Thermal Benefits With Subsea Heat Bank

2002 ◽  
Author(s):  
Kristin Falk ◽  
Rune Killie ◽  
Svein Ha˚heim ◽  
Per Damsleth
Keyword(s):  
Oil And Gas ◽  
Hydrate Formation ◽  
Cost Effective ◽  
Effective Field ◽  
Production Equipment ◽  
Cfd Simulations ◽  
Field Development ◽  
Gas Hydrate Formation ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Subsea production of oil and gas involves structures on the seabed such as manifolds and X-mas trees that require thermal insulation of piping and valves to avoid gas hydrate formation. The insulation is expensive and time consuming to apply yet may still leave areas with inadequate protection. These “cold spots” accelerate the cooling during a production shutdown. A Heat-Bank concept is developed as an alternative to conventional insulation. The entire subsea structure is covered with an insulated shell. During shutdowns the heated fluid inside the cover keeps the production equipment warm over a prolonged period before hydrates start to form. Computational Fluid Dynamics (CFD) simulations are used to quantify the heat loss effects of natural convection and leakage through openings in the cover. The CFD analyses demonstrate the relative performance of the concept compared to the traditional method of insulating individual piping components. Application of the Heat-Bank concept opens new possibilities for environmentally friendly and cost-effective field development, especially for deep water.

scholarly journals Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1107
Author(s):  
Seong-Pil Kang ◽  
Dongwon Lee ◽  
Jong-Won Lee
Keyword(s):  
Oil And Gas ◽  
Hydrate Formation ◽  
Flow Characteristics ◽  
Cost Effective ◽  
Sorbitan Monooleate ◽  
Natural Sources ◽  
Gas Hydrate Formation ◽  
Agglomeration Effects ◽  
Span 80 ◽  
Water Cut

Kinetic hydrate inhibitors (KHI) and anti-agglomerants (AA) rather than thermodynamic hydrate inhibitors (THI) are often used for flow assurance in pipelines. This is because they require much lower dosages than thermodynamic inhibitors. Although the hydrate-phase equilibria are not affected, KHI and AA prevent the formed hydrate crystals from growing to a bulky state causing pipeline blockage. However, these KHIs might have huge environmental impact due to leakages from the pipelines. In this study, two biodegradable AA candidates from natural sources (that is, lecithin and lanolin) are proposed and their performances are evaluated by comparing them with and without a conventional AA (Span 80, sorbitan monooleate). At 30% and 50% water cut, the addition of AA materials was found to enhance the flow characteristics substantially in pipelines and hardly affected the maximum value of the rotational torque, respectively. Considering the cost-effective and environmental advantages of the suggested AA candidates over a conventional AA such as Span 80, the materials are thought to have potential viability for practical operation of oil and gas pipelines. However, additional investigations will be done to clarify the optimum amounts and the action mechanisms of the suggested AAs.

Challenges in Hydrate Plug Prevention in Pipelines Seen Over the Lifetime of a Field

2009 ◽  
Author(s):  
Casper Hadsbjerg ◽  
Kristian Krejbjerg
Keyword(s):  
Oil And Gas ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Extended Period ◽  
Oil And Gas Industry ◽  
High Water ◽  
Point Of View ◽  
Field Development ◽  
Hydrate Plug ◽  
Subsea Pipelines

