Aubin was approached by a major Middle East NOC to assist with the deoiling of a major pipeline at its export terminal.
The Challenge
The client had to repair a damaged section of its pipeline and it was important that they limited the time and fluid required to deoil the line while preventing any hydrocarbon discharge. This was further complicated by the inability to introduce a pig.
The line was 48" diameter, and any solution had to be introduced from the platform via the riser, which created a number of challenges.
What Happened?
After consideration, our Gel-33XL was proposed. Gel-33XL is a viscous self-healing gel which creates an excellent barrier between fluids, allowing efficient displacement while minimising contamination. It can also be supplied as a concentrate which, due to the lack of available footprint space, allowed the job to be performed from the platform instead of a support vessel, significantly reducing cost and simplifying the pumping operation.
Following discussions with the client, careful planning and testing was arranged at the Aubin test facility to ensure optimum product selection and application. A test rig was built to evaluate the introduction of Gel-33XL into the pipework and its ability to maintain an effect barrier. Conclusions from these test were that:
The Result
The gel concentrate was initially blended with sea water before the addition of the cross linking additive to create the Gel-33XL batch. Quality was determined by sampling the blending tanks outlet of the blending tanks and also immediately after the introduction of the cross linking additive. This ensured that the gel had the correct viscosity properties prior to being pumped into the riser. The operation was conducted as planned and clean separation was witnessed at the receiving station between crude and flushing water.
The customer was pleased that the operation was conducted as per plan, and that the displacement of crude allowed the safe removal of the damaged spool piece for repair. This was achieved without any potential hazardous or dangerous release of hydrocarbons.
