Transcript
FPIT The combined free point and backoff system lets you recover more pipe more efficiently
The Schlumberger FPIT tool combined with backoff service gives you the capability you need to make immediate downhole decisions about freeing a stuck assembly.
Applications ■
Determination of the deepest free point in any string of stuck pipe
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Backoff of stuck pipe
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Determination of pipe tally
Benefits ■
Timesaving and efficient operations
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Effective operation from drillships, semisubmersibles and in highly deviated wells
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Comprehensive yet simple presentation of log data
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Improved pipe recovery decision making
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Flexibility in operation and measurements
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Measurement in almost all mechanical conditions
Features ■
Combination of tool with a backoff string shot
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Motorized positive anchoring system
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Independent measurement of torque and stretch— performed sequentially
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Measurement of left-hand and right-hand torque
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Real-time monitoring of stretch and torque as they are transmitted
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Integration of the driller parameters by the wireline surface unit
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Correlation of the drillstring configuration with tool measurements
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.
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.
FPIT measurements
Logging head
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
Casing collar locator
Upper anchor
Optional backoff shot assembly Shock absorber
Stretch and torque measurement sensors
During the course of drilling or workover, 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 primacord can be used for the combined operation’s explosive load.
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 surface 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 information, contact your Schlumberger representative.
A depth-scaled presentation of the drill string and FPIT tool readings aid in selecting the proper depth for the backoff shot.
–25
Pipe (in.)
25
10 14000
Explosive detonating primacord Crossover
Lower anchor Drill collar Stabilizer
Drill collar
14100
Free in Stretch (%)
110 10
Free in Torque (%)
110
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.
% Stretch 0
Left-Hand 100 100
% Torque Right-Hand 0
100
1
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.
2
Torque worked out Torque is released at the rotary table and worked out by a pull-release cycle. All torque is removed.
3
Left-hand torque for backoff After applying left-hand torque at the rotary table, the torque is worked down to the desired backoff depth.
4
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.
The FPIT tool accurately determines the free point in stuck drillpipe, drill collars, tubing or casing.
Logging head
FPIT Tool Specifications OD Length Temperature rating Pressure rating
Casing collar locator
Anchoring range Hole deviation
13⁄8 in. [35 mm] 17⁄8 in. [48 mm] with large hole kit 11.2 ft [3.4 m] 20.1 ft [6.12 m] combined with backoff assembly 350°F [177°C] 25,000 psi [1,720 bar] run alone 20,000 psi [1,380 bar] combined with backoff assembly 1.5 to 5 in. [38.1 to 127 mm] 0° to 90°
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.
Upper anchor
Optional backoff shot assembly
Shock absorber
Stretch and torque measurement sensors
Explosive detonating primacord
Lower anchor
www.connect.slb.com SMP-5078
©Schlumberger
October 2001
*Mark of Schlumberger
