Oil and Gas Pipelines

This paper seeks to present the uncertain events that occur during the assessment and management of corrosion data survey by using Bayes' Model. In decision making, uncertainty about the outcomes of various situations is an important element of the analysis of the alternative strategies from which the choice must be made.

In Nigeria, the majority of the oil/gas/liquids pipelines are 30 to 50 years old. Most of the pipes were laid on the surface. But these pipelines have become old, corroded and less effective. They fail due to corrosion induced leaks ( resulting from lack of pipeline integrity survey and inadequate corrosion monitoring program design ) as well as vandalism.

A close-interval potential (CIP) data survey on ~154 km of Crude Oil/Gas pipeline networks. This aim was to generate corrosion data to determine weak sections of the pipelines/flowlines and, to ascertain the effectiveness of the CP system and integrity of the Crude Oil/Gas pipeline networks. The pipeline networks were found safe for continued operation under its present condition.

Pipeline quality gas is normally dried in Triethylene Glycol (TEG).  This paper explores how TEG vapor can exist in a pipeline in a similar manner to water, and possibly lead to corrosion. TEG vapor can condense at long distances down a gas pipeline as the line cools.

This paper studies the effect of oxygen in methanol on the structures and growth kinetics of iron sulfide scales. Gravimetric weight analysis was used to evaluate the corrosion mechanisms and rates. Scanning Electron Microscope/ Energy Dispersive X-ray Spectrometry (SEM/EDX), Optical Microscope and X-ray Diffraction (XRD) were used to analyze the scale.

Oil sands hydro-transport requires pipes to be corrosion and erosion resistant.  The inside of metallic pipes must be protected. Polymeric liners may collapse d/t gases and fluids trapped at the liner/pipe interface. A filament-wound fibre reinforced composite pipe capable of venting trapped volatiles is presented. A joining method is described.

Three layer polypropylene (3LPP) pipeline coatings failed prematurely in the oilfields of Abu Dhabi in the United Arab Emirates (UAE). A failure investigation and analysis into this phenomenon was instigated. The coating disbondment has been found to be due to high residual stress concentration and adhesion loss.

This paper will outline the effect of stray current that originates from an HVDC  transmission system that runs parallel to and crosses a crude oil and natural gas pipeline system.

Periodic cleaning of sales gas lines often yields large quantities of material known as black powder. This paper describes a research study that was conducted to provide estimates for corrosion rates of carbon steel in TEG-water mixtures with TEG content in the range 0.0 wt% to 99.5 wt%.

Fusion Bonded Epoxy (FBE) is required to protect the pipes in higher temperatures. This paper reports evaluation methods for these high Tg FBE, and the performance differences between the high Tg FBE and general FBE.

Observations and guidelines to conduct hydrostatic pressure tests of pipelines and/or process equipment.  Concerns for hydrostatic pressure tests relate to the water itself, including any suspended solids, dissolved oxygen, or any Sulfate Reducing Bacteria (SRB) or Acid Producing Bacteria (APB) present in the test water.

 Case histories are presented where Oxygen ingress has led to Sulfur corrosion failures in pipelines and downhole equipment.