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Operational Challenges In Transportation of Diverse Hydrocarbon Liquids: Commingled Flow of Gasto- Liquids (GTL) Products, Conventional Alaska North Slope (ANS) Crude And Heavy Crude Through the Trans Alaska Pipeline System (TAPS)
Dandekar, Abhijit Y. (University of Alaska Fairbanks) | Igbokwe, Chidiebere G. (University of Alaska Fairbanks) | Patil, Shirish L. (University of Alaska Fairbanks) | Chukwu, Godwin A. (University of Alaska Fairbanks) | Khataniar, Santanu (University of Alaska Fairbanks)
TAPS was originally designed and built for transporting 29oAPI Prudhoe Bay type crude oil from ANS to the marine terminal in Valdez. Combined oil production from ANS steadily declined since the peak output of 2.03 million barrels per day in 1988. The dwindling ANS oil production is, however, exerting increased burden on the economic operation of TAPS, raising an important question related to its sustained economic operation in the future. The proven and recoverable reserves of conventional natural gas in the developed and undeveloped fields on ANS are estimated to be 38 trillion standard cubic feet (TCF). Additionally, estimates of unconventional gas resources in the form of hydrates and coalbed methane are also significant. This in fact creates an interesting scenario; in that these vast gas resources are stranded because the domestic gas market is far way from ANS. The in-place resources of heavy oil on ANS are also huge, ranging between 20-25 billion barrels. However, heavy oil resources on ANS have received little attention, mainly because these oils are viscous and are difficult to transport. A feasible solution, in fact, lies in the combination of the foregoing problems and scenarios. The vast natural gas resources on the ANS can be chemically converted to produce GTL products on ANS which will provide additional liquid capacity to fill up TAPS. Additionally, ANS' heavy oil resources also have the potential to become future TAPS throughput. In this manner all three issues can be addressed, i.e., increase the economic life of TAPS; monetize the huge gas resources on the ANS by bringing it to market in the form of GTL and also bringing Alaska's heavy oil to market. Although, transportation of commingled GTL products, conventional and unconventional (heavy) oils is theoretically feasible; it is this diverse throughput and Alaska's arctic environment that poses several operational challenges such as pumpability, gel strength (cold restart problem), effect on density and viscosity, and solid organic deposition.
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.49)
- North America > United States > Alaska > North Slope Basin > Prudhoe Bay Field (0.99)
- North America > United States > Alaska > North Slope Basin > Kuparuk River Field > West Sak Field (0.99)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Precipitates (paraffin, asphaltenes, etc.) (1.00)
Development of High Deformability Linepipe With Resistance to Strain-aged Hardening By Heat Treatment On-line Process
Shinmiya, Toyohisa (JFE Steel Corporation) | Ishikawa, Nobuyuki (JFE Steel Corporation) | Okatsu, Mitsuhiro (JFE Steel Corporation) | Endo, Shigeru (JFE Steel Corporation) | Shikanai, Nobuo (JFE Steel Corporation) | Kondo, Joe (JFE Steel Corporation)
Linepipes installed in permafrost ground or seismic region, where larger strains can be expected by ground movement, are required to have sufficient deformability in order to prevent local buckling or girth weld fracture. On the other hand, deformability of linepipes usually degreases with increasing strength, and this is one of the reasons for preventing wider use of higher grade linepipe for high strain application. Furthermore, external coating is necessary for corrosion resistance of pipe, but coating heat can cause strain-aged hardening which results in increased yield strength and Y/T. Therefore, there is a strong demand for developing high strength and high deformability linepipe with resistance to strain-aged hardening for a high strain application. Extensive studies to develop high strength linepipes with higher deformability have been conducted. One of the key technologies for improving deformability is dual-phase microstructural control. Steel plate with bainite and martensite-austenite constituent (MA) microstructure can be obtained by applying heat treatment online process (HOP) subsequently after accelerated cooling process. HOP process is the induction heating process that enables rapid heating of the steel plates. Variety of microstructural control, such as fine carbide precipitation and MA formation, can be utilized by this newly developed heating process. One of the significant features of the HOP process is to improve resistance to strain-aged hardening. Both free carbon and dislocation density can be reduced by carbide precipitation and tempering of bainite. Coating simulation test for the HOP applied high deformability linepipe revealed excellent deformability after coating heating. Trial production of X70 to X100 high deformability linepipes was conducted by applying the HOP process. Microstructural characteristics and mechanical properties of developed linepipes are introduced in this paper. INTRODUCTION In recent studies, it is indicated that there are significant economical advantages of using higher strength linepipes in constructing long distance pipelines.
