This document reviews hydraulic fracturing and its role in extracting unconventional hydrocarbons. It discusses how hydraulic fracturing works to propagate fractures in rock formations, allowing the flow of trapped oil and gas. The main components of fracturing include water, sand, and other additives that make up the fracturing fluid. The process involves pumping fluid into the wellbore at high pressure to fracture the surrounding rock and leave proppants to hold the fractures open, allowing hydrocarbons to flow. Potential challenges include groundwater contamination, gas migration, and surface impacts. However, with proper monitoring, these risks can be controlled. Hydraulic fracturing has enabled extensive production from unconventional sources and is now used in over 2 million wells

1. HYDRAULIC FRACTURING AND ITS ROLE IN THE MINING OF
UNCONVENTIONAL HYDROCARBONS: A REVIEW
Nosawema N. Osagiede, Isaac O. Imasuen, and Ebo G. Imeokparia
Department of Geology, University of Benin, Benin City, Nigeria.
1. INTRODUCTION
Hydraulic fracturing in a broad sense is the propagation of fractures in rocks
(especially sedimentary rocks) by injecting a pressurized fluid.
Induced hydraulic fracturing also known as hydro-fracturing or fracking is a technique
used to propagate fractures within unconventional formations, so as to facilitate the flow
of oil and/or gas (unconventional hydrocarbons) to a producing well or for drilling
directly.
Unconventional hydrocarbons can broadly be classified into two groups; the
unconventional gas resources, and the unconventional oil resources. Unconventional
gas resources include ; shale Gas, tight Gas (Tight Gas Sand), Coal Bed Methane or
Coal Mine Methane (CBM or CMM), and Oil Shale Gas. While unconventional oil
resources include; Tight Oil (light tight oil), Oil Sand (tar sand oil), and Oil Shale Oil
Hydraulic Fracturing was invented in 1947 and was first used at the Hugoton gas
field in Grant County of southwestern Kansas by Stanolind Oil. It is a proven process
which allows petroleum explorationists recover natural gas and oil from unconventional
sources safely and easily. Fracturing is carried out in deep formations suspected to
have trapped substantial amount of oil and gas. These formations could be as deep as
1800m or even more.
2. MATERIALS
The materials used for Hydraulic fracturing are broadly divided here into;
mechanical equipments and fracturing fluid.
The mechanical equipments includes; a drilling rig, slurry blender, high-
pressure/high-volume fracturing pumps, monitoring unit, perforating Gun, one or more
units for storage and handling of proppant, high-pressure treating iron, a chemical
additive unit (used to accurately monitor chemical addition), low-pressure flexible
hoses, and many gauges and meters for flow rate, fluid density, and treating pressure.
The fracturing fluid on the other hand is made up of mainly sand and water, then
other additives which constitute less than 2% of the entire fluid. A summary of the
constituents of the fluid and their significance is presented in the table below.
PRODUCT PURPOSE
Water and Sand: ≥98%
Water Expands the fracture and delivers sand
Sand (Proppant) Allows the fractures to remain open so that the
natural gas and oil can escape
Other Additives: ≤2%
Acid Helps dissolve minerals and initiate cracks in the rock
Anti-bacterial
Agent
Eliminates bacteria in the water that produces
corrosive by-products
Breaker Allows a delayed breakdown of the gel
Clay Stabilizer Prevents formation clays from swelling
Corrosion Inhibitor Prevents corrosion of the pipe
Crosslinker Maintains fluid viscosity as temperature increases
Friction Reducer Slicks” the water to minimize friction
Gelling Agent Thickens the water to suspend the sand
Iron Control Prevents precipitation of metal in the pipe
pH Adjusting
Agent
Maintains the effectiveness of other components,
such as crosslinkers
Scale Inhibitor Prevents scale deposits downhole and in surface
equipment
Surfactant Increases the viscosity of the fracture fluid
3. PROCESS OF HYDRAULIC FRACTURING
The following processes occur during hydraulic fracturing;
1. The fracturing fluid is pumped at high pressures down the wellbore.
2. It flows through the perforated sections into the surrounding formation, fracturing it while
carrying sand or proppants into the cracks to hold them open.
3. Experts continually monitor pressures and fluid properties during the process, and adjust
operations as necessary.
5. During the flowback process, the well’s pressure is reduced, leaving the proppants in
place
4. ASSOCIATED CHALLENGES
The main problems that could result from the process include;
a) Contamination of ground water
b) Migration of gases and hydraulic fracturing chemicals to the surface
c) Risks to air quality
d) Surface contamination from spills and flow back
For these reasons hydraulic fracturing has come under scrutiny internationally, with some countries
suspending or banning it; however these problems have proven to be controllable by proper monitoring
of the processes and stages. Also, enhancement and development of the technique over time has led to
a tremendous reduction in these environmental problems.
5. HYDRAULIC FRACTURING SO FAR…
The first hydraulic fracturing experiment, which was conducted in 1947 at the Hugoton gas field in
Grant County of southwestern Kansas by Stanolind Oil. The experiment was not very successful as
deliverability of the well did not change appreciably. But it was Halliburton that made the final
breakthrough On March 17, 1949, when they carried out the first two commercial hydraulic fracturing
treatments in Stephens County, Oklahoma, and Archer County, Texas. Since then, close to 2.5 million
fracture treatments have been performed worldwide and It is believed that approximately 60% of all
wells drilled today are fractured.
It is seldomly used in Nigeria but no well documented case have been established
Figure 3- Chart showing the estimated size of the global
fracturing market from 1999 to 2007. Courtesy: Michael
Economides, Energy Tribune.
Figure 4- Map showing the estimated global distribution of
fracturing equipment, including land fracturing spreads and
offshore vessels.
6. CONCLUSION
Hydraulic fracturing is a proven process which allows oil and gas producers to recover natural gas and
oil from unconventional sources safely and easily. Fracture stimulation does not only increase the
production rate, but it is also credited with adding to reserves. The entire process involved in the
technique could take 3-4 months for completion, but can result in a well that will produce oil or gas for
20-40 years.
REFERENCES
Chemicals used in hydraulic fracturing by United States House of Representaive Committee on Energy and Commerce, Minority Staff, 2011.
Facts about Hydraulic Fracturing by Chesaspake Energy (www.hydraulicfracturing.com)
Hydraulic fracturing at a glance by American Petroleum Institute (API), 2008 - www.api.prg
Hydraulic Fracturing; History Of An Enduring Technology by Carl T. Montgomery and Michael B. Smith, NSI Technologies
U.S Department of Energy Official Website (www.fossil.energy.gov)
Figure 1- Schematic diagram showing the process of fracturing.
Figure 2- Schematic diagram showing how fracturing increases reservoir content.
ACKNOWLEDGEMENT
The authors would like to thank the Nigerian Association of Petroleum Explorationists for the opportunity to present this poster at the NAPE
International Conference and Exhibition, 2013.