Formulated products used in hydraulic fracturing are designed to address specific subsurface challenges during oil and gas well completion and are intended for the treatment of a myriad of issues in a wellbore; however, there are public concerns regarding the use of certain chemical ingredients in hydraulic fracturing. Public perception of hydraulic fracturing and concerns regarding water and chemical usage provide the industry with a unique opportunity to review current chemistries and water management practices with the aim being to identify more environmentally acceptable alternatives or replacements. Herein, we describe what the industry considers to be the greatest challenges, what is currently being done, and potential opportunities to provide alternatives that lead to a more sustainable industry.

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. P. 253

The polyether bridged diphosphines,(n = 1,2) have been prepared in 60-70% yield by reduction of the corresponding diphosphinedioxides with SizCls or (i-Bu)zAIH. These diphosphinedioxides have been prepared in 75-90% yield by reaction of two equivalents of the appropriatewith one equivalent of di-and triethylene glycol ditosylate.In general, reaction between the diphosphines, Rh(COD)acac and HCIO1, gives a mixture of species, cis-[Rh(COD)(P P)] [C104] being the main complex. This complex reacts with CO to q3-transuwCOHP~P)I w41.

This paper was prepared for presentation at the 1999 SPE International Symposium on Oilfield Chemistry held in Houston, Texas, 16-19 February 1999.

Me;chant, Indian Gum IndustriesLtd. -Copyrfght 1993, ScciaW c1 Petroleum ErsJi-, Ine l%is paper was ppared fcs p_esdatkm d the 199S SPE India Oil and Gas Ccmference and Exhilsition held in New Oelhi, India, 17-19 Febiuary 199S. mls pqar wassetectad fcf -Won by an SPE Progmn Ccmmttee fdlcrtmw rak%w C# Irhrnabon ccmtainad in en afxtract wt.sn Ktsd by tha authcx( s). Contents c1 tha paper, as IXUSemted, have not lSeaiI rwiewad by tfm Sm"efy d Patrdwn Er@aers and am sukjad to ccnwtian by the adhor(s). lla matertal, as prwJented does not nacaasarily raflact rny puedtcm d the Sodety of Petmlsun Er@aers, its dfii, or manbers Papers p'aaanted at SPE medngs are sukisd 10 pb!katii 'm-w by Edtwial Canmiltaes cf 6W Sceiaty cf Patroksn EWinears Eledrcmii rqwdwlion, cistn%utii, or storaga C4 any WI c# this paper fc$ canm.amaal FWPSeS witmut ths wittsm ccmsent of tha SMe4y cf Petmlmsn Eng-is prchibitad Parmiaeion to mprcska in print is ruetrided to an s&tract of not mwe than WO wwds, diust-may not ba * ma abstrad must cxxtam wrwicwwa ac+mwk@ant d wfwre end bywfwn ths papar was presanted Write Librarian, SPE, PO. 00s S3383S. RMards'al, 7x 7X833336, U. S.A., fax 01-972-952-9435. AbstractFracturing fluid systems based on the natural polymer guar, or its derivatives, erosslinked 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 Ameriea alone, one billion gallons of fracturing fluid were pumped in 1997. These fluid systems have been designed to operate over a w-de pH range and at temperatures to 400T [about 200W] by the appropriate choice of polymer, erosslinker, stabilizer and buffkr. Not only has it become apparent that the same fi-aeturing fluid composition is not suitable over such a wide range of application% 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 seeming~y identical fi-aeturing fluid compositions may produce considerably diffit results, and the steps that may be taken to minimize the odds of making an undesirable choice.