The perfect
STORM Volume-wise, 2015 was a lean year for the pipeline industry – but those results look much less disappointing when assessed against a background of very challenging circumstances.
I
n a paper presented at AMI’s Field Joint Coating 2015 conference, Noru Tsalic described the political and economic environment affecting oil and gas-related industries as ‘a perfect storm’. As mentioned at the time, it is not unusual for these industries to face crises in some of the geographic areas in which they operate. In recent years, however, such adverse political and economic circumstances have piled up, affecting practically all regions that are relevant in terms of oil and gas supply and demand. That’s not to say that pipeline building and pipe coating activities have completely frozen. To start with, numerous projects are still economically viable; others are too advanced to cancel or postpone. In certain countries (not in the least in China, Russia and the Middle East), such projects are not driven by purely financial considerations, but are part of longer-term policy and government-set strategies. In addition, given their age and the fast progress of technology, some pipelines are in need of rehabilitation or
28 July – September 2016
replacement – for safety, rather than purely economic reasons. There is also an expanding share of non-oil and gas pipelines – in particular drinking water pipelines – which is already considerable in places like India, for example. In addition to analysing in detail the current (2015) level of demand, segmenting it by geography, application, on/offshore location, coating functionality (external anti-corrosion, internal by function, thermal insulation and concrete by function) and material, the Steel Pipe Coating report focuses on forecasting demand to 2019. Despite the ‘perfect storm’ that recently affected it, the fundamentals remain positive for the pipe coating industry. The world’s demand for energy continues to grow; oil and gas continue to provide a large share of primary energy supply and the demand for these fossil fuels continues to grow, despite increasing adoption of renewable and other sources. In fact, countries will have to progressively switch from coal to the relatively less polluting oil and (especially) natural gas, if they are to fulfil their commitments in terms of reducing CO2 emissions. Global reserves of oil and gas are still far from exhaustion, and carbon steel pipelines continue to be, in most cases, the state-of-the-art solution for cheap, safe and secure short/medium range transport and high
IN FOCUS
pressure distribution, and functional coatings are increasingly deployed to serve those pipelines. After analysing trends (including forecasts for the price of crude oil), the report concludes that demand for steel pipe coating should grow on average by circa 3% per annum between 2015 and 2019. However, the growth is unevenly distributed across that time interval, both geographically and in terms of coating types and materials. Steel Pipe Coating - The Global Market 2016 is a detailed market report from AMI Consulting.
PIPE DREAMS Oil, gas and water industries are the major contributors to a worldwide network of more than 25,000 km of pipelines every year, with demand continually rising. A projected $11.63 billion will be spent on coating these lines by the year 2020. Long service lifetimes, serious safety considerations, and some of the most inhospitable areas on the planet combine to put high demands on the coatings.
C
oatings represent about 10% of the total cost of new pipelines, with around 9% of the cost being taken up with factory pre-coatings and 1% with the field coatings which guarantee corrosion protection at end joints, T-joints and flanges. These field joints represent the greatest challenge: factory prepared sections are cut back to allow for welding end sections together, covering potentially vulnerable points.
generally recommended. These 3LPE coatings are intrinsically waterproof, can withstand operating temperatures of up to 80ºc and offer a long service life. A common factory PE preparation for small and medium diameter pipes is to dry and blast the pipes to bare metal, preheat them, and then apply liquid primer or powder coating. This is followed by an adhesive tie-layer and a PE layer, extruded into a thin film from a circular die and rolled under pressure onto the pipe. FIELD JOINTS Once in the field, joints have traditionally been protected with a combination of coating technologies and spiral wrapping of tapes, and increasingly with heat-shrink sleeves. Seal For Life Industries, part of Indiana-based Berry Plastics, are headquartered in the Netherlands. The company claim to be the biggest manufacturers and sellers of Heat Shrink Sleeves (HSS), Adhesive Pipeline Tape, and Visco-Elastic and Abrasion Resistant Overlay Ceramic epoxy. Executive Vice President, Drs Frits Doddema explains that since, by their nature, most pipeline projects involve reaching more remote and challenging areas, the logistical problems of pipeline laying and field jointing are complex. They also require careful selection of appropriate coating technologies and materials. Special requirements for coatings can even include weight, as the weight of the coating will help to prevent an underwater gas pipeline from floating away from its supports. “The pipes may need to be embedded in peat soils or clay, marshlands or sand, fresh groundwater or salt water. The field conditions are frequently difficult – whether too hot, too cold, too wet, too remote, or simply too cramped. Every situation is different, across underwater, underground, inshore, and offshore.“ The coating of weld girth joints in pipelines is a critical factor of the final integrity of the Coating inspection on pipelines is not always easy © Stopaq
FACTORY PREPARED Factory coatings include various options, depending on the purpose of the pipeline and its operating environment. For general underground and underwater service, and especially in highly corrosive soil environments or where perfect pipeline reliability is important, three-layer Polyethylene (3LPE) coating is
July – September 2016 29
IN FOCUS
Once in the field, joints have traditionally been protected with a combination of coating technologies and spiral wrapping of tapes, and increasingly with heat-shrink sleeves. © Stopaq
30 July – September 2016
completed anti-corrosion system utilized. A field coating has to resist different conditions to controlled factory-grade coatings. A field coating system with higher potential failure rates can compromise the integrity of the entire system, and may significantly reduce its intended design life. JOINT INTEGRITY CRITICAL Doddema continues: “Full integrity of the coatings at the joints is critical. Depending on the field coating selection, application might include steel blasting, pre-heating the pipe sections and pre-heating of the coating materials.” “Maintenance regimes are determined by the owners, but there is close oversight by regulators, and owners must demonstrate good management of assets. Repairs and rehabilitation of existing pipelines brings a new set of problems.” “Longevity requirements also vary with the purpose of the pipelines. In the 1960s requirements matched the expected lifetimes of oil and gas fields in Northern Holland, expected to be 30 years. Experience has shown that much longer lifetimes are now needed, and design engineering specs are now often over 50 years and sometimes as high as 80 years.”
