In 2000, ONGC announced its plan for Mumbai High redevelopment, to arrest decline and increase the production by improving the field’s oil recovery factor. The redevelopment project was in two phases; the first began in 2000 and finished in 2006. In 2009, phase two (MHN project) began. This redevelopment was required to reinstate BHN production facilities that were destroyed in a July 2005 fire.
The MHN Process Platform Project and MHN Process Gas Compressor Modules Project was awarded to Larsen & Toubro (L&T) by ONGC on 31 July 2009 on an EPIC basis. Project scope included surveys, engineering, procurement, fabrication, transportation, installation, hookup, and commissioning of the process platform. It included oil & gas processing facilities, living quarters platform, and two flare platforms, all connected by bridges. The new platforms were also to be bridgeconnected to the existing MNW platform. The new facilities along with the existing facilities of NA, NF and MNW are now known as the MHN process complex.
The MHN Project had many firsts including: the largest offshore process platform – MNP Deck (24,000 tonnes), largest living quarters in the Indian offshore (150 men), heaviest lift offshore India – MLQ LQ module (4000 tonnes), and longest bridge – MNP-MNF2 bridge (137m).
Project management of this magnitude demanded coordination between all disciplines, ensuring deliverables from various disciplines/departments as per requirements and pre-set targets. The challenge for the project management team was to ensure healthy interaction between all disciplines. The team size and diverse locations added another dimension. The project clocked 17 million safe man-hours across disciplines and locations. The solutions were implemented and installation activities were completed before onset of monsoon in phase two.
L&T Valdel Engineering (LTV) carried out engineering for MHN project. The main challenge was to execute design and engineering of the entire process platform complex that included FEED and detailed engineering. All the activities were to be performed concurrently with procurement and fabrication without affecting the overall project schedule and milestones, while meeting ONGC’s stringent requirements. In addition, review and approval of engineering documents from Aker Engineering Malaysia and ONGC design team were also required.
To give a perspective of the structural challenge, the operating topsides weight of the MNP Process Platform was about 26,500 tonnes with a jacket launch weight of about 13,500 tonnes, while the living quarters topsides operating weight was about 8400 tonnes with a jacket lift weight of about 2260 tonnes.
Engineering faced many challenges during the MHN project. The jacket had to be delivered 12 months ahead of topsides. In addition the jacket design had to be adjusted to changes in topside weights (partly engineered). Normally, jackets are designed based on inputs for topsides. However in this project, engineers had to design jackets with limited data. The jacket design was updated and optimized based on inputs for topside weights.
Completing the launch jacket engineering within the available time was a daunting task, starting from conceptualizing the installation sequence, location, shape and size of buoyancy tanks, connection details, safety and integrity of jacket during installation, and a host of other parameters that had to be decided before finalizing the design. These activities required co-ordination amongst various disciplines and teams. The MLQ jacket weight and lift radius was reaching the capacity of the planned installation barge, LTS 3000, necessitating optimization of lift weight and design.
Living quarters weighing 4000 tonnes was optimized into in single piece collaboration with M/s Specialist Services. This was the first time such a large module and LQ was engineered.
Due to the large weight of MNP platform and complex field layout, a floatover deck was not feasible. It was decided to fabricate the platform in 10 modules. The MNP deck included South East deck, South West deck, North deck, East deck and West deck. The MNP deck further supported five heavy modules: including building module, process gas compression (PGC) and one gas dehydration unit (GDU) – gas sweetening unit (GSU). To transfer this load to eight jacket legs, three heavy cantilever support frames were also required. The conceptual design of MNP platform was developed along with the installation contractor.
This construction was achieved by integration of basic and detailed engineering activities from L&T’s multi-centered engineering teams with daily monitored project schedules and close coordination with external agencies and vendors along with the project management team.
Mega projects require large quantities of materials including structural, piping, cables, equipment, and other items. Procurement scope included more than 300 equipments, 80,000 tonnes of structural steel, 50,000m of piping, more than 10,000 valves and pipe fittings, and 650km of cables. To ensure competitive prices and delivery schedules, the procurement team decided to source items from global vendors. Many of the packages were fabricated in-house and managed by the team.
