Ensure the information below is known before starting the 13 3/8” cement job:
The expected stand pipe pressure and ECD at different stages of the cement job.
The predicated fracture gradient at the 13 3/8” shoe.
The required 13 3/8” casing pressure test.
The minimum flow rate required to achieve turbulent flow.
The design temperature (confirm with Ops Eng).
If using the OverDrive system must be laid down and 500T elevators installed prior to making up BJ/Halliburton cement head. This will allow casing to be landed whilst maintaining pressure if floats fail.
Make up cement head crossover and cement head. Ensure bottom and top plugs are loaded in the cement head correctly. Drilling Supervisor to witness plug loading.
Check seals on cement head in good condition and have backup available.
Make up cement line and conduct a pre-job safety meeting with Drilling Supervisor, rig personnel and all service companies involved (agree on job sequence, pressure limits, signals for open/close valves, etc).
Pressure test lines to 5000psi (345 bar) using technical water (or saturated brine in winter months).
Confirm the displacement volume, cement slurry volumes & dead volumes and correct the chemical quantities accordingly. A lead and tail will be pumped and the minimum compressive strength is 3500 and 5000 psi respectively.
In winter time must check that everything is in place to comply with the cold weather procedure, with particular attention to the air humidity for the cement displacement from the silos.
With rig pumps break circulation slowly and circulate a minimum of 150% casing annular volume or 120% casing volume which ever is greater. (PV and YP as low as possible) Pump at the same rate to be used for cementing.
Make sure the cement slurry mix water has been prepared off-line and is ready, as soon as the cementing head is connected.
Ensure sufficient quantities of cement and additive materials for two jobs are on location.
Ensure vacuum truck is on location to clean cellar.
Confirm that the Technical Water is supplied directly from the drilling camp. Do not use rig water.
Add the cement chemicals to the Technical Water in the mixing order mentioned in the cementing programme and lab sheet.
Let the A-7 and A-2 hydrate for 30 minutes before adding the FL-25 L in the 1.6s.g lead cement mix fluid.
Thoroughly mix each chemical after adding it to the mix water. Take samples of final mix fluids, label and retain them for lab verification tests.
Prepare the MCS-A Flush & Spacer in the batch mixer tank by adding 1 gal MCS-A per bbl of technical water just prior to pumping it.
Take a dry cement sample(s) prior to the cement job and a 1 gallon mix water sample during the cement job.
Stop circulating the well with conditioned mud. Close valve from rig pump and open valve to BJ unit.
Mud logger should make sure the stroke counter set to zero before pumping spacer and displacement. Continuously monitor for loss/gain of mud during the job.
Pump 80 bbls Base Oil spacer followed by 80 bbls Hi-Vis Surfactant spacer at 5 bpm (795 LPM)
Close valve to rig pump and open valve to BJ unit.
Drop the Bottom Wiper Plug.
Drilling Supervisor to witness plug release.
Mix and Pump 1.60s.g Lead Cement Slurry.
Take samples as soon as density is stable, label & retain.
Mix and Pump 1.90s.g Tail Cement Slurry.
Take samples as soon as density is stable, label & retain.
Take minimum 3 cement slurry samples during the cement job.
Launch the Top Wiper Plug.
Drilling Supervisor to witness plug release.
BJ Unit to pump 5bbls Technical Water or saturated brine as after flush to start displacement.
Confirm plug launch.
Switch over to rig pumps.
Continue displacement as per cementing programme. Use 95% efficiency.
Flow rate will be adjusted throughout the displacement based on the required ECD.
Record circulating pressure at the displacement rate prior to bumping plug (this is to calculate the theoretical height of the cement behind casing). Report in daily drilling report.
Pump until plug bumps, however do not exceed half shoetrack volume above calculated strokes. If plug has not bumped investigate cause of the problem.
Increase pressure to 3000psi (207bar) when bump.
Hold pressure and pressure test casing at 3000 psi (207bar) for 10 minutes.
Check floats hold and bleed off mud line to determine purged mud volume (expect 10bbls return).
During the displacement monitor and determine the volumes of returned Mud, Flush and Lead Cement.