A case study looking at how Bilfinger Tebodin Middle East conducted various structural analyses for offshore oilfield platforms.
By: Brooke Azem, product marketer, Structural Analysis, Bentley Systems
Bilfinger Tebodin Middle East conducted various structural analyses for offshore oil field platforms. SACS helped save the team 1,200 resource hours to better meet the six-month timeline.
Located off the coast of Abu Dhabi in the Persian Gulf, Bilfinger Tebodin Middle East conducted a requalification study of an oil field. The facility includes 25 platforms and an extensive network of subsea lines. For this US$500,000 project, Bilfinger needed to perform detailed structural analyses of all existing platforms, many of which had surpassed their design life.
The project team would need to conduct data collection and review, as well as site visits to verify the as-is structural arrangement of the platforms with respect to their respective structural as-built drawings. The team also needed to prepare an updated weight control report with clear documentation, review the owner’s existing design criteria, review latest sub-sea inspection report anomalies, and recommend design changes and improvements in compliance with latest API RP 2SIMS and international guidelines.
As one of the leading service providers of engineering and consultancy services, maintenance, and lifecycle services, Bilfinger was familiar with the challenges of this scope and complexity. However, the organization had the added challenge of needing to keep within an extremely tight schedule. The project needed to be completed in just six months, which included the immense engineering work required. The multidiscipline engineering firm realized that it would need to integrate more digital workflows to meet the project objectives.
Modelling Platforms for Improved Analysis
Bilfinger used Bentley’s structural analysis software to requalify three process platforms and three wellhead towers, as well as perform pushover and fatigue analyses for six additional platforms. Six of platforms had not been modeled before, so the team would have to create them from scratch. To generate the SACS models, the team began by collecting data from site visit observations and most recent inspections including structural thickness measurements, and then generating the models.
The team then used SACS to model the platforms and perform in-service analysis, incorporating the structure’s dynamic behaviors. This analysis allowed the team to establish the current stress levels with the latest design standards for current in-place conditions. Bilfinger also used the application to perform pushover analysis to establish the reserve strength ratio (RSR) of the structures, cathodic protection design to establish the number of required anodes, and spectral fatigue analysis on all the platforms to assess the remaining life of the joints. These analyses optimised the structural strengthening and mitigation measures.
Extending the Life of the Platforms
By reviewing the model and establishing stress levels and structural strengthening modifications, the project team was able to create mitigation plans to extend the life of the structures for 20 years. The goal was to extend the structures’ operating life up to 2038 while still being structurally sound.
The team was better able to review the model and make the mitigation plans by eliminating the usual strict license restrictions. With SACS and Bentley’s cloud service subscription, Bilfinger team members could review the model at every stage of the process, whenever and wherever they were, without worrying about license usage. This process allowed everyone who needed to review the model to have access, saving time by catching any mistakes or inconsistencies early on. Bilfinger stated that the licensing model alone saved it about US$60,000 while still having all the required software modules, such as for the collapse and fatigue analysis that were pivotal for the successful completion of the project.
The most challenging part of this project was the extremely tight schedule and budget, as the project was scheduled to be completed in just six months. Having a centralized software solution with high-level interoperability for all the analyses was a huge advantage. Bentley’s SACS served a pivotal role in successful completion of this project.
Satya Medapureddi, Manager-Offshore Structural, Bilfinger Tebodin Middle East Ltd
Improving Client Satisfaction by Saving Significant Time and Cost
Bilfinger’s design was completed in March 2019. By using Bentley’s interoperable, centralised software, the organization was able to keep the project on budget and within the strict six-month schedule. As there were no existing models for six of the platforms, the team used SACS to generate the jacket structures with grid numbers, saving 50 hours per platform, resulting in about 300 resource hours. Additionally, using SACS to calculate the jackets’ surface area for cathodic protection design saved about 360 resource hours.
Taking into account all the other ways that SACS streamlined workflows, Bilfinger saved about 1,200 total resource hours throughout the project, leading to significant cost savings. The final design showed that there was no need to add new platforms, which will save the oil field operator US$90 million. Bilfinger was able to deliver a cost-saving design within the timeframe to the client’s satisfaction.
Project Summary
Organization
Bilfinger Tebodin Middle East Ltd.
Solution
Mining and Offshore Engineering
Location
Abu Dhabi, United Arab Emirates
Project Objectives
Products Used
SACS, STAAD
Fast Facts
ROI
Source: Pipeline ME
