Beyond NPEs

In an era where sustainability is a top priority, many large oil and gas producers find themselves at a critical crossroads. While the industry still has a choice, increasing societal and customer pressures for sustainability are driving companies to seek out alternative solutions. No longer just a trend, sustainability is a guiding force that is shaping corporate strategies across all sectors. Businesses that respond to these pressures are not only meeting the demands of their customers and employees but are also positioning themselves as leaders in a rapidly evolving landscape.

One specific challenge for oil and gas producers is the chemical processes used to expand access to these resources through hydraulic fracturing, commonly known as ‘fracking.’ As regulatory bodies, non-governmental organisations (NGOs), local governments, and consumers increasingly demand environmentally responsible practices, the industry must strongly consider making a conscious choice to begin seeking alternatives that can offer it a pathway to a more sustainable future, ensuring long-term viability and success in a world that prioritises environmental stewardship.

Narrow range ethoxylates (NREs) – a more sustainable alternative

For decades, non-ionic surfactants, particularly nonylphenol ethoxylates (NPEs), have been the standard choice in many oil and gas chemical formulations where controlling oil/water interaction is necessary. NPEs are widely used for their effectiveness in critical fluids employed in drilling, completion, production enhancement and flow assurance. Their popularity stems from their affordability, scalability and consistent performance across various applications. However, despite these advantages, NPEs are now facing increased regulatory scrutiny due to their significant environmental drawbacks.1 Aquatic and animal studies have shown that NPEs are toxic to fish and are associated with reproductive and developmental effects in rodents.2 This has led to bans not only in certain regions but also in consumer-based markets and some industrial processes as concerns grow about their long-term impact on ecosystems and human health.

The global regulatory landscape surrounding chemicals like NPEs is evolving rapidly, driven by these growing concerns about environmental impact and worker safety. For example, the European Union’s REACH regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals) imposes strict limits on NPE concentrations, signaling a global shift towards more eco-friendly alternatives. Similarly, in North America, the Environmental Protection Agency’s (EPA) proposed Significant New Use Rule (SNUR) under the Toxic Substances Control Act (TSCA) and California’s stringent limitations on NPEs in detergents reflect this trend.3

In response to these challenges, the industry is proactively seeking alternatives. Though there are several surfactant chemistries a formulator can evaluate, the first-choice alternatives with similar performance, availability and price are non-ionics based on linear or branched alcohols. These types of surfactants are generally classified into two categories: broad-range ethoxylates (BREs) and narrow-range ethoxylates (NREs). Based on the production catalyst used and the resulting distribution of ethoxymers, BRE and NRE surfactants offer a performance profile comparable to NPEs while significantly reducing the environmental impact of the oil and gas production fluids.

NREs represent a significant step forward for the oil and gas industry. There are performance and sustainability advantages associated with NREs that make them the preferred choice by operators wanting to demonstrate their commitment to environmental stewardship and improve worker safety while potentially reducing operational costs associated with handling and disposal.

As research and development efforts continue to expand the range of NRE applications and optimise their performance, these advanced surfactants are poised to play an increasingly vital role in responsible oil and gas production.

A closer look at NRE advantages

NREs are a type of surfactant made with special catalysts and offer distinct advantages over NPEs in certain oilfield applications:

• Reduced environmental impact: NREs do not use the endocrine-disrupting nonylphenol alcohol starting material which results in the significant aquatic and human health concerns associated with NPEs.3 NREs are biodegradable and produce less harmful byproducts upon degradation than NPEs, minimising their environmental footprint and reducing the risk of long-term ecological damage with use in oil and gas productions. This characteristic aligns with the industry’s increasing focus on sustainable practices and reducing its impact on water resources.
• Enhanced performance: the narrow ethoxymer distribution of NREs allows for optimised performance in specific oilfield applications. They have the ability to achieve precise hydrophilic-lipophilic balance (HLB), which is a number that indicates the relative hydrophilicity/hydrophobicity among surfactants. The narrow ethoxymer distribution also makes NREs highly effective in applications requiring clean separation interfaces, such as demulsification or for designing spacer fluids or in applications when more precise HLB values are helpful, such as organoclay activation.

NREs exhibit properties that support handling processes in oil applications:

• Lower volatile organic compound (VOC) and odours: for example, by removing low-mole ethoxymers, NREs reduce free alcohol content, resulting in lower VOC emissions and reduced odour.
• Low melting points: by removing the high-mole ethoxymers, NREs have also proven to have lower melting points compared to BREs, making them safer and easier to handle for oilfield personnel. This can be advantageous in colder environments where maintaining fluid properties at lower temperatures is critical or where heating is not available. These characteristics can also help reduce energy consumption and potentially lower transportation and storage costs.

NREs in action: key oilfield applications

The advantages of NREs can be applied to various oilfield applications. Two areas where NREs are making a significant impact are organophilic clay activation and demulsification/emulsion breaking.

• Organophilic clay activation: fracking operations can use polymer slurries that utilise organophilic clays as viscosifiers to maintain proper fluid properties to carry the proppant under challenging downhole conditions. NREs effectively activate these clays, ensuring optimal viscosity and stability of the slurry. Their precise ethoxymer distribution ensures efficient interaction with the clay, leading to improved performance compared to BREs, which may require higher concentrations to achieve similar results.
• Demulsification/emulsion breaking: the separation of oil and water is a critical step in oil production. Emulsions, however, often form during the oil production process, hindering separation efficiency and requiring specialised demulsifiers to break them down. NREs excel in this role, effectively breaking emulsions and facilitating faster flowrates. This is particularly evident during flowback operations.

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