CASE STUDY Centek UROS-CT preferred choice for deepwater wells
Customer makes UROS-CT the preferred choice to replace subs for their deepwater wells in Norway
A customer in Norway needed a centralizer package suited for a specific close tolerance operation in a deepwater well with a total depth of 9,778 TVD RKB ft and 16,614 MD RKB ft.
The desired solution had to provide a reduced insertion force and low running force, tested and proven in the restriction; along with suitable standoff and a high axial stop collar load capacity - all at a low cost to meet close tolerance capabilities. For this specific well the customer needed to run a 17" liner through a wear bushing restriction with an ID of 17.75" to 3,295 ft TVD. The high cost centralizer sub would be the traditional close tolerance application for this type of well.
To meet the challenge Centek, Halliburton and Ace Oil Tools recommended the Centek UROS-CT centralizer and the Ace Ratchet Collar.
The UROS-CT close tolerance centralizer is specifically designed for use in tight annulus applications where narrow margins between pore pressure and the fracture gradient exist. In deepwater operations the UROS-CT can compress virtually flat to allow travel through a series of tight casing strings but is still capable of expanding to the designed open-hole size.
In this instance the UROS-CT was used in conjunction with the Ace Ratchet Collar provided by Ace Oil Tools. This stop collar contains high axial load capacity along with a slim design (4.1mm WT). The stop collar consists of two parts which are pushed together and locked in place with a ratchet mechanism. It is easy and fast to install and will give an axial holding force of 103,000 lbs in this particular design and size.
By using the Centek UROS-CT centralizer and the Ace Ratchet Collar in combination all of the requirements from the customer were met and the 17" liner safely passed through the tight restriction without issue.
This combination is now the preferable solution for this type of application in the North Sea