- Materials > Metals & Mining > Steel (0.69)
- Energy > Oil & Gas (0.50)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (0.66)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (0.47)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Piping design and simulation (0.47)
Flow assurance is increasingly challenging as the oil and gas industry is moving towards deeper water and longer transport distances. Formation of hydrate and ice plugs in the pipelines will have major cost impact and must be avoided as removal of plugs is a challenging and time consuming operation. At deeper water plug removal by depressurization may be impossible. As a mitigation measure active heating may be applied. Direct Electrical Heating (DEH) is now in use on several pipelines on the Norwegian Continental Shelf. In the DEH system the current is conducted to the far end of the pipe through a DEH cable. The temperature increases as current returns in the pipe. The increase of the temperature results in melting of the ice plug. Studies have shown that it is important to keep the separation distance from the cable to the pipeline small in order to limit the required supply current. Therefore the DEH cable is normally installed with the pipeline in a so-called "piggy-back" configuration. For Ormen Lange, however, DEH is designed for remediation purposes where DEH cable and equipment will be installed on demand. Installation evaluation confirms that a maximum average gap of 0.5 meters between cable and pipeline is feasible for Ormen Lange. This paper presents results from laboratory experiments where an ice plug is formed in a 4.5 m long 30" pipejoint. The ice plug was melted using DEH. Both the separation distance and current were varied. The experiments showed that 3% of the ice plug got melted at an ambient temperature of -2ºC and a pipe current of 1300A for 48 hours. 6% of the ice plug was melted when the applied current was increased to 1500A for 48 hours.
- Europe > Norway > Norwegian Sea > Møre Basin > PL 442 > Block 6305/8 > Ormen Lange Field > Springar Formation (0.99)
- Europe > Norway > Norwegian Sea > Møre Basin > PL 442 > Block 6305/8 > Ormen Lange Field > Egga Formation (0.99)
- Europe > Norway > Norwegian Sea > Møre Basin > PL 442 > Block 6305/6 > Ormen Lange Field > Springar Formation (0.99)
- (21 more...)
Calcareous Deposit Precipitation On Cathodically Polarized Carbon Steel In Natural Seawater Exposed to Daylight Cycles
Benedetti, A. (I.E.N.I – C.N.R) | Magagnin, L. (Politecnico di Milano) | Passaretti, F. (I.E.N.I – C.N.R) | Chelossi, E. (I.S.M.A.R – C.N.R) | Faimali, M. (I.S.M.A.R – C.N.R) | Montesperelli, G. (Università Politecnica delle Marche)
This paper deals with calcareous deposit precipitation occurring on cathodically protected carbon steel in natural seawater. Daylight cycles related effects were here investigated. Being O2 both cathodic reactant and key molecule of aerobic environments, a potential involving oxygen limiting current without hydrogen evolution (–850 mV vs. Ag/AgCl) was employed. Comparison of natural seawater with NaCl 3.5% wt. solution data showed that sunlight radiation plays a primary role with respect to temperature in affecting cathodic currents even in presence of electro-accreted aragonite. Calcareous deposit morphology and composition was investigated through SEM, highlighting properties and peculiarities. INTRODUCTION Cathodic protection is a widely employed technique which allows the oxidative power of environment affecting metals to be controlled. This can be achieved making the structure working as a cathode, where the reducing power necessary for the onset of cathodic processes can be supplied by impressed current or coupling to a less noble metal. This second way is preferably used in seawater where the metallic structure is protected with sacrificial anodes of aluminum, zinc or magnesium based alloys. In aerobic environments, current requirement for completely protect the structure is reached when the oxygen that comes in contact with the metallic surface is reduced (Foster et al. 1986). Hence, all the factors that control oxygen diffusion towards the surface also control the cathodic current behavior. As a result of the cathodic polarization is the alkalization at the metal/solution interface, where the increase of OH shifts the carbon dioxide system equilibrium towards the formation of carbonate and allowing the precipitation of CaCO3 to take place (Barchiche et al. 2003). The commonly called calcareous deposit is not formed only by CaCO3; if the alkalinity is enhanced with further cathodic polarization, when pH value of 9.5 is reached Mg(OH)2 starts to precipitate (Hartt et al. 1984).
