2. Allow the cement plug adequate time to harden. The cement plug must be of sufficient quality and
quantity. Avoid plugging the bit nozzles by washing down with a minimal flow rate until the cement
is tagged. The flow rate for washing down must be above the tool's minimum flow rate.
3. If the cement plug is not firm, the sidetrack should not be attempted on highside and should be
replanned with a low side exit if applicable.
4. If the cement is of sufficient quality, increase the flow rate and drilling parameters to 75% of normal
drilling levels, and dress off the cement plug to the required kick off depth. The top of the cement
plug will often be of poor quality due to mud contamination in the transition but, will harden with
depth.
5. Make sure that the drillpipe is spaced out to allow the sidetrack to be initiated without having to make
connections. Space should also be left above the sidetrack point to allow the pipe to be worked.
6. Set the tool to a suitable toolface with the maximum steering ratio (100%). Depending on the existing
profile of the hole and proximity to offset casing strings, either magnetic or gravity steering can be
used for the kickoff. Do not use the inclination hold mode or HIA mode for kicking off.
7. If the cement plug is firm and able to take weight, attempt to drill off using normal drilling RPM but
controlled ROP.
a. Control the ROP to 10% of the drilling rate at the same depth in the main wellbore. Maintain
this rate until a clear indication of new formation is seen in the returned cuttings. Do not
increase the ROP until new formation is seen in the cuttings.
b. When new formation is seen in the cuttings, increase the ROP to 30% of the offset ROP
until 60% new formation is seen in the returned cuttings.
c. When 60% of cuttings are seen, increase the ROP to 60% of the offset ROP until 100% new
formation is seen with no more than trace cement.
Note: The time taken to sidetrack will depend on the relative strengths of the cement and formation and
can vary from ten minutes to 24 hours or more.
8. If the cement plug remains soft, consider either waiting for the cement to harden or proceeding with
the sidetrack. More care and patience will be needed in this case. It may be possible to set another
cement plug if the first sidetrack fails.
9. After the sidetrack has been initiated, closely monitor the inclination to avoid excessive doglegs, and
monitor the cuttings for indications that the new hole may have started to track back into the cement
plug.
Open hole sidetracking
All PowerDrive systems can be used for open hole sidetracks to the low side. Use of real-time inclination
will give an early indication of the progress of the sidetrack. As a guideline, the following procedure
should be used if there is no previous experience of successful open hole sidetracking.
• The success rate for open hole sidetracks is dependent on the formation drillability, it may be
impossible to sidetrack if the formation is too hard. Hole inclination also plays an important role.
Open hole sidetracks should only be considered above 70° inclination. Subsequent BHAs and
casing strings or liners will need to pass the sidetrack, making the transition from the original
hole under the influence of gravity.
• Try to choose a sidetrack point with an abrupt change in profile or change in formation. A good
example is the transition between a rotated interval and an oriented interval in a section of hole
previously drilled with a motor. Consult the parameter sheets and plot continuous inclination
against depth to aid choosing an appropriate sidetrack point.
• Choose a sidetrack point as shallow as possible to allow a second sidetrack point to be chosen
at a deeper point, and still achieve the directional objectives.
• Depending on the formation drillability, an open hole sidetrack can take anywhere from one hour
to over 24 hours to initiate. Patience is vital to make sure that the first ledge that is created is
maintained and enlarged as the sidetrack progresses.
• Make sure that the drillpipe is spaced out to allow the sidetrack to be initiated without having to
make connections. Space should also be left above the sidetrack point to allow the pipe to be
worked and the sidetrack transition to be reamed.
• The open hole sidetrack is initiated by creating a ledge on the lowside of the hole. This ledge is
then elongated until the sidetrack deviates completely from the parent wellbore.
• Set the tool to the desired sidetrack toolface (usually lowside) using 100% steering and
commence reaming with high RPM and low ROP. Mark the drillpipe at the sidetrack depth, and
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