API RP 13M:2004 pdf download.Recommended Practice for the Measurement of Viscous Properties of Completion Fluids
6 Fluid preparation using shear-history simulation (optional)
6.1 General
A shear-history simulation procedure is provided to simulate the effects of shear rate and time while a fluid is being conveyed down well tubulars. This procedure is intended to characterize the effect of shear history on fluid properties as part of the concept and development phase for a new fluid. A shear-history apparatus is used to condition the fluid at specified shear rates, times and temperatures prior to injection into a viscometer. It consists of mixing apparatus, pumping apparatus and tubing to simulate significant aspects of the surface apparatus followed by shear conditions in the well tubulars. A shear-history apparatus that satisfies the requirements can be generically classified as a tube or pipe flow device that operates in the laminar flow regime. Flow shall occur in a single-pass mode. A schematic diagram of a shear-history simulator connected to a pressurized concentric-cylinder viscometer is shown in Figure 1. In laminar flow, the energy dissipation rate is the same in any shear-history apparatus even if different tubing sizes are used. Thus the design and functioning of the apparatus can vary and still meet the desired preconditioning criteria.
8.2.2.2.2.2 Procedure
The following procedures shall be followed. a) Loading, pressurizing and heating the fluid Load the fluid to be evaluated into the viscometer immediately after the last component is added according to mixing procedure. Place 52 cm 3 of fluid in the viscometer. This volume is sufficient to fully cover the bob. Pressurize the system with nitrogen to a minimum of 2,75 MPa (400 psi) and immediately start shearing at 100 s −1 . When shearing of the fluid starts, define the elapsed time as zero (t = 0) and begin heating the fluid. All actions in this paragraph shall be completed within 45 s. Optionally, for an ambient-temperature shear ramp [described in 8.2.2.2.2 b)], elapsed time is defined as zero (t = 0) immediately after completing this ramp, and fluid heating is begun. At 20 min elapsed time, the fluid temperature shall be no lower than 5 % below (base = 0 °C) and no higher than 3 °C (+ 5 °F) above the desired test temperature. In addition, at 30 min elapsed time, and for the remainder of the test, the fluid temperature shall be within ± 3 °C (± 5 °F) of the test temperature. b) Application of shear rate ramps