Cement Bond Evaluation

The main purpose of cementing over a producing interval is to provide hydraulic isolation between neighboring zones. Hydraulic isolation prevents fluid movement into or from neighboring zones through the borehole behind casing.

Poor cementing often results in and can be identified in cases of:
• Water production or water flow behind pipe
• Depletion of gas drive mechanism allowing gas percolate into the casing annulus causing high pressure which can endanger the well
• Loss of production to neighboring zones
• Contamination of fresh water sands causing pollution of ground water
• Channeling in bonds without cement providing a path for fluid migration.

After cementing, it is important to evaluate the integrity of the cement bond. Our cement evaluation technologies measure the loss of acoustic energy as it propagates through casing. The logs produced are used to;
• evaluate the strength of the hydraulic seal
• determine cement coverage
• determine isolation between producing and non producing zones and
• locate cement top and determine zones that would require remedial cementing

Pulsed Acoustic Cement Evaluation (PACE):

Acoustic cement evaluation provides a range of options from a basic to a complete Cement Bond Logging service. Using this super sound technology; high frequency acoustic pulse is transmitted from a piezoelectric transmitter out to the casing at regular intervals. As the sound travels through the borehole fluid, it links up to the casing and travels along it before returning through the borehole fluid back to the receiver. Some of the signal passes through the casing into the cement, and into the formation before it is returned. The segmented receiver 3ft from the transmitter detects the early part of the returning signal to determine the casing-cement bond. While the 5ft receiver detects the latter part of the signal from which the VDL is gotten evaluating the cement-formation bond.
Evaluate the Cement Bond Log
• Investigate Channeling
• Evaluate gravel packs and
• Thru-tubing or casing capacity.