SY/T 6613-2005 in English

Scope

Through this standard, people can have a basic understanding of the rheological and hydraulic properties of drilling fluids and apply them to drilling practice. The calculation method used in this standard does not consider the effects of pressure and compressibility on drilling fluid density. Drilling fluid flow deformation refers to the deformation and flow characteristics of drilling fluid under the action of external forces. It involves two flow regimes: laminar flow and turbulent flow. This standard focuses on the characteristics of drilling fluid flow and how these characteristics affect the flow of drilling fluids. Specialized measurements of drilling fluids are made to determine their rheological parameters under different conditions. These parameters can be used to design or evaluate how well the circulation system will accomplish its intended goals. Drilling fluid flow deformation is of great significance in the following aspects: a) Calculation of friction losses within the drill pipe and annulus. b) Determine the drilling fluid equivalent circulation density. c) Determine the flow pattern of drilling fluid in the annulus. d) Estimate wellbore cleaning efficiency. e) Stock drilling fluid suspension ability. f) Determine the drilling cuttings settling velocity in the vertical well section. The drilling fluid rheology discussed in this standard is for single-phase liquid flow only. In this standard, common concepts regarding drilling fluid rheology and flow are listed; mathematical models between shear stress and shear rate, and formulas for estimating pressure drop, equivalent circulation density, and cuttings settling velocity. This standard uses traditional imperial units, but all calculation formulas are given with conversion factors and calculation examples so that imperial units can be easily converted to SI units. For rheology calculation examples in imperial units and sedimentation velocity calculation examples, see Appendix A and Appendix B; for symbols applicable to this standard, see Appendix C; for rheology calculation examples and sedimentation velocity calculation examples in SI units, see Appendix D and Appendix E. If no units are specifically specified, such as when deriving formulas, any unit of the same system may be used. Understanding the concepts of viscosity, shear stress, and shear rate is critical to understanding the flow characteristics of drilling fluids. By measuring these performance parameters, the flow characteristics of circulating drilling fluid can be mathematically described. Drilling fluid rheology directly affects the flow characteristics of the drilling fluid and all hydraulic calculations, so the rheology of the drilling fluid must be controlled to enable it to complete various functions.