Multiple Caverns Connected from a Single Lateral

A major salt mine in NY uses the Rotating Magnet Ranging System (RMRS) to improve production from their underground salt reserves. Three vertical wells are drilled into the salt layer, and a single lateral well is directionally drilled to intersect the three wells in series.

The first Target was acquired at 220’ range where it was determined to be more than 30’ and 9° off line from the position calculated via land and gyro surveys. The driller was able to correct trajectory, and intersection occurred at 3,525’ measured depth. With survey errors corrected for at the first intersection, Targets #2 and #3 were now direct in line with the driller’s current azimuth. Intersections were made at 4,160’ and 5,101’ MD, respectively.

RMRS enabled the mine owner to quickly and efficiently complete their production wells, eliminating days of additional rig time that would have been spent performing multiple sidetracks due to survey uncertainties. Further cost savings were realized as the direct bit to casing connections eliminated the water pumping stage as the caverns are washed out in order to guarantee well to well flow.

Challenges

Target diameters of just 7″ required precision steering for successful intersections
Errors in surveyed land and hole positions required a major change in trajectory to avoid a costly sidetrack