Thermal analysis of subsea systems at great depth is one of the challenges of pre-salt operation. Ocean temperatures can reach 4˚C and require heating by fluids or the presence of dedicated heaters. There is a limit to avoid interruption of operation due to the presence of paraffins in crude oil that must be extracted at temperatures above 40°C.
ATS carried out a study of a new, lighter insulation material for the company Ogramac. The new insulation was installed on the lines connecting the well to the surface. It was necessary to review the customer's test data, make a critical review and put it in the Petrobras report format. The new insulation proposed by Ogramac was approved thanks to the contribution of the ATS.
For Oceaneering, ATS performed a transient thermal analysis of a heating system to remediate pipeline runoff on the ocean floor below 2000 m depth. The system contained air, insulation, water and metal and heating was carried out with a PID control. The total stabilization time was close to 300 hours, depending on the configuration. This large inertia was a challenge, and ATS performed a steady-state CFD analysis and developed an analytical model based on CFD constants in order to speed up the analysis. This model was implemented in NSP Tumbi (similar to SciLab and Matlab) which would calculate the transient after validation in CFD. The analytical model was of concentrated mass of order 5 and had 9 masses. The control constants (Kp, Ki and Kd) were found by the iChrome Nexus optimizer using multiobjective and multiparametric evolutionary (genetic) optimization. Settling time, over-signal (peak) and stability were minimized. Python evolutionary optimization (yabox and scipy) was used to validate the model with CFD++ results for temperature and power. Thus, it was possible to find the values of the heat transfer coefficients by convection. Shell Houston approved the result and Oceaneering used the results to scale the test to be performed in the lab with ATS design recommendations.
ATS carried out a head loss and flow distribution study for The Constellation with the aim of studying various configurations of tubes and junctions for the oil well connection line with the surface. The software used was CFD++ and the modeling considered Newtonian fluid (water) and non-newtonian fluid (oil). The best configuration was found and Constellation was able to proceed with the project saving time and resources due to the reduction of the testing campaign.
For Halliburton, ATS studied the feasibility of an assembly for testing a part to collect oil samples that would need to be heated and subjected to extreme tensile test conditions. However, the ends of the part interfaced with the traction machine that could not be heated. The thermal analysis had been requested in FEA, only with solids and without convection and radiation, ATS made a simulation with CFD++ solving the radiation and natural convection also an alternative with forced external convection which gave a more complete solution for Halliburton, which that way you can run the test without any problems.
Also for Halliburton, ATS studied the stresses and strains in subsea equipment with FEA (Adina) analysis considering hyperelastic, fluid and solid materials. The contact between the surfaces and the sealing provided by O’rings was also studied. Halliburton thus knew the limitations of the design and was able to continue with testing and manufacturing. With the model, a cost reduction for the project was obtained.
ATS participated in a Halliburton supplier selection process, in which ATS ran test cases of non-linear and contact FEA and CFD erosion on system components simulations. ATS has been approved as a global supplier to Halliburton USA and Brazil. Today, ATS has a long-term contract with Halliburton Brasil to supply simulations for subsea systems. We are a long-term partner.
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Check out some of the companies that are part of the history of ATS