Page 153 - Handbook Of Multiphase Flow Assurance

Diamondoids 149

Production system should make identification of waste streams and their regulatory clas-
sification/disposal more straightforward. System operability should be reviewed to under-
stand how wastes are generated, identify the chemical components and develop appropriate
disposal plan.
Technologies which could be considered for management of bacterial growth in produced
fluids include:
• Biocide glutaraldehyde chemical
• biocide THPS chemical
• chlorination
• periodic scraping
• desulphation for injection water for controlling reservoir souring
• nitrate chemical for injection water for controlling reservoir souring
• preventing comingling of injection seawater and produced water
• Provision for water injection line scraping to sweep any bacterial growth
It is noted that efficiency of biocides isothiazolinone and 2,2-dibromo-3-nitrilopropionamide
(DBNPA) may drop by half or more in presence of O 2 scavengers (Folwell, 2017), so that a
compatibility test should be performed.

Corrosion products

Transport of solid corrosion products
Carbon steel pipelines are corroding both from inside and from outside. Temperature,
pressure, composition and shear of the produced multiphase fluids flowing inside the pipe-
line determine the rate of steel corrosion. Corrosion rates of <0.1 mm/yr may be deemed
acceptable yet some corrosion products enter the flow and may accumulate in the pipeline.
A 24″ pipeline and a corrosion rate of 3 mils per year (MPY), will result in almost a barrel of
material loss per kilometer pipe length.
Accumulation of the corrosion products may be managed either by periodic mainte-
nance scraping or by keeping the flow velocity above the rate where transported solids
settle out.
The flow rate for minimum transport velocity of corrosion products is similar to sand and
is on the order of 1 m/s in near-horizontal pipelines. The models for solids transport velocity
are similar to those for sand transport.

Diamondoids

Diamondoids are a class of polycyclic hydrocarbons which can be transported by gas in the
vapor phase from the reservoir. When flowing conditions change, diamondoids may deposit
as solids in the production systems.
The most common diamondoids are adamantane C 10 H 16 , diamantane C 14 H 20 and triaman-
3
tane C 18 H 24 . Their densities are 1.07, 1.21 and 1.24 g/cm .