After repairs, rejoining sections of high-pressure, cement-lined pipeline in the field was once a major problem for Saudi Aramco.

But thanks to an innovative, patented technique developed by one of the company's welding metallurgy and engineering materials experts, this difficulty has been largely overcome.

The design has been adopted as standard by the company for re-welding cement-lined pipelines in the field.

The technique allows joining of high-pressure pipeline sections with strong, highly reliable internal seal joints, especially valuable for high-pressure, corrosive water service, such as seawater injection.

Previously, lack of a sound technique meant section joints were more prone to disintegration and failure due to weld and sealant materials contaminating each other during the joining process.

Carbon steel pipeline sections connected in the procedure are strengthened at connecting joints by a thin, narrow band of steel, known as a backing ring, installed around the inside of one end of a detached pipe section. The ring is tacked to the outer pipe with a weld, and then the inside of each pipeline section is lined with spray-on cement applied by a special machine called a crawler.

Then, according to the patent document, ''The ends of the linings are... cut back and bevelled to facilitate alignment and fit-up, and to provide a cavity and anchor for the retention of heat-expanding grout that is applied to both ends of the lined mating pipe sections to seal the join.''

Ultimately, the sections are pushed together and the outer seam, widened with a bevel cut, is welded shut. In the process, the outer pipe is welded to the inner ring - but separated from the sealant grout by an inch of space or more, so both grout and welding material avoid contamination. The heat from the welding indirectly cures, or hardens, the sealant.

The technique provides excellent protection against internal corrosion and in-service failure of the weld joint.

Saudi Aramco is a leading implementer of efficient, innovative corrosion control methods to maintain operational excellence and meet growing global competition.

Effective corrosion control saves Saudi Arabia, and Saudi Aramco in particular, huge amounts of money in potentially lost natural resources.

In its ongoing battle against corrosion in the harsh environmental conditions prevalent in the Kingdom, Saudi Aramco has turned away from metals - which have been the staple material for the oil and gas industry - to hi-tech non-metallic materials.

In particular, the company continues to install phenolic gratings on offshore structures because of their superior corrosion resistance, strength-to-weight ratio and fire resistance.

Officials have said that the company should further promote the use of non-metallic materials and adapt them to its needs.

In this respect, Saudi Aramco has tested two types of non-metallic piping for oil industry application, according to the company.

Reinforced thermoplastic pipe and steel strip laminate pipe - the latter making its world debut - have already been introduced into Central Arabia.

Saudi Aramco has improved engineering capabilities in risk-based assessment and fitness-for-service determinations, and uses new technologies which allow the company to reduce the probability and consequences of certain equipment failures and focus assessments more intensively on higher risk areas.

To demonstrate further the company's commitment to the fight against corrosion, Saudi Aramco will complete 21,000 sq m of additional laboratory and administrative facilities in 2005 at its Dhahran Research & Development Center (R&DC) to house state-of-the-art corrosion testing facilities, including high pressure circulating loops to simulate field conditions.

The first phase of the R&DC was completed last year.

Regional industry officials have also called for the establishment of a Regional Corrosion Center in the Gulf.

Research and cooperation are seen as essential in meeting corrosion challenges and such a centre would, they say, focus corrosion research and technology, disseminate information and education, and provide much-needed synergy for all efforts.