Longitudinal welded joints samples of X70 and X80 API grade steel pipes were exposed to a deaerated 1% NaCl solution containing CO 2 , at temperatures in the range of 25 °C to 80 °C for 48 hours. Analogous samples were exposed to the adjacent vapour phase. The layer of corrosion products which formed on the base metal and welded regions of the samples was investigated using mass loss determinations, scanning electron microscopy and X-ray diffraction. The corrosion products formed in tests at 60 °C and were composed of FeCO 3 . The FeCO 3 which had initially formed at 80 °C was observed to have subsequently decomposed, resulting in a layer of Fe 2 O 3.

The susceptibility of girth welds to sulphide stress cracking (SSC) and hydrogen embrittlement (HE) were evaluated for API grade X80 and X56 steels, both for similar (X80/X80) and dissimilar (X80/X56) joints. Slow strain rate (SSR) and hydrogen permeation tests were performed at room temperature using sodium thiosulphate solutions at different pH levels. The SSR tests showed that the majority of the welded joints studied, though approved by the API 1104 standard's criteria, did in fact suffer a reduction in ductility and showed indications of susceptibility to sulphide stress cracking and to hydrogen embrittlement in the form of secondary longitudinal and internal transverse cracks. This was true regardless the welding process used.

The innovative promises of nanotechnologies have fomented growing investments from governments, research centers and companies. As a multidisciplinary technology, nanotechnology developments are observed in many industries, such as: chemical, automotive, pharmaceutical, aerospace and defense, electronics, energy and materials. Market researches project that the global business based on nanotechnology products will reach US$ 3.3Tri in 2018. Nanotechnologies offer opportunities in all levels of the value chain at the oil and gas industry, contributing with more efficient, less expensive and more environmentally friendly technologies. Among these opportunities, are: improved data gathering, recognizing and avoiding dry holes; enhanced materials that provide strength and endurance to increase performance and reliability in drilling, tubular goods, and rotating parts; improved elastomers, enablers for high pressure high temperature drilling environments; corrosion protection for surfaces, subsurface and facilities applications; lightweight materials; selective filtration and water management; and enhanced oil recovery through the modification of reservoir properties. Nanotechnologies applied to materials science may help to modify or manipulate the characteristics of materials at the molecular level, developing materials with exclusive characteristics for critical applications. Among nanocoatings applications are antibiotic effects, thermal insulation, dirt repellent, corrosion resistance, mist absorbent and self cleaning. Nanocoating with self-healing property is an example of an environmentally friendly application. The objective of this work is to prospect the available nanotechnologies for corrosion protection for the oil and gas industry. The methodology is based on patents and scientific papers evaluation, through bibliometric techniques to identify the players that are most representative of the market. 76 patents and 45 scientific papers have been identified. Additionally, data from companies widely recognized at the sector have verified. As a result from this work, the authors expect to diffuse knowledge of solutions based on nanotechnologies for the oil and gas sector, contributing to foster innovation at the industry.

The corrosion evaluation of steels in the oil and gas industry environments is a crucial issue because corrosion can cause economic and human losses. It is well known that H 2 S can be originated from different processes in the oil and gas industry, accelerating the corrosion process. The objective of this work was to evaluate the H 2 S corrosion resistance of an API 5L X80 steel and its welded joint obtained by submerged arc welding process (SAW). All tests were performed in an aerated 5% wt NaCl and thiosulphate aqueous solution. The H 2 S concentration, pH, weight loss, electrochemical tests, and microstructure were considered. The results obtained showed an increase of the corrosion rate values, with decreasing pH and increasing concentration of H2S generated by the thiosulphate. For the lowest H 2 S concentrations, the corrosion process was inhibited, due to the formation of a partially protective film on the samples' surfaces. The heat affected zone (HAZ) showed severe localized corrosion attack which was attributed to the microstructural characteristics of this region.