Shale Gas and Oil Terminology Explained: Technology, Inputs & Operations

This fact sheet from the Environmental and Energy Study Institute explains the technical terminology, drilling methods, and operational inputs associated with the extraction of oil and natural gas from shale formations, specifically focusing on hydraulic fracturing.

• Hydraulic fracturing, or fracking, is the primary method for extracting oil and gas from shale formations. It involves injecting fluid into rock to create fissures. While vertical drilling exists, horizontal drilling allows wells to extend up to two miles along a shale deposit, enabling 'high volume hydraulic fracturing' (also called 'slick-water hydraulic fracturing'). This high-volume method, developed in the 1990s, uses 70 to 300 times more fluid than previous methods and relies more on friction-reducing chemicals than gelling agents.
• Fracking fluids consist mostly of water, with chemicals making up less than one percent. Key chemical additives include surfactants (the largest chemical component by weight, used to reduce friction), biocides (used to kill bacteria to prevent corrosion and formation damage), gelling agents like guar gum and xantham gum, and propants (sandy materials that keep fractures open). Additionally, acidizing using hydrochloric acid may be used to open fractures more effectively, and diesel is sometimes used instead of water to carry higher concentrations of guar concentrate.
• Wellbore operations utilize a casing made of cement and steel to support the well and separate it from the surrounding geology, protecting aquifers from migrating fluids. The space between the rock and the steel pipe is called the anulus and is typically filled with cement. Rotary drilling is also required, utilizing a rotating drill and a 'mud' fluid that is typically oil-based (using diesel or synthetic oil) or a water and clay blend containing minerals like barite, chalk, or hemotite.
• The extraction process involves the release of gases through venting and flaring. Venting is the intentional release of gases—including methane, benzene, toluene, and volatile organic compounds (VOCs)—into the atmosphere, often when natural gas is not economically viable to recover. Flaring is the burning of natural gas for safety reasons, as methane is highly flammable and a potent greenhouse gas. While flaring can convert hydrogen sulfide gas (H2S) into sulfur dioxide (SO2), the resulting SO2 can contribute to acid rain.
• The Environmental and Energy Study Institute (EESI), the publisher of the document, is a non-profit organization founded in 1984 by a bipartisan Congressional caucus. It focuses on policymaker education and policy development regarding energy efficiency, renewable energy, and other environmental solutions to ensure a sustainable future for America.

APA

Glass, K. (n.d.). Shale Gas and Oil Terminology Explained: Technology, Inputs & Operations. Environmental and Energy Study Institute. https://www.eesi.org/files/fracking_technology_120111.pdf

Chicago

Glass, Kate. Shale Gas and Oil Terminology Explained: Technology, Inputs & Operations. Environmental and Energy Study Institute, n.d. https://www.eesi.org/files/fracking_technology_120111.pdf.

Wikipedia

{{cite report |last1=Glass |first1=Kate |title=Shale Gas and Oil Terminology Explained: Technology, Inputs & Operations |publisher=Environmental and Energy Study Institute |url=https://www.eesi.org/files/fracking_technology_120111.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{glassndshale, author = {Glass, Kate}, title = {{Shale Gas and Oil Terminology Explained: Technology, Inputs \& Operations}}, institution = {Environmental and Energy Study Institute}, url = {https://www.eesi.org/files/fracking_technology_120111.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }