Whatever type of packer is installed, the manufacturer's instruction for setting and the completion programme on setting depth and running must be followed if satisfactory results are to be obtained. There are too many variations in packer design and setting to go into detail, but some points to remember when installing packers are:
- do not run the packer below the scraped interval;
- ensure the correct completion fluid is maintained at the correct levels and pressure in the tubing and annulus, as specified in the programme;
- allow for drill pipe/tubing stretch when pressurising the annulus and/or tubing;
- observe limitations in test pressures for perforated and non-perforated wells;
- ensure that the measuring equipment for weights, pressure and depths are as accurate as possible and have been recently calibrated;
- carefully observe the setting-down and pulling weight on those packers that have shear pin controlled functions;
- if tubing is being run with a plug set in the bottom nipple, care must be taken to run slowly so that pressure surges do not set the hydraulic packer;
- with certain drill pipe set packers, care must be taken not to allow the drill string to turn until required to release the setting tool;
- with some wireline set packers do not 'tag' the packer to check the setting depth as the collet latch on the setting tool might re-engage and the logging cable is not strong enough to release it;
- appropriate safety precautions must be observed when using the explosive setting tool, and the necessary fishing tools for the setting tool must be on site.
Below gives the procedure for setting a Halliburton RTTS packer to illustrate a typical setting procedure and necessary checks.
- Check the packer operating envelope, slips and packer elements.
- Make up the RTTS and assemblies on the pipedeck/catwalk if being run together.
- Make up the stand of tubing to the RTTS packer in the mousehole.
- Pick up the assembly and make up to the pipe on the rotary table.
It is advisable to run a muleshoe when running tailpipe below the packer. Tailpipe up to the limit of the Mandrel can be used as the circulation point is at the end of the tailpipe.
- Pick up the assembly. When the mechanical slips and drag block body are above the rotary table work the drag block to ensure movement of the lug through the J-slot and free movement of the mechanical slips.
- Run packer to below desired setting depth.
- Work the string across the desired setting depth. Record the WIR up and WIR down. Note the slack off and stretch. Ensure that packer is not set within 5 ft of casing collar.
- Pick up string to desired packer depth and apply right hand torque.
- Release residual torque, slack off until packers starts to take weight. Circulating valve will close and continue to slack off to the recommended setting weight on the packer.
- Connect kill line.
- Close pipe rams.
- Pressure up on annulus to the recommended pressure to ensure good packer seat and no leaks on tubing string.
- Open pipe rams.
Attention must be given to the possible damage caused by the packer slips on the casing during setting and retrieval, especially in H2S environments in which special alloy steels are used.