- North America > United States (1.00)
- Europe (0.69)
The Direct Electrical Heating (DEH) system which has been qualified for flow assurance of subsea pipelines is now in use on several pipelines on the Norwegian Continental Shelf. Electrical heating has proven to be an attractive alternative for preventing plugs (hydrate) and wax deposition compared to the traditional methods that use chemical inhibitors, which are expensive and represents a risk to the environment. For design and rating of the DEH system, the supply current, the power loss (heat generation) in the pipeline and the total system impedance are the governing parameters. They are calculated by a computer program based on finite element (FE) analyses. Electrical and magnetic properties of steel pipe materials are essential data for determining heat generation and efficiency of the DEH system. These data are not available from the pipe manufacturers and have to be determined by measurements. Experience has shown that between individual pipejoints the resistivity is approximately invariant, but the magnetic properties may vary significantly even in pipejoints from the same production batch. A difference in magnetic characteristics of pipejoints results in a variation of the heat generation. Measurements of impedances have been carried out on a large number of pipejoints in a laboratory setup by supplying current directly to the pipejoints. A comparison is then made to FE simulations calculated with both linear and non-linear magnetic steel materials assuming eddy current losses only. FE simulations show good accordance for 13Cr steels (Steel material of 13% chromium content). For carbon steels the calculations deviate from the measured values. Modification of the simulation model is required in order to achieve acceptable agreement for both the system resistance (power loss) and the system reactance when using carbon steels. This will give reliable data for rating the topside and subsea DEH equipment.
Long-term Investigation of Composite Wrapping Systems For the Rehabilitation of Reinforced Concrete Structures
Karpate, H. (University of Texas at Austin) | Wheat, H.G. (University of Texas at Austin) | Jirsa, J.O. (University of Texas at Austin) | Fowler, D.W. (University of Texas at Austin) | Whitney, D.P. (University of Texas at Austin)
Almost nine years ago, a laboratory research program and field program were initiated to determine whether composite wrapping could be used as a means of rehabilitating corrosion-damaged structures. In the laboratory program, more than 60 cylindrical and rectangular specimens were designed to simulate bridge columns and beams. Some of the specimens were damaged, repaired and wrapped with composite materials, and then exposed to salt-containing environments. The composite systems used included a vinyl ester resin and two epoxy resins in combination with selected fabrics containing glass fibers. Variables included type of repair material, type of composite wrapping system, length of wrap, presence or absence of cracks, and presence or absence of pre-existing chlorides. Two years into the investigation, another set of 17 cylindrical specimens was cast and added to the investigation to examine the effect of spray-on or migrating corrosion inhibitors. Forensic analysis during the past seven years showed that in general, the composite wraps helped to minimize corrosion activity in the wrapped portions of the specimens, even if cracks and chlorides were initially present. INTRODUCTION Reinforced concrete bridge decks in marine environments and cold climates can suffer corrosion damage due to the ingress of chlorides from salt-laden air or deicing salts. Composite materials are currently being promoted for use in the rehabilitation of structures that have suffered corrosion damage. However, there is some concern that this might actually exacerbate the problem by trapping chlorides already present. One rehabilitation technique is to utilize traditional repair techniques in combination with composite wrapping systems that will restrict the intrusion of oxygen, chlorides and other aggressive species. The purpose of this investigation was to determine whether composite wrapping could be used to complement traditional repair techniques for the rehabilitation of corrosion-damaged concrete structures. Twelve reinforced concrete bridges were selected to be rehabilitated using fiber-reinforced plastic (FRP) wraps (Verhulst, 1999).
