Malaysia's Peninsular Gas system gets another segment

C.F. SaviniSaipem (Malaysia) Sdn Bhd
Kuala Lumpur

Stage III of Malaysia's Peninsular Gas Utilization Project is nearing completion by a joint venture of Saipem (Malaysia) Sdn Bhd and Peremba Construction Sdn Bhd.

Under Petronas Gas Berhad, all stages of the Peninsular Gas Utilization Project are to provide natural gas to commercial customers recovered from complexes off the east coast of the Malaysian Peninsula.

Stages I and II consist of a gas-processing plant at Kertih and a 36 and 30-in. OD natural-gas transmission system between Kertih, Segamat, Singapore, and Meru, Selangor, with laterals serving several customers on the east and west coast of Peninsular Malaysia (Fig. 1 [99,207 bytes]).

Stage III consists of 448 km of 36-in. pipeline from the Stage II teeoff in Meru, Selangor, northward to Pauh in Perlis, close to the Malaysia-Thailand border.

Stage III, Sector 1 was completed by the Saipem (Malaysia)/Peremba Construction joint venture during the first quarter of 1996. It extends from the tie-in to Stage II near Meru, Selangor, to deliver gas to a power station near Lumut, Perak, on the west coast of Peninsular Malaysia.

The project principally consists of approximately 184 km of a 36-in. pipeline from Meru to Lumut and approximately 17 km of 24-in. pipeline from Lumut to the 1,300-mw Segari power station.

Included in the permanent facilities are six main line valve stations, two scraper stations, six cathodic-protection stations, and five teeoffs.

The topography of the pipeline route is generally flat except towards the end of the 24-in. Lumut lateral where the route transverses a hilly forest reserve. The vegetation along the pipeline route is generally rubber and oil palm.

Approximately 11 km of rice fields and 40 km of continuous swamp, however, were encountered along the route. The pipeline route also crosses five major rivers.

Sectors 2 and 3 extend the Sector 1 36-in. pipeline from Lumut to Pauh. The route runs along the coast through the states of Perak, Pinang, and Kedah and terminates in Perlis.

The project principally consists of approximately 264 km of 36-in. pipeline from Lumut to Pauh and approximately 3 km of 12-in. lateral pipeline to the Petronas fertilizer plant at Gurun. Included in the permanent facilities are 13 main line valve stations, 2 scraper stations, 8 cathodic-protection stations, and 9 teeoffs.

An 18-in., 21-km lateral pipeline to the power station at Prai and a 24-in., 25-km lateral pipeline to the Teknologi Tenaga Perlis plant were included in the Sector 2 and 3 package as optional.

The topography of the Sectors 2 and 3 pipeline route is mainly flat with approximately 53 km of undulating and 8 km of hilly terrain. Again the vegetation is generally rubber and oil palm. There are approximately 63 km of rice field through which the pipeline route passes in the states of Perak, Kedah, and Perlis.

Towards the end of the pipeline in Kedah, the route passes through a forest reserve and crosses eight major rivers, a railway line, and an expressway at five locations.

This region has the highest rainfall in the Malaysian Peninsula and is used as a water-catchment area for irrigation and domestic water supply. As a result, the policy regarding environmental protection, particularly to retaining the water quality, was of the highest importance.

The customer, Petronas Gas Berhad, is a partly owned subsidiary of Petroliam Nasional Berhad (Petronas) which provides natural-gas processing, transmission, and distribution, and natural-gas liquefaction and marketing of liquefied natural gas (LNG).

Construction

Malaysia's industrialization program encourages the bringing together of local and overseas companies to perform major projects, if the expertise is not locally available. The purpose of this policy is to enable local companies to gain the experience in fields not readily available to them.

As a result, Saipem (Malaysia) and Peremba Construction combined their expertise to tender for the Peninsular Gas Utilization Project, Stage III, Sector 1 and, subsequently, Sectors 2 and 3 contracts.

Saipem (Malaysia) is a Malay company that provides engineering and construction services to the oil and gas industry through its offices in Kuala Lumpur. Peremba Construction's main activity has been in civil engineering and construction of hotels, high-rise buildings, and housing developments.

The contract for procurement, construction, and commissioning of the pipelines of the Peninsular Gas Utilization Project Stage III, Sector 1, was awarded to the joint venture in June 1994; contracts for Sectors 2 and 3 were subsequently awarded in April 1996.

