WorldWide Drilling Resource

23 WorldWide Drilling Resource ® AUGUST 2014 Environmental Monitoring by Thomas Kwader, Ph.D., P.G. Hydrophysics - Measuring Flow into a Borehole Have you ever wondered where most of the water in a borehole comes from? There is a saying that 90% of the water comes from 10% of the borehole. I find this to be true in boreholes pene- trating fractured rock and carbonates with highly developed secondary porosity (enhanced permeability) due to flowing water dissolving preferential pathways. There are many ways of determin- ing where most of the flow is coming from in the borehole. Mud rotary drill operators can watch the loss of drilling mud when a permeable zone is en- countered. Cable tool drill operators can bail the well and determine how fast the well “recharges” after bailing. One of the best ways to determine the flow from different sections of a bore- hole is to place a “spinner” flow meter in the bottom of the hole on a wireline, followed by placing a small submersible pump below the water level. As the well is pumped at a constant rate, and the flow meter is slowly pulled up the hole, the revolutions of the impeller will in- crease in revolutions per minute (rpm) as the tool is raised to the pump. If the flow into the well was equal all the way up the hole, the slope of the line would show a constant increase from 0 to 100%. If all the water was coming into the borehole at the top near the pump, the log would show 0% all the way up to the pump. If all the flow was mainly from the bottom of the bore- hole, then the percent of flow would be near 100% at the bottom and not show any increase above the bottom. Many geophysical logging compa- nies have spinner flow meters; and it is a fairly simple task to insert and pump from a small submersible below the water level. This information can also be used to isolate zones of poor water quality by taking samples from different flow zones in the well. Tom admin@ worldwidedrillingresource.com In Memoriam Kenneth Lawrence “Ken” Boyes (1964~2014) The passing of Kenneth Lawrence “Ken” Boyes of Orton, Ontario, Canada, on May 25, 2014, was sadly reported by the OGWA (Ontario Ground Water Association). He owned Boyes Pumps & Water Treatment, and was a long-standing member of the OGWA. Ken is survived by his wife Kim, and children Mitchell and Bronx. He will also be missed by his parents, sister, in-laws, and hunting buddies. The management and staff of WorldWide Drilling Resource ® offer their sincere condolences in the loss of such a young life.