Wireline Entry Guide (WEG)
Tubing shoes (or "mule" shoes) are short, cut-away lengths of tubing fitted to the bottom end of a tubing string to facilitate stabbing into a packer or packers. The outside should be barrel shaped to aid entry into the packer bore and to prevent hold-ups when running, and the inside bottom edge should be chamfered to aid wireline re-entry. When the tubing string is stepped down in diameter below the packer, some form of centralizer(s) should be fitted to, or near the shoe, especially in deviated wells.
When selecting the type of guide to be used, remember to think about the equipment that may have to pass through the guide during the life of the well.
General considerations for installing completions:
Ensure that elevators, slips, and power tongs are in proper working order, and correct dies are fitted. Do not use pipe wrenches for manual make up of joints. Apply pipe thread lubricant sparingly to pin and box thread, and sealing areas. Ensure that the correct torque is applied, modifying the manufacturers’ recommended figure, if necessary, to suit the thread lubricant used.
- Drift check each joint of tubing to ensure that no gloves, rags or other foreign bodies have found their way inside
- Record the serial number of each item as it is made up in the string, including the numbers marked on the tubing joints on receipt
- Confirm the operating envelopes of the equipment are appropriate for the expected working parameters.
- Supervisors keeping tally should cross-check with each other from time to time to ensure that the string is being made up according to the program.
- Run seal assemblies very slowly into/through packer bores.
- Avoid running a tubing string with a plug installed in a landing nipple situated close to the bottom of the string. Problems with debris accumulation on top of plugs are very frequent when applying this technique, making retrieval difficult. Other options, such as pump out plugs, are more suitable.
- Check hanging weight up and hanging weight down methodically and accurately when required to do so.
- After tagging the packer with its seal assembly, ensure that any pressure build-up in the tubing can be bled off when running the seal assembly through the packer to avoid seal damage.
- If required to make reference marks when setting down/spacing out, do so accurately, taking care not to damage any special surface finish.
- Check the completion fluid for correct composition and maintain the required levels in the tubing and annulus.
- String, using suitable wireline drifts.
General Considerations
- When carrying out pressure tests, build up pressure slowly, in stages, to the maximum level, maintain pressure for the recommended time, and record on a suitable pressure recorded.
- Note that test pressures and times may be limited if the well is perforated below the packer to be tested, as the test pressure may also act on the formation.
- After spacing out, drift the complete string, using suitable wireline drifts.
- Potential Impact of Failure:
- Failure to follow correct procedures can result to costly delays to pull and re-run the completion.
- Use of excessive pipe dope can cause severe formation damage, reducing hydrocarbon production significantly.
Hydraulic Hose make up:
- Hose must not be stretched, kinked, crushed or twisted during installation or use.
- Hose must not be bent to less than the minimum bend radius.
- Correct clamping (holding/supporting) of the hose should be exercised to securely route the hose or to avoid the hose contacting surfaces that will cause the hose damage. It is however, vital that the hose be allowed to keep its functionality as a “flexible-pipe” and not be restricted from changing in length when under pressure.
- Hoses for high- and low-pressure lines shall not be crossed or clamped together, as the difference in changes in length could wear the hose covers.
- Hose should not be bent in more than one plane. If hose follows a compound bend, it shall be coupled into separate segments or clamped into segments that each flex in only one plane