Stiff Foam:  What the Heck Is That

and How Can It Help Me Drill?

by Todd Giddings, Ph.D., P.G.

    We drilled our usual demonstration well at the Summer Field Conference, and as it turned out, the Gettysburg Formation bedrock under the site was ideal to demonstrate the benefits of using “stiff foam” during air-rotary drilling with a down-the-hole hammer.  The Gettysburg Formation bedrock consisted of alternating layers of red and maroon mudstone, siltstone, shale, and sandstone that was not well cemented, so the drilling rates ranged from moderate to really fast.  If just a usual foaming agent had been added to the injected water, the results would have been a maroon-red soup resembling thick tomato soup.  When a sandstone layer was encountered, it would have only made the soup look like a stew of rock chips.  This soup would have been blown both out of the hole and also back into the bedding planes and joints in the Gettysburg Formation bedrock, thereby reducing the ultimate yield of the well and prolonging the developing process.

Ed Anderson of Baroid first blended the EZ-Mud® polymer in a mixing tank using a standard centrifugal pump to create the shear necessary for good mixing.  The Quik-Foam® was then added to each batch of slippery EZ-Mud® polymer “thick water” and the mixture was injected into the air stream during drilling.  The EZ-Mud® polymer in the water coated each and every clay, silt, and sand particle so they couldn’t stick together and form a paste or thick soup.  The Quik-Foam® made persistent, frothy bubbles that carried the individual clay, silt, and sand particles out of the hole in the air stream.  The carrying capacity of the Quik-Foam® meant that far less volume and pressure of air was needed to clean the hole, and so the clay, silt, and sand particles were carried out of the hole and were not blown back into bedding plane and joint openings.

    You could feel each separate grain when you grabbed a handful of “cuttings” covered with the frothy bubbles of stiff foam, and the silt, clay, and sand particles were all separate; not all mixed together as in a “soup”.  The frothy foam bubbles didn’t “melt” away, and that is why it is called “stiff foam”.  We quickly developed the well yield to more than 30 gallons per minute from only a 120-foot hole.  This presentation at the Winter Conference will show each and every step in detail, and will demonstrate just how easy and effective it is to use stiff foam.

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Last modified: July 21, 2008.