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Due to the recent development of deep water fields, the mechanical loads in flexible risers have been significantly increased and very high strength wires are often needed (SMUTS ≥ 1200 MPa). Moreover, the development of deep water fields containing H2S leads to consider some H2S content during the design phase. Steel wires are not in direct contact with the conveyed fluid, but are located in the annular space which is a specific medium for corrosion less severe than the bore. The new very high strength steel presented in this paper is compatible with annulus environment containing H2S and is very beneficial for designing deep water risers. INTRODUCTION This paper presents in a first part the qualification of a new high strength carbon steel wire (SMUTS = 1200 MPa) for use in low sour service conditions typical of new deep water and ultra-deep water developments. Results of Sulphide Stress Cracking (SSC) and Hydrogen Induced Cracking (HIC) tests are presented as well as corrosion fatigue curves. In a second part, it presents how the use of these high strength wires allows to design flexible risers for water depths of 1500 meter and deeper even with H2S in the conveyed fluid. Feasibility studies and project cases will show how larger diameter pipes and/or greater water depths are achievable while keeping the total suspended weight compatible with existing installation vessels. FLEXIBLE PIPE ANNULUS SPECIFICITY Flexible Pipe Presentation Flexible pipes are composed of different unbonded layers of polymers and steels, each layer being designed to resist to specific loadings. From the inside (bore) to the outside, a flexible pipe is typically composed of the following main layers (Fig. 1):Carcass: made of stainless steel strip which is formed and spiraled into an interlocking shape: resistance to external crushing. Internal thermoplastic pressure sheath: sealing protection towards bore environment.
- Europe (0.70)
- North America > United States (0.28)
The Role of Amorphous Structure On Corrosion Resistance: Corrosion Behavior of Amorphous And Crystalline Zr2Fe In Slightly Acidic Chloride Solution
Ayer, R. (ExxonMobil Research and Engineering Company) | Ling, S. (ExxonMobil Research and Engineering Company) | Jin, H.W. (ExxonMobil Research and Engineering Company) | Pokutylowicz, N. (ExxonMobil Upstream Research Company) | Koo, J.Y. (ExxonMobil Research and Engineering Company)
A Zr2Fe model alloy system was used to investigate the role of amorphous structure on corrosion resistance. Metal spun ribbons were prepared in single phase form in both the amorphous and crystalline states, with their respective atomic structures confirmed using X-ray diffraction and transmission electron microscopy. Electrochemical polarization measurements were carried out in 0.3wt% NaCl solution, pH=5.5, and active corrosion behavior were observed. The corrosion current density of the amorphous state was a factor of 13 lower, suggesting that the amorphous structure does provide a modest improvement in corrosion resistance. INTRODUCTION As the result of their non-periodic atomic structure, amorphous materials offer an attractive design basis for potentially enhanced properties ranging from high strength, improved corrosion resistance and magnetic properties. Of these, enhancements in strength and magnetic properties have been well demonstrated (Inoue, 1999). There have also been studies claimed to demonstrate several orders of magnitude enhancement in the corrosion resistance of amorphous alloys (Pardo et al., 2002). It has been suggested that the improvement in corrosion resistance in amorphous alloys has been attributed to the absence of line and planer defects such as dislocations and grain boundaries as well as to the lack of chemistry inhomogeneity (Diegle et al., 1983). The demonstration of improved corrosion resistance of the amorphous materials compared to their crystalline counterparts, however, suffers from the fundamental drawback that it is difficult to achieve an amorphous structure and a crystalline single phase material of the same alloy chemistry in most experimental and commercial systems. The most common route to prepare a crystalline analogue is to anneal the amorphous metal at elevated temperature (Johnson, 2002), but when crystallized, the material often decomposes into several individual phases depending on their chemistries. For example, this methodology is not suitable for the widely studied amorphous iron systems (Naka et al., 1979), which typically have significant metalloid contents (B, C, P, Si) that promote second phase precipitations during annealing.
