IPC2000-238 Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021
TECHNICAL AND ENGINEERING CHALLENGES FACED IN DESIGN OF THE GELUGOR MAINLINE, PENANG, MALAYSIA
Ir. Hj. Ahmad Khairiri, Abdul Ghani, P. Eng. Site Construction Manager, Penang Lateral Projects Technical and Facilities Development Division PETRONAS GAS BERHAD
ABSTRACT environmental challenges. This paper aims to describe the PETRONAS Gas Berhad (PGB), a listed partly-owned route selection process, the pipeline design process and outline subsidiary of PETRONAS is undertaking the Peninsular Gas some of the specialist techniques employed in the design Utilization Project - Stage III (PGU III). The PGU III Sector 2 construction of the Gelugor Mainline, Penang, Malaysia. & 3 project extends from Lumut, Perak to Pauh, Perlis on the In nearly every major project a drive for cost and risk reduction West Coast of Peninsular Malaysia, with two laterals, the results in a number of new ideas with varying degree of Gurun Lateral and the Penang Lateral. The Penang Lateral is impact. Hence, the following areas will be elaborated and further divided into the Prai Lateral, Gelugor Mainline and the presented in greater details: Gelugor Tenaga National Berhad (TNB) Meter Station project • Pipeline Design. individually. • Pipe-lay vessel. This paper will focus its' discussion on the technical and • Pipeline installation methodology. engineering challenges faced in the design of the Gelugor Mainline Project. The Gelugor Mainline consist of about 7 km INTRODUCTION NPS 24 gas pipeline which runs from TNB Prai Power Plant of PETRONAS Gas Berhad (PGB), a listed partly-owned the mainline to TNB Gelugor Power Plant on the Penang subsidiary of PETRONAS is undertaking the Peninsular Gas Island. The pipeline is planned to operate at high pressure. Utilization Project - Stage III (PGU III). The PGU III Sector 2 The pipeline route traverses complex terrain with varied & 3 project extends from Lumut, Perak to Pauh, Perlis on the seabed lithology with depth up to 16m. The pipeline will cross West Coast of Peninsular Malaysia, with two laterals, the active shipping lane, zones of live electrical cables, extensive Gurun Lateral and Penang Lateral. The Penang Lateral is system of submarine pipeline, mudbank and areas susceptible further divided into the Prai Lateral, Gelugor Mainline and the to mass gravity flows. There is also an area subjected to future Gelugor Tenaga National Berhad (TNB) Meter Station project 2 development with an expected 170 kN/m distributed load with individually. The Prai Lateral consist of 21.7 km of NPS 24 3 m covers required which is an expressway and Light Rapid gas pipeline which runs from Lunas, Kedah to the TNB Prai Transportation (LRT) system, the proposed development of a Power Plant in Prai, Pulau Pinang. Commercial gas delivery "Vision City" is also a few meters away from the pipeline. The metered at Gelugor TNB Meter Station is scheduled to start in pipeline also passes by an environmentally sensitive area that mid 2000. includes the rearing of caged fishing activities. The Gelugor Mainline consist of a 7 km NPS 24 gas It is essential for the project team to determine and pipeline which runs from TNB Prai Power Plant in Prai, Pulau investigate the variable risks to the pipeline in order to take Pinang of the mainline to TNB Gelugor Plant on the Penang appropriate evasive and mitigating action in design. This Island. The pipeline passes across the Straits of Penang about required comprehensive survey activities in the busy shipping parallel with the Penang Bridge, the longest bridge in South straits. The paper will explore and detail out its' study starting East Asia. The pipeline is planned to operate at high pressure from the description of the design concept to the varied sales gas with a design pressure of 70 bar (6895 kPa). The
Copyright © 2000 by ASME pipeline route traverses complex terrain with varied seabed ROUTE SELECTION lithology with depth up to 16m. The pipeline will cross active Initially the route was to pass by the southern tip of shipping lane, zone of live electrical cable, an extensive system Penang Island to cater for a new Independent Power Producer of submarine pipeline and areas susceptible to mass gravity there but somehow this plant was not materialized. Then TNB flows to name a few. Location Plan is shown in Figure 1. power plants both at Gelugor and Prai requires gas for their Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021 power generation. It was finally decided that the pipeline route Since the risk is very high it is essential far the project should passes both power plants. The route selection process team to determine and investigate the variable risks in the identified and adapted here where merely cost driven due to pipeline project up front. Appropriate evasive and mitigative scarcity of land especially on the shore approach part. Some of action was taken in the early