ion Microscopy ◽  
Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

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