Clear Brine Fluids – Formate
When your data suggests that extraordinary conditions may exist in a well or producing zone, TETRA will specially formulate a completion fluid to address individual formation properties that help maximize well productivity.
One type of special brine solution is formate. Formate brines are monovalent and are produced from organic formic acid. Formic acid is reacted with sodium hydroxide, potassium hydroxide, or cesium hydroxide to produce solids free sodium formate, potassium formate, and cesium formate brine. Formate brines are not compatible with halide brines.
Single Salt Formate Blends
Single salt formate fluid blends are brines composed of only one salt. Densities typically range from slightly above the density of water such as 8.4 ppg sodium formate solution to 19.2 lb/gal cesium formate solution.
Sodium Formate (NaCOOH)
Used in solution as a solid-free completion fluid, where densities of 8.4 to 11.0 lb/gal are required. When properly formulated sodium formate can possibly reduce formation damage because of swelling and dispersion of reservoir clays.
Potassium Formate (KCOOH)
Potassium formate fluids can reach a density of 13.1 ppg at saturation. Potassium formate brines are very inhibitive in not allowing reservoir shales to hydrate, migrate, and/or swell thus preventing formation damage or hole stability issues when used as a reservoir drilling fluid. In addition saturated potassium formate is very lubricious and provides excellent hydrate inhibition. At higher temperatures, potassium formate can also dissolve barium sulfate.
Cesium Formate (CsCOOH)
Cesium Formate is used when fluid densities above 13.2 lb/gal or needed. The maximum density for cesium formate is 19.2 lb/gal.
Multi-salt blends are composed of two or more formate brines. The reason the brines are blended is to achieve the desired density and true crystallization temperature (TCT)/pressurized crystallization temperature (PCT) (TCT/PCT) at the lowest cost. Although not economic, sodium, potassium and cesium formate can be blended together.
Potassium Formate/Sodium Formate (KCOOH/NaCOOH) Blend
Sodium and Potassium Formate brines can be blended in densities from 11.0 lb/gal to 13.1 lb/gal. Blends lower than 11.0 lb/gal are made when lower TCTs are needed and/or additional shale inhibition is required.
Cesium Formate/Potassium Formate (CsCOOH)/ KCOOH) Blend
Potassium and Cesium Formate brines can be blended in densities from 13.1 lb/gal to 19.2 lb/gal. The fluids are blended to achieve the required density and TCT/PCT. Blending the cesium formate with potassium formate also reduces cost.