The subsea test tree is a singular subsea safety solution for well test and cleanup operations from any floating rig. The test tree provides wellbore access, dual-barrier well control, and a reliable, fast-acting means to shut in a well and disconnect, in the event of an emergency. Currently, the ability to run and operate the string is severely dependent on the weather conditions due to its influence on the riser flex joint angles. Therefore, the maximum allowable flex joint angle places severe limitations on the weather operating windows. This study outlines the use of computational analysis to formulate the design changes that are needed to extend the current capabilities of the latch mechanism that secures the landing string inside the Blow Out Preventer (BOP). Simulations are conducted using a design of experiments methodology to enhance the asset’s bending ratings. A parametric analysis is conducted and components with geometric features that can potentially impede the sliding motion of the landing string, such as the latch skirt are explicitly modeled.

The finite element analysis (FEA) technique is used to identify the critical components, which can be further optimized to determine the geometric profile, which eventually ensures that the string passes through the riser flex joint without shouldering out at the BOP annular pockets with minimal push or pull force. The study extends the capability of the Subsea Landing String for use with higher flex joint angles and establishes the structural and functional load limits for the different operational scenarios. The solution highlights the importance of using computations in design as a viable alternative to expensive and time consuming experiments, especially when solving complex problems.

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