Carlos M. Menendez

Assessment of Corrosion Under Iron Sulfide Deposits and CO2/H2S Conditions

The presence of surface deposits, such as sand, iron sulfide, or organic solids, in oil and gas production systems can lead to premature failure of fluid-handling equipment. When corrosion occurs u...

In Situ Assessment of Pitting Corrosion and Its Inhibition Using a Localized Corrosion Monitoring Technique

Abstract Pitting corrosion of pipelines remains a serious concern to operators in the oil and gas industry. Pitting is a particularly insidious and extremely rapid form of attack of a metal structu...

Film persistency of new high-temperature water-based batch corrosion inhibitors for oil and gas wells

Water-based corrosion inhibitors, in addition to providing improved performance, offer several other advantages over oil-based corrosion inhibitors, such as better water-partitioning characteristics, high flash points, and higher reportable quantities if a spill occurs. We have found in several instances that new water-based corrosion inhibitor products provide longer treatment lives and better protection than similar inhibitors in oil-based formulations. Corrosion inhibition in high-temperature (HT) oil and gas wells has been frequently accomplished using oil-based corrosion inhibitors. This paper presents some earlier laboratory work and field performance data on new water-based corrosion inhibitors relative to conventional oil-based HT corrosion inhibitors. A laboratory investigation using white light interferometry is also presented on the film thickness and uniformity measurements of corrosion inhibitor films. This information is compared with field performance of the corrosion inhibitor.

Obtaining Batch Corrosion Inhibitor Film Thickness Measurements Using an Optical Profiler

Abstract Batch corrosion inhibitors are used widely for the corrosion control of production wells and pipelines in the oil and gas industry. Rules of thumb that incorporate film thickness, contact time, and surface area are still commonly used to calculate the volume of batch inhibitor required for pipeline applications. Measuring the actual thickness of the inhibitor film on the metal and the impact of different variables on the film (e.g., inhibitor type, contact time, diluent type, dilution ratio, shear stress) offer the potential to provide a better understanding for optimizing the application procedure and required batch frequency. Optical profiling (or white-light interferometry) has long been a standard technique for noncontact, three-dimensional (3-D) measurement of surface topography. This method now has been extended to thickness measurements of semitransparent batch inhibitor films. In this paper, the impact of several variables (i.e., inhibitor type, contact time, diluent ratio, shear stress) ...

New Sour Gas Corrosion Inhibitor Compatible with Kinetic Hydrate Inhibitor

The presence of hydrogen sulfide in high pressure gas systems causes several complications. Sour gas corrosion is a major concern in the oil and gas industry due to the presence of localized corrosion. At high pressures and low temperatures hydrates can occur. Sour gas decreases the pressure and increases the temperature at which hydrate formation occurs. Operators have used both corrosion inhibitors and kinetic hydrate inhibitors to decrease the capital requirements of developing sour high pressure gas systems. The development of sour gas corrosion inhibitors that are compatible with kinetic hydrate inhibitors is a major requirement for qualifying corrosion inhibitors for these applications. This paper describes laboratory work on the development of a new corrosion inhibitor by performing various performance and compatibility tests with kinetic hydrate inhibitor. The new corrosion inhibitor needed to meet various additional requirements which made the development process even more complex. The partitioning of a corrosion inhibitor between the oil and water phases has a significant impact on inhibitor selection and treatment strategy. General corrosion performance was addressed using mass loss and electrochemical data. Evaluation of localized attack was performed using vertical scanning interferometry (VSI). The main advantage of this approach is in providing quantitative data for product performance differentiation in the presence of localized corrosion.

Cathodic Protection Requirements for Deepwater Systems

Field and laboratory experience related to requirements for cathodic protection (CP) in deep water are reviewed with emphasis on identification of the major variables that need to be specified for successful deepwater CP designs for offshore structures. The subject is addressed based on the historical development of cathodic protection design methodologies for offshore structures focusing on sacrificial anode systems and trends that have resulted in specific changes in design requirements. Three main subjects are discussed: (1) application of existing industry standards such as NACE RP0176; (2) environmental factors - dissolved oxygen, temperature, salinity, pH, water velocity and fouling; and (3) calcareous deposits - difference between shallow and deep waters. Current practice of design criteria and systems for deepwater applications is assessed, including initial polarization, use of coatings and anode materials. The results from laboratory tests are compared with available documented service experiences and field tests results.