Plugging Ruby 43-15-4674BG With Bentonite

Al Hajri, Eid Mubarak N.
Lemke, Peter
Tainsh, Allan
Cody, Shawn David
Yao, Yao
The conventional method for plugging and abandonment of coal bed methane wells utilizes concrete which is pumped down the well casing and sets to form a permanent plug. An alternative method for plugging wells is to replace concrete with bentonite. The benefits of using bentonite as a replacement for concrete include lower material costs, no need for specialized pumping equipment, as well as the flexibility and self-healing capabilities of hydrated bentonite. One issue encountered with using bentonite is its tendency to bridge-off before reaching the intended depth. Additionally, bentonite is not yet approved as a concrete replacement in the State of Wyoming. This research focuses on the production and implementation of a bentonite cylinder which resists bridging-off. Development and production of the cylinders is discussed including the design of the production equipment and plug composition. Additionally, the plugging of a coal bed methane well using the developed cylinders is presented. The original design and subsequent modifications of the well plugging procedure are discussed along with the results of pressure testing. A comparison of the actual costs for the plugging of this well and the estimated cost of using concrete make a case for replacing concrete with bentonite.
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University of Wyoming Libraries