API RP 13D:2003 pdf download

API RP 13D:2003 pdf download.Recommended Practice on the Rheology and Hydraulics of Oil-well Drilling Fluids.
The pressure constant, a. must be detennined for each drilling fluid. For waier-based fluids, the pressure efkct on shear stress is estrernely small and can be neglected. however, for oil-based fluids the pressure has an appreciable effect on ihe effective viscosity. As a general rule, the pressure effect is greater for oil-based fluids with asphaltic s’iscositIers than for those that use oil-wet inorganic solids as siscosifiers.
Note: Absolute temperature is in degrees Rankine t460 + F). Pressure is in psig.
7.6.3 Application
The use of viscosity measurements at surface conditions fr calculating hydraulics may give erroneous results.’5 For accurate work, the viscosity of the drilling fluid should be determined at the temperatures and pressures encountered in the well. To do this requires a high-temperature. high-pressure viscometer for data collection and a computer to analyze the data. However, corrections can be made to surface conditions. These correction factors are average values obtained from measurements on various types of drilling fluids under conditions of high temperature and high pressure. Although the use of these correction factors will give good estimates. they arc not as accurate as downholc viscosities that can be obtained by measurement under downholc conditions. Fig. ures 18. 19 and 20 show the correction factor to be used with water-based fluids, oil-based fluids containing asphalt. and oil-based fluids containing oil-wet inorganic viscosifiers. respectively. To obtain the correction factor:
a, Select the proper graph to be used.
b. At the temperature of interest, draw a line to the proper pressure curve.
c. From the intersection of the temperature-pressure lines. draw a line to the correction factor axis and read the correction factor.
d. Multiply the effective viscosity by the correction factor.
The pressure constant, a. must be detennined for each drilling fluid. For waier-based fluids, the pressure efkct on shear stress is estrernely small and can be neglected. however, for oil-based fluids the pressure has an appreciable effect on ihe effective viscosity. As a general rule, the pressure effect is greater for oil-based fluids with asphaltic s’iscositIers than for those that use oil-wet inorganic solids as siscosifiers.
Note: Absolute temperature is in degrees Rankine t460 + F). Pressure is in psig.
7.6.3 Application
The use of viscosity measurements at surface conditions fr calculating hydraulics may give erroneous results.’5 For accurate work, the viscosity of the drilling fluid should be determined at the temperatures and pressures encountered in the well. To do this requires a high-temperature. high-pressure viscometer for data collection and a computer to analyze the data. However, corrections can be made to surface conditions. These correction factors are average values obtained from measurements on various types of drilling fluids under conditions of high temperature and high pressure. Although the use of these correction factors will give good estimates. they arc not as accurate as downholc viscosities that can be obtained by measurement under downholc conditions. Fig. ures 18. 19 and 20 show the correction factor to be used with water-based fluids, oil-based fluids containing asphalt. and oil-based fluids containing oil-wet inorganic viscosifiers. respectively. To obtain the correction factor:
a, Select the proper graph to be used.
b. At the temperature of interest, draw a line to the proper pressure curve.
c. From the intersection of the temperature-pressure lines. draw a line to the correction factor axis and read the correction factor.
d. Multiply the effective viscosity by the correction factor.