design stage. This requires the basic criteria in selecting the route chosen include the comprehensive survey activities in largely variable terrain. The followings: main activities for the Gelugor Mainline Project can be summarized in Figure 2: Main Activities For Gelugor • Shortest possible route Mainline Project. It kicks off with an initial route selection • Avoiding hazardous area study, inclusive of various activities and complete with the • Avoiding existing anchoring zone with the planning to introduction of sales gas thru commissioning in the system. include a portion of the selected route as part of the non Engineering, procurement, construction, commissioning anchoring zone. (EPCC) contract for the project was awarded to Pi Gas • Avoiding other pipeline or cable crossings as much as Billfinger Berger Civil Construction Joint Venture which later possible. subcontract the Engineering work to Mentor Engineering and • Avoid area of intensive caged fishing activities. the post trenching activity to Sumai Engineering to name a • Avoid bottom obstruction or depressions that may create few. The owner of the system is PETRONAS Gas Bhd. The the massive pipe span. summary of the project data is included in Table 1 : Gelugor Mainline Project Data. The route selected for the project passes through a few obstacles namely the followings: Pipeline Location Gelugor Mainline Location Seberang Prai, Mainland • Extensive system of submarine pipeline - At the Prai site Peninsular Malaysia to there is 4 number of NPS 10 oil pipeline and one cable Penang Island running to a nearby jetty where the proposed pipeline had Product Natural Gas to cross. Pipeline Outside Diameter (mm) 609.6 ( 24 inch ND) • Port activities - This include a busy port and active Pipeline Wall Thickness (mm) 15.9 shipping lane where ships make a turning point here. The Pipeline Material Type/Grade Spiral Welded Carbon design of the pipeline has to cater for anchor drop and Steel API 5LX 60 drag, which might happen here in the future. During Pipeline Design Temperature 55 construction, there is also stopping of work activity every (degC) time a vessel passes by. Pipeline Length (m) 6466 • Prai River mouth or delta - Design to include high under Pipeline Design Life (years) 25 current reaching up to 4 knots and the mass gravity flow Maximum Water Depth (m) 16 on the seabed which shall be elaborated further below. The Pipeline External Corrosion 3 Layer Polyethylene sea floor of the Prai River mouth is prone to siltation Coating (sedementation built-up), which needs further design Pipeline Corrosion Coating 3.0 (minimum) condition in trench work during construction. Thickness (mm) • Non anchorage zone - This make anchoring difficult, Pipeline Internal Coating Liquid Epoxy sometimes anchoring system had to extend anchor from Pipeline Internal Coating 0.35 300 to 400 m's. Thickness (mm) • Life electrical cables - There are 5 life electrical cables Required Concrete Weight 40.0 (125 kV and 33 kV) in the Non Anchorage Zone, which Coating Thickness (mm) supplies electricity to Georgetown on the Penang Island. Required Concrete Coating 3044 Any disruption to this life cable might have a political and Density (in air, kg/m3) adverse impact to the surrounding area. A close Hydrotest Pressure (Mpa) 9.66 monitoring was implemented during the construction Table 1: Gelugor Mainline Project Data stage. • Middle Bank - This is a mudbank area where working of sandy or particulate soils. As turbidity currents develop it here is very tide dependent. Here, the proposed increases in momentum, eroding further sediments. At the Prai development of a "Vision City" is in planning stage. The river mouth, sand waves and ripples up to lm high developed planning of this proposed city shall also taken into as the tide changes. consideration the minimum distance required from the Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021 pipeline SURVEY ACTIVITIES • Expressway - There is also an area subjected to future The objective of the survey includes: development with an expected 170 kN/m2 distributed load with 3 m covers required which is an expressway and • To accurately determine the water depth (bathymetry) Light Rapid Transportation (LRT) system. However, both along the Pipeline Route, producing a seabed profile, this projects need some reclamation to be conducted first. which would be used as a baseline for the trenching and • The pipeline also passes by an environmentally sensitive burial works during the installation of the NPS 24 gas area, which include the rearing of caged fishing activities pipeline. and close proximity to houses on stilt. • To determine and map out any seabed or shallow sub- • About 2 km south of the construction area there are also seabed obstructions or anomalies along the Pipeline Route, on extensive area for cockeral cultivation. which may pose as a constraint to the installation of the NPS 24 gas pipeline. This