Running a Gauge Cutter on Slickline, Step by Step: From Rig-Up to Reading the Tool Marks

Educational content only: procedures and operating values vary between companies and wells. Always follow your company’s approved procedures, your supervisor’s instructions and the permits in force at your site.

Why start with a gauge cutter?

In most slickline programmes the first run into the well uses a simple-looking tool called a gauge cutter (also gauge ring). It is a steel cylinder with a precisely sized outside diameter, a sharp lower edge, and slots or ports that let fluid and debris pass. The run may look routine, but it protects everything that follows. If a lock mandrel, plug or gas-lift valve is run to a depth whose path has not been proven, the expensive tool can hang up, and a one-hour run becomes a fishing job lasting days.

The run has three goals:

• Drift: prove that a tool of a given diameter passes through the tubing to the required depth.
• Cleaning: the sharp edge scrapes light paraffin, scale and mud residue from the inner wall.
• Depth control: tagging the nipples, total depth (TD) or fill lets us compare depths with the completion diagram and correct the depth counter.

Technical references note that the gauge cutter is run before any subsurface flow-control device is set, and that several runs at different sizes may be needed when deposits are heavy.

Sizing: real tubing numbers

The golden rule: the gauge cutter must pass everything the next tool will pass, and must not be larger than the smallest restriction on the way. Start from the tubing table and the completion diagram. Common API values:

Drift is the diameter of the mandrel that must pass through the pipe per the specification. Up to 2-7/8 in it equals ID minus 3/32 in (2.441 − 0.094 ≈ 2.347); for 3-1/2 and 4-1/2 in it equals ID minus 1/8 in.

The tubing is not the only restriction. In 2-7/8 in 6.5 lb/ft tubing we typically find an X nipple with a 2.313 in packing bore and, lower down, an XN nipple with a 2.205 in no-go. In practice:

• If the next job is setting a lock in the X nipple, the gauge cutter is usually close to the lock OD and slightly under 2.313 in, e.g. 2.30 in. The exact size comes from company procedures and the next tool.
• That gauge cutter passes the X nipple and then tags the XN no-go shoulder, because 2.30 is larger than 2.205. This tag is useful: it confirms the XN depth.
• Do not run a gauge cutter at full drift (2.347 in) in a well with a 2.313 in X nipple: it will stop at the first nipple.

The toolstring and what each part does

From top to bottom, as in the figure:

1. Rope socket: connects the wire to the toolstring, by a knot or a small spool depending on design. Inspect it before every job: wire pulling out here is one of the commonest causes of dropped tools.
2. Stem (weight bar): steel, lead or tungsten bars that provide weight. Wellhead pressure pushes the wire out with a force equal to pressure times wire area. For 0.108 in wire, area = π/4 × 0.108² ≈ 0.00916 in²; at 2,000 psi the force is ≈ 18.3 lbf, plus stuffing-box friction. Choose enough weight to run in steadily and to give the jars a good blow.
3. Jars: an impact tool. The most common on slickline is the mechanical spang jar, a sliding stem with a fixed stroke: a fast pull then stop gives an upward blow (jar up), a fast drop gives a downward blow (jar down). A hydraulic jar is sometimes added for strong upward blows. See jar in the glossary.
4. Knuckle joint: a ball joint giving flexibility in deviated wells and bends, and helping to free a stuck tool.
5. Gauge cutter: the tool itself. Its OD is usually stamped on it; measure it with a caliper before make-up, because its size is the basis of the whole job.

Rig-up on the wellhead and pressure testing

Pressure control equipment is rigged up above the swab valve of the christmas tree. A common order from bottom to top: tree adaptor; wireline valve/BOP with rams that close on the wire in an emergency; sometimes a tool trap that catches the tool if it parts as it enters the lubricator; lubricator sections long enough to hold the whole toolstring; and at the top the stuffing box that seals around the moving wire, with a sheave. On the ground there is a well-anchored hay pulley, a weight indicator and a depth counter.

Before well pressure enters this equipment it must be pressure-tested. Recommended practice in the Canadian IRP 13 for wireline operations:

• Test on every rig-up before exposing the lubricator to well pressure.
• Retest whenever the lubricator is broken and made up again, an o-ring connection is opened or a component is added.
• Never exceed the rated working pressure of the weakest component in the assembly.

