Flow Assurance Design Considerations for Umbilical Riser Base Gas Lift System

High angle wells are compulsory in offshore fields. These types of wells require better understanding on flow assurance dynamics and better planning on well intervention to ensure their operational efficiency. It is important to note that several wells have been experiencing severe production decline even though the current reservoir pressure is still high. In order to have a comprehensive understanding on liquid fallback, a transient fluid flow approach has been employed to investigate multiphase flow during gas lift operations. The simulation presents a 3-dimensional, time-based output that can simulate liquid fallback or severe slugging in pipe as a function of pipe diameter, gas lift valve placement, injected gas rate, and reservoir pressure that can address the flow assurance dynamics. The results from this research can be developed as an additional technical consideration before designing a gas lift system in highly deviated wells. Consideration on the placement of gas lift valves are also paramount in these cases, mainly avoiding places with flow instability or regions with sudden velocity changes. Results from the study, combined with well based performance are then compiled as a general guidance for the contractor to design a gas lift system on the basis of reservoir parameters such as Productivity Index, liquid viscosity and density, well deviation and trajectory, and gas supply to ensure operational and design excellence on gas lift design for deviated wells. Transient based simulation improved completion and gas lift design modification in the Lima Field, where higher and stable liquid production from daily production monitoring resulted in less well intervention from these wells.

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Software Simulation for Making Severe Slugging Control Strategy in Deepwater Riser

Volume 5: Materials Technology; Petroleum Technology ◽

10.1115/omae2014-23031 ◽

2014 ◽

Author(s):

Bing Cheng ◽

Qingping Li ◽

Xichong Yu ◽

Haiyuan Yao

Keyword(s):

Control Strategy ◽

Oil And Gas ◽

Hydrate Formation ◽

Flow Assurance ◽

Fluid Composition ◽

Gas Field ◽

Software Simulation ◽

Oil And Gas Field ◽

Deepwater Riser ◽

Gas Lift

As one aspect of flow assurance considerations, severe slugging control strategy in deepwater riser is related to the safety of production system, therefore it’s of great significance to the development of deepwater oil and gas field. This paper summarizes commonly used severe slugging control methods briefly, then takes certain deepwater oil and gas field as an example to introduce the method of software simulation for making severe slugging control strategy of deepwater riser. Firstly the model is built with basic information such as pipeline route, production profile and fluid composition. Data of typical years is used to simulate flowing conditions to determine whether it’s within slugging zone. To mitigate slugging conditions, choking, gas lift and choking& gas lift combined methods are chosen and simulated based on the oil and gas field characteristics, and according to the results gas lift is suggested as the best solution. Factors such as riser type, gas injection location, and flexible riser depth are analyzed for better gas lift efficiency. Finally hydrate formation risk related to severe slugging is analyzed and the slug catcher size is checked. Based on the introduced software simulation procedure, severe slugging control strategy is made, which will be valuable for deepwater flow assurance design and study.

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Design Perspectives for Selection of Subsea Gas Lift Technology for Deep Water Fields

10.4043/31108-ms ◽

2021 ◽

Author(s):

Ligia Tornisiello ◽

Stephane Taxy ◽

Rick Curto

Keyword(s):

Deep Water ◽

Evaluation Process ◽

Holistic Approach ◽

Technical Solution ◽

Field Development ◽

Development Cycle ◽

Technical Solutions ◽

Gas Lift ◽

Base Gas ◽

Selection Of

Abstract Riser base gas lift is conventionally used in deep water fields to minimize backpressure on wells, smooth start-up transients, and mitigate slugging in the flowline-riser system which can cause disruption in the topside facilities. The effectiveness of riser base gas lift depends on several factors, such as the reservoir performance, the fluid properties, the field architecture, and the topography. There are several technical solutions available to deliver the lift gas to the riser base. Such technical solutions differ in terms of lift-gas supply method (distributed vs point-to-point), riser specifications, and overall system complexity. The selection of technical solution has the potential for minimizing infrastructure. Available solutions include bundled risers and concentric riser configurations that allow gas lift functions to be integrated with the main production conduit. The evaluation of riser base gas lift effectiveness and the selection of the most appropriate technical solution is typically performed early in the field development cycle. This paper presents a review of the available subsea gas lift technical solutions and discusses an evaluation process, including criteria for the selection of the most appropriate solution. The presented case study assumes a deep water Gulf of Mexico field, in which the main subsea system consists of two wet insulated piggable flowline loops. Key decision drivers were flow assurance requirements, complexity, operability, impact on field layout, interfaces, installation, and schedule are discussed. This holistic approach aids the selection of the most appropriate riser base gas lift system in the early field development cycle.

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Morphological behavior of compatibilized ternary blends prepared by mechanical mixing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151830 ◽

1993 ◽

Vol 51 ◽

pp. 1200-1201

Author(s):

S.D. Smith ◽

R.J. Spontak ◽

D.H. Melik ◽

S.M. Buehler ◽

K.M. Kerr ◽

...

Keyword(s):

Interfacial Adhesion ◽

Diblock Copolymers ◽

Ternary Blends ◽

Mechanical Mixing ◽

Design Considerations ◽

Covalently Bonded ◽

Homopolymer Blends ◽

Emulsifying Agent ◽

Surface Active ◽

Low Entropy

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).

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Theoretical And Practical Design Considerations for Ultra-High Resolution Electron Lenses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001161 ◽

1980 ◽

Vol 38 ◽

pp. 266-269

Author(s):

Y. Harada ◽

K. Tsuno ◽

Y. Arai

Keyword(s):

Optical Properties ◽

High Resolution ◽

Chromatic Aberration ◽

Point Of View ◽

Pole Piece ◽

Axial Field ◽

Design Considerations ◽

Resolution Electron ◽

Practical Design ◽

Peak Flux

Magnetic objective lenses, from the point of view of pole piece geometry, can he roughly classified into two types, viz., symmetrical and asymmetrical. In the case of the former, the optical properties have been calculated by several authors1-3) and the results would appear to suggest that, in order to reduce the spherical and chromatic aberration coefficients, Cs and Cc, it is necessary to decrease the half-width value of the axial field distribution and to increase the peak flux density. The expressions for either minimum Cs or minimum Cc were presented in the form of ‘universal’ curves by Mulvey and Wallington4).

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