Document Text Contents
Page 1
The combined free
point and backoff
system lets you
recover more pipe
more efficiently
FPIT
Page 2
Applications
■ Determination of the deepest
free point in any string of
stuck pipe
■ Backoff of stuck pipe
■ Determination of pipe tally
Benefits
■ Timesaving and efficient
operations
■ Effective operation from
drillships, semisubmersibles
and in highly deviated wells
■ Comprehensive yet simple
presentation of log data
■ Improved pipe recovery
decision making
■ Flexibility in operation and
measurements
■ Measurement in almost all
mechanical conditions
Features
■ Combination of tool with
a backoff string shot
■ Motorized positive anchoring
system
■ Independent measurement
of torque and stretch�
performed sequentially
■ Measurement of left-hand
and right-hand torque
■ Real-time monitoring of
stretch and torque as they
are transmitted
■ Integration of the driller
parameters by the wireline
surface unit
■ Correlation of the drillstring
configuration with tool
measurements
The Schlumberger FPIT tool combined with backoff service gives you the capability you
need to make immediate downhole decisions about freeing a stuck assembly.
Page 3
The Schlumberger FPIT* Free Point
Indicator Tool with combined backoff
shot determines the free point in stuck
drillpipe, drill collars, tubing or casing
and provides the force that frees the
stuck assembly. With the FPIT tool,
Schlumberger personnel can provide
accurate information about the stuck
assembly so you can save both time
and money by making immediate and
informed decisions.
During the course of drilling or work-
over, the work string can become stuck
in the borehole for many reasons: hole
conditions, formation characteristics,
mud properties, mechanical problems,
assembly tools or operational error.
Saving the well and reducing expense
means freeing the stuck assemblies
quickly and efficiently.
The FPIT tool determines how much
of the stuck assembly may be freed. In
combination with a backoff shot, the
FPIT tool efficiently frees the stuck
section of the assembly by applying
an explosive shock inside a tool joint
to which left-hand torque has been
applied. Up to seven strands of prima-
cord can be used for the combined
operation�s explosive load.
FPIT measurements
Correctly choosing the backoff depth
is a crucial part of the pipe recovery
operation. The FPIT tool consists of
a sensor section between two anchors.
The sensor package includes two
sensors. One sensor detects stretch
and is unaffected by torque; the other
detects torque.
Independent and sequential torque
and stretch measurements result in
accurate free point determination.
By observing the measurements from
both the sensors in real time, stretch
and torque are effectively applied to
give the best chance for a successful
backoff on the first attempt.
Full integration
The FPIT tool is controlled from a sur-
face unit that integrates the driller�s
parameters with the measurements
acquired during the tool�s operational
sequences. The percentage of the free
torque and stretch is automatically
computed at each measurement point
and displayed on the surface.
The operation is digitally recorded
and can be monitored in the wireline
surface unit. Using the Schlumberger
InterACT* remote communication
system, the operational data can also
be remotely monitored at the operator�s
offices. The service is customized to
specific applications to give the most
accurate results during the operation.
The combined FPIT and backoff
service is a cost-effective and efficient
method to free stuck assemblies with
successful backoff. For more infor-
mation, contact your Schlumberger
representative.
Shock
absorber
Explosive
detonating
primacord
Lower anchor
Stretch
and torque
measurement
sensors
Upper anchor
Casing collar
locator
Logging head
Optional
backoff
shot
assembly
The FPIT tool can be run alone to determine the
deepest free point or efficiently combined with
a backoff run to save you both time and money.
Free in Stretch Free in Torque
10 11010 110
14000
14100
Crossover
Drill collar
Stabilizer
Drill collar
Pipe
–25 25(in.) (%) (%)
A depth-scaled presentation of the drill string and FPIT tool readings aid in selecting the proper depth
for the backoff shot.
Page 4
% Stretch
% Torque
Left-Hand Right-Hand
0 100 100 0 100
1
2
3
4
Torque worked down
Not all torque applied at the surface is
transmitted downhole. Using a repetitive
pull-release cycle at the surface to work
the torque down will transmit the surface
torque to the target depth and result in a
desirable torque level.
Torque worked out
Torque is released at the rotary table
and worked out by a pull-release cycle.
All torque is removed.
Left-hand torque for backoff
After applying left-hand torque at the
rotary table, the torque is worked down
to the desired backoff depth.
Backoff conditions
With left-hand torque transmitted
down, a light overpull is applied at
the backoff depth, so the explosive
detonating primacord can be fired.
By monitoring the stretch and torque that is effectively applied downhole during the backoff
stage, the Schlumberger FPIT tool and backoff service provides the best chance for successful
backoff on the first attempt.
Page 5
FPIT Tool Specifications
OD 13⁄8 in. [35 mm]
17⁄8 in. [48 mm] with large hole kit
Length 11.2 ft [3.4 m]
20.1 ft [6.12 m] combined with backoff assembly
Temperature rating 350°F [177°C]
Pressure rating 25,000 psi [1,720 bar] run alone
20,000 psi [1,380 bar] combined with backoff assembly
Anchoring range 1.5 to 5 in. [38.1 to 127 mm]
Hole deviation 0° to 90°
Shock
absorber
Explosive
detonating
primacord
Lower anchor
Stretch
and torque
measurement
sensors
Upper anchor
Casing collar
locator
Logging head
Optional
backoff
shot
assembly
The FPIT tool accurately determines the free point
in stuck drillpipe, drill collars, tubing or casing.
Fishing operations are timely, cost-effective and easy with FPIT and combined backoff service.
The chosen backoff depth can maximize pipe recovery, and the combined backoff services
eliminate extra runs to save additional time.
