July 19, 2022
Demand for irrigation water wells throughout the San Joaquin Valley was so great that Scott Belknap Well Drilling, headquartered just south of Fresno in Dinuba, increased its labor force from 10 employees to almost 50.
The company also increased its drilling fleet, turning to the Epiroc Service Center, formerly known as the Epiroc – Sacramento Service Center, three hours north of Belknap’s headquarters.
Owner Scott Belknap’s first experience with a TH60 water well rig belonged to his uncle, Bill Belknap. The first rig he owned himself was a new Atlas Copco T2W. Belknap added a used T3W and two new TH60 water well rigs, one of which was a deep hole (DH) version with a pullback capability of 311 kN (70,000 lb). When it rotated out of service, Belknap ordered another TH60 DH to replace the T2W.
Belknap said he had no complaints regarding the T2W, with its 133 kN (30,000 lb) pullback capability and carrier, but he preferred the TH60. The deep-hole version has more than twice the pullback of a T2W to cover almost any depth and diameter a drilling crew needs to drill and case for the region’s agricultural customers. Yet it is compact enough to get into fields without moving trees or damaging the crops.
At least six of Belknap’s 13 drill rigs are drilling at any time. On this day, Belknap driller Wayne Tincup and fellow driller Theodoro Rodriguez were using a 40,000-pound TH60 and a 152-mm (6 in) drag bit to prove the depth of granite bedrock in three locations for a lemon orchard.
The farm’s owner has an existing well in this orchard with an unknown development history of 50.3 mts (165 ft). Even with water conservation strategies that include removing older, thirstier trees to replace them with younger growth, failure of the older well could ruin the crop. A second well was requested as a precautionary backup and supplemental irrigation supply.
Exploration was performed with a 6-in drag bit through topsoil and alluvium “as fast as she will go,” Tincup said. By noon Tincup and Rodriguez had already logged bedrock depths of 125, 145, and 150 ft (38 m, 44 m, 46 m) in the three assigned locations and were waiting on word from the owner as to which one he would like to develop.
Once the location had been chosen, the TH60 drillers completed the top of the well profile to the granite bedrock. They cased and sealed the bore with bentonite clay from the surface to 25 ft (7.5 m).
Then they switched to a down-the-hole hammer to drill through the granite to the sandstone aquifer. After 10 hours of development, the customer’s backup well produced clear irrigation water for the orchard’s driplines.
Drought conditions along the U.S. West Coast states have depleted groundwater resources for over a decade. The water deficit has been particularly severe in California’s Central Valley, one of the most productive agricultural regions in the world. Some of the worst conditions exist in the region, called the San Joaquin.
