Thermal Regime Effect on Gas-Transport Lines in the Persian Gulf
Sea lines transporting gas toward the north (Iran) and south (Qatar and Saudi Arabia) and originating from fields located in the central parts of the Persian Gulf exhibit different thermal regimes. The lowest reported arrival temperatures of the gas were 18°C and 11°C for the sea lines transporting gas to the northern and southern shores, respectively. The difference between the two is significant and could radically alter the hydrate-mitigation strategy and the associated economics. Metocean data reported in this study and from previous studies (Appendix A in the paper) show that the northern part of the Persian Gulf, which is also deeper, attains a well-mixed state during winter months. During this phase, the arrival temperature of the gas for South Pars sea lines decreases steadily and goes through a minimum at approximately the middle of February every year. In the southern region, the sea is shallow and water is more saline. Sinking of saline water when exposed to cool and dry ambient winter conditions is probably responsible for the reported abrupt decrease in arrival temperatures in the case of the Karan gas line. The immediate recovery of the same may be caused by the local wind/tide conditions. The likely origins of the observed lowest temperatures in the north and south regions are Arctic winds of short duration and desert winds of fairly long duration, respectively. This study summarizes hydrate-inhibition practices for these sea lines, and indicates a possibility of using the sea lines as “indirect thermometers” to provide important physical oceanographic data for long terms in a limited but economical way with fewer interruptions.
Executing Offshore Projects More Efficiently
Offshore project execution enhancement ideas are highlighted for debottlenecking, gas-hydrate-induced pipeline vibration, and the design of subsea systems for efficient startup.
Hydrate-Induced Vibration in an Offshore Pipeline
A computational fluid dynamics model is proposed to analyze the effect of hydrate flow in pipelines using multiphase-flow-modeling techniques. The results will identify the cause of pipeline failure, regions of maximum stress in the pipeline, and plastic deformation of the pipeline.
PHMSA Tags Construction Damage as Cause of Keystone Pipeline Spill
Weights used in the original construction of TransCanada’s Keystone Pipeline in South Dakota were identified as a preliminary cause of the failure that resulted in a 210,000-gal spill in November.
26 January 2018
12 February 2018
30 January 2018