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Technical Paper: High-Impact-Resistant Cement Allows Challenging Sidetrack in Abu Dhabi

Society: SPE
Paper Number: 100827
Presentation Date: 2006
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Abstract

The process of sidetracking an existing borehole with a balance cement plug has historically been time consuming and problematic for the drilling industry. The formations in the Middle East are classified as some of the most competent formations in the industry. These formations present its own challenges when attempting to sidetrack because of changes in the drilling trajectory. Historically, the operator has faced problems sidetracking in the Shilaif formations, where longer drilling time and/or numerous cement plugs are required to achieve this objective. These requirements lead to an increased in drilling costs.

Traditionally, a conventional cement system with a high compressive strength is used for sidetracking purposes. However, these cement systems have low resistance to impact and shock and hence will fail through rupture when placed across the competent formations. An optimized particle sized distribution cement system, combined with engineered metallic micro ribbon technology has allowed the sidetracking to be achieved efficiently.

The technology improves the durability and the resistance of the cement to load bearing capacity and fracture propagation. Further laboratary testing comparisons have confirmed the enhanced mechanical properties of this cement system. As a rule of thumb, the industry relied on the rate of penetration (ROP) as an indicator of how good a cement plug is for sidetracking purposes. It is believed that the lower the ROP is, the easier the sidetrack can be achieved.

As the technology is "tougher" than the formations, the drilling bottom hole assembly (BHA) can be deflected/ sidetracked efficiently and drilling operations resumed, in a shorter period of time compared to using conventional cement systems.

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