DeepWiki – The well service authority

Toolstring is a term for different tools connected together. There are different tool strings for different jobs in the wells.


What is tool string and how is it connected to the wireline?

• Combination of various tools.
• It is connected to the wireline by a rope socket.

What capabilities should be provided by the tool string?

• Ability to provide weight (tension & speed) (stem).
• Ability to accommodate rapid changes in inclination (knuckle joint).
• Ability to provide upward and downward jolt (jars).
• Ability to connect running or pulling tools and other tools ( swage, impression block, gauge cutter, blind box, etc).

Rope Socket

  • Simply provides a means of connecting the tool string to the end of the wireline.
  • It is a housing for the spring ,support and
  • It has a fishing neck which allows the tool string to be pulled if lost.
  • The wireline is fastned to the disk which is grooved around its entire circumference . this groove is sufficiently deep to prevent damage to the wireline when the disk comes to bear aginst the spring support


  • Wireline Stem is used to provide the weight required to overcome the well pressure working against the wire in order to ‘lower’ wireline tools into the wellbore.
  • This mass is also used to generate impact force when performing jarring operations downhole.
  • The amount of stem used in a tool string is determined by: (a) the amount of well pressure working against the cross section area of the wire, and by (b) the impact required to accomplish the downhole work to be done.
  • Roller Stem is used in higher deviation wells to minimize tool friction on the tubing wall by providing rolling contact.
  • Stem is available from 1″ O.D. to 3″ O.D. with a variety of fishing neck sizes, lengths and connections.


  • Jars are employed in most cases below the stem so that the weight of the stem will close the jars when an obstruction is encountered.
  • Needed to manipulate the tools run and pulled from the well.
  • If we desire to beat downward on an obstruction, the reel is put in a pulling position at the surface until the jars open, then by releasing the reel quickly, the weight of the stem delivers an impact on the obstruction.
  • Any upward impact can also be delivered by reversing this operation with the reel on the surface.

Knuckle Joint

  • It’s a ball and socket joint.
  • It makes the wireline toolstring flexible
  • Helps the alignment of the tools.
  • Placed above the operating tool.

Gauge Cutter

  • Originally developed for removing paraffin and wax from the l.D. of the wellbore.
  • Gauge Cutters are now commonly used to perform ‘gauge’ runs prior to retrieval of flow control devices and to check that landing nipples are not coated with deposits such as scale or wax prior to installation of a wireline plug.


  • The Tubing Swage can be used to remove large obstructions in tubing. Tubing swages of gradually increasing size can be run to progressively remove the obstruction.

Impression Block

  • Lead Impression Blocks are used primarily in fishing operations to identify what is uppermost on the fish.
  • The L.l.B. consists of a steel housing, filled with lead which is dressed to a very smooth finish prior to running.
  • When the L.l.B. is on top of the fish, one downward jar deforms the lead which can then be interpreted at surface to indicate what is downhole.

Blind Box

  • A Blind Box is used to either beat down any obstruction encountered in the tubing string or to cut (box off) wire on top of a Rope Socket during fishing operations.
  • Always ensure thatthe O.D. of the tool does not match too closely the l. D. of any downhole restriction such as a landing nipple, as the lack of fluid by-pass through the tool can cause ‘sticking’ problems.

Wireline Bailer

  • It’s a hollow cylinder container with a ball/flapper check valve at the base to contain the contents.
  • It’s used for removal of solids, liquids, debris and placing chemicals.
  • Removal of solids may be necessary to gain access to the pulling neck of the equipment.


  • Magnets are used for retrieving loose metallic debris from the wellbore and are available in a number of sizes.
  • As well as standard tools it is also possible to source and supply high performance magnets for special application.


Statoil bp ConocoPhillips Statoil Wintershall Lundin Norway Maersk Oil Baker Hughes Det Norske Oljeselskap

Husoyveien 171, 4262 Avaldsnes Tel.: (+47) 52 70 10 20 Fax: (+47) 52 70 10 21 Dutyphone: (+47) 488 98 030 Back to top