Title of Innovation: Corrosion Protection for Pipeline Microtunneling. Brief Summary: Category: Design

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1 Title of Innovation: Corrosion Protection for Pipeline Microtunneling Category: Design Nominee: Sandeep Harshadray Vyas Reliance Gas Transportation Infrastructure Ltd. Mumbai, India Web site: Date of Innovation: 2008 Brief Summary: Reliance Gas Transportation Infrastructure, Ltd. (RGTIL) has implemented ~1,460 km east-west gas pipeline (EWPL) including 1,375 km by 48-in diameter trunk line, spur lines, and related infrastructures to transport gas from Kakinada (AP) to several consumers up to Bharuch (Gujarat). EWPL is the largest pipeline project ever executed in India. Pipeline crossing at Gautami River of about 2,500 m span is done by microtunneling (MT) method by installing 2.4-m diameter RCC casing to build a tunnel and pipeline installed within the casing. Pipelines are being installed within a microtunnel at crossings and other locations, where other conventional construction techniques are either not suitable for the site conditions or not practical to implement due to variety of reasons, including technological limits. Protection of such pipelines installed within a microtunnel from corrosion is a challenging task, considering the uniqueness of the environment under which the pipelines will be operating. Concrete casing pipe installed by MT technique to eventually accommodate the carrier pipe does not permit proper functioning of cathodic protection (CP) system, due to shielding effect and absence of electrolyte. Annular space between the concrete casing and carrier pipe, if filled with grout or any other material, would serves the purpose of electrolyte; however, its composition requires due attention from corrosion and CP design considerations. For the pipeline crossing installed within a MT where the water ingress protection cannot be ensured, the corrosion threat and protection measures need to be considered at design stage of pipeline. For the system developed for corrosion protection by CP and grout selection and filling within tunnel for the pipeline within microtunnel, basic considerations were taken during design, installation, testing, commissioning of CP system, and its monitoring requirements. Requirements of annulus filling from corrosion protection ad CP functional point of view also are addressed.

2 Title of Innovation: Corrosion Protection for Pipeline Installation for Pipeline Crossing by Microtunneling Full Description: When and how was it developed? Pipelines are being installed within a microtunnel at crossings and other locations, where other conventional construction techniques are either not suitable for the site conditions or not practical to implement due to variety of reasons, including technological limits. Protection of such pipelines installed within a microtunnel (MT) from corrosion is a challenging task, considering the uniqueness of the environment under which the pipelines will be operating. Concrete casing pipe installed by MT technique to eventually accommodate the carrier pipe does not permit proper functioning of cathodic protection (CP) system, due to shielding effect and absence of electrolyte. Annular space between the concrete casing and carrier pipe, if filled with grout or any other material, would serves the purpose of electrolyte; however, its composition requires due attention from corrosion and CP design considerations. The system was designed, procured, installed, and commissioned in 2007 to 2008 and has been monitored till date. How does it work, in basic terms? The system was installed about mid-2007 and commissioned and is being monitored till date for protection for pipeline within crossing, and the monitoring results confirm the achievement of protection till date. How or why is the innovation unique? Data for such cathodic protection system and requirement for other circumferential requirements for success of corrosion protection system was to be developed first time for such large gas pipeline with about 2,500-m long crossing for first time probably. This was the first ever microtunnel in India for gas pipeline and is with longer length. What type of corrosion problem does the innovation address? 1. Probable shielding effect of RCC casing pipe offers resistance to current flow from cross-country section of pipeline. 2. Multiple metallic installations within casing itself such as supports, rail tracks for installations, cable supports. 3. Possibility of MT casing leaking and entry of water from multiple locations of casing and thus risk of pipeline to go floating, thus requiring the casing to be filled.

3 4. Installation methodology for the length of 2,500 m. For proper distribution of current throughout the crossing length. 5. Monitoring of CP effectiveness and thus corrosion within casing by means of coupons and reference cells. What is the need that sparked the development of the innovation? Protection of such pipelines installed within a microtunnel (MT) from corrosion is a challenging task, considering the uniqueness of the environment under which the pipelines will be operating. Concrete casing pipe installed by MT technique to eventually accommodate the carrier pipe does not permit proper functioning of cathodic protection (CP) system, due to shielding effect and absence of electrolyte. Annular space between the concrete casing and carrier pipe, if filled with grout or any other material, would serve the purpose of electrolyte; however its composition requires due attention from corrosion and CP design considerations. There is no gas pipeline data available for such installation on public domain thus experience availability is minimal and as this was the first such installation in India and to maintain pipeline integrity against corrosion threat is a must. Are there technological challenges or limitations that the innovation overcomes? There are challenges such as limited data availability on public domain; length of crossings; installation; and working within tunnel for installation and testing; training of manpower for installation, safety, testing, etc.; and filling the entire tunnel with CP friendly grout post installation of CP and pipeline, etc. were a few of the challenges faced during course of time to make the system successful. What are the potential applications of the innovation? The successful implementation of project and results till date proves the applicability of designed system and thus can be implemented as ready reference for future project. How does the innovation provide an improvement over existing methods, techniques, and technologies? Data for such installation is not available in public domain/standard thus can be circulated/made available in public domain for benefit of all. What type of impact does the innovation have on the industry/industries it serves? The successful implementation of CP for pipeline within microtunnel and monitoring results till date including ILI (no corrosion defect in section); confirms the integrity of pipeline crossing section and gives confidence for protection and integrity. Does the innovation fill a technology gap? If so, please explain the technological need and how it was addressed prior to the development of the innovation. Data available in public domain/standards cannot be state away implemented/fully available for such pipeline crossings, thus further study with this success and development would enhance the technology.

4 Has the innovation been tested in the laboratory or in the field? If so, please describe any tests or field demonstrations and the results that support the capability and feasibility of the innovation. 1. The CP system testing was done on pilot project of about 50 m with similar installation and results were encouraging; the same was checked with internal as well external CP effectiveness and records were used for designing this system. 2. Lab testing for the grout materials for resistivity, viscosity, composition, CP effectiveness, ph, etc., were carried out for different grout compositions, and based on mud engineers study and detailing, the final material selection was done. Is the innovation commercially available? If yes, how long has it been utilized? If not, what is the next step in making the innovation commercially available? No the innovation is requirement on case-to-case basis, however a standard guideline can be developed for such future installation requirements. Are you aware of other organizations that have introduced similar innovations? If so, how is this innovation different? No (not for CP system); several microtunneling data are available on public domain for no data on such CP system was available till date. I have published a paper, Corrosion Protection of Pipelines Located within a Micro Tunnel, at the NACE India Corcon 2009 conference in Mumbai, India. Are there any patents related to this work? If yes, please provide the patent title, number, and inventor. No patents are available. Supporting Photos: Fig. 1: Installation for monitoring system for effectiveness of installed zinc ribbon anode system within tunnel and thus current distribution and protection achievement.

5 Fig. 2: Testing for isolation of ribbon anodes for other tunnel installations and fitting on cable installation hangers.