Envisioning & Commissioning India's first Single Point Mooring (SPM) System, Floating Roof Tank Farm & Pumping Station at Vadinar, Gujarat.

My first tryst with publishing an article on Linkedin. As part of a multiple series of articles, I want to narrate my stories, my experiences & journey as a career pipeline man since 1960. Hopefully, readers, oil & gas pipeline aficionados will find these articles interesting & valuable in their own pursuits.

Indian Oil Corporation Ltd. installed a Single Point Mooring (SPM) in the gulf of Kutch for receipt of Crude oil in the floating roof tanks at Vadinar, Tank farm, and Pump Station, (Gujrat). IOCL was the first to install an SPM in India.?

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Development of the SPM system.

?During the Six-day war in 1967, Egypt closed the Suez Canal. The canal was strategically important to trade, it provided the shortest ocean link between the Mediterranean Sea and the Indian Ocean. This blockade impacted the movement of cargo which hit Japan the most, for their crude oil requirement. Japan had to depend on Gulf and other European countries for Crude oil. Tankers carrying crude oil from Gulf and other countries had to take the longer route via the Cape of?Good Hope to reach Japan. Smaller tankers used to be in operation, but Japan faced severe problems due to the cost of transportation, delays in getting crude oil, etc. So, they developed Very Large Crude Carriers (VLCC), which could carry about 2,50,000?or 3,00,000 TMT of crude oil. This created a new problem in that the berthing of VLCCs in the conventional jetties was not possible due to draft, hence the cargo was unloaded into daughter tankers in the mid-sea as the minimum draft requirement for VLCC is 30 Mts. The draft of a ship is the vertical distance from the bottom of the ship’s hull to the waterline, which determines the minimum depth of water, which the ship can safely navigate. VLCC carries a cargo of 2.5 to 3lakhs Kilolitres which will be discharged in 24hrs. Necessity is the mother of inventions. This step led to the development of the SPM.

?Single point mooring is a floating buoy/jetty anchored offshore that serves as a mooring point and is interconnected for tankers loading or offloading of gas or liquid products. The location requires a 30mts draft for a radius of 1 Kilometre or the loaded tanker should be able to rotate 360 degrees. In case of inclement weather, the tanker rotates and takes a position in the direction of the wind, hence it takes a safe position. In the present case, SPM is used for off-loading crude oil.

IOCL decided to build 2 oil refineries, one at Mathura in UP and the second at Panipat in Haryana. These are landlocked locations hence crude oil must be imported and transported through Pipelines to these locations. Also, the capacity of the Vadodara Gujarat, Oil refinery was expanded to 7 mmtpa and required additional crude oil. Looking into the above requirements, IOCL decided to put up a huge Tank farm with 10 floating roof tanks, each of 300000 mt. with adequate pumping facilities, and lay a 28-inch Pipeline up to a place called Viramgam and from there, one 18-inch line to Vadodara followed by a 24-inch line to Mathura and Panipat. 28-inch pipes were supplied by British steel as part of a grant by the UK Government. To receive Crude oil, it was decided to put up one SPM in the Gulf of Kutch. The location was selected with the assistance of a Pune-based hydrographic survey organization and with the assistance of Naval hydrographers. Subsequently, landfall points were identified and marked with a concrete pillar. The SPM would be installed 5500 mts away from the landfall point. They also laid an offshore submarine pipeline of 48inch dia for 5500mts and 2 nos of 42inch dia landline pipe of 5500 km from the landfall point at Navara Bet to the tank farm site.

The design of SPM was done by a French company and the following conditions were considered:

Sea condition, wind load, tidal state, under current, draft, climatic condition, and protection from the external environment. Manufacturing of the SPM was done at Sembawang works in Singapore.?

The Buoy was placed at the selected predetermined location. The first and foremost job was fixing anchors at six locations radially (at 60 degrees) around the Buoy about one Km away. For these piles were driven at 6 locations, each at 33mts depth at the seabed, concreted, and fixed heavy duty PU coated shackles. This job was contracted to a French Company called Frederic Harries. The Buoy was hooked up to the shackles by anchor chains having links of 1- and 1/8-inch dia. and take the shape of a catenary and this gives the name catenary anchor leg mooring system.

