Experiment

1. Insert the dowel into the clear tubing and push it all the way to the other end.

The dowel should move easily through the tubing when pushed, while making contact all around with the wall of the tubing. If the dowel does not fit the tubing closely, wrap one or two turns of cellophane tape around the end. If the dowel is too tight in the tube, then rub the outside of the dowel with sandpaper to make it a bit smaller in diameter.

2. Slowly and carefully, pour sand into the graduated cylinder to form a layer about 3 mm (0.12 in) deep at the bottom.

3. Slowly pour water into the cylinder until it is about one-third full.

For this experiment, the cylinder represents a hole being drilled into the Earth, the sand represents the cuttings that need to be removed from the hole, and the water represents a type of drilling mud with a very low viscosity.

4. Pause a few moments to allow the water to seep into the sand and wet all of the granules. If you have sand that does not accept water readily, stir the water or shake the cylinder gently to mix the sand and the water. 

Wet sand is darker in color than dry sand. In the photo on the right, you can see the dry sand as a lighter-colored layer beneath the darker wet sand. In the photo on the left, all of the sand is dark, and thus is wet with water.

5. Insert the end of the tubing with the dowel into the graduated cylinder so that it is just below the level of the water.

Slowly push the tubing farther down into the water while holding the dowel so that its end remains about even with the water level. As the tubing moves downward past the end of the dowel, it fills with water. Keep pushing on the tubing until it comes to rest on the sand at the bottom of the cylinder, and the bottom of the dowel is about even with the water level, so that the tubing below the dowel is filled with water.

The tubing represents the drill assembly, and the dowel represents the pump that will circulate the low-viscosity mud (water). The water in the tubing represents the drilling mud that will be circulated next.

6. With the end of the tubing still resting on the bottom of the cylinder, push down on the dowel steadily, driving the water out the bottom of the tubing. Observe what happens to the sand as the water is flowing.

After the dowel has been pushed all the way to the bottom of the tubing, wait a moment and observe what happens to the sand when the water flow stops.

After you have finished making your observations, it is time to prepare for the next part of the activity. Remove the dowel from the tubing. Dispose of the sand and water by pouring it into wadded-up paper towels. Place the paper towels in the trash. Do not wash the sand down a drain.

Wash and dry all the parts. Push through a piece of paper towel with the dowel to dry the inside of the tubing and graduated cylinder.

For the next part of the activity, repeat the above steps using clear shampoo instead of water, to represent a high viscosity drilling mud. How do you think the shampoo will compare with water?

After you've completed the experiment and made your observations, take a look at our results.