Two stage cementing tools for 20″ surface casing

Dear Forum,

I was looking for members' experience with two stage cementing tools for 20" casing, specifically the TAM port collar + external casing packer (20" TAMCAP).

We will be running a faily long 20" casing string (± 1000m), water depth 1400m. We have some concern in being able to get cement to seabed when cementing this string, so an option we're looking at is placing the ECP + port collar about 85m BML (inside the 36" conductor) and if we do not get good cement returns to seabed during the primary job, we would use the TAM combo tool to inflate the packer inside the 36" conductor, then open the port collar and place cement from there to seabed.

We're interested in having this section of the pipe cemented not only to isolate the annulus, but also as structural support (for bending and fatigue of the 20" and 36" below the wellhead) as we're putting a 350 ton (buoyed) BOP on it.

We've identified the following drawbacks:

• slightly increased ECD while cementing the first stage due to the ECP restricting the annulus (although it is 23" OD before inflation, inside 33" ID conductor pipe)
• Have to do a dedicated run to set the high pressure wellhead housing wear bushing, as it cannot be run pre-installed in the wellhead because the combo tool (for inflating the packer and oopeining the ports) cannot be run through the wear bushing.
  

But other than this we see this as good option to guarantee cement on the top 85m of the surface casing.

Has anyone had good or bad experiences with these tools, packer not inflating, port collar not opening, port collar not closing after job, stuck combo tool, junk in hole, etc? Any statistics you might have on running this equipment?

thanks

5 Answer(s)

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