Well cementing proposal checklist:
The following eleven points form the basis of a sound well cementing proposal. For unique circumstances, there will be additional points for planning and consideration.
- Job objectives: the main aims or goals of the cement job.
- Background information: the significant 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 us 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). For this, we use a computer model to optimize the selection and placement of the 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 we plan reciprocation or rotation. 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.
- The technical justification for the cementing fluids selection. How is the slurry type and density going to allow us 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.
- Is the displacement facilitated by cement unit, rig, or a combination?
- Displacement volume strategy: concerning 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.
- The contingency plan has to be specific for each set of job conditions and its associated risks.
This list is, in my opinion, an acceptable minimum content for a well-cementing proposal.
Based on your experience, What would you add or remove?