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PBL Split Flow
QSST is pleased to introduce a new option for the PBL Multiple Activation Bypass System for drilling,
completion and workover operations. This option is the patent pending Split Flow Dart which will allow a
pre calculated amount of drilling or completion fluid to pass through the PBL Tool and on to the BHA below
and the remaining fluid to be by passed out the PBL Tool ports. By splitting the flow, the operator is able to
have more control over available hydraulics and hole cleaning parameters.

The Split Flow Dart incorporates a jet nozzle mounted in a cone shaped dart. The ports of the PBL Tool are
also equipped with jet nozzles. By pre determining the sizes of the dart and port nozzles, a calculated portion
of drilling fluid can be by passed at the PBL Tool. This dart activates the PBL Tool in a similar manner as the
ball utilized in standard PBL operations. The Split Flow Dart contains a shear ring manufactured from the
same material as the PBL activation balls and utilizes the same, proven technology to land, activate and
shear through the seat.

At the time split flow is required, the Split Flow Dart is inserted into the drill string at the surface and
pumped to the PBL Tool. Once landing, the PBL Tool will open once a pre determined minimum flow rate is
established. After opening, the flow will be divided between the BHA and the ports to the annulus. It is
important to maintain flow above the minimum rates to keep the PBL Tool completely open. Whenever
pumping ceases, the PBL Tool will close and there will be no fluid communication to the annulus through the
PBL Tool ports.

To discontinue the split flow option, one steel deactivation ball is dropped. This ball will land in the top of the
dart and shut off flow to the BHA below. At this time the flow will be exiting through the nozzled ports of the
PBL Tool. These ports have a limited TFA due to the split flow option, and caution needs to taken to not
develop excessive differential pressure and cause the dart to shear through the seat. When de activation
(100% of flow to BHA) is required, a total of three steel de activation balls are dropped. (Drop only two
additional balls if one was dropped as above to discontinue split flow) One will land in the top of the dart (as
above), while the other two will cut off flow through the ports creating a pressure increase to the pre set
shear pressure. This will cause the dart to shear through the seat and the dart and balls will be caught in the
ball catcher cage.

The Split Flow Dart option for the PBL Tool will greatly enhance hole cleaning ability while not pumping
excessive fluid through the MWD/LWD, rotary steerable system, drilling motor or drill bit causing possible
washouts and difficulty steering. This simple and reliable system will save the operator large amount of rig
time and thus money.

Please contact your QSST Representative for more information on the Split Flow Dart.

CONTACT Qsst AS                    Tel: +47 91 69 29 36
postboks 5047       mail: post@qsst.no
N-4084 Stavanger