REPEATABILITY Field Jointing methods should provide equal durability, reproducibility, design life and other features to meet the requirements. Complex field jointing methods, when practical, are typically time consuming and extend the installation period, impacting total project costs in ways that are often overlooked. “Repeatable quality in the field is key. Most traditional anticorrosion systems have developed products and special methods of application, which can provide equal system quality at field joints” says Doddema. “Unfortunately these methods are typically complex and require special equipment and access limits that are often difficult or impossible to achieve in the field, resulting in the use of other methods that do not maintain system integrity and have a higher failure probability.” “Typically the main pipe coating costs are calculated when comparing anticorrosion systems during initial specification, and field jointing costs are assumed to be insignificant because the surface area of field applications is so small in relation to the total surface area coated. This assumption is misleading, as field jointing typically costs from three to five times more than the original parent (factory-grade) coating, and in some cases far more.”
IN FOCUS
EVOLVED COATING SELECTION Selection of pipeline coatings has evolved along geographical lines, based on owners’ preferences, pipeline construction and operating conditions. For example, coating damage is a real concern in regions where limited transport infrastructure can lead to rough pipe handling. Other difficulties come with aggressive backfills, induced current from overhead power lines, railway crossings and heavily populated areas. These factors have created a need for robust factory coatings. Where the pipes are being joined together, several types of external anti-corrosion and insulation field joint coatings are available. Besides the factor of compatibility with the factory coating, cutback length and type of parent coating, the choice of field joint coating is affected by pipe diameter, operating temperature, construction conditions, backfill, soil conditions and contractor capabilities. Seal For Life’s STOPAQ range of ViscoElastic Coatings & Sealants include innovative low cost technology for rehabilitation and new construction of pipelines and field joints. The coatings are based on fully amorphous noncrosslinakable chemistry, rather than the crosslinked molecules of molten polymers. Stopaq say this avoids degradation problems encountered with conventional systems. The new material also has additional “life saving and extending” properties due to its continuous liquid-like nature, including self-healing of small damages. It is not subject to cathodic disbondment. TAPE WRAPPING Denso, part of Winn & Coats, has over 85 years experience dealing with pipe coatings in a wide range of different conditions and surface preparations. The challenges fall into two main categories: Low quality surface preparation by hand power tools that will require surface tolerant coating systems, and high quality preparation by dry abrasive blast cleaning to a near white finish standard. The company’s Denso Tape coating systems will tolerate low quality surface preparation, using a variety of approaches including butyl and petrolatum tape systems. The tapes have a factory regulated minimum coating thickness and provide immediate mechanical and corrosion protection with excellent cathodic disbonding resistance. The tapes can all be applied by hand or by hand wrapping machine. AUTOMATED APPLICATION Another approach, the IntelliCOAT system from Canusa-CPS, takes repeatability of joint quality to another level.
SELECTION OF PIPELINE COATINGS HAS EVOLVED ALONG GEOGRAPHICAL LINES, BASED ON OWNERS’ PREFERENCES, PIPELINE CONSTRUCTION AND OPERATING CONDITIONS. The fully-automated system includes on-site computer-controlled machinery which fully encloses joint sections and applies programmed heating to pre-prepared wraps, removing most of the possibility of error by field operators. Details of each sleeve application are stored for repair and maintenance purposes. MAJOR LINES Business continues to look good across the industry. Current pipeline projects include a 48-inch diameter Trans Adriatic Pipeline, which will deliver 10 billion cubic metres per annum of new Caspian gas supplies to Europe from 2020. Meanwhile Uganda will be building a 1,400 km oil pipeline through Tanzania, and Indian-based Tata Steel has manufactured a large diameter 42” pipe which will become the deepest to be laid, across 140 kilometers in the Gulf of Mexico.
July – September 2016 33