What’s in the pipeline?

O&G gathers three industry experts to discuss corrosion, new technologies and pipeline issues in the MENA region.

“Whether we speak about In-Line Inspection, Hydrotesting or Direct Assessment, new technologies and techniques provide several opportunities for specific cases, all having both advantages and disadvantages depending on pipe location and environment”
-Khalil Ibrahim Al Gannas

The Panel
Richard Norsworthy is Director, Lone Star Corrosion Services, Polyguard Products
Khalil Ibrahim Al Gannas is CEO of JESCO
Miguel de Castro is Head of Flowmetering, Sampling, Lab Analysis at Société du Pipeline

Pipeline corrosion costs the industry billions of dollars every year. What are the main unsolved corrosion problems for the industry?
Khalil Ibrahim Al Gannas. If we analyse steel pipes corrosion history, we can see now several solutions for previously unsolved corrosion problems, and advanced technologies offer improved solutions at a very high pace. To solve an unsolved corrosion problem is related more to what is an acceptable cost on preventing corrosion against inspection and maintenance during operation. Current major unsolved corrosion problems are related to new requirements for pipeline steels that are becoming more and more severe to comply with pipeline operation at higher internal pressures, higher design factors (internal pressure related to the yield strength) and severe loading conditions, cumulated with an increase of transmission of corrosive and multiphase gases; therefore new or optimised steel and pipe manufacturing technologies are needed to cover such increasing requirements. While in pipe manufacturing there are several choices, we need to be able to source new or optimised steel specifications for use as the raw material for pipe making. Pipe making technologies need then to be adjusted to process such specifications.

Richard Norsworthy. Almost all pipelines are protected by cathodic protection (CP). One of the main corrosion problems facing the worldwide pipeline industry is the use of pipeline corrosion coatings which are not compatible with cathodic protection systems. The name of this problem is ‘cathodic shielding’. Shielding happens when the pipeline coating loses adhesion to the pipe (‘disbonds’), allowing water to penetrate. Corrosion can now occur unless the protective electrical current from the CP system can reach the steel. If the corrosion coating is one that shields (blocks) the protective electrical current when disbondments occur, then corrosion can proceed without interference. ,The problem of disbonded coatings that shield cathodic protection has been well documented in the pipeline industry over the last 25 years. Unfortunately, many in the industry do not require that pipeline corrosion coatings used on their systems be compatible with cathodic protection systems when disbondments occur.

Miguel de Castro. Corrosion problems can have costly consequences; therefore this item is usually taken into account at the design stage of the pipelines. Generally speaking, actions are mostly prevention oriented. External corrosion prevention can be hard to achieve locally, due to other networks as electrified railways, power line or pipelines which can impact Cathodic Protection efficiency. But once the area identified, field solutions exist. These solutions must take into account a large array of field problems. They must include an electro-magnetic compatibility evaluation in order to allow a performing monitoring and eventually, an effective lightning protection separated from the Cathodic Protection equipments.

Internal corrosion is a more serious matter for crude oil lines as corrosion inhibitors aren't always efficient on long distance lines. The only effective way to fight that is to closely monitor the evolution with intelligent pigging and eventually replace or reinforce default areas. This can be a little different for refined product lines, or short distances as these products are chemically better evaluated and inhibitors can be effective.

A issue is really coming out nowadays due to aging pipeline networks. The tools to detect some specific defaults aren't yet available. More specifically, stress corrosion cracks are very hard to detect and can end up with a pipeline rupture.

How are new technology and techniques providing opportunity for more efficient detection and risk management activities to ensure the integrity of pipelines.
MdC. New technologies bring up an assessment of the real condition of pipelines. For external corrosion they are based in classical techniques, but the improvement of sensors for Cathodic Protection monitoring and better positioning during close interval surveys allow to better pin point the areas and techniques for action.

Regarding internal corrosion it must be pointed out that the development of intelligent pigging in the last 10 years, really brought the possibility of having a reliable evaluation of a pipeline without going for a pressure test. A regular metal loss control by ultrasonic means (which requires a perfect cleaned line) or a magnetic tool (more tolerant to the line cleaning condition), associated with a more close interval acoustic pigging, give a good base for pipeline risk assessment and therefore a risk management plan.

Technical evolution is providing many new tools. As to the usual monitoring equipment used for pipelines operations can be now added computers with specific softwares risk oriented. To work correctly, these softwares need much information and a perfect model of the line behaviour. Those are the existing limits for a general implementation of such systems Anyway, pipeline industry is a dangerous industry, therefore all means should be used in risk management. Something as simple as line balancing with performing meters can give very good real time information regarding leak detection. This kind of simple tools must be included in the risk management plan.

