A new technical standard has been developed for assessing the performance and physical characteristics of heavy brines used in completion, packer, and drill-in operations. This technical standard includes procedures for evaluating the density, specific gravity, clarity, amount of suspended particulate matter, crystallization point, pH, and iron contamination. It also contains a discussion of gas hydrate formation and mitigation, brine viscosity, brine crystallization at high pressures, corrosion testing, buffering capacity, and a standardized reporting form.


The American Petroleum Institute (API) has developed recommended practices (RP) for testing heavy brines. These recommended practices have been generated and documented by brine experts from industry under the auspices of API Committee 3, Subcommittee 13, Task Group 6. The first recommended practice for clear completion brines was published June 1, 1986 as "API Recommended Practice 13J Recommended Practice for Testing Heavy Brines" (RP-13J) [1]. This document contained three sections: Brine Density, Brine Crystallization Temperature, and Brine Clarity. Each section of the document was enhanced in the Second Edition[2] published March 1996. The Third Edition[3] was published December 2003 and greatly expanded the scope of RP-13J. In addition to substantially upgrading the existing sections of the document, the Third Edition added four new sections and six annex sections.

The new additions to RP-13J are titled:

  • Section 9Solids evaluation by gravimetric procedures,

  • Section 10pH,

    Section 11Iron contamination,

  • Section 12Daily completion fluid report,

  • Annex ACompletions Fluid Report Form,

  • Annex BGas Hydrates,

  • Annex CBuffering capacity of brines,

  • Annex DPressure crystallization of brines,

  • Annex EBrine viscosity, and

  • Annex FPrinciple of corrosion testing.

As we entered into the 21st Century, it became abundantly clear that recommended practices and standards needed to be globalized. Consequently, the API and authors of the Third Edition of RP-13J transformed that edition into the format required by the International Organization for Standardization (ISO). The resulting document, " Petroleum and natural gas industries- Completion fluids and materials- Part 3: Testing of heavy brines" [4] was generated and given the designation "ISO 13503–3: Testing of heavy brines" or more commonly ISO 13503–3. As of this writing, the document was being circulated in Final Draft for vote that will conclude in November 2005.

This document and its counterpart API RP-13J (3rd Edition) are "living documents" that undergo continual enhancement. By convening appropriate work groups, Task Group 6 will continue to expand and update the documents, and provide procedures and standards for new sections such as buffering capacity and pressure crystallization.

The purpose of this paper is to communicate information about the document "ISO 13503–3: Testing of heavy brines" to the oilfield industry, particularly to those engineers involved with the use and maintenance of clear completion brines.

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