MagMapper is a free citizen-science app developed at the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, with funding from the U.S. Department of Energy's CATALOG program. It turns an ordinary smartphone into a magnetic survey instrument that helps locate undocumented, abandoned oil and gas wells so they can be assessed and properly plugged.
Visit the MagMapper website magmapper.app ↗
Opens the project website (external to colorado.edu)
Why it matters
More than a century of drilling in the United States has left hundreds of thousands of wells with no records and no responsible owner. Only about 123,000 orphan wells are formally documented; researchers estimate the true number of undocumented wells is between 310,000 and 800,000. A well that was never properly sealed can act as a pathway between deep rock layers and the shallow groundwater that communities depend on, and deteriorating casings pose physical hazards near homes and farms. Before any of these wells can be plugged, they first have to be found — and nobody has a complete map. MagMapper was built to help close that gap.
How it works
Every drilled well was cased in steel, and steel is magnetic. A buried casing distorts the Earth's magnetic field — often by thousands of nanoteslas above the roughly 50,000 nT background — and that distortion reaches the surface, where the magnetometer already inside a smartphone (the same sensor that powers the compass) can measure it. To run a survey, you walk a grid over a suspected site while the app records the magnetic field and your GPS position. MagMapper computes the median reading in each grid cell and paints it on a map: red for high magnetic intensity, blue for low. A buried casing appears as a focused red high standing out from its surroundings.
From your phone to the public map
Finished surveys upload to CIRES servers, where they pass automated quality control and human review before being added to the public community map and open data downloads. The app also estimates a well's depth with a physics-based magnetic inversion, exports raw and gridded data as CSV files for further analysis, and rewards contributors with scores, badges, and a community leaderboard. MagMapper has been validated against research-grade magnetometer equipment, including helicopter and ground-based surveys, and the underlying methods are published in the peer-reviewed literature.
Who it's for
State and federal agencies conducting orphaned-well inventories, landowners checking their own property, environmental researchers and field technicians — and citizen scientists anywhere who want to contribute to a national well-finding effort with nothing more than the phone in their pocket.
The project website has a getting-started guide, the live community well map, and the project's publications. The app is available for iOS and Android. Questions and feedback: magmapper@colorado.edu · Privacy policy
MagMapper is managed by CIRES at the University of Colorado Boulder and funded by the U.S. Department of Energy.