Chemical Systems Engineering

SPE 125785 - Effect of THPS on Discharge Water Quality: A Lessons Learned Study

2010 Abstract, Karthik Annadorai, SPE; Adam Darwin, GATE, LLC

Biocides typically have an adverse impact on overboard water. THPS (tetrakishydroxymethyl phosphonium sulfate), one of the most commonly used biocides offshore has a similar effect on produced water. The effect of THPS on seawater used for hydrotesting and bulk storage is seldom studied and rarely documented. The effect of temperature, pH, water depth, dissolved oxygen concentration and various ions in the system is important to note. Once a certain volume of water is treated with any chemical, it is now deemed to be chemically treated seawater which cannot be discharged unless verified using the NOEC (No Observable Effect Concentration) testing method.

This experience will provide a detailed understanding of the discharge of chemically treated seawater as well as the interaction of THPS with potential ions in the matrix. Additionally, regular sampling and associated analyses will be presented that demonstrate the degradation and half-life of the THPS molecule in varying temperatures.

Periodic sampling of the THPS chemical in the seawater has provided a detailed understanding of the half-life degradation of the chemical. The interaction of the chemical with the cations present in the system and subsequent aversion to the neutralization reaction with hydrogen peroxide has also been studied and presented.

Source: SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, 12-14 April 2010, Rio de Janeiro, Brazil

Copyright 2010. Society of Petroleum Engineers

NACE 10401 - Prevention Of Corrosion In Carbon Steel Pipelines Containing Hydrotest Water - An Overview

2010 Abstract, Adam Darwin, Karthik Annadorai, Gibson Applied Technology and Engineering, LLC; Krista Heidersbach, Chevron Energy Technology Center

A critical step in proving a pipeline is fit for operational use is the hydrostatic test, in which it is filled with water and pressurized to 125% of its Maximum Allowable Operating Pressure (MAOP). The water that is used in this testing can cause corrosion of the pipe, potentially leading to failure early in its operating life. Failures have occasionally been reported even before a pipeline enters service.

The most common mechanisms by which carbon steel pipelines may undergo corrosion on exposure to hydrotest water are Microbially Induced Corrosion (MIC), oxygen-related corrosion, galvanic corrosion and under-deposit corrosion. An overview of these mechanisms is presented, along with a discussion of the influence of different environmental factors on them. Factors considered include water source, degree of filtration, exposure period and temperature, air pockets, presence of internal pipe coatings and future pipeline service conditions.

Maintaining the risk of pipe corrosion from hydrotest water within acceptable limits is discussed. Factors considered are:

How long the untreated water may be allowed to be present in the pipeline.

Should water treatment be required, what must be used?

Disposal requirements for the treated water, including chemical treatments.

Source: CORROSION 2010, March 14 - 18, 2010 , San Antonio, TX

Copyright 2010. NACE International

SPE 110205 - Successful Application of Chemical Injection Rate Control Valves

2007 Abstract, H.J. Duhon, SPE, and K.M. Annadorai, SPE, Gibson Applied Technology and Engineering

This paper presents an overview of a systems approach to the design and troubleshooting of IRCVs (Injection Rate Control Valves) used in deepwater chemical injection systems.  The inherent problems associated with these simple flow regulators stem largely from the failure of design engineers to take a systems view in design.  Along with the application of lessons learned from previous IRCV system failures, this systems approach provides a design method which will allow users to avoid many of the pitfalls inherent in design, installation, testing, commissioning and operation of IRCV systems.

Source: SPE Annual Technical Conference and Exhibition, 11-14 November 2007, Anaheim, California, U.S.A.

Copyright 2007. Society of Petroleum Engineers

NACE 05633 - The Impact of Reservoir Souring upon Decision Processes Made During the Design of New Deepwater Developments

2005 Abstract, Lee C. Jordan, Justin P. Landry, Howard Duhon, and Grant T. Gibson, GATE LLC

This paper presents an overview of the impact of potential future reservoir souring and associated H2S production on the design decisions that must be made during the development of a deepwater production asset. The problem is inherently one of decision making under uncertainty, as determination of the likely magnitude of reservoir souring is a process requiring review of a large number of variables and the application of predictive techniques of limited accuracy. This paper reviews some of the practical uncertainties involved in predicting souring and identifies how these subsequently impact design and operability issues. By exhaustively identifying design objectives in the form of an objectives map it is possible to assess the impact of souring on all aspects of the design. Best practice approaches to risk management and mitigation are also presented in relation to the design of both water injection and production facilities.

Source: CORROSION 2005, April 3 - 7, 2005 , Houston, Tx

Copyright 2005. NACE International