History & Development
GeoSierra's patents, specialized equipment, and expertise for its "trenchless construction" of deep PRBs are based on the discovery in 1992 that it was possible to induce and control the direction (orientation pathway) of a vertical fracture in certain soils. We conceived the idea to perfect the process of controlled vertical hydraulic fracturing, with the objective of applying the process as a key technology component of the installation of PRB walls in the subsurface.
An extensive series of hydraulic fracturing experiments in soils and weakly cemented sediments included over 250 tests in a variety of soil conditions. Excavations verified the extent, orientation and thickness of the resulting vertical hydraulic fractures.
The experiments proved the earlier discovery that creating an artificial fracture at the required azimuth in the soil allowed us to maintain controlled vertical hydraulic fracturing of the soil and assure fracture coalescence between multiple injections, thus providing the subsurface pathway for the formation of an iron PRB wall. It was the discovery in 1992 that ultimately led to four patents being awarded to GeoSierra from 1999 through 2002 pertaining to its proprietary technologies and for installation of iron PRBs.
2016 Cascade Environmental Holdings, LLC Acquires GeoSierra Environmental, Inc.
To further expand GeoSierra Environmental’s portfolio of services, GeoSierra Environmental, Inc. and its sister company, Panther Technologies, Inc. were acquired by Cascade Environmental Holdings, LLC.
2013 First Multi-Azimuth Source Treatment Installation Completed
Originally designed as a pneumatic fracturing project for permeability enhancement of an existing pump and treat system, a multi-azimuth grid network of sand and iron filled vertical fractures was designed and installed by GeoSierra Environmental working jointly with the client in Sacramento, CA . The upper sand fractures were directed towards existing extraction wells with the lower zone iron fractures for permeability enhancement and reductive dechlorination.
2012 Worked Jointly with Global Oil Company to Develop Multi-Azimuth Casing
Adapted from the single azimuth PRB installation technology, GeoSierra Environmental commercialized and field tested a state-of-the-art multi-azimuth vertical inclusion propagation process in Medford, NJ along with a multi-national oil field service company. While initially testing as an oil well enhancement technology, the system has been modified and adapted to allow for source area remediation as well as permeability enhancement for existing injection/extraction systems and potable water supplies.
2011 Expansion of Services to Include Pneumatic Fracturing
Pneumatic fracturing technologies were added to GeoSierra Environmental’s core services with the addition of key personnel and equipment. The ability to radially or directionally enhance the soil permeability using pneumatic methods and emplace remedial amendments significantly broadened the company’s capabilities, resulting in additional opportunities.
2008-2009 GeoSierra Environmental Constructs First PRB Project
GeoSierra Environmental successfully completes a PRB installation in Pleasant Hill, CA within a local park and right-of-way on a highly trafficked main road. The PRB is 480 feet long and is installed between 15 and 50 feet below ground surface and was installed to cut off a plume that was causing residential vapor intrusion issues.
2006-2007 GeoSierra Environmental, Inc. is Established
In 2006, the founder of GeoSierra, LLC decided to personally change his technology focus and sold the asset and license rights to Panther Technologies, Inc. GeoSierra Environmental, Inc. was formed as the exclusive North America license holder of the original vertical hydraulic fracturing and geophysical monitoring patents with rights to use new or enhanced patents to the technology.
1999-2002 Four Patents Awarded Involving Deep PRB Installation
GeoSierra’s proprietary technologies for design and installation of iron PRBs resulted in the application and award of four US patents.
- US 6,443,227 Azimuth control of hydraulic vertical fractures in unconsolidated and weakly cemented soils and sediments
- US 6,330,914 Method and apparatus for tracking hydraulic fractures in unconsolidated and weakly cemented soils/sediments
- US 6,216,783 Azimuth control of hydraulic vertical fractures in unconsolidated and weakly cemented soils and sediments
- US 5,944,446 Injection of mixtures into subterranean formations
1997-2003 Active Resistivity Imaging Development for Deep PRB Installation Monitoring
The active resistivity method of providing real-time images of injected fracture geometry during construction was conceived and developed over a number of years by GeoSierra. The first commercial application of the technology was during the installation of the iron PRB at the Caldwell Superfund Site in Fairfield, NJ in 1997. Since that time the real time imaging technology has been used at all GeoSierra PRB installations to ensure the PRB is constructed as planned according to quality assurance specification requirements. Since the technology has consistently demonstrated the proper emplacement of PRBs and proppants, we have begun to see a trend of clients that have elected to omit resistivity imaging as it reduces the capital cost for projects.
1998-1999 Major Breakthroughs Led to Current Technologies and Processes
Two major technology advances occurred during 1998 and early 1999:
- the development of a rapid breaking enzyme capable of breaking even the highest pH iron gel mixtures, and
- the development of the orientated metal frac initiation casing system allowing multiple frac injections at various depth (stacked) horizons, forming a continuous vertical wall. The new enzyme gel breaker assured rapid (within 1 to 2 hours) and clean breakdown of all iron gel mixtures, even those with pH >10.
The new casing system was a major breakthrough and provided four new key advantages for the construction of PRBs, namely:
- Made it possible to induce repeated frac injections at the same horizon.
- Made it possible, through the use of casing delimiters and pore pressure relief, to ensure fracture coalescence between injection wells, even with slight drilling offsets and/or casing orientation misalignment.
- The stronger and more robust casing system provided a more stable tool for the frac injections of the iron gel mixture.
- Resulted in greater productivity due to its reusability and contribution to more logical sequencing of tasks and simplification of PRB construction processes.
1997 Second Generation and First Commercial Fracture Initiation Device Employed
The first commercial fracture initiation device developed by GeoSierra was a 6-inch diameter 12 foot long tool, that was inserted into a 6.25-inch diameter PVC casing pre-drilled and grouted into the soil to the full depth of the required fracture. The tool was a chain saw cutting device that, upon insertion to the required depth, cut the PVC casing and grout and could then create a 5-foot long vertical cut in the soil extending upwards to 20 foot high. This fracture initiation device was developed for two markets: the shallow environmental application of constructing vertical groundwater permeable treatment walls (iron PRBs) and the much deeper application for petroleum recovery applications in existing hydrocarbon reservoirs.
1996 First Generation of fracture Initiation Device Demonstrated
One of the forerunners of GeoSierra's fracture technology was field demonstrated as a proof of concept under contract to the U.S. Army Corps of Engineers at a site in New Hampshire. These demonstration tests utilized the earliest form of the fracture initiation device consisting of a driven flat-faced probe with an inflatable packer mounted above the probe. The proof of concept demonstrated, from the initiation and propagation of 23 vertical hydraulic fractures, that fracture azimuth could be controlled and maintained, fracture coalescence of multiple injected fractures could be assured, and fracture thickness of up to 9-inches could be accomplished.