- Materials > Metals & Mining (0.67)
- Energy > Oil & Gas > Upstream (0.48)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
The present investigation was carried out based on the idea to use nanometallic particles in thermal spray powders to give much more homogeneous metal binder phase in the sprayed coating with associated enhancement of the corrosion resistance. The nanosized particles of metal binder were made by spray pyrolysis experiments using microwave heating technology. The results achieved in this project clearly demonstrate the ability to make powders with nanometallic films deposited on WC particles. However, there was a huge oxygen problem related to the process and equipment employed. Moreover, this problem also caused metal loss during spray pyrolysis, as shown for both Co and Cr. Therefore, the oxygen problem should be eliminated during further experimental testing. The present way of making pre-alloyed metal binder deposited on WC particles represents huge potential for rapid implementation of advanced nanotechnology principles into practical industrial use, also allowing high volume production. INTRODUCTION In thermal spraying of erosion and corrosion resistant ceramic-metallic (cermet) coatings, the corrosion resistance is dependent on the metallic binder phase (Berget, 1998, Berget et al, 1997a, 1997b), while the erosion resistance is taken care of by the ceramic particles with WC as the best candidate (Rogne et al, 1999). Conventional production of powders for thermal spraying is based on agglomeration of WC powders with particles of single metals with final sintering and sieving. The use of such pure metal particles will inevitably provide very inhomogeneous metal binder, which may give insufficient corrosion resistance in certain applications. Therefore, the present investigation was carried out based on the idea to use nanometallic particles in thermal spray powders to give much more homogeneous metal binder phase in the sprayed coating with associated enhancement of the corrosion resistance. The nanosized particles of metal binder were made by spray pyrolysis experiments using microwave heating technology.
- Materials > Metals & Mining (0.49)
- Energy > Oil & Gas (0.47)
High pressure acid leach (HPAL) exposes low grade ore to very severe processing conditions in order to hydrometallurgically recover metals such as nickel, cobalt, and gold. Ball valves play a critical role in containing and directing the flow of the very hot acidic slurry within the autoclaves. A nanostructured titanium oxide (n-TiO2) coating has been developed with dramatically, superior abrasive and erosive wear resistance. Ball valves witH the n-Ti02 coating are currently being used in ten HPAL installations around the world. INTRODUCTION In 1996, United States Office of Naval Research's (ONR"s) Dr. Lawrence T. Kabacoff initiated a program entitled, "Thermal Spray Processing of Nanostructured Coatings". This program generated a number of successful coatings with practical and economical values (Kabacoff, 2202). Coatings exhibiting enhanced toughness, superior wear, and increased adhesion, have been developed, qualified (MIL STD 1687A) and applied onto Navy components. The high-pressure acid-leach (HPAL) process is currently being used to extract nickel, cobalt, and gold from low-grade ore. The HF"AL technology relies on very severe processing environment to economically leach and extract metal: The current processing environment consists of very hot (− 260 °C) and corrosive (up to 95 % sulfuric acid) slurry (20 wt% solids) at high pressures (4,700 to 5,500 kPa). The severe conditions found in Ni/Co HPAL require the ball valves to have protection against abrasive wear, erosive wear, and extreme corrosion. To extend the life of the ball valves while meeting the general mechanical requirements of the components, titanium alloy balls and seats are treated with various surfacing techniques. Amongst the surfacing technologies available, thermal spray application of single- and multi-layer coatings is predominantly used. Past and present specifications use top coats of chromia-blend or titania on titanium balls and seats with or without a metallic bond coat.
- North America > United States (0.49)
- North America > Canada (0.48)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (0.95)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (0.95)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (0.69)