Sag Shoe Assembly

Sag Shoe Assembly Model   RCSSA-130

The Viscometer Sag Shoe Test (VSST) is a well site and laboratory test that

measures the weight material sag tendency of field and lab-prepared drilling

fluids under dynamic conditions. The VSST provides an intrinsic fluid property

without regard to the conditions under which the fluid has been or will be

used. As such, results must be combined with operational factors to correlate

results with sag experienced in the field.

The VSST designation is derived from the rotational viscometer used as

a mixer and the thermoplastic insert (Sag Shoe) designed to concentrate

sagged weight material in the bottom of a viscometer thermocup. Sag

tendency is determined by the density increase of samples extracted from the

collection well over a 30-minute period at a standard temperature and under

a consistent rate of shear.

Weight-material bed pickup can be run as an optional measurement to

characterize bed removal by higher shear levels. Results can be used to

suggest opportunities for bed removal in the field prior to tripping out of the

hole.

Recommended Equipment:

- VSST Sag Shoe

- Direct-indicating API rotational viscometer capable of operating at 100

and 600 RPM

- Viscometer thermocup, with temperature control

The VSST Sag Shoe should fit inside of the thermocup without being too

tight.

- 10 mL Luer Syringe

- Cannula with luer connection

- Timer capable of measuring ± 1 second

- Balance with 0.01 g resolution

- Pycnometer, retort cup, or weigh boat