Drilling advances

The outlying stench was wholly incompatible with the perfectly manicured meadows, rolling vineyards and lush botanical gardens, all within the shadows of regal Mt. Taranaki and abutting one of the world’s most pampered coastlines. Well north of bucolic New Plymouth, on New Zealand’s North Island, the pungent smell of decaying and burning wastes provided a less-than-inviting welcome, as we pulled off rural Highway 3 and into the Uruti Composting facility.

Among the myriad rubbish being remediated were symmetrical, tarpaulin-covered rows that could easily be mistaken for an everyday vegetable garden, save for the nose-pinching odor and the resulting crop. For there, beneath the coverings, thousands of common earthworms chowed down on drill cuttings generated from a specially formulated M-I SWACO paraffin-based drilling fluid. During the April 2008 site visit, it was explained that the collective end-result of the creatures’ digestive process was commercial-grade fertilizer that found an eager market with area garden centers and the local government, which used the nutrient-rich product for community landscaping.

The pilot project represented the first attempt at using vermiculture to convert cuttings from a waste product to a marketable resource. Five years on, worm-driven drilling waste management may still seem like an out-of-the-box methodology to some, but with reducing the volume and costs of the well construction waste stream even more de rigueur, it appears that any proposal not utterly implausible will remain on the table. Owing in no small part to the ramp-up in shale exploration, nearly all the investigations into beneficial reuse of cuttings have focused on using the erstwhile waste in more straightforward applications, such as bases for lease roads and drilling pads. However, that has not stopped folks from continuing to propose more unconventional recycling treatments.

British cuttings patent. Last December, the UK’s World Intellectual Property Organization (WIPO) published a patent application that Aberdeen-based Total Waste Management Alliance Ltd filed last summer, which calls for using North Sea drill cuttings in plastics manufacturing. The integrated drilling waste management company said that the patent-pending process would treat and reuse much of the estimated 40,000 of contaminated cuttings shipped to shore each year from wells in the UK North Sea. The potential feedstock promises to increase exponentially, if the UK follows through and exploits its purportedly sizeable onshore shale reserves.

 According to the filing, the process thermally treats the cuttings to extract entrained hydrocarbons, much of which, likewise, can be reused. Afterwards, the company’s patented TCC RotoMill process can be used to grind the solids into an ultra-fine powder that is compressed and mixed with recycled plastic, to form pellets. The pellets are then used in the manufacture of bollards, planters, benches, decks and other rigid plastic products.

Making new roads. The new-age recycling options notwithstanding, most people agree that properly treated drill cuttings are intrinsically well-suited for use in laying down roads, drilling pads and the like. Such initiatives are gaining a receptive following in the U.S. shale plays, where transportation to often-remote disposal sites creates a host of economic and environmental headaches.

One of the more enduring projects has been in the Permian basin, where Scott Environmental Services of Longview, Texas, used specially treated water-based mud cuttings to construct a lease road. The access road has accommodated rig traffic for nearly five years with no side effects, said David Burnett, a director and research coordinator at Texas A&M University’s Department of Petroleum Engineering, who has monitored the project since its inception. “We monitored to see if there was any dust or leaching. It does not leach out, and has held up well to the West Texas environment. It is very environmentally acceptable,” said Burnett.

Scott uses its proprietary Firmus process, which is based on accepted solidification and stabilization technology, to treat cuttings from water, oil and saltwater-based muds for conversion into construction material for lease roads, drilling pads, compressor station pads, tank battery berms, and similar load-bearing structures.

According to the San Antonio Express-News, Scott has similar projects in Madison County, Texas, in the Eaglebine play, as well as in the East Texas portion of the Haynesville shale, the Granite Wash and elsewhere. The waste management company also is looking for opportunities for oil-based cuttings in the core EagleFord play. While the process would seem a natural fit for public roadways under constant assault by rig traffic, thus far the recycling option has been restricted to operator-controlled projects, such as lease roads and drilling pads.

In a related project, fellow Texas-based waste management concern, Polk Operating LLC, plans to begin operating a cuttings and liquids recycling facility in the heart of the Eagle Ford later this summer. The Polk Karnes R3 facility in Karnes County is designed to remediate oil-based mud cuttings into commercial road construction material. The facility also includes a saltwater disposal system that was recently permitted by the Texas Railroad Commission. The Bowie, Texas-based company operates a similar recycling facility in Jefferson County, Okla.

Polk spokesman Christopher Saenz said the facility now under construction will process and recycle more than 25,000 cubic yards/yr of drill cuttings, as well as over 25,000 bbl of liquids.