Dr. Xavier Sava (left) and Dr. Anahí Grosse-Sommer of BASF review the study's results

BASF, the world’s largest chemical company, announces conclusions from a detailed investigation into the ecoefficiency of high-density completion brines. The two products put under the spotlight by BASF were formate brine and bromide brine.

In a world of diminishing resources how to do more with less? Whether in business or in our private lives this is always an important question. In a nutshell, this is what eco-efficiency is all about: identifying those products and manufacturing processes that most closely align with the tenets of sustainable development. The term ‘eco-efficiency’ was first coined in 1992 by the World Business Council for Sustainable Development and is based on the concept of fulfilling the economic, environmental and social requirements of today’s society without adversely affecting the development potential of future generations. Critical aspects of eco-efficiency are:

• Reduction in use of material and energy

• Reduction in dispersion of toxic materials

• Increased product durability

• Increased service intensity of goods and services

• Minimisation of life cycle costs

One of the first and possibly most well-known methodologies for quantifying sustainability is BASF’s Eco-Efficiency Analysis. Since 1996, this methodology has been used in more than 400 studies for the likes of Bosch Siemens Hausgeräte, Unido, Wella, Bündnis 90/Die Grünen (German Green Party), Environmental Ministry Rhineland-Palatinate and BASF itself. These organisations use the results as a basis for strategic decision-making and/or marketing.

The Eco-Efficiency Analysis developed by BASF compares the life cycles of products or manufacturing processes by analyzing ecological and economic data. The ecological analysis is based on a life-cycle assessment, which records all relevant emissions, material and energy flows through the product’s life cycle from cradle to grave, including a CO2 balance (carbon footprint). Environmental impact categories taken into account during the full ecological analysis are energy use, raw material consumption, land use, air and water emissions, solid waste levels, toxicity potential and risk potential.

The ecological factors comprise one side of the equation. On the other side are the economics. BASF uses a life cycle costing calculation, which goes further than cost of purchase to include costs attached to product use, such as energy, maintenance and disposal costs. When the full study is complete the products’ or processes’ eco-efficiency can be clearly judged against one another.

Comparing heavy brines

Dr. Xavier Sava, Product Development Manager at BASF, commissioned the brine study on behalf of his company: “An eco-efficiency analysis is always begun by defining a customer benefit. In this case, it was ‘the completion of an average HPHT gas well in the North Sea’. From the data we gathered this brought us to a brine density of 1.85 s.g. (15.44 ppg), which gave us two clear-brine alternatives – formates and bromides, or specifically, blends of cesium/potassium formate and zinc/calcium bromide,” he says.

The study itself was conducted by BASF’s Eco-Efficiency unit. Dr. Anahí Grosse-Sommer is responsible for the work. “We took into account all upstream and downstream environmental factors and costs, including production and use of brines and additives, emissions and end-of-life treatment within the stringent regulatory regime of the North Sea”, she explains. “The results show that formate brines are significantly more ecoefficient than bromide brines with both cost and environmental-impact factors in their favour. Formate brines score well on system costs, lower toxicity potential and critical emission levels. The waste category is particularly problematic for bromide brines. Large amounts of zinc bromide-contaminated solids and well water have to be shipped to shore, treated and landfilled as toxic waste,” says Grosse-Sommer.

“Formate brines clearly offer the most sustainable solution,” says Sava. “Although we do need to recognise that to achieve a 1.85 s.g. brine you need to use somewhat more formate salt than bromide salt, so overall material consumption is higher with formates”, he states. The conclusions from this study are clear, but it doesn’t stop there. Further work is planned for this year when clear completion brines will come under the eco-efficiency spotlight again, but this time for other scenarios involving different geographic areas and fluid densities.

In the set scenario formate brine is more eco-efficient than bromide brine