Approximately 22,000 fewer wells are now required annually to develop the same amount of oil and gas reserves as in 1985, while new technologies have significantly reduced emissions of greenhouse gases. Moreover, environmentally friendly drilling fluids have been developed and many oil and gas companies have adopted new techniques such as reverse osmosis and filtration systems for cleaning the contaminants in water produced during well operations.

BG Group, a leading player in the global natural gas market, has taken environmental awareness one step further by creating a natural system for waste management at its desert drilling site in Oman’s Empty Quarter.

“We’re the first company to take this technology and apply it in an oilfield use,” says John Watters, regional well engineering manager for Europe, Oman, China and West Africa.

BG Group’s safe drilling approach

The UK-based company’s business principles state that, ‘We go beyond compliance with local environmental regulations to meet internationally accepted best practice’, and in order to achieve this, Watters and his colleagues have been looking at the way BG has tackled safety over the last decade.

“BG’s desert drilling project is the first example of the company’s green approach to waste management.”

“One of the core lessons we have learnt from our focus on safety is that there are initial costs in the application of safety standards, but the rewards we get through the reduction of incidents and accidents far outweigh this expenditure,” he explains. “Our biggest challenge is to take this mindset and apply it to environmental challenges in order to find approaches that benefit the environment, society and our business.”

BG’s desert drilling project is the first example of the company’s green approach to waste management and many challenges were faced to implement the necessary control and instrumentation systems for the 60m³ of effluent produced per day.

The waste needed to be managed on site, in a remote location 600km from any approved disposal centre, which meant that transporting equipment in and out of the location would have an effect on the environment. In addition, the isolated nature of the site meant that any system BG selected had to be robust.

Reed-bed system

After a thorough risk assessment, the team chose a reed-bed system.

“The design was kept simple and it is unlikely to break down because it has few moving parts,” says Watters.

Sewage enters the first of three ponds and flows through the reed bed plantations. The movement through the reeds then allows the micro-organisms living within the system to break down the nutrient load. It is run entirely by three pumps, which are turned on and off by the operator, who spends one hour a day working at the reed bed. Clear water suitable for evaporation and bio-solids suitable for compost or burial on site are the only
by-products – the water can be used for irrigation, the humus for arable use and the fodder for animal consumption.

Routine mandatory sampling of the discharge water by the Ministry of Health ensures compliance with state legislation; the treated water and humus are monitored weekly to ensure that they fall within recommended limits.

“The monthly savings came to a total of $9,200, based on reduced transportation costs.”

The reed bed system compares favourably with the traditional sewage treatment plants that are often used for the same purpose.

The substitution of complex technology for a low-tech solution leads to significantly lower operational costs and reduced maintenance requirements.

Moreover, a dehydrated intermediate product, which is unusable and needs to be disposed of in a landfill site, is replaced by naturally stabilised humus.

“If you plan the system properly, you will keep people safe, reduce breakdowns and end up with a much more efficient overall process,” Watters says. “We don’t feel that there has to a compromise between cost and safety. We believe that by investing in good safety procedures, we are also impacting positively on performance. The idea that environmental solutions can be cost-effective is very powerful.”

When BG balanced the cost of using a reed bed system against that of transporting waste to disposal sites, the company found that the natural system became cost-effective at 18 months.

The construction costs came to $170,000, while maintenance is $50 a day, but the monthly savings came to a total of $9,200, based on reduced transportation costs.

“After 18 months, it begins to save companies money,” Watters says. “The system we used had a high cost element because it was a pilot scheme, but if we used it regularly and could purchase all the necessary equipment in bulk, it would cost significantly less.”

Other benefits of the system include improvements in the morale of the crew due to large scale greenery on site and a reduction in the distance of truck driving by 500,000km per year, which also cuts health and safety risks.

Future of green technology

The Empty Quarter project is set to continue and Watters is looking to expand this kind of technology to other desert areas.

“Many challenges were faced to implement the necessary control and instrumentation systems for the 60m³ of effluent produced per day.”

“There are a lot of challenges to this,” he says. “We have to make sure that the legislative envelope within each country allows us to implement such a system.”

Other environmentally friendly systems in the pipeline include using microwave technology to treat drill-cutting systems, and bioremediation, which involves treating the oily, contaminated cuttings with bacteria and can be useful for growing plants and vegetables.

“If we think about it properly, rather than treating our by-products as toxic and dangerous, we can find better purposes for them,” explains Watters, adding that one idea being explored was using large-scale solar sills for water treatment in the future.

While the industry has several challenges to overcome before natural control and instrumentation systems are commonplace in waste management, interest is certainly growing.

“There is a lot of enthusiasm within the business for finding these types of solutions and demonstrating they can work,” Watters concludes. “To see how fast it picks up will be interesting, but oil and gas companies are beginning to show that it’s possible to act responsibly in the environmental area.”