Specially Tailored Reservoir Drill-In Fluid and Acid Precursor Technology with Applicability in Ultra Deepwater Gulf of Mexico Wells

Abstract

The Gulf of Mexico (GoM) presents an array of complex challenges, including ultra-deepwater depths, narrow pressure window environments, low permeability, and elevated temperature zones. Operators in the GoM frequently experience highly reactive, unstable shales while drilling long, heterogenous open hole lateral wells. While traditional Reservoir Drill-in Fluids (RDF) and breakers are well known for use in production wells, the filter cake cleanup can often be non-uniform, corrosive to completion assemblies, and result in variable drawdown. This disparity in pressure drawdown across the reservoir section can ultimately result in the creation of positive skin damage. Injector wells offer a more extreme scenario in comparison to production wells because no flowback occurs, which can make it more difficult to deliver sustainable uniform injection. The solution to these challenges lies in the development of RDF and breakers specifically tailored to provide uniform, time delayed coverage, minimal corrosivity, and effective removal of the RDF filter cake. In order to successfully maximize injection and maintain performance for the scope of the field life, an RDF was customized in tandem with an optimized, delayed-release filter cake breaker to limit formation damage and provide complete uniform filter cake removal. This paper will discuss how the learnings from Eastern Hemisphere operational activities directed at optimizing treatment designs for more difficult injector wells can be tailored for efficient use in the GoM. Results from laboratory testing and global field applications of the new RDF and breaker designs will be presented, as well.