The installation program for the Sector 1 pipeline was developed to be compatible with the line-pipe delivery schedule and progress of construction northward from Meru, while a special spread performed the construction activities concurrently in the swamp section.

Progress was initially hampered, however, by unusually high rainfall combined with the high and tidal natural water table in the lower regions.

To mitigate the effect on the construction schedule, Saipem opened work areas where other construction activities could proceed concurrently with the main pipeline construction.

The work force was increased and additional equipment mobilized to enable this strategy to be implemented.

The Sector 1 project was divided into four distinct sectors: main spread, the special spread for the swamp section (Fig. 2 [30,493 bytes]), the 24-in. lateral Poor Boy spread, and the construction associated with the main line valve stations, scraper stations, cathodic protection stations, and teeoffs.

To meet the challenges of Sectors 2 and 3, five distinct operations were identified: main line spread, special spread for the wet sections, special spread for the hilly sections, the 12-in. lateral Poor Boy spread, and installation associated with the main line valve stations, scraper stations, cathodic protection stations, and teeoffs.

In addition to normal pipeline-construction techniques, various other methods were used in areas of high and/or tidal water table.

The extremely wet conditions meant that unconventional techniques were adopted for the pipeline installation. Use of equipment fitted with swamp tracks or low-pressure tires and lifting equipment operating on support matting were mandatory.

To confirm that the pipeline would be stable in areas with a high water table, buoyancy-control calculations were performed that used raw data collected from the field. These data included readings from stand-pipe piezometers and field and laboratory tests to establish the properties of the soil to be used in the design where backfill was considered as a resisting force.

The results of these calculations showed that continuous weight coating was necessary in the Sector 1 swamp section and seton and bolt-on weights (Fig. 3 [26,175 bytes]) were required at the other low areas of the pipeline route.

During construction, 20 crossings were installed with horizontal directional drilling. The longest crossing, at the Perak River, had a drilled length of 1,340 m and required 22 days (Fig. 4 [14,658 bytes]).

A feature of these crossings was the need to minimize the buoyancy of the 36-in. diameter pipe in the drilled hole. This was achieved by controlled flooding of the pipeline string as it was pulled into the hole.

Piping associated with the main line valve stations, scraper stations, and tee-offs was fabricated at support bases and transported to the required locations for installation. This piping was hydrostatically tested before being tied into the main pipeline.

All main line welding was to have used Saipem's Passo semiautomatic welding technique. The goal of using the most people possible from local communities forced manual welding to be used throughout the projects.

Training of local welders was necessary to achieve the high welding standards required by the customer.

There are 19 main line valve stations, 4 scraper stations, 13 tee-offs, and 14 cathodic-protection stations located along the pipeline. Of these stations, all the scraper stations and 15 main line valve stations are provided with supervisory control and data acquisition (scada) capabilities.

Thirteen locations required preloading with wick drains and a further 14 required 6 months' loading before start of piling. All the stages of construction were subject to the approval of the customer. The access roads to the main line valve stations, scraper stations, and cathodic protection stations were constructed to requirements of the Malaysian state road works department.

All materials, except main line valves, Sector 1 scraper traps, and 36 and 24-in. line pipe supplied by the customer, were procured by Saipem. Included in the procurement activity were those line-pipe sections required for induction bending, insulating joints, field-joint coating, and pipe, valves, and fittings for the station works.

All suppliers, manufacturers, and subcontractors were scrutinized by the customer and subject to his approval.

Six support bases were built at strategic locations to meet the needs of construction. These bases provided office accommodation for the customer, contractor, warehousing, selected subcontractors, and equipment maintenance.

In addition, medical facilities, capable of performing first aid and emergency stabilization treatment, were located at these bases.

Local Malay companies performed various activities, services, and supplies in line with Saipem's policy of utilizing local resources in Malaysia.

Such activities as material and equipment supply, nondestructive testing, cathodic protection, right-of-way preparation, thrust boring, microtunneling, civil and mechanical works, and revegetation were all being performed by local Malay companies.

Cathodic protection

Upon completion of the pipeline installation, a permanent impressed-current cathodic-protection system consisting of several cathodic-protection stations located evenly along the pipeline was commissioned to operate continuously.

