Use of tracers in drilling muds to allow the stimation of in-situ formation water compositions from drilling-mud-contaminated formation water samples

摘要

It was been proposed (e.g. Ref. 1) that formation water compositions can be calculated from drilling mud contaminated sample analyses using a simple mixing model if a tracer is added to the drilling mud. In this paper we test this proposition using field data obtained from 18 wells on the edge of the Irish Sea Basin. Our evaluation shows that, in some circumstances. it is not valid to apply the simple model to Na. Ca. Mg. K. Sr. Cl. Br and SO_4 data. Similarly, we have found that apparent mixing trends in data can be misleading and it is improtant to attempt to validate the results of contamination correction calculations by alternative methods to support formation evaluation and production operations.