The well completion used 285 ft of 13-3/8" surface casing and 1,665 ft of 9-5/8" production casing. Pilot borehole drilling used a 7-7/8" bit, whereas production casing was installed into a 12-1/4" borehole.

Dolomite crystals are shown in a petrographic thin section. Intercrystalline porosity (blue) was measured by image analysis of the photo.
Madison Aquifer Well Development
Wyoming Water Development Commission
Newcastle, Wyoming

Planning, design and construction services were provided for a Madison aquifer well drilled to 2,156 feet. The artesian well has a surface pressure of 55 psi and open discharge of 100 gpm. When pumped, the well can yield greater than 500 gpm. The installation substantially exceeded the flow requirements for the water system.

A small diameter pilot borehole was drilled from the lower part of the overlying Minnelusa formation into the Madison in order to tag the formation top and accurately locate production casing. The pilot borehole was extremely effective for determining production casing depth, set 5-ft into the Madison. The well was built in full compliance with State Engineer requirements for Madison wells.

The well fully develops the Madison aquifer present at the site, which was 475 feet thick. The fully penetrating borehole is protective of water rights from future Madison wells that could be developed in the area.

Hydraulic testing included a 7-day pumping phase run at 300 gpm. Fitting of a hydraulic model to the test data was used to establish pumping capacity in excess of the test rate.

On-site geological logging of the well and petrographic analysis of selected samples was used to characterize the geology. Two series of geophysical logs were included in the project and used to interpret borehole geology and well construction (caliper, gamma, SP, gamma-density, neutron, array resistivity, cement bond, spinner flow meter, and video).

Water entry into the borehole occurrs through rock fractures observed on video. Flow from the fractures was measured by a spinner flow meter log of the well.