Selecting high-density fluids for well completion and workover without reservoir permeability impairment
Abstract
Well workover fluids have technical and technological characteristics similar to well completion fluids but require a low solid phase content to avoid adversely affecting the natural permeability of the near-wellbore zone. Additionally, these fluids need to be thermally stable, non-corrosive to equipment, safe for humans, and environmently friendly. Well workover fluids are used to restore oil productivity and extend well lifespan, thereby enhancing its economic efficiency [1].
The paper presents the research and blending results of the PV-BrinVis fluid system used in well workover and completion processes. The system is based on salts with a density range of 1.3 - 2.0 combined with viscoelastic surfactants and surface hydrophobizing agents for reservoir rocks, along with other additives such as corrosion inhibitors and oxygen scavengers. The system will create a suitable rheological fluid that can adjust the density within the required range while also having the capability to clean the well. The viscoelastic surfactants can be easily flushed out of the near-wellbore zone after the well workover process without causing sub-well contamination. With this excellent clay inhibition properties and low corrosion rates, this advanced salt-based drilling fluid system offers many advantages, preserving the reservoir permeability as well as the integrity of equipment during well completion, workover and maintenance.
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