- Job objectives: the main aims or goals of the cement job.
- Background information: the major challenges and concerns. Especially any adverse experience on offset wells, best practices and lessons learned.
- The job method and design, e.g., 2 stage, inner string, top and bottom plug, reverse circulation, TOC, WOC, etc. How is the job method allowing to achieve the job objectives?
- Strategy to optimize (maximize) mud displacement (cement coverage) including:
- Centralisation based on caliper or anticipated hole size (excess based on experience in similar jobs) using a computer model to optimise selection and placement of bow-spring centralisers, rigid or semi-rigid centralisers and/or turbolizers to maximize cement coverage and achieve zonal isolation.
- Pipe movement – software should be used to calculate swab and surge pressures or torque and drag if reciprocation or rotation is planned. Pipe movement may not be possible in some cases such as 2nd stage cementation or when individual well conditions prevent their implementation,
- Mud properties – reviewed against the mud program and offset well data
- Spacer and cement slurries properties and volumes (as required to maximize cement coverage)
- Fluid compatibility (as per API RP 10B-2 / ISO 10426-2 section 16).
- Displacement rates (targeting maximum ECD below the losses or fracture margin)
- For liner cementing operations the effect of the annular restriction at the liner hanger shall be considered for accurate ECD estimation. This is of particular importance in operations where higher ECD are already expected, like narrow annular clearances.
- Losses prevention strategy.
- Technical justification for the cementing fluids selection. How is the slurry type and density allowing to achieve the job objectives?
- Minimum laboratory test requirements for cementing slurries:
- Pumping schedule: fluids, fluids densities, volumes, rates, pauses (dropping plugs, etc.), time stage and time total.
- Displacement done by cement unit, rig or combined.
- Displacement volume strategy: with reference to the shoe track volume (e.g., 50% shoe track volume), pump-till-bump, etc.
- Post-pumping tasks: Check returns, WOC, Pressure testing – when, and to what pressure.
- Contingency plan has to be specific for each job conditions and its associated risks
This is in my opinion an aceptable minimun content for a cementing proposal.
Based on your experience, What would you add or remove?