drills domestic, irrigation, municipal, industrial, and water quality depth sampling wells.
Hardrock & Casing Driven Wells
Johnson Drilling Co. is capable of many types of drilling. We drill hardrock wells in the mountain areas, casing driven wells in the valley and we are one of the few companies capable of drilling in cobble rock in the river bottoms. Many times a well needs more than one type of drilling (casing driven and hardrock) to finish the well to the required depth.
Our general drilling area for irrigation, domestic, and municipal wells is the east side of Highway 99 encompassing Auberry, Clovis, Dinuba, Elederwood, Exeter, Fresno, Friant, Kings Canyon National Park, Lemoncove, Millerton, Miramonte, Orange Cove, Orosi, Porterville, Prather, Reedley, Sanger, Shaver Lake, Squaw Valley, Three Rivers, Visalia, Wonder Valley, and Woodlake.
Undereaming, Tubexing or Odexing
Johnson Drilling Co. is one of the few drillers capable of this process. The underreaming method allows the driller to advance an outer casing along with the drilling bit. This method allows for completion of the annular seal and screened sections through loose (running) decomposed rock and cobble. An outer casing is carried along as the drilling progresses until it can be landed in consolidated formation. After landing the casing, wings on the bit are retracted and the drill-string assembly pulled. This casing can then be perforated with a down-hole air perforator and the inner casing, with perforations at selected locations, is installed. The space between the two casings is filled with gravel-pack material except for the upper 20 to 50 feet which is completed by placing a bentonite annualar seal. The ability to deal with these difficult saturated zones of highly weathered rock accounts for the majority of successful water wells in the Shaver Lake and river bottom areas.
Water Quality Depth Sampling
The objective of a casing hammer method test well is to enable collection of information on subsurface geology, water production potential, and vertical variations in water levels and quality at different depths. Water samples are collected from approximately one dozen depths.
The casing hammer method is used to drill and drive casing. The procedure consists generally of installing 6-5/8" diameter steel casing as the drilling proceeds and airlifting the water from various water bearing strata as they are encountered.
After the shallowest zone to be sampled is reached, the driller continues to drill and case the test hole until a clay or other fine grained stratum is encountered. The casing is landed in that stratum and the drilling continues through it into an underlying sand or gravel stratum. Water is then airlifted to the surface for a minimum of fifteen minutes. Sufficient air pressure is provided to lift the water. This test procedure is repeated at approximately thirty foot intervals as directed by the Engineer. The Engineer then collects the water samples for chemical analysis.
In addition to the above described test sampling, approximately three depths are selected by the Engineer for pumped samples. We install a submersible pump, and pump the test hole for two hours to obtain samples of water. The water samples are then collected by the Engineer for chemical analysis.
Upon completion of the test, the well is abandoned in accordance with applicable provisions of the State of California, Department of Water Resources. The Engineer will use the information gained from water quantity and chemical analysis to design a production well.
Our general drilling area for water quality depth sampling test wells is Merced on the north to Bakersfield in the south.
Well Jetting and Cleaning
We clean wells by injecting air into them and removing any sediment, clay, or sand from the bottom. You will have an approximate yield in gallons per minute.
We clean the bottom and work any perforations in order to prolong the life of the well. Quite often this is the only way of knowing whether a well is still usable or if a new one should be drillied.
We strongly advise pump developing of all large diameter wells to increase production, reduce sanding, and to assist the design of the production pump.