High-profile accidents refocus inspection and maintenance regimes

Paul Boughton

A number of high profile explosions in recent times have put renewed emphasis on the inspection and maintenance technologies and regimes used by the oil and gas industry. Eugene McCarthy investigates.

Today’s oil and gas engineers and technicians are faced with new challenges in the marinisation of increasingly complex machinery and in the subsea monitoring of critical assets to ensure safe, reliable production. This requires an intelligent network of sensors, leak detection systems and other devices designed, tested and installed in key areas on the ocean floor. This information also must be integrated into a consistent software platform that is supported by analytical models to interpret and drive subsea service activities.

Demonstrating the company’s sensor expertise and ongoing commitment to innovation, GE’s measurement and control business has announced two innovative condition monitoring and sensing solutions for the subsea sector: the acoustic leak detection (ALD) system and the subsea multi-domain condition monitoring (SMCM) system.

The ALD system uses passive, acoustic hydrophone technology to detect and locate subsea oil and gas leaks by discriminating the noise of a leak from other sources of sound. Developed from naval military technology, the sensing system enables extremely sensitive and accurate measurement of subsea acoustics and can be used to detect ‘silent’ leaks that occur when there is low flow rate or low differential pressure. GE says its solution is the leading ISO-qualified technology for permanent (25 years) deployment available today that can detect both crude oil and gas with sufficient sensitivity while providing wide area coverage of up to 500 metres.

For its part, the company’s SMCM system combines electric emission monitoring and acoustic hydrophones specially designed for monitoring the operating condition of subsea machinery and processes — from pumps and valves to supporting infrastructure. Typically combined with ALD to detect subsea leakage, the system performs multi-domain analysis supported by proven pattern recognition and machine learning algorithms to identify and display subsea structure, machine and pipeline activities and anomalies.

“Oil and gas customers trust GE to provide condition-based monitoring services for their offshore topside platforms. As subsea exploration and production becomes increasingly important globally, many customers are looking to expand these topside capabilities to the seabed. By combining subsea sensors and acoustic condition monitoring with existing GE technology, customers can expand their view into operations and make intelligent, critical decisions about their operations,” said Jens Abrahamsen, Naxys business leader for GE measurement and control, a GE oil and gas division.

Preferred suppliers

Independent technical advisor GL Noble Denton has signed a new agreement with BP in a move that will see it become a preferred supplier of vendor inspection services across BP’s global portfolio of upstream assets.

The three-year deal will allow the company  to become one of a small number of inspection specialists to assess the safety, quality and performance of equipment acquired for BP’s high-profile capital and operating expenditure projects (Fig. 1).

Under the agreement, GL Noble Denton will offer bespoke inspection expertise to BP projects across the world through a network of highly-qualified engineers in more than 80 countries. The company will play a central role in BP’s procurement process, ensuring that goods supplied to the oil company are compliant with industry best practice.

Pekka Paasivaara, member of the GL Group executive board, said: “BP has taken a major step in refining its selection of inspection partners to ensure it consistently receives a world-class service in vendor assessment. We are delighted that GL Noble Denton has been selected to play a central role in this, and we look forward to aiding BP’s continued drive to operate safe and sustainable assets.”

In a separate development the GL Group has received a combined certificate of compliance with the BS OHSAS 18001, ISO 9001 and ISO 14001 standards after successfully passing an integrated management system audit conducted by the German certification body DQS. The Group is the first technical advisor for assurance, consulting, classification and certification to receive such a combined matrix certificate.

GL group says the DQS certificate was issued as proof of the compliance of its management system with the international standards that assess occupational health and safety management systems - BS OHSAS 18001 - the quality standards of products and services - ISO 9001 - and the environmental friendliness of processes, products and services - ISO 14001.

Meanwhile, in January 2012, UTC, a diversified company providing a broad range of high-tech products and services to the global aerospace and building systems industries, awarded SGS a contract to conduct on and off-site inspection and testing on heat exchangers at the Refap refinery in Brazil. Since then, an on-site SGS mechanical team has been opening, inspecting and testing heat exchangers. The agreement is scheduled to expire in December 2013.

