B41oa oil and Gas Processing Section a flow Assurance Heriot-Watt University

3.7 Wax Control 
Wax consists of a wide range of hydrocarbons, i.e., C
18
to C
70
. These 
hydrocarbons have vastly different melting temperatures. Considering the fact 
that the fluid temperature plays the primary role in wax deposition, one can 
expect wax formation in reservoir, wellbore/tubing, and pipelines. 
Samples taken from various depths in the wellbore demonstrate that there are 
significant changes in the wax composition deposited at different depths. As 
expected, wax deposits at greater depths (i.e., higher temperatures) have 
higher concentrations of heavier hydrocarbons, while deposits at lesser depths 
(i.e., lower temperatures) consist of lighter hydrocarbons. 

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TOPIC 3: Wax Deposition 
 
 
 
19 
©H
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NIVERSITY B41OA December 2018 v3 
Similarly, one can expect a variation in the deposited wax composition as the 
temperature profile varies along a pipeline. Wax deposition could be prevented 
by preventing a reduction in the pipeline temperature, by either reducing the 
heat loss to the environment and/or applying heat to the system. Pipeline 
insulation, or using pipe-in-pipe arrangements, are two way of reducing and/or 
preventing wax deposition. 
In addition, the use of tube bundles or pipeline heating (by electrical means) 
could reduce and/or prevent wax deposition – this is achieved by either 
supplying heat or maintaining the pipeline temperature. 
Different chemicals could also be used for the reduction and/or the prevention 
of wax deposition (this is detailed later). It should be noted that once wax 
deposits are formed, in order to maintain optimum production and prevent any 
blockage, they should be removed. Various methods are used to remove wax 
deposits – the main approaches are as follows: 
1. Mechanical Methods. 
2. Thermal Methods. 
3. Chemical Methods.