Special Session: Advances in Flexible Riser Technology: Flexible Pipe Curved Collapse Behavior Assessment for Ultra Deep Water Developments for the Brazilian Pre-salt Area

2010 ◽  
Author(s):  
Judimar Assis Clevelario ◽  
Fabio Pires ◽  
Gelson Falcao ◽  
Zhimin Tan ◽  
Jing Lu ◽  
...  
Keyword(s):  
Deep Water ◽  
Behavior Assessment ◽  
Special Session ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Water Developments ◽  
Collapse Behavior

Optimization Applied to Buzios Flexible Riser Systems and Subsea Layout

2021 ◽  
Author(s):  
Vinicius Gasparetto ◽  
Thierry Hernalsteens ◽  
Joao Francisco Fleck Heck Britto ◽  
Joab Flavio Araujo Leao ◽  
Thiago Duarte Fonseca Dos Santos ◽  
...  
Keyword(s):  
Deep Water ◽  
Technology Use ◽  
Capital Expenditure ◽  
Lessons Learned ◽  
Internal Diameter ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Injection Wells ◽  
Gas Field ◽  
Field Development

Abstract Buzios is a super-giant ultra-deep-water pre-salt oil and gas field located in the Santos Basin off Brazil's Southeastern coast. There are four production systems already installed in the field. Designed to use flexible pipes to tie back the production and injection wells to the FPSOs (Floating Production Storage and Offloading), these systems have taken advantage from several lessons learned in the previous projects installed by Petrobras in Santos Basin pre-salt areas since 2010. This knowledge, combined with advances in flexible pipe technology, use of long-term contracts and early engagement with suppliers, made it possible to optimize the field development, minimizing the risks and reducing the capital expenditure (CAPEX) initially planned. This paper presents the first four Buzios subsea system developments, highlighting some of the technological achievements applied in the field, as the first wide application of 8" Internal Diameter (ID) flexible production pipes for ultra-deep water, leading to faster ramp-ups and higher production flowrates. It describes how the supply chain strategy provided flexibility to cover the remaining project uncertainties, and reports the optimizations carried out in flexible riser systems and subsea layouts. The flexible risers, usually installed in lazy wave configurations at such water depths, were optimized reducing the total buoyancy necessary. For water injection and service lines, the buoyancy modules were completely removed, and thus the lines were installed in a free-hanging configuration. Riser configuration optimizations promoted a drop of around 25% on total riser CAPEX and allowed the riser anchor position to be placed closer to the floating production unit, promoting opportunities for reducing the subsea tieback lengths. Standardization of pipe specifications and the riser configurations allowed the projects to exchange the lines, increasing flexibility and avoiding riser interference in a scenario with multiple suppliers. Furthermore, Buzios was the first ultra-deep-water project to install a flexible line, riser, and flowline, with fully Controlled Annulus Solution (CAS). This system, developed by TechnipFMC, allows pipe integrity management from the topside, which reduces subsea inspections. As an outcome of the technological improvements and the optimizations applied to the Buzios subsea system, a vast reduction in subsea CAPEX it was achieved, with a swift production ramp-up.

Cathodic Protection Design Consideration for an Offshore Flexible Riser Connected to an Impressed Current System

2021 ◽  
Author(s):  
Thierry Dequin ◽  
Clark Weldon ◽  
Matthew Hense
Keyword(s):  
Cathodic Protection ◽  
Sacrificial Anode ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Linear Resistance ◽  
Flexible Pipes ◽  
Flexible Risers ◽  
Impressed Current ◽  
Host Structure ◽  
Impressed Current Cathodic Protection

Abstract Flexible risers are regularly used to produce oil and gas in subsea production systems and by nature interconnect the subsea production system to the floating or fixed host facilities. Unbonded flexible pipes are made of a combination of metallic and non-metallic layers, each layer being individually terminated at each extremity by complex end fittings. Mostly submerged in seawater, the metallic parts require careful material selection and cathodic protection (CP) to survive the expected service life. Design engineers must determine whether the flexible pipe risers should be electrically connected to the host in order to receive cathodic protection current or be electrically isolated. If the host structure is equipped with a sacrificial anode system, then electrical continuity between the riser and the host structure is generally preferred. The exception is often when the riser and host structure are operated by separate organizations, in which case electrical isolation may be preferred simply to provide delineation of ownership between the two CP systems. The paper discusses these interface issues between hull and subsea where the hull is equipped with an impressed current cathodic protection (ICCP) system, and provides guidance for addressing them during flexible pipe CP design, operation, and monitoring. Specifically, CP design philosophies for flexible risers will be addressed with respect to manufacturing, installation and interface with the host structure’s Impressed Current Cathodic Protection (ICCP) system. The discussion will emphasize the importance of early coordination between the host structure ICCP system designers and the subsea SACP system designers, and will include recommendations for CP system computer modeling, CP system design operation and CP system monitoring. One of the challenges is to understand what to consider for the exposed surfaces in the flexible pipes and its multiple layers, and also the evaluation of the linear resistance of each riser segment. The linear resistance of the riser is a major determinant with respect to potential attenuation, which in turn largely determines the extent of current drain between the subsea sacrificial anode system and the hull ICCP system. To model the flexible riser CP system behavior for self-protection, linear resistance may be maximized, however the use of a realistic linear resistance is recommended for evaluation of the interaction between the host structure and subsea system. Realistic flexible linear resistance would also reduce conservatism in the CP design, potentially save time during the offshore campaign by reducing anode quantities, and also providing correct evaluation of drain current and stray currents.

