Low residue well treatment fluids and methods of use
View Patent ↗A low residue well treatment fluid comprises: an aqueous solvent; a gelling agent comprising one or more modified polysaccharides, the modified polysaccharides having hydrophilic groups; and a crosslinking composition. The fluid may optionally further comprise a gel breaker, a buffer and/or a proppant. The fluids generate no or minimal residue upon being broken, and are particularly useful in well fracturing operations.
1. A well treatment fluid comprising:
an aqueous solvent;
a gelling agent comprising one or more modified polysaccharides, said modified polysaccharides having amphoteric hydrophilic groups selected from the group consisting of alkanolamides, alkyl betaines and sultaines; and
a crosslinking composition.
2. The well treatment fluid of claim 1 wherein the aqueous solvent comprises fresh water, salt water, seawater, natural brine or synthetic brine.
3. The well treatment fluid of claim 1 wherein the one or more modified polysaccharides are modified from one or more polysaccharides selected from the group consisting of guar gum, locust bean gum, tara gum, karaya gum, arabic gum, ghatti gum, tragacanth gum, hydroxypropylguar (HPG), carboxymethylguar (CMG), carboxymethylhydroxypropylguar (CMHPG), a carboxyalkyl cellulose ether, a carboxymethyl hydroxyethyl cellulose (CMHEC), a hydroxyalkyl cellulose, a hydroxyalkylalkyl cellulose, an alkylalkyl cellulose, an alkylcarboxyalkyl cellulose, an alkyl cellulose and an alkylhydroxyalkyl cellulose.
4. The well treatment fluid of claim 1 wherein the gelling agent is present at about 0.12% weight % to about 0.48% weight % based on the total weight of the aqueous solvent.
5. The well treatment fluid of claim 1 wherein the crosslinking composition comprises one or more crosslinking agents, and wherein said one or more crosslinking agents are selected from the group consisting of boric acid, boric oxide, pyroboric acid, metaboric acid, borax, sodium tetraborate, pentaborate, titanium dioxide, zirconium oxychloride, zirconium lactate, zirconium glycolate, zirconium lactate triethanolamine, zirconium acetylacetonate, titanium citrate, titanium malate, titanium tartrate, a titanium chelate and a zirconium chelate.
6. The well treatment fluid of claim 1 wherein the crosslinking composition comprises zirconium, titanium or mixtures thereof.
7. The well treatment fluid of claim 1 wherein the crosslinking composition is present at about 0.05 weight % to about 0.6 weight % based on the total weight of the aqueous solvent.
8. The well treatment fluid of claim 1 further comprising one or more components selected from the group consisting of a gel breaker, a buffer, a proppant, a clay stabilizer, a gel stabilizer, a surfactant and a bactericide.
9. The well treatment fluid of claim 1 further comprising a gel breaker selected from the group consisting of ammonium persulfate, sodium persulfate, sodium bromate and sodium chlorite.