For more than 20 years, drilling fluid suppliers have focused on developing systems and additives that deliver minimal impact to the environment. While this remains the prevailing focus, the tide has shifted dramatically with emphasis now being placed on not only minimizing the waste ultimately generated at the wellsite, but also actually converting it into a resource that is beneficial to the receiving environment.
Historically, contaminated drill cuttings and other waste produced from drilling operations were considered just that – a necessary evil that had to be treated and disposed of through a variety of techniques, all of which compounded overall project costs appreciably. Today, in the Gulf of Mexico, North Sea, West Africa, the Caspian Sea, and elsewhere, regulations governing the treatment and disposal of drilling wastes have tightened considerably. Many of these areas, for instance, appear to be moving steadily toward a total ban on the overboard discharge of drill cuttings. These governmental restrictions combined with operators' internal environmental policies, increased public scrutiny, long-term liability issues, and project economics mandate that the volume of waste produced at the wellsite be reduced significantly.
In today's business climate, improving the operational and economic efficiencies of drilling operations, while simultaneously protecting the environment, are no longer viewed as disconnected goals. Rather, striking the correct balance between the two is seen as a critical component in the management of everyday business. In fact, waste management has been identified as one of the highest growth areas of our industry, regardless of the level of activity. Consequently, operators and service suppliers alike are joining forces to conceive innovative, and sometimes highly creative, techniques to minimize drill wastes – methods that have the potential to be both profitable and sustainable.
A prioritized strategy for waste management holds that waste handling must be elevated to the highest level possible. Clearly, that level is to reduce the amount of waste at its source. The second highest level is to reuse drilling fluid components as much as possible in their original form, followed by recycling components for purposes other than their original use. The second lowest level is to recover components and attempt to move them up the strategy pyramid. The lowest level in this reverse pyramid is to isolate the residue and dispose of it in a responsible manner.
From a drilling fluid perspective, systems previously were developed to deliver maximum drilling performance characteristics with little thought afforded the eventual treatment and disposal of the waste. At present, the philosophy behind fluid development has changed radically, with developers now engineering the initial system to provide an environmental solution at the end of the process. In what we refer to as "reverse wave" development, drilling fluid systems now are being engineered to not only provide optimum performance, but formulated in such a way as to reduce the ultimate volume of waste to be generated. This essentially redefines waste through fluid design because the obvious point to begin remediation is in the early stage of the development of a new system.
Fluid researchers first elevated waste management issues to a higher level with the introduction of synthetic-base drilling fluids offshore. For the first time, operators were able to achieve the high performance characteristics intrinsic to an invert emulsion fluid system with the environmental acceptability of water-base fluids. By the mid- to late-1990s, the recovery and reuse of water-base drilling fluids was proven to be a cost-effective fluid handling method that economically benefited both the operator and drilling fluid provider.
The concept of reuse has since reached an entirely new dimension with the conversion of waste material into a commercially useful product. One of the more creative offshoots of the "reverse wave" fluid development strategy is worm-based bioremediation of drill cuttings generated from a specially engineered synthetic-base drilling fluid. While worm farming or vermiculture is a well-established method of treating organic wastes, a pilot project in New Zealand represented the first attempt at applying this treatment method to drill cuttings. As of this writing, more than 1,000 tons of cuttings have been "worm farmed" successfully, converting what was once waste into a saleable organic fertilizer with proven environmental benefits.
Here, the fluid system was designed at the outset to yield an end product that actually enhances soil quality. The fluid was formulated specifically to interact with the raw cuttings, which are later blended with nutrients. The concoction is then fed to the worms, resulting in a mulch that can be sold to farmers as fertilizer.
Obviously, designing fluids to resolve challenging waste issues is the appropriate start; however, in the near term, programs that consider the entire range of activities from well planning to production may have a higher likelihood of achieving the optimum balance between operation and environmental efficiency. A holistic integrated approach to fluids engineering, for example, considers every aspect of a well design to not only achieve the highest operational performance, but to do so with zero to minimal envir-onmental impact and at the lowest total project costs. Such programs may become the norm rather than the exception, especially in high-cost and high-risk environments like deepwater.
As environmental drivers become more stringent, dealing with wastes can no longer be an afterthought. Instead, it must be considered in detail throughout the process, from fluid development to well execution. The drilling fluid, solids control, and waste management sector, working hand-in-hand with operators, will continue to develop technologies to significantly reduce the waste that remains at the end of the fluid stream. We will do so, not just because our clients and regulators demand it, but because it is critical to the continued health of our industry, and quite simply the right thing to do.
Loren Carroll
President & CEO, M-I LLC
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