Can you speak about cement bondlog CBL?

As discussed above, the CBL is called the Cement Bond Log. This is the log which is recorded before any perforation is performed in the well.

To discuss few important things regarding CBL, The CBL examines the bond between the Casing and the Cement. There should be a perfect isolation from the water bodies / water bearing zones.

CBL also provides us a perfect assessment of the Cementing, if not done properly, cement squeeze job can be planned accordingly.

After satisfactory report on CBL, the well can be perforated and production can be started from the well.

Cement plugs are used for various reasons, including

• Solving a lost-circulation problem during drilling operations by spotting a cement plug across the thief zone and then drilling back through the plug;
• Plugging a zone or abandonment of a well by sealing off selected intervals, a dry hole or a depleted well;
• Sidetracking or to initiate directional drilling to help guide the drill bit in the desired direction;
• Provide an anchor for an openhole test, particularly when the zone to be tested is significantly off bottom
• Other remedial work

Proper cement placement between the well casing and the formation is essential:

• To support the casing (shear bond)
• To prevent fluid from leaking to the surface
• For isolating producing zones from water-bearing zones (hydraulic bond)

more info check this website :

http://petrowiki.org/Cement_bond_logs