ABSTRACT
The application of effective Corrosion Inhibition (CI) in Oil and Gas production is essential to enable long-term use of Carbon Steel (CS) in corrosive systems. CS as a low cost material requires proper validation of CI effectiveness to assure operational integrity. CIs change in the face of the challenges of field maturation, new recovery approaches, regulations, and new field exposures (e.g. higher H2S content). These needs have also spurred development of new test protocols. Further, to address higher integrity expectations, it has become essential to assure that field applied CI maintains effectiveness within its Integrity Operating Window (CI-IOW).
A range of CI test methods have evolved - some useful and others less so. A lack of understanding of corrosion fundamentals can introduce fatal pitfalls into both test design and protocols. No standards exist that defines the need for a CI testing program, yet proper qualification may require test points at both the boundaries and within the IOW.
Based on a combination of operational experience and in-house CI testing, methods have been developed for CI testing to ensure effective CI deployment in its IOW. The combined understanding of corrosion processes, Oil and Gas operations, and laboratory test methods have proven to be crucial for effective CI assessment and deployment. This paper provides guidance for CI testing and interpretation to assure and improve the integrity of CS applications.
INTRODUCTION
The base case for material selection in Oil and Gas production is the use of Carbon Steel (CS), even in aggressive internal corrosive production environments. This use implies, for assurance of field equipment integrity, that all relevant corrosion management issues associated with the use of CS are adequately addressed [1,2]. Corrosion inhibition (CI), both continuously and batch applied, is one of the common methods used to control internal (process) corrosion of CS in oil and gas production, transportation and processing facilities. A large number of commercial CIs are available, and new products are continuously introduced to handle new and more corrosive conditions and meet ever more stringent regulations. This document is intended to provide guidance on definition of the critical operational conditions and the use of that definition for selection and validation of CI products.
