Marine Hydraulic Oil

Castrol Transaqua HT2

Water-based subsea production control fluid


Castrol Transaqua™ HT2 is a water-based hydraulic control fluid specifically formulated for use as the control medium
in subsea production control systems. The fluid incorporates all the features required for operation throughout the
control system including Sub Surface Safety Valves (SSSV) and intelligent well completions.

Transaqua™ HT2 has been developed and qualified under a Quality Management System with ISO 9001:2000
Certification and an Environmental Management System with ISO 14001:2004 Certification for Research and

Qualification testing carried out in accordance with ISO 13628-6 Annex C (2006 E) requirements.

  • Designed for use in all conventional and high pressure, high temperature applications (according to API 17 TR8).
  • Can operate over a temperature range of -30ºC (-22ºF) to 170ºC (338ºF).
  • Passed ISO 13628-6 Annex C (2006 E)/API 17F TR8 testing at 170°C (338°F)
  • Track record of use in subsea production control systems at tempertures up to 170°C (338°F)
  • Tested to 180°C (356°F) in SSSV Equipment to OTO 99 001
  • Suitable for use within Electro-Hydraulic Multiplex (EH-Mux) or direct hydraulic control systems.
  • Designed for use throughout the entire production and workover control systems, covering Topsides and Subsea
    applications: both open water and well bore; and Downhole from control of a single SSSV through to complex
    intelligent well completions.
  • Tested according to OSPAR requirements and is registered for use offshore in the UK, Netherlands and Norway.
    Rigorous environmental testing has been completed in many geographies worldwide.
  • Has an identical formulation to the field proven Castrol Transaqua HT with a replacement dye and ultra violet
  • Contains a leak tracer to allow rapid detection of subsea leaks either visually or using a dedicated ROV
    mountable leak detection sensor.
  • Maintains corrosion performance with seawater contamination.
  • Tolerant of the high well temperatures encountered by those parts of the control system located at the well bore.
  • Fully compatible and miscible in all proportions with other products in the Castrol Transaqua range and most
    other water-based subsea control fluids.
  • Compatible with a wide range of materials commonly used in subsea control systems (see Tables 3 & 4). More
    detailed compatibility information is available on request.

Castrol Transaqua HT2 is compatible with many materials commonly used in the construction of modern production
subsea control systems. As with any fluid a complete materials review should always be carried out before using
Castrol Transaqua HT2.

Metals to be avoided
The following metals are best avoided with all glycol water-based fluids: Aluminium, Cadmium, Magnesium and Zinc.
For coating compatibility data please contact Castrol.

Seal Materials to be Avoided
Rubber Impregnated Fabric Composites are not compatible with Castrol Transaqua HT2. These materials must be
changed out from equipment to be used with Castrol Transaqua HT2.
Painted and other Surface Coatings

It is recommended that in accordance with good working practice the internal surface of the hydraulic system should not
be coated. However, external surfaces may require coating and as with all control fluids conventional paint systems will
tend to soften or strip. It is therefore recommended that these be replaced by cured epoxy, nylon, or Phenolic types as
commonly used subsea. Surface preparation prior to paint application is critical.
Where it is necessary to use internal surface coatings such as PTFE these should be assessed for suitability of use.
Manufacturers guidelines should be observed with regards cure times and temperatures and as with paints systems
surface preparation specifications should be adhered to


Care and Handling
This product has been manufactured to a tightly controlled cleanliness specification. Any container that has been
opened for use must be re-sealed to avoid contamination ingress from the environment (eg particulates or water). Any
contaminants entering the product can affect its performance. The integrity of the product once the container is opened
is the responsibility of the end user. It is good practice to use tarpaulins or drum lids to cover all containers to prevent
ingress of contamination.

As with all glycol based control fluids, CastroI Transaqua HT2 must never be mixed with control fluids of different base
types such as synthetic fluids (e.g. CastroI Brayco Micronic SV/3) or mineral oils (such as the CastroI Hyspin range).
Contamination of CastroI Transaqua HT2 by either of these types of products can seriously affect the product

If you need advice on any of the above, please contact your local Castrol Technical Service Engineer for more specific

All containers should be stored under cover and protected from exposure to direct sunlight. Do not store containers in
temperatures below minus 5ºC or above 45°C. 208L plastic drums can be stored a maximum of 2 high, providing a
pallet is used to distribute the upper load evenly. In addition, the fill level of the upper drums should be less than or
equal to the fill level of the lower drums. It is not recommended to store 208L plastic drums horizontally

Castrol Transaqua HT2 Lubricant Oil

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