Indian Oil Corporation (IOC) proposed the Salaya – Mathura Pipeline System in the early 1970s. The system was planned to deliver imported and Bombay High crude oil from India’s west coast to the company’s proposed refinery at Mathura in the state of Uttar Pradesh.

In 1978, IOC had set up a single point mooring (SPM) system in the Gulf of Kutch to receive imported and Bombay High crude oil via tankers. The crude oil was delivered into storage tanks at Salaya, Vadinar, through a subsea pipeline system and twin onshore pipelines. From here, the crude was to be transported via the proposed Mathura – Salaya Pipeline to the company’s refinery in Mathura, and to IOC’s Koyali Refinery via a branch line.

In-house engineers at IOC prepared a detailed project report based on surveys, crude oil characteristics and the hydraulic design of the system. The design was evaluated by consultant Pipe Line Technologists. A detailed project report for offshore facilities was prepared by an Indian consulting firm Engineers India Ltd with backup support from Fedric R. Harris of Holland.

Project details

The pipeline project comprised a 275 km, 28 inch diameter pipeline from Salaya to Viramgam, a 141 km, 18 inch diameter pipeline from Viramgam to Koyali and a 24 inch diameter pipeline, which extends 803 km from Viramgam to Mathura. The project also included the SPM system in the Gulf of Kutch along with an onshore terminal at Salaya.

The initial transmission capacity of the Salaya – Viramgam section was 10 MMt/a, with the option to increase to 12 MMt/a following an envisaged expansion of the Koyali Refinery. The capacity of the Viramgam – Koyali section was initially planned to be 3 MMt/a and that of the Viramgam – Mathura section was 7 MMt/a. The pipeline system included a station at Salaya, two pump stations at Viramgam, as well as two intermediate stations, located at Abu Road and Sendra, on the Viramgam – Mathura section.

Route selection was guided by a number of criteria. IOC wanted to achieve the shortest route possible while avoiding hilly areas, marshland, forest reserves, wildlife sanctuaries, highly populated areas, and mining areas when possible.

The construction process

The Salaya – Mathura Pipeline was laid by establishing two main spreads in each section. Spread camps were strategically located so that the mainline could be covered with minimal movement of men and machine. For this project, construction crews for each spread were divided into two groups – one crew was responsible for front-end activities such as right-of-way, acquisition, grading, stringing and welding, while the other group looked after trenching, over the-ditch pipe and joint coating, welding, radiography, lowering-in, backfilling and tie-ins. Apart from these two major divisions, specialised teams would focus on the construction of railway, road, canal and river crossings, and the tie-ins. During the construction period of this pipeline, horizontal direction drilling (HDD) technology was not common. Because of this all rivers, channels, streams, and canals along the route were crossed using the submerged crossings method.

Facing the elements

The varied environmental conditions along the 1,200 km pipeline route, such as the rocky and hilly terrain of Rajasthan and the agricultural fields in the state of Uttar Pradesh, presented many challenges during pipeline construction. In addition, extreme weather conditions were experienced. Construction continued through both winter and summer seasons, with temperatures rising to 50 degrees Celsius in the summer in the states of Rajasthan and Gujarat, and heavy rains for a three to four month period in Uttar Pradesh.

Also, crossing bodies of water was made difficult by flooding. While working on many of the river crossings, flash flooding occurred, which increased risk when completing the open-cut submerged crossings.

Protecting the pipeline

The mainline was coated with coal tar enamel (CTE) for protection against corrosion. This coating was applied over the ditch. The high temperatures experienced during the summer would soften the coating, resulting in the development of coating ‘holidays’. Close monitoring of the temperature of the CTE and the quantity applied was required to make sure that optimum thickness was achieved.

Cathodic protection (CP) was also installed on the pipeline system as protection against external corrosion. While the Salaya – Mathura Pipeline system is ageing, a recent intelligent pig survey found that the pipeline is in good condition. This can be attributed to regular monitoring and maintenance of the mainline and CP system.

Expanding the Salaya – Mathura Pipeline

IOC decided to set up a refinery with a capacity of 6 MMt/a in India’s northwest region near the district now called Panipat. The company planned to supply crude oil to the refinery by increasing the capacity of the Salaya – Mathura Pipeline by 6 MMt/a, as well as laying a branch line from Chaksu to the Panipat Refinery. A second SPM system was installed at Salaya to handle the additional crude oil.

The expansion was carried out between 1994 and 1996. The expansion involved the construction of a number of loop lines and additional intermediate pump stations. From Chaksu, a 24 inch diameter, 349 km branch line was laid to the refinery in Panipat.

Currently, IOC has plans to further increase the capacity of the Salaya – Mathura Pipeline System to approximately 25 MMt/a.

During the initial construction period of the Salaya – Mathura Pipeline, the technologies available for laying the pipeline and completing the crossings were not as evolved as those currently available in India.

At the time when the Salaya – Mathura Pipeline was laid, IOC was operating a products pipeline network of 2,843 km. Currently, the company operates a pipeline network of over 11,000 km, which includes crude oil, petroleum products and gas pipelines.