Major packages were fabricated at MFF Hazira in order to meet delivery schedules and quality. This included the GDU & GSU package integrated into one module weighing 1700 tonnes. Other packages fabricated at Hazira included primary and secondary FG skids, and the produced water conditioning system package.
This was the first time that a GSU package was installed on an ONGC platform. This posed many challenges, first to prepare the functional specification, followed by approval of specific vendors. This was done by regular interaction with ONGC’s Offshore Engineering Services.
Health, safety & environment
The HSE department ensured that all personnel were given safety induction before mobilization and after reaching the worksite. This included safety induction of subcontractor personnel, vendors, etc. This helped maintain safety standards and strict discipline at the project site.
Periodical HSE inspections were carried out by officers/engineers and line managers to ensure a safe working conditions. Any deficiencies found were rectified with top priority.
Fabrication was carried out in-house at Hazira and Oman and involved 13 million man-hours without any major loss time incident. At peak, more than 6000 personnel were working at MFF Hazira.
Apart from managing the workforce, managing material quantities was a large task involving quality requirements, storage, material tracking, and timely allocation. Action was required to procure small quantities of material on an urgent basis.
MNP jacket had all the complexity that an eight-legged jacket can have. The outside legs had double batter, whereas the inside (launch frame) was single batter, with 23 pre-installed risers on the jacket including one CRA clad riser, huge buoyancy tanks on side panels, and large sump caissons. The fabrication sequence was reviewed and optimized to arrive at the finally accepted sequence, which optimized resources and had the lowest fabrication cycle of 10.5 months.
Major changes in boat-landing design and a change from three to four steps were also accommodated during later fabrication stages. Mammoet was involved in skidded load-out of this jacket and the same was carried out smoothly. The extent of planning and execution of MNP jacket fabrication is shown above.
While L&T Oman was working to fabricate the MNP and MLQ jacket, MFF Hazira was also working to meet fabrication requirements. In 2010/11, MHN Project needed delivery of two flare jackets (750 tonnes each) and piles for all jackets (13,500 tonnes). In addition, the work had started on phase two structures for MHN Project (33,500 tonnes), MHN PGC Project (5000 tonnes), and MNW-NF Project (500 tonnes).
Quality assurance and inspection
Apart from employing regular quality assurance and control, quality was also confirmed and emphasized by being proactive. Material and equipment were categorized based on criticality ratings. Representatives conducted inspections at every stage to ensure quality.
Innovation and adoption of new techniques was considered a key factor, providing leverage to the tight project schedule and commitment to continual improvement. One of the major achievements was obtaining approval of phased-array ultrasonic testing (PAUT), in lieu of radiographic testing (RT) for structural and piping joints. Because there was no radiation hazard, work could progress in adjoining areas, resulting in improved productivity during fabrication at yard and hook-up offshore. A special RT technique called small controlled-area radiography (SCAR) was employed offshore during hook-up. This technique requires a much smaller safe radiation zone (1m). Hence, progress was enabled around the clock.
Special attention was paid on storage and preservation of E&I items and critical equipment by providing necessary materials, like vapor corrosion inhibitors pouches (VCI), VCI sheets, dehumidifiers, stretch films, etc. Inspection documents were strictly controlled. This helped clear inward material inspection reports, which in turn helped clear material for fabrication
A thorough control on minimized with fewer fabrication punch points.
The Hazira yard has a tidal jetty. Load-out and sail-out operations are tide dependent and cannot be done throughout the fair weather season. Load-out and sail-out need tidal levels of 3.9-4.5m, and 4.7m, respectively. There are only a few available times that have the required tides for these operations.
Large modules require a large barge, which represented a further constraint. Transporting 400ft cargo barges through Hazira channel safely was difficult. Another challenge was posed by extralong bridges (137m long) for the flare lines of MHN and MNW-NF projects, which had significant overhang.
The execution of the schedule concluded when the MNP-MNF2 bridge was successfully loaded-out on 29 February 2012, and sailedout safely from Hazira channel on 7 March 2012. Forty-five barge movements were carried out in 3.5 months and used almost every available tidal slot. Jetty utilization was above 85%, setting a record.
