������ � ���� An Overview of Hydraulic Fracturing • History • Processes • Technology • Risks • Trends Daniel Mackay Managing Director, NRG Well Management Ltd www.the-nrg-group.com
An Overview of Hydraulic Fracturing Section 1: Hydraulic Fracturing – A Brief History
A Brief History… • A common misconception..? • What is it…? Given the attention over the last 15 years • • Hydraulic Fracturing, or ‘Fracking’ is or so, many people are under the ‘simply’ the fracturing of subterranean rocks using hydraulic (fluid) pressure impression ‘Fracking’ is a new technology… ‘unconventional’ • A fluid mixture is pumped into and techniques have been in existence for against the formation where it cracks, creating fissures which are held open nearly 150 years! using proppants, allowing Commercial Hydraulic Fracturing • hydrocarbons to flow to surface (Fracking) has been in use since the • Most commonly used extracting oil 1940’s, pioneered in the USA with the and gas from ’tight’ (low permeability) use of acids on limestone formations, formations (generally shales) followed by the use of oil, then finally the water / proppant mixtures we see today
• The Breakthrough and Rise of the USA • The Fracking we are familiar with today really came about in the early 1980’s as the technology was combined with horizontal drilling, and was used to exploit gas from shale formations in the USA • Although already widespread in the USA and elsewhere in the world, as the oil price boomed in the early 2000’s more and more money was invested A Brief • Shale oil and gas was exploited, causing a seismic shift in the energy market as the USA no longer relied on an energy policy dependent on importing oil and gas History… • The USA was one of 19 global LNG exporters in 2017 and accounted for 5% of the almost 40 Bcf/d global LNG market - up from nothing just a few years ago! 4
Photograph: Christopher Thomond for the Guardian • What about the UK…? • Hydraulic fracturing in the United Kingdom started in the A Brief History… late 1970s with fracturing of the conventional oil and gas fields of the North Sea • Since the early 1980’ its been used by approx. 200 onshore oil and gas wells • Cuadrilla (shown above) have recently fracked the first well in the UK since 2011 and are flowing gas to surface 5 after being shut down due to seismic activity levels out
An Overview of Hydraulic Fracturing Section 2: Hydraulic Fracturing – The Processes
Getting Permission in the UK Successfully dealing with the UK regulatory and local bodies involved in the fracking approval process is arduous, and in most cases almost impossible • A Petroleum Exploration and Development Licence (PEDL) is required from the OGA • A series of steps are then taken to obtain permissions from the landowner and council planning authorities • The operator then requests a permit from the Minerals The Planning Authority (MPA), who together with the local planning authority, determine if an EIA, funded by the operator, is required. Process: • Two permits are required under the Water Resources Act 1991 and one permit required under the Control of Major Step #1 – Accident Hazards Regulations 2015 are obtained from the appropriate environmental agency, to ensure that onshore hydraulic fracturing operators fulfil strict environmental Permission! regulations • The well then has to be well examined as per the DCR Regulations which govern independent verification of well designs and operations in the UKCS • And finally a hydraulic fracture plan (HFP) is required to be agreed with OGA in consultation with the EA. Hydraulic fracturing consent (HFC) is then granted following an application to BEIS - once it has been reviewed by the Secretary of State and complies with requirements to mitigate any seismic risks.
The US Regulatory Regime on Fracking The US presents a very different regulatory environment when compared to the UK • Various, and differing, laws can affect Fracking at the local, state and federal level in the US, making it extremely complex and almost impossible to summarize • Debates currently center around whether Fracking should be regulated at these lower levels or at the federal level – there are good cases for both • Interestingly Since 1997, as per the EPA, hydraulic fracturing in the USA does not fall under the remit of the ‘Safe Drinking Water Act’ and EPA studies have demonstrated that it has no bearing on water quality • A lot of federal moves to regulate Fracking in the USA with Acts and proposed regulations have failed to become law, demonstrating the power that this technology and the lobbying energy industry has especially as it is making the USA secure in energy supply and resistant to market forces
The Process: Site Preparation & Spatial Constraints US Vs. UK!
The Process: Methods Involved… • There are generally 4 stages involved in the overall process: • Drilling Generally straight forward, a vertical well is drilled to approx. 2,000 – 3,000m and • kicked off to horizontal using geo-steering technology to place the well – these horizontal sections can be thousands of feet long • Care is taken to case and cement across the water table, ensuring no groundwater contamination • Perforation & Isolation • The cased well is perforated using shaped charges, which are detonated at selected locations in the production zone, also making slight fractures into the formation • These sections are then hydraulically isolated from one another • Stimulation (hydraulic fracturing) • A high-pressure fluid (usually water) containing chemical additives and a proppant is injected into a wellbore to create an extensive system of small cracks in the formation, In turn providing the pathway for hydrocarbons to flow to surface • When the hydraulic pressure is removed from the well, the small grains of hydraulic fracturing proppant hold the fractures open when the pressure is released. • Flowback • With the well fully fracked, the injected fluid is flowed back to surface however it can contains high levels of salt and be contaminated with radioactive material • Ideally this will be re-injected for future fracking operations, or disposed of downhole (currently not permitted by UK authorities) - otherwise it has to be treated to remove all containments before being put back in water supply
An Overview of Hydraulic Fracturing Section 3: Hydraulic Fracturing – Technology
Fracking Fluids Fluids are a very a controversial aspect of the • Fracking Process Its estimated a 100 billion gallons a year of fluid is • used for fracking in the USA The The Main purpose of the fluids are to extend • Technology fractures, and carry proppant into the fractures – Fluids! Most of the operators Intellectual property lies in • the formulation of these fluids, so the recipes are trade secrets….? Hence how do you gauge risk to groundwater contamination? In the UK companies are obliged to report the • chemicals used, however not in the USA, although Baker have fully disclosed their formulas – unlike HAL and SLB
The Technology – Fluids! The fracturing fluid varies depending on fracturing type desired, and the conditions of specific wells being fractured - The fluid can be gel, foam, or water-based. While most fluid formulations are different they will generally follow the same recipe: typically a slurry of water, proppant, and chemical additives. Additionally, gels, foams, and compressed gases, including nitrogen, carbon dioxide and air can be injected. Typically, 90% of the fluid is water and 9.5% is sand with chemical additives accounting to about 0.5%. However, fracturing fluids have been developed using liquefied petroleum gas (LPG) and propane in which water is unnecessary
The Technology – Proppants The proppant is a granular material that prevents the created fractures from closing after the fracturing treatment. Types of proppant include silica sand, resin-coated sand, bauxite (Aluminium ore), and man-made ceramics. The choice of proppant depends on the type of permeability or grain strength needed. In some formations, where the pressure is great enough to crush grains of natural silica sand, higher-strength proppants such as bauxite or ceramics may be used. The most commonly used proppant is silica sand, though proppants of uniform size and shape, such as a ceramic proppant, are believed to be more effective
An Overview of Hydraulic Fracturing Section 4: Hydraulic Fracturing – Risks and Risk Management
Risks & Risk Management: Overview • Risks posed are generally similar to Conventional wells – Fracking poses a wide range of risks to operators, however the operational risks associated with unconventional wells are very similar to conventional wells • ‘Major Risks’ in public eye due to perception – The major issues the public sees – groundwater contamination, seismic activity do not constitute the greatest risks posed by fracking operations when viewed from a frequency / severity scale • Spatial constraints are Key! – The largest risks are on the surface and are site dependent – space and environmental constraints play a major part in this like topography, location geology, available infrastructure etc.
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