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Lost Circulation:
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The PBL Multi-functional Bypass System was developed to aid operators in dealing with lost
circulation problems. With the tool run as low in the BHA as possible it can be opened (activated)
by simply dropping a ball. When the tool opens operators are not limited in the size or
concentration of LCM they can pump. With the Bypass System in the hole the limitations rest with
the surface equipment. With the tool open and circulation regained the tool can now be closed.
Simply drop another ball to close the tool and drill ahead. If the problem is encountered again
there is no problem because the PBL Multi-Functional Bypass System can be opened and closed up
to six times a bit run.
Although the tool was designed to correct lost circulation once it gained more utilization and
exposure it became apparent that there were other cost/time saving advantages for the tool such
as workovers and completions along with horizontal drillings.
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Workovers & Completions:
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Circulating rate and pressure loss application, this application proved very effective for operators
working in wells with liners on bottom. It is utilized to bypass small working strings inside liners.
With the tool positioned directly above the slim hole string in the liner it can be opened to bypass
the friction loss associated with the slim hole working string. Increased flow rates can be as high
as five times that of the rate achieved while circulating through the slim hole string.
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Horizontal Acidising & Stimulation:
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In multilateral horizontal wells it is necessary to find the lateral leg which requires stimulation.
For this reason it is necessary to run expensive MWD Tools. With the PBL tool run directly above
the MWD tool, stimulation can be achieved with no adverse effects on the MWD tool. All acid can
be pumped through the PBL Tool and the PBL Tool can be opened and closed so that the operator
can regain signals from the MWD Tool.
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Horizontal Drilling:
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With increased activity and demand for horizontal drilling it became apparent that there were yet
more applications for the tool in this specialized area. One of the more interesting applications is
using the tool to break circulation while running in the hole with downhole motors.
This application allows operators to break circulation through the PBL Bypass System when
running in the hole. This is an advantage when running motors with bent housings and PDC bits
it eliminates motor and bit rotation preventing bit wear and tear as well as casing wear. With the
BHA on bottom the Bypass System can be closed to commence with drilling.
These three applications for the PBL Multi-Functional Bypass System have proven effective to
operators in some of the most extreme environments worldwide.
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Under Balanced Drilling
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The tool can be used for this application, most commonly the tool is run in the vertical
section of the well. The tool is used so that the open hole, the horizontal well bore, is not
exposed to any other fluid but native crude. The tool can be opened up to allow the
displacement of weighted material in the vertical part of the well bore for safer tripping of
the pipe or for well control operations. For this application the ball catcher can be run
down the string just above the MWD or non-mag tools this will allow free point and back
off operations to be performed as low in the hole as possible
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Fixed Cutter/Bi-Centre Bits Or Rwd And Under-Reamer Applications.
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When these above mentioned tools are run in conjunction with down hole motors some
operational problems can be eliminated with the use of the Bypass System. Pumping
through drilling motors with the above mentioned tools is not recommend as the OD of
the bi-centre bits and the RWD tools is very close to the ID of the casing. In most cases it is
not recommended to turn these bits inside the casing with the motor. The Bypass System
can solve this problem as follows:
Before running in the hole:
With one of the above mentioned assemblies, put the activation ball, preferably with a
dart combination into the Bypass System. With the ball in place in the tool circulation
can be achieved when desired with the flow going out of the PBL Bypass System and not
through the motor or MWD. When the drill string enters the open hole the Bypass System
can be deactivated to close the Bypass System and allow for circulation through the MWD
and motor.
Before coming out of the hole:
Drop the activation ball and circulate bottoms up through the tool. Leave the ball in place
and come out of the hole, this will allow the drill string to be tripped dryer. The weight of
the trip pill will effect the speed of the drill string drainage. This will also allow circulation
while coming out of the hole with out the bi-centre bit or RWD turning in the casing.
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Sub Sea Riser/Bop Jetting
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The PBL Bypass System can be utilized to jet BOP's and risers during drilling and
completion operations. The jetting application can be performed by opening and closing
the Bypass System without the need for tripping jetting tools in and out of the hole.
Jetting your sub sea BOPÕs will clean shale and debris out of the cavities in the sub sea
BOP stack greatly enhancing safety. Jetting the riser will effectively clean the riser during
completion operations.
Utilizing the PBL Bypass System for jetting sub sea BOP's and risers will greatly reduce rig
time. By having the tool as a component of the BHA, this jetting operation can be
performed during each trip as and when required.
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Tripping Dry Pipe:
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The PBL Bypass System is also effective in helping operators trip more dry pipe.
The procedure for this is as follows:
- Drop the activation ball or ball dart combination into the drill string.
- Open up the bypass system and circulate bottoms up through the tool.
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It is recommended to pump a weighted pill down the drill string. This pill will help
to add differential to over come the force of the spring and sleeve allowing the port
in the tool to open. The required pressure differential acting on the ball and sleeve is
between 100 psi - 130 psi to open the port.
This above-mentioned application will have very positive results when operators are
running bi-center bits or ream while drilling tools in conjunction with downhole
motors. With the combination of these tools in the drill string it is not recommended
to circulate while the bi-center bits or MWD tools are in the casing. The PBL Bypass
System will allow operators to circulate at any time thus eliminating wear and tear
to the casing, as well as the bit or tools in the drill string.
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