ALS has developed the TAZ™ circulation sub to provide a truly unlimited number of activations downhole.
When drilling a well, it is often necessary to pump large volumes of drilling fluid or LCM. To allow this capability it is prudent to run a circulating sub in the BHA. Such subs usually need to be cycled open and closed a number of times.
The TAZ™ circulation sub remains dormant in the BHA until opened by dropping a TAZ™ activation ball, which then disappears completely. The resulting pressure drop allows the j-slot mechanism to engage, opening the ports to the annulus. The TFA of the nozzles within the ports can be selected to suit the application, with the percentage of diverted flow being a function of their size and the pressure drop below the tool.
The central feature of the TAZ™ system is that the ball ‘disappears’ upon activation, ensuring that a through bore clearance is maintained through the tool at all times. Closing the ports is achieved by pumping down an identical TAZ™ ball, which also ‘disappears’ upon de-activation, leaving the tool dormant and ready to be activated again in a truly endless cycle.