Fly Ash Grout for Plugging Wells

Oklahoma University's Well Construction Technology Center (OU WCTC, website http://www.ou.edu/wctc) is exploring the use of fly ash, a by-product from coal-fired power plants, in grouts as a substitute for conventional oilfield cement for plugging abandoned oil and gas wells. Work is being conducted through a project with the Integrated Petroleum Environmental Consortium (http://ipec.utulsa.edu). In the project, grouts using fly ash from five coal-burning power plants in Oklahoma were formulated. In addition to obvious cost advantages ($1-$2 per sack versus $11-$13 per sack for cement) for producers, this approach would reduce a disposal problem for coal-fired power plants. 

Properties that were tested included: thickening time, free water, product durability, compressive strength, fluid loss, and pumpability through coiled tubing and pipe. Tests were encouraging, with the grouts exhibiting properties that indicated they would be acceptable for plugging wells. In a proposed Phase II of the project, some test wells will be plugged. Current Oklahoma Corporation Commission (OCC) rules require that Portland cement be used, but OCC is aware of this project and open to changing the statute if testing confirms that fly ash grouts are an acceptable alternative.

Progress reports are available through IPEC's website (http://ipec.utulsa.edu).

For more information, contact Dr. Subhash Shah at OU, phone 405-325-2921 or e-mail subhash@ou.edu.

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Methane Emission Reductions in 2000

The U.S. Environmental Protection Agency's (EPA) Natural Gas STAR program recently announced methane emission reduction results for 2000. Total emission reductions for all sectors—production, transmission and distribution—were 34 Bcf. 

The Natural Gas STAR program's mission is to reduce gas losses through market-based, voluntary activities that are both profitable and beneficial to the environment. Industry partners choose among a number of best management practices recommended by EPA, or they can implement other practices that reduce methane emissions. Within the production sector, the following were the leaders in reducing methane emissions:

• Install vapor recovery units (4.5 Bcf)
• Install plunger lift systems in gas wells (3.0 Bcf)
• Identify and replace high-bleed pneumatic devices (2.8 Bcf)
• Install flash tank separators on glycol dehydrators (0.7 Bcf)

For one example of a vapor recovery application, see the "Vapor Jet" case study published in PTTC/World Oil's Petroleum Technology Digest in September 2000 (http://www.worldoil.com/Magazine/MAGAZINE_DETAIL.asp?ART_ID=2107&MONTH_YEAR=Sep-2000).

For more information on the Natural Gas STAR program, visit their website (http://www.epa.gov/gasstar/) or contact Program Manager Carolyn Henderson (phone 202-564-2318).

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Industry Applying Technology to Reduce Environmental Costs

An environmental thread is woven through PTTC's regional activities. Here are examples of industry applying technologies to reduce their environmental costs.

• An environmental consultant is employing visualization software learned about through PTTC to model pollution plumes. Hours are saved in the modeling effort, and clients reap benefits. The consultant noted that results were vital in at least five cases. In those instances, all cases were decided in the company's favor with savings ranging from $20K to $1,000K.
• Staff from another environmental company noted how knowledge gained through a workshop on "Wyoming Air Permitting" reaped direct benefits for two clients—one with permitting for compressors in a coalbed methane project and, for another client, learning that permitting was not required, which saved the client a substantial amount of money.

Vapor recovery (see Natural Gas STAR) article is yet another topic with a definite environmental focus.