Page 191 - Shale Shakers Drilling Fluid Systems
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174 SHALE SHAKERS AND DRILLING FLUID SYSTEMS
Determine the Density of Drilled Solids 4. Determine the weight of drilling fluid in the
dish by subtracting the weight of the dish
1. Select large pieces of drilled solids from the from combined weight of the dish and drill-
shale shaker and wash with the liquid ing fluid.
phase of the drilling fluid (use water for 5. Divide the weight of drilling fluid in the dish
O O
water-based drilling fluid, oil for oil-based by the density of drilling fluid (step 1). This
drilling fluid, or synthetics for synthetic is the volume of drilling fluid.
drilling fluid) 6. Dry the material in the dish in an oven at
2. Grind the drilled solids and dry in an oven 250°F for at least four hours.
or retort 7. Weigh the dish containing dry solids
3. Weigh the assembled, dry pycnometer 8. Subtract the dish weight from the weight of
4. Add the dry drilled solids to the pycnometer the dish containing the dry solids. This is
and weigh the weight of solids.
5. Add water to the drilled solids in the pyc- 9. Divide the weight of dry solids (step 8) by the
nometer, pressurize, and weigh weight of drilling fluid in the dish (step 4).
6. Determine the water temperature This is the weight fraction of solids in the
7. Determine the water density drilling fluid.
8. Subtract the weight of the dry pycnometer 10. Subtract the weight of dry solids (step 8)
from the weight of the dry pycnometer con- from the weight of drilling fluid in the dish
taining the dry drilled solids. This is the (step 4). This is the weight of liquid in the
weight of drilled solids. drilling fluid.
9. Subtract the weight of the dry pycnometer 11. Divide the weight of liquid in the drilling
containing drilled solids from the weight of fluid (step 10) by the density of the liquid
the water, drilled solids, and pycnometer. phase of the drilling fluid. This is the vol-
This is the weight of water added to the ume of the liquid phase.
pycnometer. 12. Subtract the volume of the liquid phase
10. Divide the weight of the water (determined (step 11) from the volume of the drilling
in step 9) by the water density. This is the fluid (step 4). This is the volume of solids
volume of water added to the pycnometer. in the drilling fluid.
11. Subtract the volume of the water added to 13. Divide the volume of solids in the drilling
the pycnometer (step 10) from the volume fluid (step 12) by the volume of drilling
of the pycnometer. This is the volume of fluid. This is the volume fraction of solids
drilled solids contained in the pycnometer. in the drilling fluid.
12. Divide the the weight of drilled solids 14. Multiply the volume fraction of solids in the
(step 8) by the volume of drilled solids drilling fluid by 100 to obtain the volume
(step 11). This is the density of the drilled percent of solids in the drilling fluid
solids. This may be used in the previous
equations to determine the volume percent Sample calculation. While drilling a relatively
of drilled solids in the drilling fluid. uniform 2,000-foot shale section, a 200 x 200
mesh continuous screen cloth is mounted on a
The pycnometer may also be used to more linear shale shaker. An 11.2 ppg, freshwater, gel/
accurately determine drilled solids in the drill- lignosulfonate drilling fluid is circulated at 750
ing fluid: gpm while drilling. Given these parameters, the
following determinations can be assumed.
1. Determine the density of the drilling fluid Large pieces of shale are removed from the
with the pycnometer shaker screen and the excess drilling fluid is washed
a. Weigh the pycnometer filled and pres- from the surface with distilled water. The shale
surized with drilling fluid pieces are ground and dried in a 250°F oven over-
b. Subtract the weight of the dry pycno- night. The shale is placed in a 173.91 cc pycno-
meter from the weight of the filled, pres- meter and weighed. Water is added to the pyc-
surized pycnometer nometer and pressurized to approximately 350 psi.
c. Divide weight of drilling fluid in pycno- The increase in weight of the pycnometer deter-
meter by the volume of the pycnometer. mines the volume of water required to fill the
This is the density of the drilling fluid. pycnometer. (Room and water temperature is 68°F,
2. Weigh a metal or heat-resistant glass dish therefore, the density of water is approximately 1.0
3. Add a quantity of drilling fluid to the dish gm/cc.) Subtracting this volume of water from the
and weigh known volume of the pycnometer calculates the