Moreover, risk management is coming out from a purely technical approach to a more Quality Management approach. That requires inspection plans systematic reviews with experience feedback and technology improvements evaluation.

RN. Advances in Internal Line Inspection (ILI) tools along with the use of External Corrosion Direct Assessment (ECDA) have helped companies to determine where and why corrosion is occurring on these pipelines. Although these methods are not 100 percent effective, they have greatly improved over the last few years. If a non-shielding pipeline coating has been installed on the pipeline, Direct Current Voltage Gradient (DCVG) surveys will allow the operator to find disbonded coatings and make necessary repairs. If shielding pipeline coatings are used, disbonded areas are unlikely to be found.

KG. Whether we speak about In-Line Inspection, Hydrotesting or Direct Assessment, new technologies and techniques provides several opportunities for specific cases, all having both advantages and disadvantages depending on pipe location and environment. On the side of risk management, the new API 5L is differentiating pipes for non-sour application versus sour service and/or offshore, and therefore increase number of inspections and their severity for these products. For example, API 5L 44th edition requires now ultrasonic test for laminar imperfections for line pipes ordered for sour services and/or offshore applications. There are also requirements for seamless pipes to pass HIC, SWC and SSC tests. Actually, there is a clear differentiation now on line pipes classification not only as a product specification level but also according to the end use and specific environment. All of additional requirements are intended to ensure the integrity of pipeline in given conditions.

Are there any unique pipelining challenges for the oil and gas industry in the MENA region – is its difficult and often inhospitable environment a problem?
RN. This area does present a challenge. The Subkha sand areas are very corrosive environments with cyclic (wet and dry) conditions which cause damage to many types of coating systems. Cathodic protection can also be a challenge in these environments. Another challenge is that of higher temperature production. As the depth of drilling increases, so does the temperature of the production. There are also areas where hot methods are used to stimulate production. Once the higher temperature production is transported in a pipeline, both coatings and CP are affected.

KG. The MENA region is having similar difficulties in terms of pipelining as other regions have in regards of steel used and anti corrosion techniques. Still, this region has relatively recently started to explore offshore and we expect certain specific difficult and inhospitable environments as projects developed. If we speak about Saudi Aramco – for example, their specification for line pipes has been revised to differentiating further sour service and offshore applications and adding its specific requirements to those mentioned by latest edition of API 5L. We expect that oil companies within MENA to expand their exploration and production offshore and therefore we expect related challenges.

MdC. As a European pipeline operator, we are not really familiar with MENA region specific problems. Our experience regarding MENA region concerns metering as we calibrate meters to be installed there. Our experience is therefore more related with Crude oil quantity and quality assessment. We didn't identify specific problems in that field. Flowmeter calibration for MENA region isn't significantly different than calibrations for other regions. The issue is to have similar characteristics between calibration and field product.

How are your products and services benefiting the oil and gas companies today?
KG. JESCO products are obtained by using the most advanced technology, with most advanced available manufacturing equipment, including advanced automation systems, mathematical models to set up and optimize the process parameters, extended process control to allow effective continual improvement. The main benefits our products are bringing to the oil and gas companies are resulting from high dimensional precision, very smooth surface, quality of surface and lack of internal defects, the uniformity of the metallographic structure and mechanical properties – even for extra heavy wall, special tailored chemistry for specific projects, very low sulphur and residuals, making them suitable for sour service, offshore application, automatic welding and coating (FBE).

MdC. SPSE is mainly a pipeline operator. We generally share our 50-year experience in pipeline operation and maintenance in different committees or on demand. The only out of core services provided are sampling and meter calibration. These have an interest on a commercial point of view and also on the monitoring of the lines. They give access in a reliable manner to what gets into the pipeline system and what gets out. Metering allows a very good control of deliveries, and as a consequence keeps losses as low as possible which in the existing economic situation is a major issue.

RN. Polyguard’s most successful product has been the development of a non-shielding, field applied pipeline coating system that now has over 20 years of proven success in the field. This particular non-shielding coating system will allow adequate CP to be effective if there is a disbondment and water does penetrate between the coating and the pipe.

Though it is rare for this coating system to disbond, poor application or surface preparation has allowed water to be present under the coating on five different occasions that we are aware of at this time. None of these locations reported metal loss. When the pH of the water under the coating was checked it was between 10 and 12, indicating adequate CP was able to protect the area under the disbonded coating. We have developed a higher temperature version of this pipeline coating system that will retain these same protective properties.