A key component of operations is performing subsea intervention to troubleshoot issues and / or replace components. Many problems arise from the formation of calcareous deposits as a by-product of the cathodic protection system (see Science of Stuck post) which hinders the removal of items subsea.
It is important to fully understand the implications of exposing materials to acid cleaning, methanol and other chemicals used during operations; both on single components (e.g o-ring) or on an entire component (electrical connector). Polymeric components are potentially at risk from swelling, cracking and deplasticisation, whilst metalic materials run the risk of corrosion; in addition to this there is a risk of coating breakdown / delamination.
A60N offers a range of different testing services and can provide several different options dependent on the scope of work. We are able to conduct some testing in house at ether our laboratory facility in West Perth or at the STAR Labs which is our offshore test site at Rous Head, Fremantle. In addition to this we have build relationships with local laboratories and universities. We can offer:
Materials compability with acid and other chemicals
Seawater exposure in real life conditions
We also able to assist with the design of testing programs to ensure that the results are meaningful and enabling our clients to be confident in the reliability and quality of the data they receive.
SolidCitric Acid Cleaning
Australian subsea assets are highly susceptible to calcareous depositions and acid cleaning of interfaces is required in order to remove scale build-up. Traditionally this acid cleaning has been very time consuming, occupying the vessel or rig for hours. By use of SolidCitric operational efficiency can be increased and HSE onboard the vessel will be improved as there is no need for any mixing of acid.
SolidCitric is a field proven technology, which improves the efficiency of marine operation when performing maintenance, repair or intervention activities. SolidCitric is bio-friendly citric acid in solid form designed to free up vessel time as a “set and forget” solution.
SolidCitric and an adapter tool for the interface to be cleaned, is brought to the subsea worksite with the ROV. The adapter tool is installed and the SolidCitric cartridge is fitted into the adapter tool. The SolidCitric is left to be dissolved by seawater, creating a localised and efficient acid cleaning. When the acid dissolves it will flow and displace / saturate the raw seawater which is entrapped in the adapter tool. The ROV then removes the adapter tool and gives the treated surface a light clean with a brush or a water jet. SolidCitric is ideal for the cleaning of wellheads, hubs, mounting bases, MQC plates, valve receptacles, stabs and other common subsea interfaces. A60N are also able to supply custom adapter tools if required.
SolidCitric acid was provided to remove calcareous deposits from UTA Class 4 MQC interfaces as part of an electric fault finding campaign. The project included:
Provision of 12kg SolidCitric blocks and Class 4 interfaces
Provision of ROV handling adapters
Provision of custom SolidCitric acid sticks to transfer acid into hard to access hydraulic coupler areas
Material Compatibility Testing
A serious of tests were developed for a client to ascertain the effect on various polymer connector materials subjected to acid used for the removal of calcareous deposits. The work included:
Test program design
Disassembly of components to source various polymers materials
Acid compatibility testing at a series of exposure durations, inc. hardness, tensile, volume change tests
Electrical insulation resistance (IR) testing in a partially separated connector state when exposed to acid