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Applying a comprehensive, standardized environmental assessment process to products enables hydraulic fracturing and more.
When Baker Hughes introduced its SmartCare family of environmentally responsible chemical products in 2009, the intention was to help operators balance performance, cost, and environmental stewardship in hydraulic fracturing operations. Three years later, the product line has been expanded to include drilling and completion fluids, production chemicals, and additives used in cementing and stimulation operations.
Components of a chemical product are assessed and rated for potential environmental, health, and physical impacts according to a comprehensive, rigorous, and customized evaluation process that is based on leading US and global standards. The product is further qualified for optimal performance, cost effectiveness, consistent quality, and compatibility. Insights gained from the rigorous evaluation also guide the R&D of increasingly sustainable solutions.
Toward a global standard
Currently the US has limited federal regulations governing oilfield chemicals. However, several states have passed, or are in the process of passing, regulations intended to improve transparency of oilfield chemicals through FracFocus.org? . Approximately 600 different schemes for evaluating or approving and labeling chemical products as “green” are administered throughout the world by a wide range of organizations. Content, terminology, definitions, and evaluation criteria vary significantly, and evaluations range from relative rankings to pass/fail.
Many existing ranking systems focus only on environmental impact, and most are based on the inherent hazards of the products at full strength, without taking into consideration use conditions or actual exposures. The situation is exacerbated by the lack of a global hazard communications standard for use in product development and marketing. The United Nations (UN) Globally Harmonized System of Classification and Labelling of Chemicals (GHS) has brought international consensus to hazard criteria, definitions, and quantification. However, implementation is slow and arduous, and several GHS hazard end-points are either inappropriate or need modification to address the unique needs of oil-field operations.
Based on a review of existing systems, a clear, structured chemical evaluation process/review (CEPR) system was developed to augment existing regulations. The process uses the most appropriate GHS end points and also screens components against US Environmental Protection Agency Priority Persistent Bioaccumulative and Toxic Chemical and UN Environment Programme Persistent Organic Pollutants chemical lists. The evaluation provides a numerical rating of the HSE risk associated with both the individual components of each chemical product and the product as a whole.
Additionally, CEPR prescreens products and components to determine their potential to meet North Sea criteria, which regulate the use and discharge of oilfield chemicals. The process also assesses 22 different regulatory lists from throughout the world to help identify and address potential regional regulatory conflicts and to establish benchmarks where none exist.
The overall evaluation enables comparison of functional groups such as surfactants, clay stabilizers, and corrosion inhibitors so that the most environmentally preferred option can be selected. Compliant components can then be combined to create chemical solutions that match reservoir characteristics and reduce environmental impact. By creating a standard communication platform, the evaluation also enables operators to provide credible and transparent information to regulators, investors, and the community.
The chemical evaluation process is administered by Baker’s Environmental Services Group, with laboratory capabilities in St. Louis, Mo., and Stavanger, Norway. Chemical evaluations are typically performed by inhouse chemists and toxicologists. However, the company also employs a third-party consulting group to identify and assess components from outside suppliers without compromising intellectual property concerns.
The information from the CEPR provides a benchmark by component for future product improvement. Once a product has been assessed, all of its components are input into a database that can be accessed by technologists to develop new, more sustainable chemicals. The database currently contains more than 2,500 products and 25,000 datapoints. Both numbers grow continually as more products are evaluated.
Expanding environmentally responsible options
When the product line was introduced in 2010, it contained 45 fracturing additives. Today, more than 100 products have been certified for stimulation applications, and almost 100 more are ongoing or queued for Smart-Care assessment.
The SmartCare-certified clay stabilizer, ClayCare, is used abundantly in US shale plays by a major independent operator to reduce the environmental impact of hydraulic fracturing fluids. Tetramethylammonium chloride is replaced by choline chloride, whose primary non-oilfield use is as an additive to chicken feed. This is one of the first instances in which the choline chloride-based product has been used.
Sorb solid inhibitors penetrate deep into the reservoir to prevent damaging buildup of organic materials and minerals. The slow-releasing, long-lasting chemicals inhibit flow-blocking depositions over an extended period of time. As solids, they eliminate potential surface liquid spills that could leach into groundwater or surface water. They also can reduce concentrated chemical returns that often follow liquid chemical well treatments. And they can eliminate or significantly delay workovers and associated deferred production and nonproductive time. Compared to liquid chemical squeeze treatments, which typically last for six to 12 months, the longest recorded treatment of ScaleSorb solid scale inhibitors is seven years. The highest cumulative treated production without scaling problems is more than 2 MMbbl of water. RSP Permian has used ScaleSorb and other SmartCare products to treat more than 120 wells in the Wolfberry trend in the Texas Permian basin since 2010, with no intervention required. The operator estimates intervention-related savings approaching US $2 million based on an average cost of $15,000 per well per year.
New water-based drilling fluid systems are more environmentally favorable than oil-based systems and offer the wellbore stability and superior drilling speed and performance normally associated with invert emulsions. The water-based fluids eliminate disposal of oily cuttings and can help reduce on-rig cleanup time by as much as two days. The fluids’ specially purposed lubricants coat metal surfaces, drill cuttings, and formation walls to reduce torque and drag, particularly in HP/HT applications, and enable greater amounts of hydraulic horsepower to reach the drill bit for faster penetration rates.
Sustainability initiatives help instill confidence in operators, regulators, and the public that the chemicals deployed in oilfield operations are thoroughly qualified to reduce environmental concerns without jeopardizing performance or economics.