1. RUN drillpipe with a stinger of tubing to the planned depth of the bottom of the plug.
Note:
* The stinger should have side jets and should be at least 100 ft longer than the planned cement plug. Use 3.1/2in or smaller tubing in holes with a diameter of 12.1/4in or less.
* The smaller the diameter of the stinger, the less the disturbance to the cement when pulling out of the plug.
2. CIRCULATE a minimum of 150 % of the drillpipe/stinger contents prior to setting the cement plug. The mud must have a constant gradient prior to commencement of the job.
3. PUMP preflush.
4. MIX and PUMP cement.
Note:
The slurry for cement plugs should be batch mixed if possible. When this is not possible, the slurry is mixed on the fly at a consistent gradient as possible. Density shall be checked using a pressurised mud balance
5. PUMP postflush, to balance the preflush pumped ahead of the slurry.
6. CHASE with mud and UNDER-DISPLACE cement by 1bbl ie., STOP displacing when top of cement in drillpipe/tubing stinger is 100-150 ft above the planned top of cement.
7. PULL BACK to the required top of cement. If the excess cement is to be circulated out conventionally, PULL BACK to a position 300 ft higher than the required top of cement to minimise disturbance caused by the jetting action of the stinger.
8. CIRCULATE out excess cement immediately after placing the plug. The top of good cement should be known with fair accuracy after the job. USE reverse circulation except in the circumstances detailed below.
Conventional circulation shall be used when:
formation strength is known to be sufficient to support the increased back pressure
there is no chance that the back pressure will cause differential sticking
if in open hole circulate conventionally and if in cased hole reverse circulate.
9. If the plug has to be tagged after the cement has hardened, POOH, wait on cement (WOC) and RIH with dress assembly to tag/dress cement plug.. NEVER stab the cement stinger back into the plug when the displacement is finished as this may cause plugging of the stinger.
10. SET the next plug or POOH.