One of the primary challenges of cementing and achieving effective zonal isolation is removing nonaqueous drilling fluid from the wellbore. Microdebonding of the cement sheath is a significant risk to overall well integrity, potentially leading to sustained casing pressure and health, safety, and environment (HSE) hazards. Field applications of a new fiber technology, designed with an optimized surfactant and mutual solvent package, have provided improved cement evaluation logs. Such trials also reduced or eliminated sustained casing pressure.

This novel application of fiber technology in weighted spacers ahead of cement placement has been tested and evaluated with success. Modified rheometer rotors were among several new techniques developed to identify the efficacy of these cement spacer packages. These tests provide greater insight into fiber, surfactant, and mutual solvent performance, and have been validated in the field with ultrasonic and acoustic cement evaluation log results.

Detailed laboratory analysis suggests superior effectiveness of the fiber, surfactant, and mutual solvent design. These preliminary results established the confidence to pursue a field trial on a number of development wells in an unconventional liquids play.

Cement evaluation logs confirmed that the new technique successfully reduced microdebonding. Additionally, sustained casing pressure was significantly reduced, indicating that the log response correlates to a tangible improvement in well integrity.

The novel use of fiber technology considerably improves the surface cleaning effectiveness of cement spacer package. Additionally, new laboratory testing procedures enhance our understanding of surfactant package function. Successful laboratory results were validated by field applications that reduced the microannulus in sample wells and minimized sustained casing pressure.