When the oil and gas industry explores subsea resources in remote areas and at high water depths, it is important to have advanced simulation tools available in order to assess the risks associated with these expensive projects. A major issue is whether hydrates will form when the hydrocarbons are transported to shore in subsea pipelines, since the formation of a hydrate plug might shut down a pipeline for an extended period of time, leading to severe losses. The industry practices a conservative approach to hydrate plug prevention, which is the addition of inhibitors to ensure that hydrates cannot form under pipeline pressure and temperature conditions. The addition of inhibitors to subsea pipelines is environmentally unfriendly and also a very costly procedure. Recent efforts has therefore focused on developing models for the hydrate formation rate (hydrate kinetics models), which can help determine how fast hydrates might form a plug in a pipeline, and whether the amount of inhibitor can be reduced without increasing the risk of hydrate plug formation. The main variables determining whether hydrate plugs form in a pipeline are: 1) the ratio of hydrocarbons to water, 2) the composition of the hydrocarbons, 3) the flowrates/flow regimes in the pipeline, 4) the amount of inhibitor in the system. Over the lifetime of a field, all 4 variables will change, and so will the challenge of hydrate plug prevention. This paper will examine the prevention of hydrate plugs in a pipeline, seen from a hydrate kinetics point of view. Different scenarios that can occur over the lifetime of a field will be investigated. Exemplified through a subsea field development, a pipeline simulator that considers hydrate formation in a pipeline is used to carry out a study to shed light on the most important issues to consider as conditions change. The information gained from this study can be used to cut down on inhibitor dosage, or possibly completely remove the need for inhibitor.

Abandonment Best Practices in Unitised Area for Wells and Facilities Straddling Two Countries in Malay Basin: A Case Study

2021 ◽  
Author(s):  
Kumar Nathan ◽  
M Arif Iskandar Ghazali ◽  
M Zahin Abdul Razak ◽  
Ismanto Marsidi ◽  
Jamari M Shah
Keyword(s):  
Oil And Gas ◽  
Late Life ◽  
Cost Effective ◽  
Successful Outcome ◽  
Maintenance Cost ◽  
Gas Field ◽  
Field Development ◽  
Host Government ◽  
Cycle Oil

Abstract Abandonment is considered to be the last stage in the oil gas field cycle. Oil and gas industries around the world are bounded by the necessity of creating an abandonment program which is technically sound, complied to the stringent HSE requirement and to be cost-effective. Abandonment strategies were always planned as early as during the field development plan. When there are no remaining opportunities left or no commercially viable hydrocarbon is present, the field need to be abandoned to save operating and maintenance cost. The cost associated on abandonment can often be paid to the host government periodically and can be cost recoverable once the field is ready to be abandoned. In Malaysia, some of the oil producing fields are now in the late life of production thus abandonment strategies are being studied comprehensively. The interest of this paper is to share the case study of one of a field that is in its late life of production and has wells and facilities that planned to be abandon soon. The abandonment in this field is challenging because it involves two countries, as this field is in the hydrocarbon structure that straddling two countries. Series of techno-commercial discussion were held between operators of these two countries to gain an integrated understanding of the opportunity, defining a successful outcome of the opportunity and creating an aligned plan to achieve successful abandonment campaign. Thus, this paper will discuss on technical aspects of creating a caprock model, the execution strategies of abandoning the wells and facilities and economic analysis to study whether a joint campaign between the operators from two countries yields significantly lower costs or otherwise.

scholarly journals Performance of Waterborne Polyurethanes in Inhibition of Gas Hydrate Formation and Corrosion: Influence of Hydrophobic Fragments

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5664
Author(s):  
Roman S. Pavelyev ◽  
Yulia F. Zaripova ◽  
Vladimir V. Yarkovoi ◽  
Svetlana S. Vinogradova ◽  
Sherzod Razhabov ◽  
...  
Keyword(s):  
Corrosion Inhibitor ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Oxygen Demand ◽  
Oil And Gas Industry ◽  
Dual Function ◽  
Structure Property ◽  
Tert Butyl ◽  
Waterborne Polyurethanes ◽  
Gas Hydrate Formation

