ANSI 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 diferent tubing sizes are used. Thus the design and functioning of the apparatus can vary and still meet the desired preconditioning criteria.
6.2 Requirements for proper shear-history simulation
The fllowing procedures shall be fllowed:
a) record and report the test temperature;
b) ensure thorough mixing of all fluid -activating additive(s) immediately before the fluid enters the shear-history tubing.
6.
Conditions for sample delivery
The fllowing conditions shall be fuill:
a) continuous delivery of base fluid while additives are added and cup is being flled;
b) constant shear rate within the shear-history tubing;
c) while fluid is being injected into the viscometer, shear rate within gap of the viscometer is a nominal 100s]1.
6.4 Conditions for standard shear-history simulation
The fllowing conditions shall be fill:
a) for fluid temperatures less than or equal to 93 °C (200 °F), shear rate 675 SD1 for 2,5 min;
b) for fluid temperatures greater than 93。C (200 °F), shear rate 1 350 S01 for 5 min. .