would be performed with a side Seabed Condition scan sonar and sub-bottom profiler. Teknik Lengkap Geohydrographics Sdn Bhd performed the geophysical survey in December 1998 for the proposed A total of five (5) longitudinal survey lines centered at the route. However, a pre-installation route survey was again NPS 24 PGU HI Gas Pipeline Proposed Route (original route) conducted in May 1999. Generally, the soil is soft grey marine was designed and surveyed. The line spacing is 25 meters clay (mud) accumulated especially in the shipping channels. forming a survey corridor of 100 meters wide. Cross lines were The remainder is light grey, fine to medium grained sand with run at every 500m interval, extending to about 250 meters shell fragments especially towards the shore and sandbanks. south of the Proposed Route. Specific mobilization tasks The seabed reaches a depth of nearly 16 m at the shipping carried out during this period included the following: lane. The Middle Bank nearer to Gelugor cm the Penang Island mainly consists of mud. During transition phase of low and • Wet testing of temperature / salinity / depth probe. high tide, the current turbidity around the Middle Bank create • Appropriate rub and wet testing of the side scan sonar a fast action reaction. This is further worsen by the "venturi" system. effect of the Straits of Penang and the Prai River deposits. Two • Installation and interfacing testing of all computer system. small islands had resurface near the Penang Bridge after the • Running of software (on-line and bathymetric data construction of the bridge and the reclaimation activity near acquisition) by. This is the result of the above phenomena where bottom • Measuring vessel offsets twice and independently. profiles slope reduce the rate of deposition increases and the • Safety instructions I briefing material pile-up to form an island. The Prai River makes the matter worse where strong undercurrent makes the diving In summary, two large channels in North-South namely activity very difficult. Neap tide is the only time where diving the Middle Shipping Channel (KP 2.250 - KP 3.200) and could be perform excellently. western channels (KP 5.200 - KP 5.800) characterize the seabed profile. Maximum water depth observed within the Mass Gravity Flow (Seabed profile) Middle Shipping Channel is 15.7 meters (below Chart Datum, Mass gravity flow on the seabed can develop as a CD) at whilst the maximum water depth observed within the consequence of soil instability. The general term covers three western channel is 9.7 meters (below CD). In between these types of gravity flows: mudslides, debris flows and turbidity channels lies the Middle Bank, from KP 4.200 to KP 5.130, currents. Mudslides most likely occur in clay soil where it is over a distance of 930 meters along the Route. The Middle the resultant of coherent failure of the slqpe. This mudslide Bank has an average height of 0.5 meters above CD, which may disintegrate into debris flow where it is characterized as a dries during low tide. An area of shallow water was observed dense fluid consisting of different sizes of suspended particles. in the Eastern Bank with a minimum water depth of 2.7 meters This form of loading on a pipeline is less severe compare to (below CD) at KP2.14. The edges of all the sand banks mudslide but it can reach a certain distance. Larger particles presence within the survey corridor has an average gradient of fail out of suspension as the debris flow progress and upon 1 in 10. An area of irregular seabed, which is thought to achieving properties of "dense water" form into turbidity associate with cemented shell build up, is observed between KP current. This type of current is more likely to develop in areas 5.300 and KP5.430. Side-scan sonar records reveal distinctive areas of low to height is used in the design for both installation and medium sonar reflectivity. Low sonar reflectivity is associated operational condition. with very soft clayey seabed, whilst medium sonar reflectivity • Spanning analysis. Since the pipeline is post trench and is associated with fine to medium grained sand. The seabed Horizontal Directional Drilling (HDD), this analysis is morphology is dictated by the current, flow in North-South perform for the installation and hydrotest cases where direction, and tide conditions within the Straits of Penang. The freespans may result from laying the pipeline onto uneven Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021 sandy seabed is characterized by the areas of sand waves and seabed. ripples observed within the survey corridor. A few patches of • In-situ stress analysis. Both fully restrained and high sonar reflectivity associated with possible cemented shell unrestrained pipeline section conditions were investigated build up, of height ranging from less than 0.3 meters to 1.5 here. meters, were observed between KP 5.400 and KP 5.450. • On-bottom stability