Optimization of Lead Cement Slurry for Use on Utica Deep Intermediate Casing Strings

Abstract

The depth of the Utica formation poses many challenges during drilling operations. In Belmont, Jefferson, and Monroe counties of Ohio, lateral sections are often drilled with mud weights from 13.5 to 15.5 lb/gal. To support these mud weights, the various loss and flow zones encountered above the pay zone must be isolated by a deep intermediate casing. This paper describes the process of optimizing a cement slurry that is light enough to be circulated to surface in a single stage but also has additional properties to ensure that the potential corrosive formations are properly isolated and the casing has long-term protection from damage. The process compares the properties of four cement slurries in the 12-to-12.5lb/gal density range. Conventional tests were performed on each slurry (thickening time, free fluid, fluid loss, and compressive strength). Linear expansion tests determined whether the slurries would be capable of providing a long-term seal, against both formation and casing, to mitigate gas migration and annular pressure buildup. In addition, the team performed initial permeability tests for each slurry. Single-stage jobs were executed using three of the four newly formulated slurries, and this paper presents the success of those jobs as well.