Oil-based mud and centralization limitations result in mud channeling
A Permian Basin operator drills long horizontal wells with 10,000-ft laterals to accommodate multistage plug-and-perf completions with hydraulic fracturing. The operator is concerned about the possibility of zone-to-zone fracture communication behind the casing if cement bond quality is inadequate.
Moreover, diesel-based muds that are commonly used in the Permian Basin for horizontal sections complicate the ability of conventional cements to achieve optimal zonal isolation. To mitigate the mud challenge, the operator uses industry-recognized cementing best practices: running casing with at least one centralizer per joint for good standoff, pumping spacers with surfactants ahead of cement, and optimizing cement placement using CEMENTICS zonal isolation software models to ensure that the rheological parameters optimize mud removal.
Still, the cement BI for the operator’s wells is lower than ideal, often falling in the range of 0.5 to 0.6. The operator tried rotating and reciprocating the casing to improve mud removal, but this operation is limited in use due to safety and logistics concerns.
To optimize zonal isolation and cement bonding without adding operational complications and costs, the operator asked Schlumberger for a new solution.
