Initial Statement of Reasons for Marine Oil Terminal Engineering and Maintenance Standards The purpose of filtering completion fluid or well bore clean up fluids, also known as brine is to prevent the downhole contamination of the formation. Contamination reduces production and shortens the productive life of the well. Contamination can occur during perforating, fracturing, acidizing, workover, water- flooding, and gravel packing as well. Any time fluid is put into the well bore with a solid content, no matter how slight; there is a chance of damaging the well. A fluid contaminant can come in many sizes and forms. Drilling operations produce cuttings, rust, scale, pipe dope, paraffin, undissolved polymer, and other material on the casing or pipe string. All these materials contribute to the amount of solids in the fluid.