analysis. An installation condition Numerous patches of high sonar contact are observed within (pipeline empty) subjected to 1 year return period wave the Middle Bank. They are thought to associate with mounds and current was included here. of stiff to hard sediment, with diameter ranging between 0.5 • Pipeline expansion analysis. Both operating and hydrotest meters and 1.5 meters and is generally of less than 0.3 meters cases plus expansion offset was investigated which include in height. the following basis: no axial restraint at the end of the The sub-bottom profiler (pinger) data generally reveals a pipeline, maximum operating temperature, minimum series of well-defined sub-horizontal to cross bedded sediment installation temperature, design pressure, low (realistic) sequence. The seabed sediment is thought to comprise mainly estimation of axial friction and minimum content densities of sand, which changes to clay towards both Prai and Gelugor where applicable Landing Point. The lower interval of pinger record is • Pipeline installation analysis. This includes pipelay characterized by a series of well-defined channel development initiation, abandonment and recovery analysis. and erosion sur£ace. Channel in fill sediments is thought to • Cathodic protection design. Design to cater for minimum comprise mainly of firmer clay and sand with organic material. design life of 25 years and pipe to soil potential between - Diffraction is occasionally observed at the base of the channel 0.8 and -l.lv (silver/silver chloride reference cell) indicate the presence of biogenic gas, which is associated with • Pipe supports design inclusive of maximum pipe load decomposition of organic materials within the channel. together with environmental (wind) loading. Diffraction coupled with partial to total masking of underlying • Rock armoring or rock cover. The design involves in horizons is also observed between KP 0.000 - KP 0.400, KP selecting the right rock size plus the filtering layer around 3.600 - KP 3.800, KP 5.000 - KP 5.200, KP 5.380 - KP 5.470 the pipe prior to it. and KP 5.900 - KP 6.000. They are associated with possible • Impact analysis. This is to determine the approximate cemented shell build up or dense sand layers with podcets of required rock cover thickness due to impact load firm silty / sandy clay to dense coarse sand. associated with the transfer of energy from the impacting Besides that, the geotechnical evaluation used cone- trawl board to the pipe and its coating. The impact penetrometer tests (CPT), hydraulic coring, and box coring, direction and the amount of energy transfered to the pipe vibro-coring and piston gravity coring for soil sampling. depends on the pipe diameter, span height, shape of the Information on the preliminary pipeline route was made front of the trawl board/anchor and the direction of travel available to the client by other data i.e„ Ikram, Penang Port relative to the pipeline. and the Marine Department. An environmental impact assessment was also perform to meet the relevant authority PIPELAY VESSEL requirement. A highly extensive and iterative exchange of The pipelay vessel for the project was built partly from information was achieved between all concern parties sketch. It requires an overlapping vessel concept between contributing to the successful route selection process. offshore application and shore approach. The barge is a non self-propelled 'make-up' flat top barge design for working in PIPELINE DESIGN the area. The pipe lay vessel chosen requires less tension load The Gelugor Mainline design has adopted an extensive thus widen the choice of vessel for installation. Lower pipeline design approach to ensure the pipeline was constructed to the tension has the benefit of lower pipeline residual tension which best of engineering practice. Some of the pipeline design leads to a shorter pipeline unsupported spans and reduction in criteria adopted for the project are as follows: the risk to the installed pipeline. An elevated pipe lay ramp was fixed on the starboard side and runs along the entire • Wall thickness, buckling and collapse analysis. Highest length of the barge. A fixed 24 m stinger section is attached to Astronomical Tide (HAT), inclusive of surface wave the stern to support the pipe overboard region. The barge has 3 welding stations arranged for maximum 15 m long pipes with no pipe tensioning capacity. Pipes are loaded from the port side revised to include pulling of the pipeline via a pull winch of the barge using a 136 ton crawler crane. Using a boom barge accordingly. length of 140 feet, the crane loads the pipes and moves it to the A pipeline installation methodology based on a lay barge ready rack. It is transferred onto the bead stall for beveling and pulling operation activity concurrently with HDD activity and to the stalking (line up) station. The details of the pipelay post trenching activity at a later stage was