SQUEEZE CEMENTING PLACEMENT TECHNIQUES

PLACEMENT TECHNIQUES

There are 3 main placement techniques for carrying out a squeeze:
1.  Retrievable squeeze packer
2.  Drillable cement retainer
3.  Bradenhead placement.

RETRIEVABLE SQUEEZE PACKER 

The main objective of using a packer is to isolate the  casing and wellhead while high pressure is applied
downhole. The advantage of the retrievable packer is.....
the  fact that it can be set and released many times,(Figure
6.14 and Figure 6.15).  Retrievable squeeze packers can be either compression  set or tension set. Compression set packers are generally  preferable based on industry experience. Squeeze packers have a by-pass valve to allow  circulation of fluids while running in and pulling out of  the hole (to prevent high swab and surge pressures) and  also when the packer has been set (for reversing out of  excess cement without excessive pressures).Drillable or retrievable bridge plugs can be set to isolate the casing below the zone to be  treated.When running the retrievable bridge plug, it is normal to drop frac sand on top of the  plug to prevent cement setting in the release mechanism.



DRILLABLE CEMENT RETAINER

Cement retainers (Figure 6.15)are drillable packers provided with a two-way valve that
prevents flow in either or both directions. The valve is operated by a stinger run at the end of
a work string.
Drillable cement retainers run on wireline are used instead of packers to prevent backflow
when no dehydration of cement is expected, or when high negative differential pressures
may disturb the cement cake.
When cementing multiple zones, the cement retainer isolates the lower perforations and  subsequent zone squeezing can be carried out without having to wait for the cement to set. These retainers are also used for well abandonment purposes.