ENGINEERED SOLUTIONS
Examples of panels and valves needed to solve a problem
Client required a pilot-operated valve with metal-to-metal seal. A very thick grease was being pumped through the isolation valve for a downhole packing application.
Problem - Client wanted a physical position indicator to verify valve was closed even after pilot pressure was released. Indicator needed to be visible by ROV camera.
Solution - PDS extended and modified our Triton Pilot mechanism to include a geared indicator that would provide positive metal seal position reading.
Triton Isolation Valve with modified pilot assembly was hyperbarically tested for an equivalent depth of 11,000 feet. This is a video demonstration conducted in shop. Quantity 6 of these were supplied.
Problem - Client had a sizeable investment in 10K flexible flow lines and wanted to be able to continue to use them with 15K capping stacks. At the time 10K flexible flow lines were protected by 2" rupture discs. The major issue was in the event a 2" burst disc ruptured, it would result in a well shut in, burst disc tree retrieval and replacement of burst disc, and redeployment. During downtime there was a very high risk of seawater ingression and hydrate formation and the problems and costs associated with it.
Solution - PDS proposed and engineered a PRV unit that would relieve pressure then re-seat and re-seal. Our PRV unit sensed pressure via a transfer barrier with well-bore on one side and clean hydraulic fluid on the other. Our Triton trigger valve receives pressure from the transfer barrier. Once set point (trigger point) is reached, the trigger valve fires and pilots open our 2" Cerberus dump valve. As soon as well-bore pressure is reduced below set point, the pilot pressure bleeds down and the dump valve closes and reseals. Effectively the unit can "burp" pressure and reseat and reseal itself thus protecting equipment and preventing seawater ingress.
The PRV Units contain several layers of redundancy. The units have the ability to run in automatic mode (trigger, relieve, and reset) or manual mode (trigger, relieve, and ROV reset via paddle operator). In addition the dump valve can be manually opened or closed via Class IV ROV overrides regardless of system state.
PRV units are API PSL3 15,000 psi 350F rated
Customer performing intervention work was using a shear seal type DCV to operate a shearing/cutting device. Custom 10K accumulator bottles were used to provide power subsea closer to shear/cutting operation. During subsea operation the shear seal type DCV was used to switch from circuit A to Circuit B after a cut was completed.
Problem - After the cut the pressure degradation took 20-22 seconds before the shift from Circuit A to Circuit B. The length of time required resulted in an extended loss of high-pressure accumulation before the circuit shift occurred. They had also experienced leaks with shear seal due to fluid cleanliness issues and the susceptibility of shear seal valves leaking when the sealing surface is no longer pristine.
Solution - PDS designed a DCV based on our existing Triton Technology. Our DCV provided the ability to shift from Circuit A to Circuit B in 0.25 seconds. Our design allows for separate circuit adjustments to include speed of shift and interflow or non-interflow all in one package. In addition, our technology utilizes a machined soft seal and is highly debris tolerant.