IOCL awarded the contract for the installation of SPM, laying of a 48-inch dia. off-shore pipeline of 5500 mts from the landfall point up to the SPM and other allied works to M/S Nippon Kokkan of Japan. They had employed a Delhi-based company M/S Bhasin Associates as their Indian agent for all local activities.

The Buoy is about 7 mts dia. and height of about 3mts. The buoy had six chambers of which 3 chambers are filled with solid polyurethane (pu) foam and the remaining 3 are empty. The empty and foam-filled are alternate chambers. The foam is to prevent the sinking of the buoy in case of damage by the tanker or due to any external factors. One empty chamber housed a hydraulic system pneumatically operated, for the opening and closing of four nos PLEM valves. PLEM (Pipeline End Manifold) is located at the seabed, which is anchored to the seabed and has 2 inlets and one outlet which is hooked up to the off-shore 48-inch pipeline. The 2 inlets are connected to the buoy with 20-inch dia. under the buoy flexible special type of rubber hose pipes, connected in Chinese lantern shape to take care of tidal variations. The 2 floatings are fitted with ball valves to isolate the floating in case of any emergencies.?

The tanker is moored to the buoy by means of a hawser arrangement which contains heavy-duty Nylon or Polyester rope shackled to the integrated hook on the buoy deck. Chafe chains are connected at the tanker end of the hawser to prevent damage from the tanker.?

The buoy is connected to the tanker with 2 nos of 24-inch floating hoses for the transfer of product. No sooner the tanker is berthed and hooked up to SPM, the tanker picks up the floating hoses and hooked up with the tanker manifold. The hose strings are provided with a breakaway coupling (a special type of coupling with breaking points, which will break at a predetermined, activating internal valves which will automatically close at both ends and prevent further release of the product to prevent oil spill).?

The buoy contains a bearing system called a turn table at the top of the buoy. With this system, the buoy along with a floating hose connected to the tanker can rotate 360 degrees during heavy wind and rough sea conditions. During high winds, the taker moves around and takes a safe position. No doubt during cyclonic conditions, it is moved out to safe locations.

The SPM uses a swivel system that connects to the PLEM to buoy. The swivel system provides flexibility for the movement of the tanker during the transfer of products. This portable pipe connection system prevents premature hose failure due to traction or handling stress.

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Visit of dignitaries: -Air Chief Marshal Arjun Singh along with a Vice Admiral of the Indian Navy, who was a Hydrographer, visited Vadinar, and reviewed the works the location of the SPM, and commended that the location was ideal. The Vice Admiral indicated that the location is secluded and protected from natural calamities and undercurrents. They were very happy and appreciated the work being done in operations, and maintenance facilities.

A few months later Vice Admiral R.L. Pereira (who subsequently became the Chief of Naval Staff) who was heading western Naval command, along with the Commodore of the Valsura Naval base at Jamnagar, visited Vadinar. The Commandant of the Coast Guard was also present. They were taken around the tank farm having 10 nos floating roof tanks, each having 1lakh kilolitres capacity, pumping station, FF system, etc. the Admiral was taken around the SPM and KPT facilities. He was very happy to see the facilities and was highly impressed. Lunch was hosted for the dignitaries at the KPT guest house. An interesting incident happened after lunch, the Admiral picked up a pack of 555 cigarettes from the shirt pocket of the Commandant and the commandant lit the cigarette with his lighter, which shows the closeness between the senior and Junior officers.?