One deepwell and five shallow-anode ground beds were constructed to provide cathodic protection to the Sector 1 pipelines. To provide cathodic protection to Sector 2 and 3 pipelines, seven shallow groundbeds and one groundbed comprising of six deep well anodes in line were installed.

At horizontal directionally drilled crossings and where lateral pipelines from the 36-in. main line occur, 44 monolithic isolation joints were strategically installed.

Electrical interference from the HVAC distribution power lines which traversed Sectors 2 and 3 pipelines was encountered following commissioning of the Segari power station at Lumut, which utilizes gas transported by Sector 1 pipelines.

Induced HVAC voltage on the coated pipeline can pose hazardous step-voltage shock to personnel who may be required to perform tasks associated with the pipeline facilities.

This is predicted at aboveground pipe work associated with scraper stations, main line valve stations, teeoffs, and cathodic-protection test stations. To safeguard personnel working at these locations, the HVAC-induced problem has been mitigated by installation of equipotential mats.

In addition, the test stations have been designed to include fully insulated, Zapguard-type test points complete with underground zinc ribbon anodes. These devices will dissipate hazardous induced voltages to ground thereby preventing danger to personnel.

To monitor the performance of the cathodic-protection system, test stations have been installed at 1-2 km intervals along the pipeline. To mitigate stray current interference, test stations were installed at foreign buried pipeline crossings.

Hydrostatic testing; QA

Hydrostatic testing along the coastal lowlands can be characterized as testing with simple pumping requirements and more difficult water sourcing. The maximum pump head on Sector 1 was 30 m compared to 200 m on Sectors 2 and 3.

Most large rivers were unsuitable as water sources because of sediment load. Most of these rivers were crossed by horizontal directional drilling resulting in the accessible ends of the pipe being remote from the water. While irrigation canals were sometimes available, the water level was seasonal, depending on agricultural demands.

Some water sources had high acidity as a result of high sulfate levels in the soils, while others were brackish and tidal. To avoid the risk of contamination to water that may be used for domestic or irrigation purposes, chemicals were not used. Instead, the water was used for as short a time as possible, and the best available water sources were used.

Test sections were determined on the basis of location class, with a maximum length of 25 km and elevation changes. Test pressures were between 90% and 110% specified minimum yield stress (SMYS) for 24 hr. Sector 1 pipe was cold-expanded; testing rarely exceeded 30 hr duration.

For Sectors 2 and 3, spiral welded pipe was used which was not cold expanded with tests regularly extending beyond 30 hr because the test pressure was kept at the same pressure level for the full duration of the test.

To meet contract requirements and deliver a quality product to the customer, all work was conducted in accordance with ISO 9002.

The Saipem Peremba Joint Venture received full ISO 9002 certification in September 1995 during Peninsular Gas Utilization Project Stage III, Sector 1, and has been successfully audited since by the certification authority.

The joint-venture quality management system is documented in the Project Specific Quality Assurance Plans which detailed procedures for meeting the quality requirements of the project. The plan details how the quality system is to be effectively implemented for the project.

The quality assurance plan was submitted in two parts. The first addresses quality-assurance activities planned for first 3 months after the award of the contract. This was submitted at the project mobilization meeting. The second part of the plan was submitted 2 months after the award of the contract.

Together, the two parts form the Saipem Peremba complete Quality Assurance Plan, addressing the means of controlling and monitoring all aspects of the contract which may affect quality.

The joint venture also verified that vendors were able to provide materials and equipment that would meet or exceed the project requirements. This included ensuring that vendors had sufficient capacity to meet demands, had quality programs in place, and that they were capable of meeting or exceeding the requirements of applicable technical standards for the manufacture or fabrication of materials and equipment they were to provide.

The joint venture ensured that vendors and inspection agencies provided all necessary documentation to certify that each item of the material and equipment complied with the specification.

Material-test reports, pressure-test certificates, and compliance certificates were part of the deliverables required from the vendors at the time of each item's delivery. The original documentation was traceable to each item and was included in the procurement close out report.

On completion of the work, the joint venture handed over all original documentation, such as weld books, radiographs, radiographic reports, materials test certificates, compliance certificates, pressure test certificates, and other records pertaining to the quality of the work.

This documentation was submitted as part of the final documentation package and was bound and compiled in a logical and orderly manner to enable adequate identification and traceability of materials from source to their locations in the pipeline.