Completion fluid is the general term for the working fluid used in the completion operation. According to its purpose, it can be divided into drilling fluid, cleaning fluid, perforating fluid, kill fluid, workover fluid, gel breaker, etc. Sea water, fresh water or salt water is generally used as the base fluid for the preparation of the completion fluid. Since the completion fluid has requirements on the size of the particle diameter, the base fluid used for preparation must be filtered first.
1. Seawater filtration
The generally used processes for filtering seawater are grid, sedimentation, multi-media filter, and precision filtration. The filtered seawater base fluid generally requires a particle diameter of less than 2 microns and a turbidity of less than 30NTU. Due to the high salt content in seawater, the equipment for the precision filtration process generally uses FRP Security Filter Housings, and the consumables generally use High Flow Filters, Pleated Filter Cartridges, Melt Blown Cartridges, String Wound Cartridge or Liquid Filter Bag with a filtration accuracy of 2 microns.
2. Fresh water filtration
The general process for filtering fresh water is precipitation, multi-media filter, and precision filtration in order. The filtered fresh water base fluid has the same requirements as the sea water base fluid that the particle diameter is less than 2 microns, and the turbidity is less than 30NTU. The equipment of the precision filtration process generally uses Stainless Steel Security Filter Housings, and the consumables are generally selected as Filter Cartridges or Liquid Filter Bags with the same accuracy of 2 microns as the seawater filtration. The salt water base fluid can be added with inorganic salt as needed on the basis of the fresh water base fluid.
3. Recovery and utilization of completion fluid
Due to the high cost of configuring the completion fluid, we should recycle it as much as possible. The recovered completion fluid contains a variety of impurities and has the characteristics of high salt content, so filter treatment should be carried out before use. The filtration system generally selects a FRP Security Filter Housings with a filtration accuracy of 10 microns for pre-filtration, and a FRP security filter housings with a filtration accuracy of 2 microns for terminal filtration.
Completion fluids are used in every aspect of the process from drilling of oil layers to oil production and various stimulation measures. The quality of completion fluids is one of the important factors that determine the recovery rate of oil fields. Therefore, the filtration process of fresh water, sea water, and brine base fluids used in the preparation of completion fluids is indispensable.