A PBL circulation sub is an auto-gate bypass system for multiple activations, a simple and reliable tool installed in BHA for drilling, development and workover of wells. This equipment allows to achieve significant reduction of time spent on expensive pool out of hole and pool into the hole (hereinafter POOH).
PBL® circulation sub is a circulation valve which allows multiple switching of fluid flow from the interior of the drill column to annular space bypassing all the BHA elements located in the layout below PBL.
The original design allows pumping aggressive plugging materials and increasing circulation. PBL tool has been designed to facilitate a lot of operations in drilling, development and workover of wells, such as:
– Pumping all types of fillers and mud, including aggressive and cement compositions.
– Increased circulation volume for complete cleaning of the well, reducing the number of "idle" rotations of downhole motor and increasing the rate of penetration.
– Increased flow rate in the annular space in highly deviated wells and horizontal shafts, where washing and removal of the sludge is difficult.
– Replacement of fluid.
– Blowout prevention system.
– Acid and stimulating treatments.
– Core drilling.
– Completion after fracture treatment: for cleaning of well fracturing, pumping of acid, nitrogen and mixture of foam to stimulate the inflow.
PBL® has a unique feature: circulation ports of activated PBL® close at stoppage of drilling pump, preventing reverse flow of washing liquid from the annular space to the drill column.