Bulk means liquids and powders carried in the vessel’s tanks rather than in cargo units: drilling mud, cement, barite, brine, base oil and fresh water. Bulk operations carry their own risk profile and their own failure modes.

Why bulk is handled separately

Bulk is transferred through hoses between vessel and installation while the vessel holds position. The operation is not a lift but a connected transfer — and therefore needs its own procedures for connection, pressure and emergency disconnection.

Contamination is the main risk

Bulk tanks are dedicated to product types. Residue of the wrong product in a tank can ruin an entire load and, in the worst case, affect the drilling operation.

That is why documented cleaning and product history are required before a tank can take a new product type. This is a planning task, not something resolved on the quay.

Planning bulk requirements

  • Estimated consumption per operation, not just current stock.
  • Tank availability on the vessel for that specific product type.
  • Transfer time — bulk takes time, and that time must fit the weather window.
  • Return of surplus fluid and slop.

Common mistakes

  • Bulk requirements are notified too late to secure the right tank type on the sailing.
  • Missing product history means the tank cannot be used.
  • Transfer time is left out of the weather-window calculation.
  • No plan for slop return, so it stays offshore.

Frequently asked questions

What is brine in this context?

Brines are salt solutions used as completion or well fluids. They are handled as bulk and require dedicated, clean tanks.

Why can one tank not carry every product?

Because residue from a previous product can contaminate the next load. Tanks must be cleaned and product history documented before a change of product.

Does bulk transfer take long?

Transfer runs at a limited rate and can take considerable time depending on volume. That time has to be planned into the vessel’s alongside time and the weather window.

Need help applying this in practice?

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