Encapsulated Bentonite for Abandoned Well Sealing

NON-TECHNICAL SUMMARY: What can be done to ensure a high level of water quality for wildlife, agriculture, and humans around the world? More and more wells, whether they are for water, oil and gas, or coal-bed methane, are deeper than ever and are at risk from surface pollution and inter-aquifer mixing. Cement, long known as the only alternative, has been shown to have serious drawbacks. This proposal builds on previous research that has demonstrated bentonite sealing and plugging characteristics. Sodium bentonite chips are recognized as a superior well sealing/plugging material for shallow wells. Its tremendous ability to swell when hydrated allows it to resist dislodgement pressures of hundreds of pounds per square inch. Additionally, it is inert, durable, self-healing if disturbed and more economical than Portland cement. But its swelling capacity also makes it difficult to deliver successfully to well depths much deeper than 500 feet. We expect to find compounds and/or materials that will economically transport bentonite chips to well depths over 500 feet. This technique must maintain bentonite's superior sealing characteristics and be economical to ship and to handle at the well site. Successful research will lead to a prototype that will greatly expand bentonite's use as a low cost, safe, superior sealing solution for abandoned drill holes. Primary commercial benefactors are: oil and gas exploration/drilling companies, coal-bed methane producers, water well drillers, and others who will no longer be required to use much more expensive, less safe well-sealing technologies.