WorldWide Drilling Resource

Tales from the Field by Jeremy C. Wire Geoconsultants, Inc. A Drill Operator’s Ingenuity Saves a Well in the Wine Country Several counties north of San Francisco Bay are known for their vineyards which produce fine California wines, and not surprisingly, the region is collectively known as the Wine Country. In most of the region, wells are a primary source of water for vineyards and resi- dences, and groundwater can be relatively abundant or scarce, depending on the geologic setting. Some rugged areas in the region are underlain by geologically re- cent volcanic rocks, and a general rule of thumb in well drilling with air rotary in this setting is if you don’t find any or very little water in the upper several hundred feet, just drill deeper, and you will find it. Accordingly, it is not unusual for small-diameter irrigation and domestic wells in such instances to reach total depths of 800 to 1000 feet. In one such project, the target depth for drilling was estimated to be about 600 feet, but when this depth was reached, very little water was found, so the drill operator decided to go deeper. By 1000 feet, enough water was developed for this residential project. At the time, we were working at a site relatively close by, and finding out the well was being cased, decided to stop and see how the work was progressing. Everything seemed to be going as expected, and all but about 80 feet of PVC casing was in the hole when suddenly the drill operator turned around with a painful look. Apparently, he could tell the casing had somehow parted! Upon pulling the bro- ken section of casing out of the hole, part of a coupling had cracked, and the re- maining casing was now at the bottom of the hole. So, what to do? While everyone else was standing around thinking about this problem, the drill operator noted a discarded one-gallon plastic bottle. Quickly taking his pocket knife, he cut the bottom off and part of the top, and fitted the small end over the damaged coupling. Securing the modified bottle with duct tape, he had effectively fashioned an “overshot” which fitted inside the 9-inch-diameter borehole, and hopefully would allow the coupling to be reconnected. Since the water level was about 400 feet deep and the sanitary seal was planned for only 50 feet deep, the gravel pack would surround the coupling and hold everything in place once the well was constructed. The casing sections were coupled back together and carefully lowered into the hole. The drill operator thought he could feel the proper engagement of the coupling, and measurements confirmed the right casing length. Pea gravel pack was then placed in the annulus, and the well was sealed and developed. A down hole video was run before installing the pump which confirmed the integrity of the joint at the damaged coupling, and there was no damage to the screen section due to impact against the bottom of the hole. A few months later, there was a large earthquake in the area, but as far as we know there was no damage to this well that was saved by the action of a very creative drilling professional. Jeremy Jeremy Wire may be contacted via e-mail to michele@ worldwidedrillingresource.com September 21-22 Royal Plaza Hotel & Trade Center, Marlborough, MA For more information call 877-632-4748 or visit www.nda4u.com Save the Date – 2017 NDA Convention Exhibitor & sponsor opportunities are available! President’s Dinner with Awards • Golf Outing • Presentations Approved for CE Credits • Outdoor Static Displays • Entertainment • And More. 42 JULY 2017 WorldWide Drilling Resource ® The deadline for the September issue is almost here! Space Reservation: July 25 th Display & Classified Ad Copy: August 1 st