Forming drilling fluid from produced water

A method of generating calcium bromide in solution in water from produced water for a drilling fluid having the calcium bromide, the method comprising:

• flowing the produced water through a bed of resin comprising bromine-specific ion-exchange resin, wherein the produced water comprises produced water discharged from a subterranean formation;
• sorbing bromide ions from the produced water onto the resin;
• giving the calcium bromide in solution in water via regenerating the resin with regenerant, the regenerant comprising calcium cations and the water, wherein regenerating the resin with the regenerant comprises flowing the regenerant through the bed of resin;
• discharging the calcium bromide in solution in the water from the bed of resin;
• and
• concentrating the calcium bromide in the water to give the water concentrated in the calcium bromide in solution for the drilling fluid having the calcium bromide in solution.

A method of generating calcium bromide in solution in water from produced water for a drilling fluid, the method comprising:

• operating in a first mode comprising sorbing bromide ions from the produced water onto ion-exchange resin in a vessel;
• operating in a second mode comprising:
• regenerating the ion-exchange resin in the vessel with regenerant comprising calcium cations and water, wherein the regenerating comprises releasing the bromide ions from the ion-exchange resin into the water in the vessel;
• forming the calcium bromide in solution in the water in the vessel, the calcium bromide comprising the bromide ions released into the water from the ion-exchange resin and the calcium cations;
• discharging the calcium bromide in solution in the water from the vessel;
• and
• concentrating the calcium bromide in solution in the water for the drilling fluid comprising the calcium bromide in solution in the water.

A method of generating calcium bromide in solution in water from produced water for a drilling fluid, the method comprising:

• receiving the produced water discharged from a subterranean formation;
• subjecting the produced water to ion exchange comprising sorbing bromide ions from the produced water onto ion-exchange resin and desorbing chloride ions from the ion-exchange resin into the produced water;
• regenerating the ion-exchange resin comprising desorbing bromide ions from the ion-exchange resin into water and sorbing chloride ions from the water onto the ion-exchange resin, wherein regenerant employed in the regenerating comprises calcium chloride and the water;
• and
• giving the calcium bromide in solution in the water via the regenerating, the calcium bromide comprising calcium ions from the calcium chloride and the bromide ions as desorbed from the ion-exchange resin into the water.

A calcium-bromide drilling-fluid production system, comprising:

• a first vessel to store produced water from a subterranean formation;
• a pump to provide the produced water from the first vessel to a second vessel comprising a bed of ion-exchange resin that is bromine-specific ion-exchange resin;
• the second vessel having the bed of ion-exchange resin to sorb bromide ions from the produced water onto the ion-exchange resin and desorb anions from the ion-exchange resin into the produced water and discharge the produced water, wherein the second vessel to receive regenerant comprising calcium cations and water to regenerate the ion-exchange resin to desorb bromide ions from the ion-exchange resin into the water to form calcium bromide in solution in the water with calcium ions from the regenerant and the desorbed bromide ions;
• and
• a processing system comprising a third vessel to receive the calcium bromide in the water to concentrate the calcium bromide in solution in the water to give the water concentrated in the calcium bromide for a drilling fluid comprising the calcium bromide.