Exploration • Drilling • Field Services
Corrosion protection for valves and pipes
Corrosion protection is a big industry, especially against that of H2S (sour gas) corrosion of steel. Brian Zielinski-Smith reports.
W
ith the advent of oil exploration and recovery of deep natural reservoirs, CO2
has been used
to enhance recovery; this introduction along with the
presence of naturally forming hydrogen sulphide (H2
S) produced by sulphate-reducing bacteria,
and free water can cause severe corrosion problems within pipelines and valves. Tis type of corrosion is heavily influenced by, H2
S, and CO2 content, water
chemistry, flow velocity and the composition/surface condition of the steel used.
When just one of these factors change, the
corrosion rate of steel changes drastically. Te result of this corrosion can in most cases be a costly replacement which exceeds by many times the cost of corrosion control.
Wasting resources Recognising that corrosion is a major player in the waste of precious natural resources and causes endless problems when operating in these conditions, Welding Alloys has made major investment in developing new technology to handle the hot wire TIG process of depositing base metal/ overlay combinations which form protective barriers in valves and pipelines, to name a few; namely those of austenitic, 22Cr duplex and 25Cr super duplex stainless steels and nickel/cobalt based alloys, eliminating the need to produce a whole component or item of plant from an expensive corrosion resistant material. Within the oil and gas industry, quality control and monitoring is paramount, insuring pipelines are well maintained, avoiding inclusions of cavity corrosion which lead to pipeline and valve failures.
Control system As corrosion protection is an integral part of pipeline creation and maintenance, the new control system from Welding Alloys is specifically designed for this application and focuses on meeting the stringent quality requirements of valves and pipeline cladding within this industry. Te company has been able to differentiate
itself by allowing online and real-time weld deposit monitoring and full data logging functionality. Because of this it is now possible to provide a
Fig. 1. A valve being internally clad using the new and advanced Welding Alloys control system to protect against corrosion.
www.engineerlive.com 35
full and comprehensive ‘quality trail’ for every part clad; in addition, this allows the systems’ controls and parameters to be completely customised and programmed, minimising production time and increasing weld deposit control by giving precise feedback and position information. Te oil and gas exploration and recovery industry has had major financial investment in recent years,
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74