Session: 12-03-05: General: Mechanics of Solids, Structures and Fluids

Paper Number: 145196

145196 - Optimized Cutting Ball Design for a Subsea Valve 

        Subsea valves are an integral part of the in-riser landing strings that are used for test and cleanup operations from floating rigs. The ball valve is used as a controlled barrier to secure the well, by containing wellbore fluid flow at the subsea blowout preventer (BOP). The ball valve needs to provide cutting capability while still maintaining the sealing integrity even when intervention media such as wireline, slickline or coiled tubing reside across the valve.

        In the past, incorporating the shear and seal mechanism using a floating ball valve was especially difficult in the limited available radial space around the tubing inside the riser. Alternative solutions such as using a separate cutter module for the shearing function might not be feasible due to the length constraints imposed by the BOP spaceout requirements. Therefore, the ball design needs to be optimal to cut the largest size of tubing, while still ensuring that the seals and associated interfaces are not compromised. The design must be sufficiently robust to accommodate different types and sizes of wireline, slickline, and coiled tubing. Each of these can have different implications for the design.

        This paper focuses on the development of a cutting ball that can shear different wireline, slickline, and coiled tubing media, while maintaining the seal integrity. Experimental cut tests were conducted on an existing ball valve using different intervention media. The cut test results were analyzed to determine the parameters that influence the cut test efficiency. Damage to the cutting surfaces and its impact on the sealing function were analyzed. A simplified finite element analysis model was set up to simulate the ball cutting mechanism, which is benchmarked using experimental test data. Cut test simulations were conducted to characterize the influence of different parameters such as the ball geometry on the ball deformation and damage. Simulations provide a much cheaper alternative to experimental tests, which can be both time consuming and expensive. A large data set was generated for a range of parameters using computational analyses. On the basis of the simulation results, an optimized ball was designed such that the damage was minimized. Experimental tests were conducted to validate the improved performance from these design improvements.

        The paper provides a solution to a complex problem using a combination of experiments and computational simulations. Parameters that are most relevant to cutting and sealing functionalities were characterized and optimized to design a ball that improved reliability and performance.

Presenting Author: Mahesh Shenoy Onesubsea

Presenting Author Biography: Dr. Mahesh Shenoy is the Product Development Engineering Manager for SLB’s Subsea Landing String product line. He started his oil & gas career in 2006 as a Mechanical Engineer in SLB. He has extensively worked in product design and development in both Subsea and Surface Testing. Most recently, he received the 2021 Performed by SLB (PbS) Gold Award for his outstanding engineering contributions in developing the world’s first 20 Ksi landing string system.
Dr. Shenoy was awarded his PhD from the Georgia Institute of Technology with concentration on design optimization, material characterization, and failure analysis. He has authored numerous book chapters, international technical journals, and conference proceedings. He is also the recipient of several patents and has served in several industry design standardization committees.

Authors:

Mahesh Shenoy Onesubsea
Gaurav Bansal Onesubsea
Vivek Abnave Onesubsea
Hemra Esenyyazov Onesubsea