The following best practices should be considered for fishing operations:
- All fishing tool details shall be recorded on a drawing prior to running the tool. In particular, the safe working load for all fishing tools and associated equipment shall be determined.
- Internal diameters of fishing tools to be run shall be checked to verify that back-off tools can pass through.
- Where a twist-off has occurred, the fish shall be tagged prior to pulling out of the hole and the pipe shall be strapped on the trip out.
- If a twist-off occurs the hole shall be circulated clean and mud conditioned prior to pulling out of the hole. The required overbalance for well control shall be ensured.
- The size, shape, and condition of the fish shall be determined.
- A bumper sub shall be considered for use in all fishing assemblies.
- The pull shall be limited to 80 % of the minimum yield strength of the pipe for used pipes.
- Prior to connecting to the fish the following information shall be obtained:
- Establish circulating pressures and rates.
- String weight up/down and rotating (with and without circulation)
- Free rotating torque of string.
- Pipe stretch and stroke of bumper sub, jars, etc.
- After engaging a fish, circulation shall be established for well control purposes if circulation is possible.
- After freeing the fish, circulate bottoms up before POOH, if circulation is possible through the fish (the degasser shall be checked for proper operation).
Recommended Fishing Assembly
The choice of fishing componen, overshot, spear etc. is dependent on the actual fishing operation.
The fishing BHA shall be made up of the following:
- fishing component eg., spear, overshot, mill
- bumper sub
- hydraulic jar
- drill collar (equal to fish weight)
- accelerator
- 3 x drill collar
- drillpipe