Flexible Spools Solution for Hybrid Risers Base for Green Fields Developments

2015 ◽  
Author(s):  
S. Tarbadar ◽  
S. Legeay ◽  
M. Bonnissel ◽  
O. Nossa ◽  
A. Karnikian
Keyword(s):  
Soil Properties ◽  
Deep Water ◽  
Oil Fields ◽  
Direct Connection ◽  
Flexible Pipe ◽  
Vortex Induced Vibration ◽  
Single Top ◽  
Dynamic Loadings ◽  
Operating Constraints ◽  
Steep Wave

Rigid spools are commonly used at the riser base of hybrid riser systems such as STTRs (Single Top Tensioned Risers) or BHORs (Bundle Hybrid Offset Risers) for the deep water oil fields. Rigid spools design is critical and governed by numerous operating constraints such as dynamic loadings (due to motion of the vertical riser, Vortex Induced Vibration, slugging, etc.), soil properties and soil/spools/structures interaction. Recent surveys on existing brown fields have highlighted unexpected issues on existing rigid spools. To solve these issues, an innovative flexible spool solution has been developed, combining unbonded flexible pipe structures in a “steep wave” configuration to accommodate the riser motions and FLET (Flowline End Termination) excursions avoiding soil deterioration and preventing unexpected spool behavior which could ultimately jeopardize its integrity. A steep wave configuration solution can be introduced with distributed buoyancy over the flexible spools length. This design allows a direct connection between the riser base assembly and the flowline termination, solving the embedment issue and easing accommodation of the hybrid riser motions. This paper describes the recent issues with rigid spools design and describes the solutions developed with flexible spool configurations to provide a more reliable riser base spools system for green fields.

Finite Element Modeling of Flexible Pipes Under Crushing Loads

2013 ◽  
Author(s):  
Eduardo Ribeiro Malta ◽  
Clóvis de Arruda Martins ◽  
Silas Henrique Gonçalves ◽  
Alfredo Gay Neto
Keyword(s):  
Finite Element ◽  
The Finite Element Method ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Simplified Models ◽  
Accurate Representation ◽  
Ring Model ◽  
Flexible Pipes ◽  
Operational Lifetime ◽  
The Moment

The launching procedure can be one of the most critical stages of the operational lifetime of a flexible pipe. From the beginning of the pipe unrolling off the reel to the moment of its separation from the launching vessel, the flexible pipe is subjected to severe loads such as crushing and tension. This paper focuses on the crushing load applied to the flexible riser by the shoes of the caterpillars on the launching vessel. The objective is to present an effective methodology to evaluate the stresses at the structural nucleus of a flexible pipe during launching using the Finite Element Method. Firstly, a tridimensional ring model is used to represent the structural nucleus of the flexible pipe. In that model, the geometry of the interlocked carcass and the pressure armor is accurately represented. Then, similar models are constructed including a series of geometry simplifications. Those simplified models are compared to the baseline in order to evaluate the relevancy of an accurate representation of the geometry of the metallic layers. The results of these comparisons are presented and discussed.

Long Pile Upending Lifting Study for Fixed Platform on Offshore Oil and Gas Field

2014 ◽  
Author(s):  
Yandong Zhou ◽  
Facheng Wang
Keyword(s):  
Deep Water ◽  
Oil And Gas ◽  
Cost Effective ◽  
Analysis Model ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Water Developments ◽  
Oil And Gas Field ◽  
Offshore Oil And Gas ◽  
Offshore Oil

Fixed platform have been widely employed in the offshore oil and gas reservoirs development. Pile foundation reliability is critical for these platforms where drilling, production and other functions are integrated. The lifting operation for the long pile, being a key step in the jacket installation, has been considered for further developments. With deep water developments, the sizes and weights of long piles are reasonably bigger. The corresponding process and equipment employed are subsequently altered, which brings challenges to developing a cost-effective, easy-operable approach for lifting operation. In this paper, the technology for the offshore long pile upending lifting operation including pile feature, installation methodology, lifting rigging and analysis model, covering water depths ranging from shallow to near deep water zone (60–300 m water depth) has been suggested. In addition, the applicability of the adoptable novel approaches has been discussed considering the practical project experience.

In Situ and Real Time X-Ray Computed Tomography for the Micromechanics Based Constitutive Modelling of the Unbonded Flexible Riser

2015 ◽  
Author(s):  
Ketan Pancholi ◽  
Vineet Jha ◽  
Neville Dodds ◽  
Dehong Huo ◽  
James Latto
Keyword(s):  
Computed Tomography ◽  
Real Time ◽  
Bulk Material ◽  
Compressive Loading ◽  
Constitutive Modelling ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
X Ray ◽  
X Ray Computed ◽  
Global Modelling

The failure mechanism of the composite flexible riser, comprising a pipe with melt fused carbon fiber tape or pultruded composite rods, is not well understood. As there is change in the configuration of the composite layers and its manufacturing methods, so the bulk material property also changes significantly. To capture the correct material model for global FE analysis, real time x-ray computed tomography was performed while the flexible pipe was being compressed. For developing a constitutive model for the composites, a time series of 3D volume images were analyzed quantifying the local strains responsible for the debonding of the layers and the crack development. These values were then used to understand the inter-layer adhesion leading to correlation between the FE global modelling and experiments capable of capturing the progressive delamination. The resulting global modelling was used to determine the area under compressive loading. The effect of global sea conditions and cumulative damage was noted. A correlation between the global model and experiments can be used to optimize riser performance. This method hopes to capture the overall behavior of flexible pipe under compressive loading.

Sign in / Sign up

Export Citation Format

Share Document