fluid, then the injection masses of 2 600 and 18 300 kg equate to 0.26 ML and 1.8 ML of fluid, respectively. Typical classes of chemicals used in drilling and hydraulic fracturing and their functions are shown in Table 2.1. Table 2.1 A typical listing of chemicals used in drilling and hydraulic fracturing for coal seam gas recovery Type Function Additive Proppant seam fractures open to allow Sand, sintered bauxite, zirconium gas/fluids to flow more freely to the well oxide, ceramic beads Clay stabiliser Prevents clay swelling and improve Calcium chloride, calcium chloride the cement/formation bond anhydrous, potassium chloride Cement Enhances strength of the well Bentonite, calcium sulfate additive pH control Adjusts the pH of the in order to Sodium hydroxide, potassium maximise the effectiveness of other hydroxide, calcium hydroxide, citric additives acid, sodium bicarbonate, sodium carbonate, potassium carbonate, acetic acid Bactericides Inhibits growth of bacteria in the wells Sodium hypochlorite, that interfere with hydraulic fracturing tetrakis(hydroxymethyl phosphonium fluid chemistry and may restrict gas flow sulfate, glutaraldehyde, sodium hypochlorite Viscosity Thickens the fracturing allowing the Bentonite, polyanionic cellulose, control fluid to carry more proppant into the carboxymethyl cellulose, hydroxyethyl fractures. cellulose, synthetic polymers, guar gum Gel To maintain gel stability Borate salts, monoethanolamine, and ethylene glycol, potassium hydroxide stabilisers Gel breakers To break down gel for return to the Sodium persulfate, hemicelluloses surface enzyme, t-butylhydroperoxide Mineral To dissolve clay minerals Hydrochloric acid, acetic acid dissolution Iron To prevent iron precipitation Citric acid complexation Corrosion To prevent pipe corrosion N,N’-dimethyl formamide, gelatine, inhibitors methanol, ammonium bisulfate Scale To prevent scale formation Ethylene glycol, ammonium chloride inhibitors Friction To reduce surface tension 2-butoxy ethanol, isopropyl alcohol, reducers terpenes and terpenoids, sweet orange oil, polyacrylamides loss Fluid loss control Modified polyacrylates, Lignosulfonates, Resins, Starch,
fluid, then the injection masses of 2 600 and 18 300 kg equate to 0.26 ML and 1.8 ML of fluid, respectively. Typical classes of chemicals used in drilling and hydraulic fracturing and their functions are shown in Table 2.1. Table 2.1 A typical listing of chemicals used in drilling and hydraulic fracturing for coal seam gas recovery Type Function Additive Proppant seam fractures open to allow gas/fluids to flow more freely to the well Sand, sintered bauxite, zirconium oxide, ceramic beads Clay stabiliser Prevents clay swelling and improve the cement/formation bond Calcium chloride, calcium chloride anhydrous, potassium chloride Cement additive Enhances strength of the well Bentonite, calcium sulfate pH control Adjusts the pH of the in order to maximise the effectiveness of other additives Sodium hydroxide, potassium hydroxide, calcium hydroxide, citric acid, sodium bicarbonate, sodium carbonate, potassium carbonate, acetic acid Bactericides Inhibits growth of bacteria in the wells that interfere with hydraulic fracturing fluid chemistry and may restrict gas flow Sodium hypochlorite, tetrakis(hydroxymethyl phosphonium sulfate, glutaraldehyde, sodium hypochlorite Viscosity control Thickens the fracturing allowing the fluid to carry more proppant into the fractures. Bentonite, polyanionic cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, synthetic polymers, guar gum Gel and stabilisers To maintain gel stability Borate salts, monoethanolamine, ethylene glycol, potassium hydroxide Gel breakers To break down gel for return to the surface Sodium persulfate, hemicelluloses enzyme, t-butylhydroperoxide Mineral dissolution To dissolve clay minerals Hydrochloric acid, acetic acid Iron complexation To prevent iron precipitation Citric acid Corrosion inhibitors To prevent pipe corrosion N,N’-dimethyl formamide, gelatine, methanol, ammonium bisulfate Scale inhibitors To prevent scale formation Ethylene glycol, ammonium chloride Friction reducers To reduce surface tension 2-butoxy ethanol, isopropyl alcohol, terpenes and terpenoids, sweet orange oil, polyacrylamides loss Fluid loss control Modified polyacrylates, Lignosulfonates, Resins, Starch,
technical-report-number-01-lit-rev-summary-report.docx