Introduction
The Multi-cycle Circulating Sub is a sub could control its side entrance “open” and “close” at down hole by dropping the ball from the well head to realize the link or break of the connection between annular and water hole several times. It is an ideal tool for extended reach drilling and Horizontal Drilling.
Advantages
1.The “open” operation of this tool is depended on drive ball get through the circulating sub rather than reach the catcher seat.
2.There are two large side entrance of this tool to reduce the risk of blockage.
3.The multi-cycle circulating sub is the only one in the tools with the same function which allows the cross-over circulation at entire basin area.
4.The special design ensure that the side entrance is already open before the drive ball reach catcher seat, so to prevent the drive ball be shear into catcher basket by accident.
5. Multi-cycle circulating sub should be at “Open state” to go down the well.
6.The Multi-cycle circulating sub allow at least six times “Open” and “Close” working cycle, it also could be design to add double cycles at request.
. After activating theDRILL MATE and prior to dropping locking ball, Record Pump Pressure
________ and Pump Strokes ___________. This will be used as a reference to confirm
whenDRILL MATE is locked open.
2. Calculate the fluid displacement volume and time in the drillstring to estimate when the
locking ball will reach the Bypass Tool. Break drillstring at floor and drop one (1) vinyl
locking ball. Refer to chart below to determine proper size.
3. It is then recommended to maintain normal drilling pump rates, keeping the pressure 500
psi below the locking ball shearing pressure as indicated on the Tool Order. Displace
70% of the volume inside the drillstring, and then reduce the pump rate to 50% until the
ball lands in the port. The vinyl ball may seat sooner than the calculated pump strokes.
The vinyl locking ball has an equivalent density of 11.2 PPG drilling fluid. NOTE: Care
should be taken when pumping the vinyl ball down. Pumping the locking ball into
port at high fluid rates or pressures may cause the locking ball to blow through the
port.
4. When the locking ball lands into port, one of the two bypass ports will be blocked and a
pressure increase might be noted. Compare the pump pressure and pump strokes
recorded in step one to determine if the ball is into the port. The pumps may now be
switched off and the tool is locked open. Fluid will drain or fill through the one open
port. Use caution not to over pump after tool is locked open, causing the locking ball to
shear.
- Rotating and reciprocating the drillstring is good practice while activating the DRILL MATE
Multiactivated Bypass Circulating Sub
Multiple Activation Bypass System for drilling, completion and
workover operations. This option is the patent pending KW which will allow a precalculated amount of drilling or completion flfluid to pass through the mccvTool and on to the BHA below and the remaining flfluid to be bypassed
out the mccvTool ports. By splitting the flflow, the operator is able to have more control over available hydraulics and hole
cleaning parameters.
The KW incorporates a jet nozzle mounted in a cone shaped dart. The ports of the mccvTool are also equipped
with jet nozzles. By predetermining the sizes of the dart and port nozzles, a calculated portion of drilling flfluid can be
bypassed at the mccvTool. This dart activates the mccvTool in a similar manner as the ball utilized in standard mccvop
erations. The KW contains a shear ring manufactured from the same material as the mccvactivation balls
and utilizes the same, proven technology to land, activate and shear through the seat.
At the time split flflow is required, the KW is inserted into the drill string at the surface and pumped to the mccv
Tool. Once landing, the mccvTool will open once a predetermined mini flflow rate is established. After opening, the
flflow will be divided between the BHA and the ports to the annulus. It is important to maintain flflow above the mini
rates to keep the mccvTool completely open. Whenever pumping ceases, the mccvTool will close and there will be no flfluid
communication to the annulus through the mccvTool ports.
To discontinue the split flflow option, one steel deactivation ball is dropped. This ball will land in the top of the dart and
shut off flflow to the BHA below. At this time the flflow will be exiting through the nozzled ports of the mccvTool. These ports
have a limited TFA due to the split flflow option, and caution needs to taken to not develop excessive differential pressure
and cause the dart to shear through the seat. When deactivation (100% of flflow to BHA) is required, a total of three steel
deactivation balls are dropped. (Drop only two additional balls if one was dropped as above to discontinue split flflow)
One will land in the top of the dart (as above), while the other two will cut off flflow through the ports creating a pressure
increase to the preset 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 KW option for the mccvTool will greatly enhance hole cleaning ability while not pumping excessive flfluid
through the MWD/LWD, rotary steerable system, drilling motor or drill bit causing possible washouts and diffificulty
steering. This simple and reliable system will save the operator large amount of rig time and thus money
