The production of hydrocarbons from pressure-depleted zones is becoming a common practice around the world and drives the constant development and improvement of cementing technology. This paper addresses the evolution of lightweight cement slurries to ensure zonal isolation and mechanical stability of casing in highly permeable and depleted formations.

To prevent lost circulation while cementing depleted formations, a new technique has been developed based on adding inert fibers to ultralightweight slurries. During the cementing operation, the fibers create a network across the loss zone, to enable the cement to bridge off these zones and regain circulation. Also, these fibers enhance the mechanical properties of the cement as the created net provides additional stability to resist tensile stresses.

This paper discusses the challenges and solutions of developing ultralightweight slurries (without foaming) that control rheology and cement properties by the interaction of fibers and cement particle size distribution.

The paper addresses the synergies that cement slurries and inert fibers, with specific gravity values between 1.0 sg and 0.88 sg, bring to cement production casings in the Cantarell field of Mexico. The pay zone of the Cantarell field is a highly fractured, highly permeable, vuggy, and depleted Cretaceous formation that is typically drilled under total loss of circulation. The ability to reduce and prevent losses of slurry by adding this engineered fiber helps to ensure that the cement slurry is placed according to design to provide good zonal isolation and to permit completion of the new well.

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