Environmental Fracturing
Environmental fracturing has many benefits and is implemented in a variety of methods and configurations:
- Permeability enhancement - increase the geologic pore space or dilate existing bedrock fractures
- Passive treatment systems – permeable reactive barriers
- Permeable reactive treatment zones – active zones with enhanced permeability for amendment injection such as ISCO or ISCR
- Increase thermal well efficiency
- Conventional remedial technology enhancement, i.e., pump & treat, DPE, SVE
It even has its place in the potable water industry for increasing the efficiency of public water supply wells.
So how does environmental fracturing differentiate with fracking or hydrofracking in the energy industry?
In the environmental industry, fracturing has several benefits for expediting remediation or providing greater contact of remedial amendments. Two main methods are used – hydraulic fracturing and pneumatic fracturing – simply one uses liquid and one uses gas. The following table below lists a few other differentiators:
Considerations
Lithology
Fracture Tendency
Fracture Pattern
Amendment Delivery Capacity
Target Depth & Spacing
Hydraulic Fracturing
Silts, clays & bedrock (including swelling clays)
Creates new fractures
Larger single fracture
Higher
Typically between 10-300 feet bgs at 24-100 inch vertical spacing
Pneumatic Fracturing
Well-suited for “self-propping” lithologies
Dilate and propagate interstitial pathways
Micro-fracture network
Lower
Typically between 10-200 feet bgs (without proppant) at 24-40 inch vertical spacing
Hydraulic fracturing was first used in the oil industry in 1947 in Western Kansas to stimulate oil and gas wells. However, the issue became a public concern after the first Marcellus gas shale well was drilled and fracked in 2004, primarily due to its potential environmental impacts. Unfortunately due to this negative public perception, the word fracturing or fracking came under scrutiny even if the technology was benefitting the environment like enhancing potable water wells, a technology that has been used since the late 1960’s/early 1970’s.
Hydraulic Fracturing – Well Water vs. Oil and Gas, NGWA Position Paper, 2/10/10.