implemented. For Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021 vessel used for the project are as per Figure 3 below. The the shore approach, once a section of the pipeline in completed pipelay vessel also included A-davit for tie-in purpose, cabins it will be towed out to the respective HDD hole and pull into it. which function as offices, NDT viewing facilities, compression The pipeline will be partially filled with water via an insertion chamber, cooking area and the relevant welding stations of a HDPE pipe inside the steel pipe to ensure the pipe is not inclusive of radiographic examination area and mastic buoyant. The fabrication area will be on the lay barge and the application area. pipe string will be pulled accordingly until a section spread is completed prior to towing out. A total of three (3) above water PRINCIPAL Classification ABS tie-ins' were perform for the 7 km stretch. PARTICULARS Port of Registry Singapore By implementing the revised construction methodology, Year of 1994 the contractor has managed to achieve the same result in Built Singapore comparison to having the fabrication work onshore. The pipe CONSTRUCTION Length Overall 252 ft fabrication activity on the lay barge is an independent activity DETAILS Breadth Molded 80 ft prior to having any effect to the shipping movement across the Depth Molded 6ft shipping lane in the port area as previously identified. Deadweight 5990 MT GRT/NRT 2371/712 Horizontal Directional Drilling fHDDl Deck Loading 7.5 MT/SQ There are initially three HDD areas to be perform, each at Hull Type/No. Of 2-Longtitudinal the shore approach and one across the shipping lane. However Bulkheads 5-Transverse the construction methodology changes during the construction DECK 1 Set Diesel-Powered Anchor stage where only the shore approach part was materialized. EQUIPMENT 1 Pc Stockless Anchor HDD in the pipeline industry may be defined as a technique SMT Towing Brackets - 4 Sets enabling the laying of a pipeline under a land surface obstacle. fable 2: Details of the Shallow Water Lay Barge This is accomplish by drilling a directionally controlled hole to accommodate the pipe, along a predetermined curved path under the obstacle and drawing a pre-joined, coated and tested pipe-string back through the hole. The technique is now well PIPELINE INSTALLATION METHODOLOGY understood and widely practiced by specialist contractors Initially, the contractor plan to execute the work by perforating available worldwide. Crossings for pipelines up to 42 inch the fabrication work i.e. welding, NDT, pretest etc. onshore (at diameter have been successfully completed. The longest 3 locations). Upon completion of a certain section, the pipe recorded 18 inch diameter HDD pipeline crossing is more than will be towed out to the designated location for the next 1700 meters in length. The Prai HDD was supposed to be an activities i.e. pulling into the respective Horizontal Directional NPS 20 1600m long but the distance was cut short to only 650 Drilling (HDD) hole which was prepared earlier, trenching m long after three unsuccessful trials. However, the Gelugor and jetting at the marine spread and finally tie-in prior to HDD 1100 m was successfully completed. commissioning. However, upon contract award and details In sand, loam or softer clays the drilled hole may be discussion with relevant authority i.e. Penang Port, the achieved by jetting. The jetting tool at the leading end of a drill contractor found out that there are safety, space and time string has a beveled face with mud jets strategically placed to constraint for them to perform the onshore fabrication and favor material removal on one side in preference to the other. towing out activity. This include an area to string and weld the Spoil is removed from the hole by mudflow. In order to pipe to a certain length, platform/jetty having the proper produce a straight portion of hole the complete drill string is strength and safe enough for it to withstand the high hydrotest uniformly rotated. To initiate a curve the drill string is held in pressure (pretest). It should also be near enough to be easily the preferred rational allowing the jet tool, in conjunction with towed out offshore plus the hindrance that it had on the marine tool thrust, to establish and sustain the required curve. The traffic in and out from the port. The other is the difficulty they required a hole for entry and exit points for the shore approach encountered which was tide dependent (the existence of the and intervening ground surface are surveyed before any middle bank) and the numerous anchoring along the Non drilling is commenced. This data governs the design of the Anchorage Zone; the construction methodology was then drill in both plan and elevation which is carefully planned to ensure that the minimum radius of curvature is acceptable for both the pipe to be inserted and the drilling process. Here operational time, reliability