View Topic Comments

Emergency handling in Sub-Sea POL /LPG Pipelines

Query Raised By: Mr. Sehgal VS, G M MAINT (PIPELINES), HQ, G M MAINT (PIPELINES), HQ, BPCL ADMIN. BLDG, MAHUL VILLAGE, CHEMBUR

India has a growing network of Hydrocarbon Pipelines. These lines are laid through various terrains in on-shore and at varying depths in off-shore section. The challenge for the pipeline operators is to attend the emergency (arising from hydrocarbon leakage from pipeline into the environment) in the least possible time and restrict the loss of human life and property. Though various emergency response & repair systems are in place for onshore lines, offshore lines still remains a challenge for the pipeline maintenance team. Query 1. – What is the methodology for attending a leakage from sub-sea pipeline (MS/HSD/SKO/CRUDE/ATF) due to damage by either ship’s anchor or any other reason. Query 2. – What is the methodology for attending a leakage from sub-sea LPG pipeline due to damage by either ship’s anchor or any other such reason. Remarks – 1. Evacuation of entire LPG from line by hot flaring at SV stations doesn’t ensure that the pipeline is hydrocarbon free. 2. The visibility is poor as the water is turbid in the shallow sea, thereby making maintenance activities difficult to execute. Query 3. – What is the philosophy & procedure to refurbish the coating (pipeline protective coatings / concrete) removed during sub-sea line repairs? Query 4. – What kind of flaring should be used (Hot or cold) during evacuation process of the LPG pipeline? Remarks – 1. As per our knowledge, options available are mobile & fixed flaring unit. Limitations are on the cold flaring quantity per hour. 2. There are statutory limitations on space around the permanent hot flaring area.

(1)  Comments

  • Gautam Chakravarty, CGM (Gas-O&M), GAIL(Expert)   -   15-Apr,2019 15:05

    Query 1 2 & 3: Installation of sleeves / clamps and repair of coating by compatible materials are still the acceptable repair methods. Only the installation method differs where use of diver-operators, Remotely Operated Vehicles (ROV), Autonomous Underwater Vehicles (AUV), support vessels, pipe layers / barges etc. are employed in sub-sea pipelines. DNV-RP-F113 ‘Pipeline Sub-sea repair’ is a ‘Recommended Practice’ document which can be referred for more details. Query 4: Hot flaring is the safe mode of evacuation of LPG from pipelines. Mobile or fixed flaring units are employed depending on the design basis. The design rate of flaring will define the size / type of flaring and associated safety distances.