About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 89, No. 8 (August 2005), P. 1005-1018.

Copyright copy2005. The American Association of Petroleum Geologists. All rights reserved.

DOI:10.1306/03100504040

Chlorine isotope residual salt analysis: A new tool to investigate formation waters from core analyses

V. Wouleacute Ebongueacute,1 N. Jendrzejewski,2 F. Walgenwitz,3 F. Pineau,4 M. Javoy5

1Laboratoire de Geacuteochimie des Isotopes Stables, Institut de Physique du Globe, Universiteacute Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France
2Laboratoire de Geacuteochimie des Isotopes Stables, Institut de Physique du Globe, Universiteacute Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France
3Total, Centre Scientifique et Technique Jean-Feacuteger, Avenue Larribau, 64018 Pau Cedex, France
4Laboratoire de Geacuteochimie des Isotopes Stables, Institut de Physique du Globe, Universiteacute Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France
5Laboratoire de Geacuteochimie des Isotopes Stables, Institut de Physique du Globe, Universiteacute Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France

ABSTRACT

This article presents the first results of chlorine residual salt analysis (Cl-RSA), a new technique that allows investigation of the isotopic composition of chlorine in oil-field waters from core analysis. As water evaporates, the residual salts precipitate in the pores of a core. Unlike the routinely used strontium isotope residual salt analysis (Sr-RSA) technique, which determines the composition of a trace element (strontium), the Cl-RSA technique allows the determination of the isotopic composition and origin of one of the most abundant anions in natural waters. The results show that combining the delta37Cl of two successive leachates of a core sample leads to an isotopic composition that is representative of pore water. The reproducibility of the method applied to sandstone samples is considered to be plusmn0.05permil. The Cl-RSA technique was tested on two wells from the Elgin area (North Sea, United Kingdom). The delta37Cl results in formation waters range from minus1.03 to minus0.57permil, with an overall increase with depth. These results have been compared to the 87Sr/86Sr ratios of pore waters determined in the same wells using the Sr-RSA technique. The similarity of form between the delta37Cl and 87Sr/86Sr profiles with depth confirms that residual salts permit a reliable investigation of the chlorine isotopic composition from core analysis. As with the Sr-RSA technique, Cl-RSA could be used to test the isotopic homogeneity of a sample and to assess the compartmentalization of oil fields and reservoirs. This technique could provide key information regarding the origin of the salinity and its evolution during the reservoirs' filling, as well as help in the monitoring during field production.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].