Various inhibitive additives are used during drilling in the Vankor deposit to stabilize the clay slate, such as Polyacrylamides, Acrylic polymers, inorganic Silicates, Asphaltens and Glycol mixtures. These reagents are used in aqueous slurries to help drill surface casing and process and extract columns.
Complex drilling conditions related to well trajectory, increased penetration speed, and increased rate of locating an instrument at the bottom hole continue to warrant the search for improved tools to better penetrate wells, increase wall stability, and optimize the drilling slurry process. For such reasons, it was decided to perform an industrial test on a new compositional inhibitor with a secondary function as a lube additive and microsealant.
The service company proposed (and the operator supported) compositional inhibitor testing consisting of a dissolved sulfur asphalten mixture in glycol in certain proportions specially developed to increase the efficiency of inhibitive properties and the multifunctionality of an additive.
The testing was applied in a complex well (168° along the azimuth, horizontal projection length of 1,771 m, and a penetration angle of unstable argillites at 63.5°) to help demonstrate the technical efficiency of the new reagent (full dispersion in the aqueous drilling fluid, reduced processing time, and improved productivity of the treatment system) and the practicality of launching it (reduction/replacement of single-component inhibitors) in industrial volumes within Vankor field wells.