L&T breaks new ground in offshore engineering and construction

India’s heavy and growing dependence on imported energy is putting financial strain on the economy. More than half of India’s $191 billion trade deficit in the financial year 2012-13 was due to oil imports, of which 82 per cent came from Gulf countries. Geo- political events such as the civil war in Syria or unrest in the Middle East have left the country vulnerable to price spikes. To meet the growing energy demand and enhance its energy security, India is making major investments to augment its own oil exploration and production capacity.

Mumbai High is an oilfield with big potential. Located in the Arabian Sea about 160 km west of the Mumbai coast, Mumbai High has more than 551 oil wells and 33 gas wells, and is operated by Oil and Natural Gas Corporation Ltd. (ONGC), the largest producer of oil and natural gas in the country.

The Mumbai High North Project

On 27 July 2005, the Mumbai High North (MHN) platform was gutted in a devastating fire that caused major production loss. ONGC decided to redevelop Mumbai High by reinstating production facilities destroyed in the fire, besides building new facilities as part of a new MHN complex.

ONGC awarded this project to Larsen & Toubro (L&T) Ltd., one of India’s largest engineering and construction companies, with extensive experience in hydrocarbon EPIC (Engineering, Procurement, Installation and Commissioning) business. L&T won the project against stiff competition from international players such as National Petroleum Construction Company, Hyundai, and Samsung.The MHN project was valued at $1.1 billion, and is considered one of the largest and most sophisticated projects undertaken anywhere in the world.

The contract included construction of multiple platforms for the processing of oil and natural gas, commonly referred to as Mumbai North Platform (MNP). These would include three process gas compression (PGC) modules (separate contract to L&T for 3 PGC modules); Mumbai Living Quarter (MLQ) platform for safe operational and life support requirements for those working offshore; and two flare platforms for residual/unused gas, during the extraction of petroleum crude oil at production sites.All of these platforms were to be connected by bridges to form a single complex. The massive project would require a total of 80,000 metric tonnes of steel. The scope of work for L&T included surveying, engineering, procurement, fabrication, installation, and commissioning of the facilities.

Project Highlights

• The engineering and fabrication in India of a massive offshore process platform with a topside (commonly known as the deck) weighing 26,500 tonnes
• Construction of 13 large pre-fabricated modules, weighing a total of approximately 21,000 tonnes, integrated offshore into a single MNP platform topside
• Construction of an MNP platform jacket of 13,500 tonnes fabricated and loaded out within a record timeframe of 10 months from L&T’s Modular FabricationYard at Sohar, Oman
• Construction of the largest living quarter (weighing 4,000 tonnes) in the Indian offshore industry with a capacity to accommodate 150 people
• The fabrication and loading within 18 months of a total of 35,000 tonnes of structures from L&T’s Hazira manufacturing facility
• Construction and installation of a 137-meter bridge, the longest bridge in Indian offshore
• This project set many records in the Indian offshore industry that led L&T to win the 2013 PMI
• India Best Project of the Year award for project management excellence.

The Prime Project Objectives

A key project objective was to achieve a total well fluid handling capacity of 270,000 barrels of liquid per day and 6.9 million metric standard cubic meters per day of compressed gas and a total oil handling capacity of 50,000 barrels of oil per day. For operational safety, the new living quarter platform would be separate from the production and accommodation facilities. It would include safety accessories, support systems, a switchgear room, an integrated control system, transformers, utilities, and an emergency diesel generator.

All the new platforms would be interconnected and the new facilities connected with the existing platform, commonly referred to as the Mumbai NorthWest (MNW) platform. In addition to the new platforms, the scope also included additional facilities for the MNW platform, such as an additional survival craft for rescue operations and a new 15 metric tonnes capacity overhead crane, removal of 2.9 km of existing subsea pipeline, and a new mooring facility for supply boats.

The Challenges Scope and Schedule

The project’s initial execution time frame of 39 months was reduced to 33 months to an extended tendering and evaluation process. Project estimates were based on inputs and the size/area of the platform available in the bid documents. Elaborating on the challenges, Mr. Kumar Rudra, project director, MHN Projects, said, "During detailed engineering, we realized that we needed an additional 45 per cent area to incorporate all the facilities on the MNP platform. This led to substantial increase in the weight of the process platform and an increase in the number of splices. In effect, the MHN complex layout turned out quite different from what it looked like at the time ONGC had awarded us the contract. Further, ONGC also changed flare orientation during the engineering stage." These fundamental changes demanded revision in engineering and design, leading to changes in L&T’s scope of work, which in turn affected the schedule.

Engineering

Such heavy platforms are best suited for float-over installation. However, due to a complex network of subsea pipelines, and the presence of nearby platforms, this was not feasible.The first level of the MNP deck was fabricated in eight parts, including three cantilever frames. It further supported five heavy modules, and that load needed to be transferred onto the MNP jacket with eight legs as support structures. The conceptual design of the MNP platform was developed with the installation contractor during the early project stages.

Further, L&T had to deliver the jackets, the tubular joints that hold and support large platforms, 2 ore the topside as read as per co tractre uirement. Generlly, jacets are on weight distr in this L&T to go aheadthe jac ets first without having confirmed data on the topside weight because the topside design could not be finalized so early in the project.

Procurement

Challenges included adhering to the client’s recommended vendors, global sourcing , development of new vendors for timely procurement and delivery of goods, and fabricating larger packages in-house. In addition, managing the logistics of multiple modules and other resources simultaneously for safe transportation as well as on time availability for 80,000 tonnes of material, including over 300 tonnes of equipment; 50,000 meters of piping; more than 10,000 valves and pipe fittings, and 650 kilometers of cables presented additional complications.

Fabrication

Fabrication was done completely in-house at L&T’s HaziraYard in India and SoharYard in Oman. Despite 17 million human hours, there were no fatal accidents. At peak construction, more than 6,000 people worked at MFF Hazira. Managing safety and production efficiency of the large work force was a challenge.

Managing large quantities of material proved a Herculean task, involving quality management, storage, material tracking, and allocation of resources. It was also necessary to ensure timely availability of inputs at each phase of the project. Drawings and materials of the engineering phase were made available at the fabrication stage for reference, thus minimizing standbys.

Load-out & Sail-out

The MHN project demanded back-to-back load-out of modules as heavy as 4,500 tonnes from Hazira, L&T’s fabrication facility in Gujarat. This necessitated micro planning of load-out and sail-out activities with continuous monitoring to avoid any schedule slippage.

Rupchand Lohana, deputy general manager, Hydrocarbon Upstream Division L&T, said, "PMI techniques are very generic and following these guidelines helps in project management. PMI techniques and guidelines help in addressing issues in a structured manner."