Raising Frac Limits: The Stress Caging Approach

Abstract

The Dilemma of Limestone Formations is their temperamental nature. The same conductivity that threatens with Loss also promises production and at the same time deceives log outputs. Presence of conductive fractures is characteristic of these carbonates and even if the operator does drill past these thief zones via controlled drilling ECDs and LCM loaded systems, the hazard is never eliminated. One of the poorest timing for this menacing loss to resurface is during cementing of these reservoir carbonate sections, when ECDs tend to rise as soon as the cement slurry dares rise above the loss zone. Conventional LCMs are not the candidate for formation strengthening and cementing every loss zone can be rather tiresome for the drilling time-depth curves, not to forget damaging to the reservoirs. So, the approach to case these conductive carbonates while maintaining their conductivity remains a work in progress for the cementing technical community. This paper suggests not to merely drill through or fight against the loss but to mould the formation properties to operator's requirements. The stress caging technique may be one of the key puzzle elements to strengthen fractured limestones and their successful cementing.