Phosphonate Speciation - Challenges and Solutions

As the oil and gas industry continues to operate in more complex and deeper water environments downhole scale control via scale squeeze treatments becomes an ever-increasing technical challenge. It is therefore essential that effective scale management strategies are adopted which incorporate suitable scale inhibitor (SI) selection, analysis and treatment design procedures to provide optimal and cost-effective squeeze treatment lifetimes to maximise oil production and reduce well intervention costs. In this paper key factors are evaluated in order to provide a guidance to selecting a suitable treatment strategy for downhole scale control in co-mingled sub-sea well and the impact of chemical retention, minimum inhibitor concentration (MIC), limit of quantifiable detection (LOQD) and well dilution factors on treatment design and strategy are discussed. The pros and cons of different treatment strategies are presented in this paper and consideration is given to following three treatment strategies: Treating all wells with the same chemical and over designing the chemical treatment lifetime ie 18 months and then re-treating all wells after 12 months;Treating individual wells with tagged versions of the same scale inhibitor chemical;Treating individual wells with different scale inhibitors. Options (ii) and (iii) offer the ability to design similar treatment lifetimes for each well but have the flexibility to monitor wells individually and re-squeeze when required. Examples are provided for treatment options (ii) and (iii) based upon a field example to illustrate the design concepts for fluorescent (F) and phosphorus (P) tagged polymers in two co-mingled wells and a theoretical example for treating three co-mingled wells with different scale inhibitors, one of which could be a phosphonate with two tagged polymers. This paper presents an overview of the key factors that influence chemical selection and treatment design for co-mingled wells in the same flow line. In addition, it will highlight important concepts to provide guidance for the design of effective treatment strategies for squeezing co-mingled wells in sub-sea and deepwater environments.

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Application of Advanced Fluorescence Detection Technology to Improve Scale Management in Both Conventional and Sub-Sea Fields

Heath

Toivonen

Vuori

et al. 2019

SPE International Conference on Oilfield Chemistry

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Scale inhibitor (SI) analysis is an extremely important part of scale management and, in recent years, much work has been done on the development of specialist scale inhibitor analysis techniques like Liquid Chromatography Mass Spectroscopy (LCMS) to push the boundaries of low level scale inhibitor detection. However, LCMS requires costly and complex instrumentation and there was therefore still a need for the development of other advanced techniques like fluorescence (F) and Time resolved Fluorescence (TRF) that can be used on site to provide near "on line" data. Fluorescence techniques are particularly suited to tagged polymers and naturally fluorescent molecules like polyamines whereas the operation principle of TRF is based on interactions between lanthanide ions and various functional groups of polymer or phosphonate scale inhibitors. Both techniques work individually or in combination and this provides a distinct advantage for multiple scale inhibitor analysis in produced brines that enable the design of packages of different products for specific field applications. In addition, TRF and fluorescence techniques offer the capability of on-site detection compared to the majority of scale inhibitor analysis techniques and other advanced methods like LC-MS. The ability to detect both phosphonate and polymeric scale inhibitors at very low MIC (<1ppm) has the potential for significantly extending scale squeeze lifetimes. This has now also allowed highly efficient, F tagged polymers, to be used in field situations where scale squeezing was either stopped or the lifetime was significantly compromised because of the lack of confidence in the residuals analysis. Specific field and theoretical examples from both sub-sea and conventional wells will be presented where the application of both advanced fluorescence and TRF techniques has shown significant improvements in scale management. This paper will compare and contrast the pros, cons and limitations of both fluorescence and TRF techniques for both phosphonate and polymeric scale inhibitors. In addition, it will highlight examples where scale management significantly improves through the application of Fluorescence and/or TRF scale inhibitor analysis techniques in complex production scenarios.

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Phosphonate Speciation - Challenges and Solutions

Cited by 7 publications

References 17 publications

Combining advanced oxidation principles and electrochemical detection for indirect determination of phosphonate in scale inhibitors employed in the oilfield

Combining advanced oxidation principles and electrochemical detection for indirect determination of phosphonate in scale inhibitors employed in the oilfield

Strategies for Squeezing Co-Mingled Wells in the Same Flow Line in Sub-Sea and Deepwater Environments - Guidelines for Scale Inhibitor Selection and Effective Treatment Strategies and Design

Application of Advanced Fluorescence Detection Technology to Improve Scale Management in Both Conventional and Sub-Sea Fields

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