Testing is normally with liquid (water or water-glycol), at a low then a high stage as per the company programme. Nobody approaches the equipment while it is under pressure, and pressure is bled off through the bleed valve before anything is broken.

After a good test the tool is pulled up inside the lubricator and the depth counter is zeroed at an agreed reference. The swab valve is then opened slowly, counting turns, until pressure equalises above and below it, and the rig-up is checked for leaks.

Running in (RIH) and tagging

Run at moderate speed through clear tubing and slow right down before known depths: nipples, fluid level, deviated sections, the packer and bottom. Secondary sources quote around 200–250 ft/min in clear sections and very slow speeds (about 30–50 ft/min) near restrictions. These are guidance figures only; your company procedure and the well condition govern.

Watch the weight indicator constantly:

• Running weight is below static weight because of friction and well pressure. A sudden weight drop means the tool has set down on something.
• In wax the drop is gradual and the tool "chews" through. Advance slowly, pick up a little and go down again; never force the tool or it will pack off.
• At a nipple or no-go the stop is sharp and clean. Record the depth and compare it with the completion diagram, correcting for wire stretch if needed.
• At bottom or fill the stop is softer. Record the depth: it shows how much sand has settled in the well.

If the tool hangs up (overpull)

When pulling, tension may rise above normal pick-up weight: that is overpull. Do not keep adding pull blindly. General rules:

• First try jarring down if the tool stuck after being pushed into wax.
• If you must jar up, pull until the jar fires and repeat, always staying below the safe wire tension set by your procedure (a fraction of the wire's rated breaking strength).
• In heavy wax the answer may be several runs, smaller then larger, or hot-oil/solvent treatment before returning.

Pulling out (POOH) and reading the tool

Pull at moderate speed and slow right down over the last few hundred feet, so the tool does not hit the stuffing box and part the wire at the rope socket. Once the tool is in the lubricator, close the swab valve counting turns, bleed off the lubricator, then break it.

Inspect the gauge cutter carefully; it is the well's "report":

Record the results in the job report: depths, weights, overpull and photos of the tool.

Who does what?

A typical slickline crew has the unit operator, who runs the drum and watches the weight indicator and depth counter, and one or more helpers on the wellhead who rig up the equipment and open and close valves. The operator's representative or site supervisor approves the programme and the permit to work. Communication between the operator and the wellhead must be clear and agreed in advance, by hand signals or radio, especially when opening or closing the swab valve and when the tool approaches surface. A short toolbox talk before starting reviews hazards and the emergency plan.

Common problems and how to avoid them

• Dropped tool: caused by a poorly made-up rope socket, loose connections or hitting the stuffing box. Fix: inspect before every run, use a tool trap, slow down near surface.
• Bird-nesting of the wire: running faster than the tool weight allows, or stopping abruptly. Fix: enough weight and controlled speed.
• Wrong depth: counter not zeroed or wire stretch. Fix: a clear reference point and constant comparison with the completion diagram.
• Stuffing-box leak: worn packing or wrong adjustment. Fix: inspect and adjust, and stop work at any leak of well fluid or gas.
• H2S wells: need sour-service equipment, gas monitoring and breathing apparatus, as in the permit-to-work article.

Reminder: never close a tree valve on the wire except in an emergency as per procedure: it cuts the wire and damages the valve. The means of closing on the wire is the wireline BOP rams.

Summary for the technician

A gauge cutter run asks the well one question: is the path open, at the size I need, down to the depth I want? Size the tool from real tubing and nipple numbers, rig up and test the pressure equipment, slow down at every critical point, watch the weight, then read the marks on the tool like a lab result. For the other tools, see the lesson Slickline explained.

Test your understanding

Glossary terms

• Slickline
• Tubing
• Lubricator
• Jar
• Packer
• Christmas Tree

Related lessons

• Slickline in detail: tools and fishing
• Well anatomy: from wellhead to bottomhole
• Why does production tubing get choked by wax? All about paraffin
• Workover operations: from well failure to production restart

Sources

1. Halliburton - XN/RN landing nipples and lock mandrels (bore and no-go sizes)
2. Production Technology - Slickline service tools
3. Rebco Oil Tools - Gauge cutters (product data)
4. Parveen - Tubing gauge / paraffin cutter (catalogue PDF)
5. Energy Safety Canada - IRP 13: Wireline Operations (Ed. 2, 2020), pressure control equipment testing
6. OSHA eTool - Special services: wireline operations hazards