Wireline Operations

It is quite common to conduct electric wireline operations in cased hole during a workover. Operations prior to removal of the Xmas tree are generally conducted using conventional wireline lubricator systems as in figure 1.

Wireline Operations Over BOPs

After the BOPs have been installed, Wireline operations are generally conducted through the BOPs. These include:

■ Setting sump packers, bridge plugs or straddle assemblies

■ Reperforation with large / oriented guns

■ Cased hole evaluation

■ Casing wear evaluation

■ Perform CMT Plugs by cement bailers

■ Cut tubing strings (RCT)

Operations are sometimes conducted through the BOPs with no other pressure control equipment. Should primary well control be lost it will be necessary to close in the well using the annular preventer or to cut the wire. When blind-shear rams are in use, these will be able to cut the wire. Otherwise, it will be necessary to cut the wire at surface prior to shut- ting blind rams.

?

It is unlikely that an effective seal will be achievable using the annular preventer against significant pressure. It will also not be possible to move the wire through the annular preventer without damaging the sealing element.

Cutting the wire at surface will result in a fish as well as a significant amount of bulky wire lost in the hole. Well killing operations down the well-where the only realistic option is to bullhead-will tend to bunch up the wire making it harder to recover.

?

For these reasons it is sound practice to use a shooting nipple. These are, however, not without hazard too.

?

Shooting nipples were originally fabricated from a length of tubing or casing with a flange welded on one end and a casing or tubing thread on the other end. A pump-in sub was sometimes welded near the top to provide access to the well from the rig floor.

?

Depending on the BOP and rig configuration the shooting nipple will be installed in one of the following three places:

?

1- Attached to the top of the annular preventer

- Uses the API flange usually on top of the annular

- Requires removal of the bell nipple and flow line

- Requires the ring groove and bolt holes to be in good condition

2- Secured using a flange below the annular BOPS

- Not suitable for all designs of annular preventer

- Flange can damage closing mechanism and/or packing element under high pressures

3- Secured using a flange below the top pipe rams

- Requires solid pipe rams sized for the shooting nipple above the blind rams

- Requires accurate installation to avoid fouling the blind rams