and operability. The know-how 500D is the required minimum radius. associated with laying pipeline in shallow water has further To ensure that the drill path adheres to the design as enhanced the knowledge in the field of the local contractor. It closely as possible and to provide position and directional data has also allowed the optimizing of local engineering and during drilling, the driller uses a down-hole survey tool which subsequently the construction far beyond expectation. The is located in the drill string behind the bit and motor. At usage of advance survey equipment has nessitate early Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021 regular intervals during drilling a reading is taken from the identification of problem areas. The successful completion of survey tool to provide the position of the instrument relative to this extremely difficult project was due to the excellent the drill entry point. This position is compared by specialized performance of all suppliers and contractors, especially Pi Gas computer software to the pre-entered design path thus allowing Engineering, Mentor Engineering, Sumai Engineering, Bill corrective action to be taken by the drilling superintendent Finger Berger Drilling Co., and others. when appropriate. Here, some of the benefit of using HDD is as follows: ACKNOWLEDGMENTS • Avoidance of environmental disturbance in construction, Tuan Ifl. Mohd Sohaimi Ahmad, Project Manager, Penang i.e. rearing of caged fishing activity and houses on stilt. Lateral Projects, PETRONAS Gas Bhd. • Enable some crossings not previously possible. OGP Technical Services Sdn Bhd. • Increase the number of alternative pipeline routes En.Sidek Atan, Project Manager, Pi Gas Engineering Sdn available. i.e. shore approach at both power plants. Bhd. • Improve security for the completed crossing (against natural and third party hazards). • Provide overall cost reduction. REFERENCES 1. 8th Offshore Pipeline Engineering Course, Kuala Anyway, the lesson learnt in this particular project is to Lumpur 1998. have more soil samples and test at closer intervals to determine 2. DNV, "Rules of Submarine Pipeline Systems, 1981" the soil condition accurately. 3. DNV, "Rules of Submarine Pipeline Systems, 1996" 4. DNV, "Recommended Practice Cathodic Protection Post Trenching over the Mud Bank Design, 1993" Initially, the jetting/eduction machine was proposed to be 5. Environmental Statement For The Proposed PGU IE - use here. However due to accessibility problem encounter here Prai Lateral, Gelugor Mainline and Gelugor Meter Station, where the area is only accessible during high tide, the usage of Biro Rundingan, Universiti Kebangsaan Malaysia. the above machine is restricted due to insufficient water level. 6. Teknik Lengkap Sdn. Bhd. TL Report No. MAL-072 Barges available are also found to be too large and/or with Rev. Ola (Survey Report). deep draught which is difficult to handle besides the close . PI GAS Billfinger Civil Construction Company proximity to the non-anchorage zone. Finally, the contractor procedure and calculation (Confidential) through their post trenching subcontractor Sumai Engineering Sdn Bhd adopts the use of a cutter suction pump catamaran. See Figure 5 & 6 below on the equipment use over the mudbank. Here, once the trenching machine is lowered on to the pipeline using mechanical hoist with divers assistance, the jetting pump is started followed by the suction pump. The catamaran can move approximately 0.5 m above seabed level. With a water depth at maximum tide recorded between 1.0 to 1.5 m. A trench of about 0.5 m cover was achieve in a single pass. A total of four passes were required to meet the contract requirement.
CONCLUSION There are a few technological advances related to submarine pipeline laying in shallow water applies here namely the usage of shallow water barge for laying and pulling activities, the Horizontal Directional Drilling and the post trenching activity. All this allows to a considerably decrease in Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021
Figure 1: Location Plan
ROUTE ROUTE SPECIALIST PIPELINES CONSTRUCTION COIUMISSIOHIHG SELECTION SURVEY STUDIES DESIGN Route Environmental Front-End Horizontal Hydrate sting Selection Feasibility Directional Suvey. Assessmeri Engneering & Study. Basic Design. Drilling Design Basis Commissioning for Route Geotechnical Detail Design. Laying Selection Survey & Soil Test Tie - In
Post Trenching
Rock Armonring
Figure 2: Main Activities for Gelugor Mainline Project Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021
Figure 3: Lay Barge Arrangement Including Welding Stations
Figure 4: A-Davit and Stinger Diagram Downloaded from http://asmedigitalcollection.asme.org/IPC/proceedings-pdf/IPC2000/40252/V002T07A013/2507795/v002t07a013-ipc2000-238.pdf by guest on 28 September 2021
Figure 5: Catamaran Rigging Up
k Cm * 11
FISSSSSW
Figure 6: Catamaran In Action at The Mud Bank