Fracturing fluid systems based on the natural polymer guar, or its derivatives, crosslinked with boron or certain transition metals, such as zirconium, have become the staples of the pumping services industry worldwide. It has been estimated that in North America alone, one billion gallons of fracturing fluid were pumped in 1997. These fluid systems have been designed to operate over a wide pH range and at temperatures to 400F (about 200C) by the appropriate choice of polymer crosslinker, stabilizer and buffer. Not only has it become apparent that the same fracturing fluid composition is not suitable over such a wide range of applications, but it is also becoming increasingly apparent that seemingly identical fluid compositions yield different results.
This paper is the result of a systematic effort to demonstrate some of the reasons why seemingly identical fracturing fluid compositions may produce considerably different results, and the steps that may be taken to minimize the odds of making an undesirable choice.