Squeeze cementing is a critical process in the oil and gas industry. It involves injecting a cement slurry through perforations in the casing to create a seal in specific locations, effectively bridging undesired gaps. A common misconception is that the cement penetrates the pores of the rock. However, the cement slurry actually dehydrates against the formation walls, forming a seal known as a cement filter cake. Due to the size of cement particles (20โ50 microns), the permeability of the formation must range between 2โ100 darcies for any significant penetration of cement grains into the formation.
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Squeeze cementing is necessary for various reasons during drilling and production operations, including:
- Zone Isolation Before Production Perforations
Ensures that specific zones are sealed off prior to production commencement.
- Rectifying Faulty or Inadequate Primary Cement Jobs
Addresses issues where the primary cementing job does not meet requirements.
- Fixing Casing Leaks
Repairs breaches or leaks in the casing to maintain integrity.
- Shutting Off Unwanted Reservoir Water or Gas Inflows
Controls and halts the undesired inflow of water or gas into the wellbore.
- Abandoning Non-Productive or Depleted Zones
Seals off zones that are no longer productive or are depleted to facilitate abandonment.