The design of new dual-function inhibitors simultaneously preventing hydrate formation and corrosion is a relevant issue for the oil and gas industry. The structure-property relationship for a promising class of hybrid inhibitors based on waterborne polyurethanes (WPU) was studied in this work. Variation of diethanolamines differing in the size and branching of N-substituents (methyl, n-butyl, and tert-butyl), as well as the amount of these groups, allowed the structure of polymer molecules to be preset during their synthesis. To assess the hydrate and corrosion inhibition efficiency of developed reagents pressurized rocking cells, electrochemistry and weight-loss techniques were used. A distinct effect of these variables altering the hydrophobicity of obtained compounds on their target properties was revealed. Polymers with increased content of diethanolamine fragments with n- or tert-butyl as N-substituent (WPU-6 and WPU-7, respectively) worked as dual-function inhibitors, showing nearly the same efficiency as commercial ones at low concentration (0.25 wt%), with the branched one (tert-butyl; WPU-7) turning out to be more effective as a corrosion inhibitor. Commercial kinetic hydrate inhibitor Luvicap 55 W and corrosion inhibitor Armohib CI-28 were taken as reference samples. Preliminary study reveals that WPU-6 and WPU-7 polyurethanes as well as Luvicap 55 W are all poorly biodegradable compounds; BODt/CODcr (ratio of Biochemical oxygen demand and Chemical oxygen demand) value is 0.234 and 0.294 for WPU-6 and WPU-7, respectively, compared to 0.251 for commercial kinetic hydrate inhibitor Luvicap 55 W. Since the obtained polyurethanes have a bifunctional effect and operate at low enough concentrations, their employment is expected to reduce both operating costs and environmental impact.

CO2-saturated Salinity Environment Effects on Ni-Mo Alloys at Gas Hydrate Formation Temperatures

2019 ◽  
Author(s):  
Christopher Ozigagu ◽  
Ting Zhou ◽  
Stephen Sanders ◽  
Teresa Golden
Keyword(s):  
Corrosion Resistance ◽  
Deep Water ◽  
Gas Hydrate ◽  
Surface Characterization ◽  
Oil And Gas ◽  
High Salinity ◽  
Hydrate Formation ◽  
Test Solution ◽  
Low Salinity ◽  
Gas Hydrate Formation

Corrosion and gas hydrate formation are flow assurance problems that can cause serious safety problems in deep water environments. One aspect that has been given less attention is the corrosion behavior of materials in salinity environment where gas hydrate formation and CO2 (sweet) corrosion can both occur. This type of environment is common in oil and gas deep water environments. The aim of this work is to investigate the effects of CO2-saturated salinity environment on Ni-Mo alloys at gas hydrate formation temperatures using electrochemical, SEM/EDX, and XRD surface characterization techniques. The immersion test solutions were sweet low-salinity (CO2 + 1 wt% salt + 5 oC) and sweet high- salinity (CO2 + ~24 wt% salt + 5 oC) environments, respectively. The as-deposited Ni-Mo alloy coating has the highest corrosion resistance of 33.28 kΩ cm2. The corrosion resistance dropped to 14.36 kΩ cm2 and 11.11 kΩ cm2 after 20 hrs of immersion in the sweet low-salinity and sweet high-salinity test solutions respectively. From grazing incidence XRD, the (111) reflection peak of the Ni-Mo coating was depressed and broaden after immersion in both test solutions due to increase in oxide layer formation on the surface of the Ni-Mo coating. SEM revealed a cracked surface morphology after immersion in sweet high-salinity test solution and elemental analysis shows the presence of oxygen after immersion in both test solutions. The oxygen content increased from 1.70 wt% after immersion in sweet low-salinity test solution to 2.37 wt% after immersion in sweet high-salinity test solution.

Design of a Thermal Mass Flow Meter for Measurements Within the Rotor Rim Ducts of a Hydroelectric Generator

2018 ◽  
Author(s):  
Kevin Venne ◽  
Laurent Mydlarski ◽  
Federico Torriano ◽  
Mathieu Kirouac ◽  
Jean-Philippe Charest-Fournier ◽  
...  
Keyword(s):  
Mass Flow ◽  
Cost Effective ◽  
Thermal Mass ◽  
Complex Flows ◽  
Cfd Simulations ◽  
Flow Meter ◽  
Hydroelectric Generator ◽  
Computational Fluid Dynamics Cfd ◽  
Critical Components ◽  
Proper Operation