During this work, many new records were set. The heaviest module load-out in India went to MNP South East deck at 4521 tonnes. A new record for the largest number of axles in one load out was 200 and was shared by MNP South East deck and MNP South West deck. While MNP East deck created the record for longest axle line in India with 44 axles and 70m in length.
After surmounting challenges of fabrication and load-out, installation of the modules was another large task. A total of 250 installation barge days were used for offshore installation. A total of 72 vessels were mobilized during the entire marine spread. Both phase one and phase two campaigns took more than 120 days each.
Phase one installation was performed by L&T’s own installation group, formed in joint venture with Sapura Crest of Malaysia. The installation of the heaviest MNP jacket was smooth and without problem. Phase two installation was started by DB-101, which installed MNW-NF bridge, MNW crane, MLQ deck, MNF2 jacket, and OSV mooring buoy.
One challenge during installation was integration of Level 1 of MNP deck, comprising five splices and three cantilever supports. Precision work and fine tolerances were required for successful installation and integration.
The structural integration of modules into a single structure was required at each stage and significant time was taken in this integration. Integration of CSF frames with South East and South West modules took 12 days, after which East, North and West decks were installed. It took 11 days for integration of MNP platform’s Level 1. However, after integration, the next five modules, three bridges, two cranes, and two flare stacks were installed. Installation was completed on 20 April 2012, and Oleg Strashnov sailed back after a successful campaign.
Hook-up and commissioning
After installation was completed, this left 25 days for hook-up before onset of the monsoon season and demobilization of the hook-up barges.
The MNP platform required a large number of splices and modules (10 modules and three cantilever frames) to be integrated offshore. Fifty percent of the cabling was to be done offshore and could not be started before installation completion. Cables had to run from MNW platform to MNP and MLQ platforms. Dry run and final commissioning occurred in parallel. Four barges worked simultaneously for installation and hook-up in the same complex.
The MLQ hook-up had a large GRE piping and plumbing scope. Hook-up work was started in parallel with installation. MNP platform hook-up work was started soon after installation of South East and South West deck. It was necessary to work in parallel with the installation. Additional safety measures and precautions were taken during the overlapping period. Simultaneous operations meetings were held regularly.
Due to the anchor patterns of the installation barge, the hook-up barge could not be connected to MNP platform using a gangway. The accommodation barge was anchored 2.5nm away from the platform from which passengers were ferried daily in crew boats. Software identified the spools and tracked the work. Software also helped managers make quick decisions without referring to the engineering center. At peak, three hookup barges were used: East Wind, Sea Stallion, and Sea Jaguar, along with 850 construction personnel, including 750 workmen.
Substantial hook-up work was completed by 30 May 2012, before monsoon onset. Residual hook-up work, pre-commissioning, and commissioning of the MNP platform was completed with ONGC’s support by accommodating manpower on the MNP platform and MLQ platform during monsoon.
The MHN process complex was commissioned and the platform started production in October 2012. The process complex was inaugurated on 21 October 2012 by CMD-ONGC. This complex will help in meeting growing oil and gas requirements.
The successful execution of MHN project was achieved by exemplary co-ordination between engineering, execution, construction, installation and commissioning. OE
|Kumar Rudra is a chemical engineering graduate from Jadavpur University Kolkata. He is currently head – projects and is the project director for the MHN Process Platform Complex Project. He has more than 22 years of experience in project management, engineering, business development, execution, and onshore/offshore construction of platforms.|
|Sandeep Badhe is a mechanical engineering graduate from Mumbai University. He is project manager for MHN Process Platform Complex Project. He has more than 23 years of experience in project management, engineering, quality assurance, execution, and onshore/offshore construction of platforms.|
|Devendra Awadhiya is a chemical engineering graduate from Marathwada University. He is a chartered chemical engineer with more than 19 years of experience in process design and engineering. He has been responsible for process design, engineering, start-up, commissioning, process optimization, and trouble-shooting of on- and offshore process plants/platforms.|
|Rupchand Lohana is a chemical engineering graduate from IIT, Mumbai. He has also completed an Executive MBA from SP Jain Institute. He is presently leading projects control discipline in Upstream Oil & Gas Projects. He has 14 years experience in process engineering, commissioning/troubleshooting, strategy, management, marketing, and business development.|