The well was drilled as a gas producer. A 40 inch casing was cemented with casing shoe depth at 314 ft. Unable to get cement all the way to surface after several attempts, they tried to cement from top side, also without success. The result was oil flow through annulus between 40 and 36 inch casings, 15–18 bbl/day. At the same time there was communication in the top section to surface and into annulus between 36 and 32 inch casings.
200 gal ThermaSet®
plug in top casing section of 40 and 36 inch, was designed to cure after 2 hours. A second plug of 180 bbl and 10,4 ppg. ThermaSet®
was then used as casing cement in 40-36 inch annulus. We used a low temp ThermaSet®
designed to cure after 220 minutes, both at 70 °F surface temperature, as well as 40 °F sea bed temperature.
Communication test in 40-36 inch annulus was done with 60 bbl drill water and slick 5, with an injectionate of 1.75 bpm.ThermaSet®
Cleaner was used to clean out the residue of slick 5.180 bbl ThermaSet®
pill with 10,4 ppg was prepared on site in batch mixer. A third ThermaSet®
low temp pill, 6.5 bbl at 11,9 ppg , was pumped and dropped on top of cement in annulus of 36-32 inch casings, to seal off any future communication/cement leaks.
Top section in 40 inch was plugged and oil flow in annulus was shut off and secured. ThermaSet®
plug in 40 inch was essential, in order to successfully cement the casing. Mixing and pumping operation was conducted as planned. All three plugs tested ok, oil leakage was stopped, and both casings secured.