The combined free
point and backoff
system lets you
recover more pipe
more efficiently
FPIT
Page 2
Applications
■ Determination of the deepest
free point in any string of
stuck pipe
■ Backoff of stuck pipe
■ Determination of pipe tally
Benefits
■ Timesaving and efficient
operations
■ Effective operation from
drillships, semisubmersibles
and in highly deviated wells
■ Comprehensive yet simple
presentation of log data
■ Improved pipe recovery
decision making
■ Flexibility in operation and
measurements
■ Measurement in almost all
mechanical conditions
Features
■ Combination of tool with
a backoff string shot
■ Motorized positive anchoring
system
■ Independent measurement
of torque and stretch�
performed sequentially
■ Measurement of left-hand
and right-hand torque
■ Real-time monitoring of
stretch and torque as they
are transmitted
■ Integration of the driller
parameters by the wireline
surface unit
■ Correlation of the drillstring
configuration with tool
measurements
The Schlumberger FPIT tool combined with backoff service gives you the capability you
need to make immediate downhole decisions about freeing a stuck assembly.
Page 3
The Schlumberger FPIT* Free Point
Indicator Tool with combined backoff
shot determines the free point in stuck
drillpipe, drill collars, tubing or casing
and provides the force that frees the
stuck assembly. With the FPIT tool,
Schlumberger personnel can provide
accurate information about the stuck
assembly so you can save both time
and money by making immediate and
informed decisions.
During the course of drilling or work-
over, the work string can become stuck
in the borehole for many reasons: hole
conditions, formation characteristics,
mud properties, mechanical problems,
assembly tools or operational error.
Saving the well and reducing expense
means freeing the stuck assemblies
quickly and efficiently.
The FPIT tool determines how much
of the stuck assembly may be freed. In
combination with a backoff shot, the
FPIT tool efficiently frees the stuck
section of the assembly by applying
an explosive shock inside a tool joint
to which left-hand torque has been
applied. Up to seven strands of prima-
cord can be used for the combined
operation�s explosive load.
FPIT measurements
Correctly choosing the backoff depth
is a crucial part of the pipe recovery
operation. The FPIT tool consists of
a sensor section between two anchors.
The sensor package includes two
sensors. One sensor detects stretch
and is unaffected by torque; the other
detects torque.
Independent and sequential torque
and stretch measurements result in
accurate free point determination.
By observing the measurements from
both the sensors in real time, stretch
and torque are effectively applied to
give the best chance for a successful
backoff on the first attempt.
Full integration
The FPIT tool is controlled from a sur-
face unit that integrates the driller�s
parameters with the measurements
acquired during the tool�s operational
sequences. The percentage of the free
torque and stretch is automatically
computed at each measurement point
and displayed on the surface.
The operation is digitally recorded
and can be monitored in the wireline
surface unit. Using the Schlumberger
InterACT* remote communication
system, the operational data can also
be remotely monitored at the operator�s
offices. The service is customized to
specific applications to give the most
accurate results during the operation.
The combined FPIT and backoff
service is a cost-effective and efficient
method to free stuck assemblies with
successful backoff. For more infor-
mation, contact your Schlumberger
representative.
Shock
absorber
Explosive
detonating
primacord
Lower anchor
Stretch
and torque
measurement
sensors
Upper anchor
Casing collar
locator
Logging head
Optional
backoff
shot
assembly
The FPIT tool can be run alone to determine the
deepest free point or efficiently combined with
a backoff run to save you both time and money.
Free in Stretch Free in Torque
10 11010 110
14000
14100
Crossover
Drill collar
Stabilizer
Drill collar
Pipe
–25 25(in.) (%) (%)
A depth-scaled presentation of the drill string and FPIT tool readings aid in selecting the proper depth
for the backoff shot.
Page 4
% Stretch
% Torque
Left-Hand Right-Hand
0 100 100 0 100
1
2
3
4
Torque worked down
Not all torque applied at the surface is
transmitted downhole. Using a repetitive
pull-release cycle at the surface to work
the torque down will transmit the surface
torque to the target depth and result in a
desirable torque level.
Torque worked out
Torque is released at the rotary table
and worked out by a pull-release cycle.
All torque is removed.
Left-hand torque for backoff
After applying left-hand torque at the
rotary table, the torque is worked down
to the desired backoff depth.
Backoff conditions
With left-hand torque transmitted
down, a light overpull is applied at
the backoff depth, so the explosive
detonating primacord can be fired.
By monitoring the stretch and torque that is effectively applied downhole during the backoff
stage, the Schlumberger FPIT tool and backoff service provides the best chance for successful
backoff on the first attempt.
Page 5
FPIT Tool Specifications
OD 13⁄8 in. [35 mm]
17⁄8 in. [48 mm] with large hole kit
Length 11.2 ft [3.4 m]
20.1 ft [6.12 m] combined with backoff assembly
Temperature rating 350°F [177°C]
Pressure rating 25,000 psi [1,720 bar] run alone
20,000 psi [1,380 bar] combined with backoff assembly
Anchoring range 1.5 to 5 in. [38.1 to 127 mm]
Hole deviation 0° to 90°
Shock
absorber
Explosive
detonating
primacord
Lower anchor
Stretch
and torque
measurement
sensors
Upper anchor
Casing collar
locator
Logging head
Optional
backoff
shot
assembly
The FPIT tool accurately determines the free point
in stuck drillpipe, drill collars, tubing or casing.
Fishing operations are timely, cost-effective and easy with FPIT and combined backoff service.
The chosen backoff depth can maximize pipe recovery, and the combined backoff services
eliminate extra runs to save additional time.
