Primary cementing of production casing for cyclic-steam wells in shallow, weak formations is critical and presents several challenges. Maintaining well integrity over time is essential for project success. In addition to providing zonal isolation, a consistent, competent cement sheath minimizes buckling, parting, or elongation of casing caused by thermal stresses. Complicating factors include low formation fracture gradients, lost-circulation zones, and variable hole sizes caused by washouts. High temperatures can cause strength retrogression, and low-pH steam can cause chemical decomposition after cement placement.
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