Clear brine fluids are the saline liquids that are used in various oil well drilling completion operations. They are use in preparation of a penetrating bore well hole for oil and gas drilling. There are various classes of brines like chloride brines, bromides, and formats. Amongst these the bromides, because of their characteristic high densities are a popular choice as drilling fluids. Sodium Bromide liquid (NaBr) and zinc bromide liquid (ZnBr) are heavily used clear brines for oil well completion activities. Used as completion and workover fluids, these clear brine fluids need to be stable at surface and downhole conditions. There do not plug the formation in completion and workover drilling operations, which make them a better choice over the traditional drilling muds. High densities, carried by this bromide are suitable for deepwater production and allow for a well pressure control.
Sodium Bromide liquid
Sodium Bromide liquid (NaBr), a salt is used alone or in a combination with sodium chloride or zinc bromide to form clear workaround and drilling fluids with densities of 8.4-12.5 lbs/gal. Non-damaging to the formation, it can be mixed with other solutions of bromide and chlorides. It is especially useful when used in formations that are known to have sensitivity towards calcium. When chloride ion is not desirable and when calcium may not be the preferred choice. It is extensively used in situations where formation of waters contains high levels of sulfate or carbonate that may precipitate with the calcium ion.
Zinc Bromide liquid
It is a clear, solid-free brine fluid with minimum density of 19.2 lbs/gal. It is used in completion fluids and offers features and benefits like It is non-damaging to the formation, It is thermally and chemically stable, and It can be blended with other solutions containing bromides and chlorides. It can be used with other bromides and chlorides to prepare non-damaging liquids with densities ranging from 15.1 lbs/gal to 19.2 lbs/gal. It can never be produced as dry material in sufficient quantity to be used in the completion fluid market it can be prepared only as a liquid brine.
Both, NaBr and ZnBr can be used as single-salt brines or can be mixed with other bromides and chlorides to form better brines as required. Amongst the popular multi-salts prepared, the blend of Zinc Bromide and Calcium Bromide (CaBr2) and Sodium Bromide and sodium chloride (NaCl) are popular blends used to form excellent drilling, completion, and packer fluids.
Zinc Bromide/Calcium Bromide Blend
It is a clear, solids free brine fluid of 19.2 lbs/gal density, with 53-58% ZnBr2 and 20.0-23.0% CaBr2. It can be blended with other solutions containing bromides and chlorides. This blend is used primarily when higher densities are required.
Sodium Chloride /Sodium Bromide Blend:
It is a clear brine fluid that is formulated to meet and crystallization temperature requirements and individual density, covering the density range from 8.4 lb /gal to 12.7 lb /gal. This blend is often used when the calcium ion is not desirable and costs are a concern, as it is less expensive than pure sodium bromide brines.