Onshore Cementing Operations and Equipment
Purpose and Applications of Cementing
Cementing in onshore drilling operations serves multiple purposes, including sealing the wellbore to prevent water penetration, sealing the annulus after casing installation, addressing lost circulation zones, and plugging wells for abandonment or directional drilling
Cementing Process
Preparing The Cement
Before commencing cementing operations, it’s crucial to determine the required amount of cement and its physical properties, such as density and viscosity. This is achieved through caliper logs to measure the wellbore diameter and selecting the appropriate cement type and additives
Cement Placement
The bottom plug is introduced into the well, followed by pumping the cement slurry behind it. The float collar catches the bottom plug, allowing the slurry to enter the wellbore. Pressure is increased to rupture the bottom plug’s diaphragm, enabling the slurry to flow up the casing’s exterior
Mixing Cement
Specialized mixers combine dry Portland cement with water to create the slurry. Additives such as accelerators, retarders, lightweight or heavyweight materials, and extenders are incorporated to tailor the cement properties to specific well conditions
Completion
Once the desired volume of cement is pumped, a top plug is introduced to displace the remaining slurry and ensure proper placement. After the top plug reaches the bottom plug, the pumps are stopped, and the cement is allowed to set, forming a barrier between the casing and the wellbore