Description:The present invention related to “Liner Hanger Tie-Back Receptacle Polish Mill with
TBR top chip-off feature”
Liner Hangers are integral part of Oil and Gas well drilling. Smooth entry of the
Drilling/Completion Bottom Hole Assembly (BHA) in the Tie Back Receptacle (TBR) is
must if the well has to be drilled/completed smoothly and to put the well on oil/gas
production safely. Any damage to the TBR top will cause loss of rig days at the least and
well loss at the worst. All scenarios will have high financial implication for an E&P
operator. The newly invented system will remove the root cause of all potential failures
associated with entry of BHA on the Liner Hanger Tie-Back Receptacle top and will
result in significant financial savings and optimization for Exploration and Production
Companies worldwide.
Background of the Invention
Liner Hanger (LH) is similar to casing, is a tool/system that is used to hang a casing in a
production well. But this casing segment is not run through the full depth of the well. A
liner hanger allows the casing below it to be suspended in the previous casing string to
reduce material cost and provide completion solution options. A seal is required at the
top of the liner hanger to prevent transfer of fluid or pressures from either direction.
Tie-Back Receptacle (TBR) attaches to the Liner Top Packer and provides a sealing
bore. This polished bore is used to tie the well back to surface, provide a sealing bore
for fracturing operations or for landing a second trip packer in case of a liner-top leak.
Tieback equipment allows existing liners with a receptacle to be extended to the surface
or farther up hole, and provides a high-pressure seal at the top of a cemented or
uncemented liner.
The TBR has two surfaces/angle on the top as shown in the Figure 1. Debris/Residual
Cement often gets deposited on these surfaces. Before Running in Hole (RIH) of Drilling
String or Completion Tools these surfaces have to be cleaned along-with the Inner
Diameter (ID) of the TBR.
The prevailing solution is to run a Polish Mill: A combination of Clean Out Mill (to clean
the Inner Diameter (ID) of the TBR) and Top Dress Mill (to clean the top of the TBR).
However, the current solution has an inherent technical issue. Since the TBR top does
not have a constant angle for allowing the entry of the Drilling/Completion BHA, so in
many wells (specially the horizontal/inclined ones) when the BHA tags on the top of the
TBR, it damages the TBR top and then BHA cannot enter the TBR. Due to damaged
TBR top, one more milling trip will be required to mill away the damaged TBR top.
Milling is the process of steel removal. It will also result in a removal of the steel
obstruction in the wellbore and continue drilling to the well target.
This causes several days of loss of rig time and very often this extra milling operation is
not successful and is likely to weaken the TBR structural integrity. Out invented design
of the Polish Mill will have cutting inserts mounted (as shown in figure 2) on the bottom
surface of the Top Dress Mill. So, in one single trip, our newly invented design will serve
the purpose of conventional Polish Mill as well as will make one smooth surface/angle
at the TBR top for the Drilling/Completion BHA to enter. Thus, completely eliminating the
possibility of TBR top getting damaged, or need of any extra RIH or possibility of
weakening of the TBR structural integrity.

The main object of the present invention is to provide Liner Hanger Tie-Back
Receptacle Polish Mill with TBR top chip-off feature, which obviates the drawbacks of
the hitherto known prior art as detailed above.
Another object of the present invention is to provide smooth entry of Drilling/Completion
BHA at the TBR Top which reduce the rig downtime and extra milling operation cost.
Still another object of the present invention is to avoid weaken the TBR structural
integrity due to non-dependence upon milling operation.
Details of the Invention
Achieved outcome of the present invention is innovation in Liner Hanger Tie-Back
Receptacle Polish Mill by addition of TBR chip-off feature. Newly invented in Liner
Hanger Tie-Back Receptacle Polish Mill will have cutting inserts mounted (as shown in
figure 2) on the bottom surface of the Top Dress Mill. These cutting inserts will mill a
calculated chamfer by chipping off some material without compromising the wall
thickness of Tie Back Receptacle. So, in one single trip, our newly invented design will
serve the purpose of conventional Polish Mill as well as will make one smooth
surface/angle at the TBR top for the Drilling/Completion BHA to enter. Thus, completely
eliminating the possibility of TBR top getting damaged, or need of any extra Running in
Hole (RIH) or possibility of weakening of the TBR structural integrity. The present invention is illustrated in figure 1 to 2 of the drawings accompanying this
specification. In the drawings like reference numbers /letters indicate corresponding
parts in the various figures.
, Claims:Accordingly the present invention provides Liner Hanger Tie-Back Receptacle Polish
Mill with TBR top chip-off feature comprises:
1. Invented Liner Hanger Tie-Back Receptacle Polish Mill with TBR top chip-off
feature reduces the rig downtime.
2. Invented Liner Hanger Tie-Back Receptacle Polish Mill with TBR top chip-off
feature consists of cutting inserts mounted on the bottom surface of Top Dress
mill which provides smooth entry of Drilling/Completion Bottom Hole Assembly
at the TBR Top without any obstruction.
3. Invented Liner Hanger Tie-Back Receptacle Polish Mill with TBR top chip-off
feature avoid weaken the TBR structural integrity due to non-dependence upon
milling operation.