Chemicals in hydraulic fracturing operations: Apache’s Model for Sustainability

1. What are the major categories of chemicals by function?

  • Surfactants – detergents that helps wash out contaminates down hole so the well can make more oil and gas.
  • Biocides - disinfectants to kill bacteria down hole that can corrode the pipes.
  • Scale Inhibitors - a compound that keep scales from forming in the pipes that can slow the oil and gas flow.
  • Gel Systems – a chemical compound that thickens water to allow it to carry more sand into the fractures, making them wider and more permeable to produce more oil and gas
  • Friction Reducers – a chemical compound that ‘slicks the water’ to minimize friction and pressure allowing the fluid to carry more sand into the fractures, making them wider and more permeable to produce more oil and gas

Friction reducers, gel systems, and surfactants are needed to complete the frac.

Surfactants, biocides, and scale inhibitors are needed post frac to ensure oil and gas flows properly and to maintain pipe integrity.

2. How do hydraulic fracturing techniques determine the makeup of the chemical packages?

The two primary frac fluids are gel and slick water systems. With respect to chemical additives, they are similar in that they may use surfactant, scale inhibitor, and biocide. Both use similar pumping systems that use the fluid to fracture the shale formation to release oil and gas. The gel or slickwater is then brought back to the surface along with oil, gas, and produced water (the water that is produced when oil and gas are extracted from the ground). Oil and gas is transported to market and the produced water is recycled as frac fluid. Produced water and flow-back water from the well is captured and used as the water for future fracs.

The difference is that gel systems use a thickener and less overall fluid. Because the gel is thicker, it can carry more sand into the fractures, keeping the fractures open and allowing oil and natural gas to be pumped out.

Slick water systems are thinner but pumped at higher pressure rates in order to carry the sand. The higher pumping rate causes friction and pressure, which necessitates the need for friction reducer.

3. Will you provide a rough comparison of chemical packages among shale plays?

The composition of the chemical package is depends on whether the well is in a gas or oil shale play because this determines the volume of produced water. If a well yields more produced water, it will require more scale inhibitors, biocides and surfactants to ensure the flow of oil or gas and to maintain pipe integrity. Gas shale plays have less produced water therefore will use less chemical additives.

Gas shale plays include: Marcellus, Haynesville, Barnett and others. Oil shale plays include: Eagle Ford, Permian, Granite Wash, Bakken and others.

4. How would you evaluate the progress in reducing chemical volume in fracturing operations?

New technology for friction reducers (FR): Apache, for instance, is pursuing new technology to use a powder friction reducer. Friction reducers “slick the water” to minimize friction within the pipes. This powdered type will reduce the FR volume required by two-thirds due to the elimination of carrier solvents and chemical surfactants. It will also reduce volatile organic carbon (VOCs) caused by FR use. In addition, due to the lower volume of chemical required, this will result in fewer trucks on the road leading to reduction of CO2 emissions by two-thirds. The number of truck accidents (one of the largest safety issues facing E&P companies) should also be reduced by two-thirds.

Concentrates for chemicals: In addition to dry friction reducer, Apache is developing new technology to reduce the amount of carrier solvents in surfactants, scale inhibitors, and biocides by concentrating the products. In addition, Apache is using greener carrier solvents identified by the EPA’s Design for the Environment (DFE) program. This program helps guide consumers, businesses and institutional buyers towards products that are cost-effective and safer for the environment. This approach will also reduce the chemical volume required, VOCs and CO2 truck emissions as seen with the dry friction reducer.

Enlisting a chemical subject matter expert (SME): Historically, operators relied on service companies to provide best technology in compliance, costs, and performance. Enlisting an experienced chemical expert allows companies to use and develop best technology for sustainable cost performance while allowing them to audit systems used by service companies. Many times a simple product review can improve sustainability and cost performance and reduce chemical use rates.

5. How would you describe your progress in reducing chemical toxicity and using greener frac additives?

In general the drive is for improvements in three areas: lowering chemical volumes, improved environmental fate, and lower toxicity. The strategies include:

  • Overall chemical volume reduction
  • Reduction in Volatile Organic Carbon (VOC) emissions – less volatile solvents
  • Reduction in CO2 emissions via transporting lower chemical volumes
  • Reduction in chemical component toxicity including the elimination of diesel, BTX, endocrine disruptors, and carcinogens
  • Use of more bio-degradable chemical components and migration to EPA DFE listed components

    Use of chemical components that are less bio accumulative (accumulation of substances, such as pesticides, or other organic chemicals in an organism.)

6. How do energy producers organize/manage their chemical selection and how does this factor into contractor selection?

The best approach is for the operator is to enlist a subject matter expert (SME) from the chemical industry to monitor and control chemical recommendations. Apache has hired an SME to review drilling, fracturing, and production chemicals used. The best approach is for the expert to review all chemicals recommended and review with the vendor’s Environmental Health & Safety (EHS) group. This will ensure compliance with the various regulatory groups for air, water, waste, etc. while advocating for greener ingredients that are more sustainable. Companies should also incorporate guidance from organizations like the EPA’s Design for the Environment (DFE) program, which helps consumers, businesses and institutional buyers identify products that are cost effective and safer for the environment.

7. What are the contractors/chemical suppliers doing to reduce chemical toxicity?

Many have developed ranking systems. They are also mothballing older products, while developing more environmentally sustainable products. Also operators, contractors and service companies are participating in more forums in order to learn from each other, learn new techniques and products. Apache personnel chair both the Society of Petroleum Engineers (SPE) and American Chemistry Society (ACS) – Green Chemistry forums to further the use of greener chemistry in frac operations.

8. What are the overall dynamics of the market in terms of questions 6 and 7 above, including consideration of efficacy and pricing?

From Apache’s perspective, with the advances in chemistry and technical processes, it is reasonable to conclude that sustainable chemicals can be achieved with a very competitive cost performance. Apache is moving towards a new chemical sourcing model for frac chemicals, which will eliminate the confidential business claims from vendors and will ensure Apache is aware of all chemical components being used in its operations. Apache’s goal is to reduce and eliminate chemical use while striving to use EPA DFE-listed chemistries via its new sourcing model for chemicals.

Presented by Danny Durham, Apache’s manager of Global Upstream Chemicals. Durham has more than 35 years of experience in the use of chemicals in the upstream oil and gas industry. He holds several patents and has served on several industry committees.