To ensure the proper operation of hydroelectric generators, their cooling must be well understood. However, the airflow within such machines is difficult to characterize, and although Computational Fluid Dynamics (CFD) can be a reliable engineering tool, its application to the field of hydroelectric generators is quite recent and has certain limitations which are, in part, due to geometrical and flow complexities, including the coexistence of moving (rotor) and stationary (stator) components. For this reason, experimental measurements are required to validate CFD simulations of such complex flows. Of particular interest is the quantification of the flow within the rotor rim ducts, since it is directly responsible for cooling the poles (one of the most critical components of a hydroelectric generator). Thus, to measure the flow therein, an anemometer was designed. The anemometer had to be accurate, durable, cost-effective, easy to install, and able to withstand the extreme conditions found in hydroelectric generators (temperatures of 45°C, centrifugal forces of 300 g, etc.). In this paper, a thermal mass flow meter and a method for validating its performance, using hot-wire anemometry and a static model of a rotor rim, are described. Preliminary tests demonstrate that the thermal mass flow meter is capable of i) measuring the mass flow rate in the rotor rim ducts with an accuracy of approximately 10%, ii) fitting inside small rectangular ducts (12.2 mm by 51 mm), and iii) resisting forces up to 300 g.

scholarly journals EPS Conceptual Design for GoM Deepwater Fields

2010 ◽  
Author(s):  
Michael Choi ◽  
Andrew Kilner ◽  
Hayden Marcollo ◽  
Tim Withall ◽  
Chris Carra ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Oil And Gas ◽  
Cost Effective ◽  
Test System ◽  
Well Test ◽  
Well Performance ◽  
Compressed Natural Gas ◽  
Full Field ◽  
Field Development ◽  
Early Production

To avoid making billion dollar mistakes, operators with discoveries in deepwater (∼3,000m) Gulf of Mexico (GoM) need dependable well performance, reservoir response and fluid data to guide full-field development decisions. Recognizing this need, the DeepStar consortium developed a conceptual design for an Early Production System (EPS) that will serve as a mobile well test system that is safe, environmentally friendly and cost-effective. The EPS is a dynamically positioned (DP) Floating, Production, Storage and Offloading (FPSO) vessel with a bundled top tensioned riser having quick emergency disconnect capability. Both oil and gas are processed onboard and exported by shuttle tankers to local markets. Oil is stored and offloaded using standard FPSO techniques, while the gas is exported as Compressed Natural Gas (CNG). This paper summarizes the technologies, regulatory acceptance, and business model that will make the DeepStar EPS a reality. Paper published with permission.

New «green» inhibitors of gas hydrate formation for the oil and gas industry based on polysaccharides

2021 ◽  
pp. 33-40
Author(s):  
V.A. Dokichev ◽  
◽  
A.I. Voloshin ◽  
N.E. Nifantiev ◽  
M.P. Egorov ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Field Tests ◽  
Oil And Gas Industry ◽  
Quasi Equilibrium ◽  
Green Inhibitor ◽  
Gas Industry ◽  
Gas Hydrate Formation ◽  
Thermobaric Conditions

The thermobaric conditions for the formation of gas hydrates in the presence of the sodium salt of carboxymethylcellulose, dextran, and arabinogalactan were studied in a quasi-equilibrium thermodynamic experiment. It is established that polysaccharides slow down the rate and change the conditions of gas hydrate formation of a mixture of natural gases, showing the properties of a thermodynamic and kinetic inhibitor with technological efficiency exceeding methanol by 170-270 times when used in the same dosages. The results of the development of a «green» synergistic inhibitor of gas hydrate formation «Glycan RU» on their basis are presented, which includes a combination of thermodynamic and kinetic inhibitors. Pilot field tests of «Glycan RU» were carried out at the wells of the Priobskoye, Prirazlomnoye, Ombinsky, Zapadno-Ugutskoye oilfields. It was found that at dosages of 1000 g/m3 and 500 g/m3, there is no formation of hydrate plugs in the annulus. «Glycan RU» is recommended for industrial use by the technology of periodic injection and/or continuous dosing through wellhead dispensers. Keywords: carboxymethylcellulose; dextran; arabinogalactan; polysaccharides; «green» inhibitor of gas hydrate formation; «Glycan RU».

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