“If finding and producing energy in America were as easy as Jed Clampett and his rifle made it look in the opening credits of the Beverly Hillbillies, we probably wouldn’t have needed to pioneer a well stimulation technology known as hydraulic fracturing. But it isn’t, and so we did – first using the process in 1947 to stimulate flow of natural gas from the Hugoton field in Kansas.” Source: Halliburton [Ref 1]
My first post on the above topic, Fracking and the Geology Behind It, sets the stage for understanding how carbon energy sources like shale gas and crude oil formed in the earth’s surface. The second post, Fracking’s Early History, provides a crude history of this sub-surface gas stimulation process. An exploding torpedo mixture was dropped down a well by a well shooter. This rubblized the hard rock formations around the well and stimulated the release of oil or gas trapped beneath the surface…unfortunately, it also didn’t leave room for any errors on behalf of the well shooter.
Today’s post picks up from what is probably now considered a very famous experiment in the Hugoton field of Kansas in 1947. One thousand gallons of gelled gasoline (napalm) and sand were mixed together and injected into the gas producing limestone formation at 2,400 feet. While the experiment was considered not very successful in appreciably increasing the delivery of gas flow from the well, a patent was issued on this process in 1949 with the exclusive rights being issued to Halliburton. Halliburton performed the first two commercial hydraulic fracking treatments in Oklahoma and Texas that year. [Ref 2]
Now say what you want about the folks at Halliburton, they didn’t get to be the giant that they are in energy exploration sitting on their thumbs or resting on their laurels. One or more members of their team had enough business savvy to license and patent a process that is now known as fracking or hydraulic fracturing to the rest of the world. A few years after commercialization of the fracking process, it caught on in other countries around the world.
Here are some important events in the timeline of hydraulic fracking [Refs 1, 2, &3]
- 1947 Halliburton performs first experimental fracking operation for Stanolind Oil in Kansas.
- 1949 Halliburton performs first commercial fracking operation for Stanolind Oil.
- 1960 Massive or High-volume hydraulic fracking is introduced. Massive hydraulic fracturing is generally defined as treatments greater than 330,000 pounds (about 150 short tons) of proppant.
- 1972 WaterFrac Process introduced. Water frac or slick water is water containing a friction reducer. It has a low viscosity and requires a high pump rate to transport the proppant. It is commonly used in gas wells.
- 1976 The first US funded research of hydraulic fracturing. The U.S. government funded the creation of the Eastern Gas Shales Project.
The Technology: Hydraulic fracking is often mistaken as a drilling technique. It is actually a technology that is used to enhance the flow of energy from a well after the drilling has been completed.
The process of hydraulic fracturing begins with building the necessary site infrastructure including well construction. Production wells may be drilled in the vertical direction only or paired with horizontal or directional sections. Vertical well sections may be drilled hundreds to thousands of feet below the land surface and lateral sections may extend 1000 to 6000 feet away from the well. [Ref 3] Horizontal drilling as an enhancement to the fracking process will be discussed in the next post on this topic.
Why is hydraulic fracking considered a game changer in the oil and gas industry? It made shale gas, once considered unrecoverable, extractible, and it now accounts for over 30% of U.S. natural gas production.
Fracking Fluids: Fracking fluids are commonly made up of water and chemical additives. They are pumped into a geologic formation at high pressure during the fracking process. When the pressure exceeds the rock strength, the fluids open or enlarge fractures that can extend several hundred feet away from the well. There are primarily three types of fracturing fluids currently used [Ref 4]: water frac or slick water, linear gel, and crosslinked gel. All three of these frac fluids have different properties and applications.
Water frac is water containing a friction reducer and possibly a biocide, surfactant, breaker or clay control additive. This fluid has a low viscosity of 2 – 3 centipoise (cP) that requires a high pump rate to transport the proppant. Small proppant size like 40/70 is common with this fluid due to its low viscosity. Water frac is the least damaging to the proppant pack of the three frac fluid types and it is commonly used in gas wells [Ref 4]
After the fractures are created, a propping agent is pumped into the fractures to keep them from closing when the pumping pressure is released. After fracturing is completed, the internal pressure of the geologic formation cause the injected fracturing fluids to rise to the surface where it may be stored in tanks or pits prior to disposal or recycling. Recovered fracturing fluids are referred to as flowback. Disposal options for flowback include discharge into surface water or underground injection.
Other Uses: In addition to use in the oil and gas industries, hydraulic fracking has been used to stimulate flow of water from water wells, geothermal wells, and as a remediation tool for cleaning up Superfund sites. Other uses include [Ref 2]:
o preconditioning or inducing rock to cave in mining.
o Enhancing waste remediation processes, usually hydrocarbon waste or spills.
o Disposing of waste by injection into deep rock formations.
o Measuring the stress of the earth.
o Extracting heat to produce electricity in enhanced geothermal systems.
o Increasing injection rates for geologic sequestration of CO2.
According to the U.S. Energy Information Administration (EIA), the combination of horizontal drilling and hydraulic fracturing over the past decade has allowed access to large volumes of shale gas that were previously uneconomical to produce. The production of natural gas from shale formations has rejuvenated the natural gas industry in the United States.
The next post on this topic will discuss the enhancements that horizontal drilling has added to the hydraulic fracking process.
1. Hydraulic Fracturing 101, http://www.halliburton.com/public/projects/pubsdata/Hydraulic_Fracturing/fracturing_101.html, last viewed on 04.17.2014.
2. Fracking, http://www.wikipedia.org
3. Hydraulic Fracturing: Background Information, USEPA, http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/wells_hydrowhat.cfm, last viewed on 04.18.2014
4. Fracturing Fluids 101, FracLine, Spring 2012 edition, http://momentivefracline.com/fracturing-fluids-101