Heat exchangers or changers, which efficiently transfer thermal energy from one medium to another, are common and essential equipment in chemical and petrochemical plants. Construction and operational characteristics determine which qualify as pressure vessels under the Brazilian NR-13 regulations and which therefore require initial safety inspections prior to operational use.

The Refap refinery is located in Canoas, Rio Grande do Sul state and, as the fifth-largest refinery in the Petrobras system in Brazil, has an installed capacity of 200,000 bbl/d of oil. In addition to petrochemical naphtha, propylene, liquified petroleum gas, jet fuel, fuel oil and asphalt, diesel and gasoline make up most of the refinery's production.

Since the beginning of this year, SGS engineers have been opening, inspecting and testing heat exchangers at the Brazilian location. This process includes opening the equipment covers, removing the tubular bundle, measuring the thickness and performing a hydrostatic test and closing the equipment covers. Certain types of heat exchangers may require up to three pressure tests on the hull, bundle and floating lid. Depending on the size and location of the heat exchanger, removing the bundle might only be possible with the implementation of a bundle-puller, a load-bearing device for bundles weighing less than five tonnes with a length of up to five metres and installed higher than ground level. Bundle-pullers reduce risks associated with this activity, such as danger to personnel and damage to equipment.

For this reason SGS has developed its heat exchanger life assessment system (HELAS). This allows quick and efficient inspection of heat exchangers in which corrosion is expected only on inside tubing.

Data collected is directly analysed to produce a complete life time assessment of the inspected heat exchangers to include a wall thickness report. HELAS measures the ultrasonic immersion length converted into corrosion depth on the inside of cooling water and air fin tubes. Based on the highest value of corrosion measured, extreme value analysis is performed to estimate the remaining life-expectancy of the heat exchanger by evaluating the maximum possible corrosion depth throughout the heat exchanger.

Finally, Wood Group has secured 11 new contracts in Africa totalling approximately US$240 million (€180 million).

Wood Group PSN, which provides brownfield production services, won contracts to provide operations and maintenance and construction services to clients in Equatorial Guinea, Chad and Algeria.

Wood Group GTS, specialists in rotating equipment solutions, has secured a long-term service agreement covering two GE Frame 9E gas turbines for an operator in Ghana.

Wood Group Mustang, the process and facilities group of Wood Group Engineering, is providing detailed engineering for wellhead platforms, a production processing platform and a living quarters platform for an offshore project in Angola.

James Crawford, Wood Group PSN’s managing director for Africa, said: “We are committed to building a sustainable business in Africa and are very clear about the countries and projects which we target, knowing where and how our expertise can enhance our customer’s operations. Creating opportunities for local training and employment, Wood Group employs over 3000 people in eleven countries across Africa. It is a key operating region, and these wins feed our ongoing growth strategy for the continent.”

Ability to offer a full range of inspection services is critical

Since its foundation in 1988 Delta Energy Services has focused on supplying high-quality inspection services to many operators and contractors. Today, the company offers clients a complete range of inspection and expediting services across Scandinavia, UK, Europe and other international locations, providing experienced personnel for either single or regular visits plus the option of continuous cover for the duration of projects.

Delta says the keys to success in today’s 24/7 world of inspection are offering services that are fast, flexible, cost-effective, and completely tailored to meet individual needs of clients. Operating as clients’ ‘eyes' and 'ears', Delta works to reduce the multitude of potential risks that they face. These include:  non-conformity to contractual requirements, on-site production variations, revised specifications, sub-standard quality and materials, delays in manufacturing schedules and shipping.

“We assist your suppliers and manufacturers to implement and reinforce their own quality system and look to drive through improvements in quality, reliability and cost efficiency. With Delta Energy Services' support, conformity to specifications is monitored independently and any required corrective actions are identified and followed up locally on-site,” notes the company.

In addition, the company has an extensive network of strategically located field inspectors ready to assist and support regional quality needs – all of which is designed to build on Delta’s reputation for quality personnel, the speed and flexibility of its response and the wide scope of quality services it can provide.

Typical inspection services offered include: witness and verification of critical activities; quality programme management; status reports; quality system audits; and project and procurement expediting services.

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