Laying of the offshore pipeline. The pipeline is a 48 inches dia., double random in length i.e., about 10.5 to 12mts in length, from the Buoy/PLEM to the landfall point at 5500 mts. There are two ways of laying an offshore pipeline. One is by the lay barge method which is deployed for a longer length of pipeline laying and the second is by the barge pull method for a shorter distance. At Vadinar, the second method was adopted since the distance was only 5500mts. Initially, the line is pipe short blasted in the coating yard, followed by coal tar primer applied, and after drying of the Primer 2 coats of Coal Tar enamel with fiberglass and the final outer wrap is wound and holiday detection carried out. Further, the CTE-coated pipes are concrete coated a half-inch thick with nominal reinforcements, as an anti-bounce measure. At both ends of the pipe, 30 cm are left bare for welding and joining the pipes. The t-landfall point at Nararabet's large concrete platform was prepared with beams across for rolling and joining of the pipes. All the welds were radiographed to ascertain the soundness of the weld placed. Meanwhile, from the landfall point towards the buoy, 2 nos of heavy-duty backhoes were put on barges to prepare a trench for about 1 km as about 1 km away from the landfall point there was a steep fall of about 3 mts. The sudden fall was smoothened out with the backhoes. Another crew was engaged in the placement of 2 big barges, one loaded with 2 nos of 250 tons of winches for pulling the pipe string, interlinked with electronic controls for interchange of the winch at a specified interval, positioning of the barge as per the requirement. In another barge, 2 nos of 100-ton Cranes were loaded. Communication was established between the barge and pipe yard with 4 number launches. Heavy-duty steel ropes passed through 3 sheeve pullies and were taken to the piping yard at Nararabet. At Nararabet, the coated pipe is rolled in line and the specified alignment and Pipes are welded Radiographed and the results are ascertained, hand coated and wrapped concrete coated, and pulled towards the buoy. Another group with help of theodolite checks the alignment. Floats are tied at every 12 meters so that during the pull the pipe string is floated and the pipe string is lowered into the seabed by releasing air from the float. Once the pipe string reaches the barge, the end is welded to the PLEM and the PLEM with the pipe string is placed over the seabed with help of deep-water divers the PLEM is anchored at the seabed. Finally, the line is hydrostatically tested and observed pressure for 24hrs. One CP station was installed at Nararabet for the protection of the pipeline.

As per the hydraulic gradient, there was a pressure drop at the landfall point, hence 2 nos of 42inch dia. pipeline, 5500 mts were laid to the tank farm at Vadinar.

SPM was commissioned on 25th Aug.1978. MT Vivekananda SCI tanker with 1lakh ton crude oil was berthed to the SPM. SCI had deputed one Capt. Retired Patanker and support services provided by KPT. Commissioning was done successfully. Sri. S Kumar GM Pipelines and Sri Varma, Chairman KPT were present. The product was taken in Thank number three in which water was filled above the inlet nozzle level.

Floating roof tanks are mandatory for gaseous fuel like crude oil, MS (petrol), and SKO (superior Kerosine oil) which emits vapor during summer. In a Floating roof tank, the oil touches the roof plate and moves up and down depending on the oil level, due to which there will be no vapor formation. The station control room monitors receipts and withdrawal of oil.??

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The coastal town of Vadinar in the state of Gujarat in India has undergone significant progress since 1978 when the SPM was commissioned by the Indian Oil Corporation, the first of its kind in India. This was a key milestone and one of the key factors driving the town's development. It also laid the path for the establishment of the Vadinar Oil Refinery in 1996, which has become a major contributor to the town's economy. In addition to this, the development of the town's infrastructure, including the construction of roads, bridges, and other facilities, has significantly improved the town's connectivity and accessibility. The establishment of educational institutions, healthcare facilities, and other basic amenities has also played a significant role in improving the quality of life of the town's residents. As a result of these developments, Vadinar has transformed from a small, relatively unknown town to a bustling hub of economic and social activity, attracting both domestic and international investment.

About the Author: Sri P.S. Balasubramanian is a career pipeliner, having served with Indian Oil Corporation for over 3 decades. He was the lead engineer responsible for the Salaya-Koyali-Mathura-Pipeline, and Hazira-Bijapur-Jagdishpur Pipeline among others. He retired as GM Pipelines from Indian Oil Corporation in 1999.