OS FREE PIPE WTD - Pipe Freeing Agent for Weighted Pills



Differential Sticking

Differential sticking is still a common problem during drilling operations, resulting in lost drill strings, lost rig time and costing many millions of dollars. Differential sticking occurs when the drillstring is held in the filter cake across o permeable zone of lower pressure. When differential sticking occurs it is very important to spot pipe freeing agent across the stuck zone as soon as possible since the sticking force increases significantly with time as the string sinks further into the cake. Pipe freeing agents should be spotted quickly and torque worked into the string while jarring.


Product Information 

OS FREE PIPE WTD is a balanced formulation designed to give the necessary surfactant and lubricating properties needed to disrupt the filter cake thus allowing the differential pressure holding the pipe down to equalise and free the string. OS FREE PIPE WTD can be weighted up to higher densities with the addition of barite. OS FREE PIPE WTD is a blended mixture of emulsifiers, lubricants, oil wetting agents and clays.


Typical Physical Properties 

Appearance   -   Opaque Beige to Brown liquid                   

S.G. @ 20oC   -   0.95 – 1.10 gm/ml                  

Flash Point   -   Greater than 150oF

pH   -   5.0 – 7.0                                               

Pour point   -   Approximately 10oC



OS FREE PIPE WTD can be weighted up such that a balanced pill may be spotted across the stuck zone. Balanced pills will not migrate up the hole as unweighted pills do and will therefore stay in contact with the stuck zone for longer.

For many rigs in many drilling situations it is recommended that an unweighted OS FREE PIPE pill is spotted as quickly as possible to be followed by a weighted OS FREE PIPE WTD pill after 2-3 hours. This allows the all-important immediate stuck pipe treatment to be followed by a pill which will not further decrease the hydrostatic pressure, with potential well control consequences, and will not migrate away from the problem.



OS FREE PIPE WTD should be mixed at 4 drums per 50 bbl of finished weighted pill.


Add the base oil or diesel to the mixing pit, add the OS FREE PIPE WTD, add the water to make the required O/W ratio and then add barite to the desired density when the rheology has stabilised after the water addition.


We recommend an approx 75/25 O/W ratio for finished densities up to 16.0 ppg and approx. 80/20 for densities between 16.0 and 18.0 ppg.


The finished weighted pill will have a high degree of stability, and rheological property control.  The oil wetting agent in the product gives the flexibility of varying mud weights, while holding adequate rheology.  The surfactant in the product acts upon the filter cake, reducing the adhesion problem and releasing the drill string.  



OS FREE PIPE WTD is packaged in 55 US gallon drums.

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