Hydrofracturing

Remediation Injection

Packer Services

Borehole Video Camera

About Hydrofracturing

Geologic map of Idaho Springs Quadrangle showing location and description of surface rock materials.

Hydrofracturing is a well stimulation or well development technique that has been applied to oil and gas wells for over 50 years.  I have studied the oil field procedures and over the past 30 years, in conjunction with the late Colorado State University professor, Jim Waltz, have developed and refined a scaled-down version of the oil field techniques that can be cost-effectively applied to dry water wells and low producing water wells.

The hydrofracturing of a mountain domestic water well is custom designed to fit the particular site conditions. Site information that is desirable includes: drilling data with well depth, age, static water level, water locations at the time of drilling, formation changes, hard/soft zones, drilling rate, and hole stability.  Additionally, knowledge of neighboring wells with depth, flow rate, and production history is helpful.  The local area is studied for topography, relief, potential sources of contamination, recharge areas, and surfacial geology.  Of particular interest would be the observation of surface fracture patterns, their density and orientation.  The use of geologic quadrangles, topographic maps, and air photos may be helpful. 

What are the hydrofracturing procedures and equipment?

Packer uninflated and inflated to accommodate standard 6 inch diameter mountain well.

The procedures and equipment used are the result of over 30 years of research and development and are based on the hydraulic fracturing techniques that are routinely used on oil and gas wells. The procedures are tailored to fit the geologic setting and the construction of the well being serviced. The hydrofracturing is usually applied to an "open" water well. In cases where equipment is present in a well, the pump and any liner casing material are removed by a licensed pump contractor.

The equipment used for the hydrofracturing setup consists of a single Baski inflatable packer, flexible hose assembly for positioning the packer, packer inflation system, a water supply of 2000 gallons, an injection pump, and a control panel for managing and monitoring downhole conditions.

Hydrofracture in process near Estes Park, CO. Note presence of PVC liner casing removed from well to allow fracturing of bare borehole.

 

After hydrofracturing a well, clean water is circulated in the well to remove fine materials that were liberated from flushed out fractures.

The basic procedures involve initially setting the packer at some depth below the known or perceived static water level.  Once the packer is inflated, injection through the center of the packer is started at a rate that fits the conditions described above.  Pressure will build on the formation below the packer up to a level that represents the strength of the weakest fracture.  Once a fracture begins to open (which is indicated by a drop in pressure), water (typically 300-500 gallons) is pumped into the fracture seeking nearby water-bearing fractures that were not previously connected to the well.  The fracture is cleaned, flushed to remove fine silt and clay materials, and developed to produce a maximum increase in fracture size and interconnection. Data are recorded for injection rate, injection pump pressure, downhole injection pressure, water volume injected, packer pressure, and water level in the well.  When the injection is complete, the packer is deflated, repositioned at a deeper location and the procedure is repeated. Injection rates and volumes are adjusted in response to fracture behavior.

With a success rate in excess of 90%, a dry water well or a low producing water well can be improved to satisfy the needs of the well owner.

View of control panel during hydrofracture operation showing down-hole injection pressure of 1000 psi.

 

Ray Boyle, geologist, collecting data during hydrofracture of well near Telluride, CO

One major assumption that is used in the data interpretation is that when a length of borehole is confined (below the packer) and pressurized, the downhole pressure can only build to a level that represents the weakest fracture below the packer.  That is, only one fracture can be developed at a given packer setting.    Typically, the weakest fracture below the packer is relatively shallow, since the fractures tend to decrease in size and number, and increase in strength as depth increases. 

The maximum pressure observed is called the breakdown pressure and is essentially the signature pressure for the weakest fracture below the packer. If at subsequent deeper packer settings, the breakdown pressure is higher, it can be assumed that a new fracture has opened.  If the maximum pressure observed at a deeper location is lower than the previous shallower breakdown pressure, it can be assumed that the same fracture is being developed.  It has been my experience, that for the most part, these scenarios seem to prevail.

Installing packer in well near Golden Gate Canyon west of Golden, CO

Hydrofracture in process on well in downtown Glen Haven, CO

What are some of the possible benefits of hydrofracturing?

• Increase long term flow from a dry water well or low producing water well.
• Improve reliability of the well during dry seasons and drought years.
• Improve water quality through the reduction of suspended sediment.
• Increase usable water storage in the well.
• Reduce drawdown levels during pumping, which reduces energy costs and lengthens pump life.
• Achieve water production goals with shallower (less expensive) wells.
• Increase availability of mortgage loans.
• Increase property value and marketability due to improved water supply.

References

Several references are shown which may be helpful in understanding the technical and practical aspects of hydrofracturing.

Atkinson, B. K., 1987. Fracture Mechanics of Rock. Academic Press Inc., London, England

Baski, Hank, 2004-2006. The "Ask Hank" column, featured in Worldwide Drilling Resource Magazine, offers information on a wide variety of topics related to hydrofracturing. Click here to view the article.

Boyle, R. E., 2000. Hydrofracturing as a Way to Enhance Water Well Production. Presented at the American Ground Water Trust “Well Rehabilitation Workshop”, Denver, Co., April 18-19, 2000.

Domenico, P. A. and F. A. Schwartz, 1990. Physical and Chemical Hydrogeology, 2nd ed. New York, NY; John Wiley and Sons.

Ellis, E. E., 1906. Occurrence of Water in Crystalline Rocks. In Underground –Water Papers, 1906. U S Geological Survey, Water-Supply and Irrigation Paper No. 160, Washington, D. C., pp19-28.

Gale, J. E., 1982. Assessing the Permeability Characteristics of Fractured Rock. In Recent Trends in Hydrogeology, Geological Society of America, Special Paper no. 189, pp 163-181.

Johnson Division. Groundwater and Wells. Saint Paul, Minn. UOP Inc. Edward E. Johnson, Inc. 2007.

Long, C. S. Jane, 1996. Chairman, Committee on Fracture Characterization and Fluid Flow. Rock Fractures and Fluid Flow, Contemporary Understanding and Applications. National Academy Press, Washington, D. C., 551 pp.

Topper, R., 2002. Colorado’s Fractured-Rock Aquifers-An Atlas Perspective. Presented at the Environmental Protection Agency “Fractured-Rock Aquifers 2002” Conference, Denver, Co., March 13-15, 2002.

Trainer, F. W., 1987. Hydrogeology of Plutonic and Metamorphic Rocks; In Back, W., et al, Hydrogeology: Boulder, Colorado, Geological Society of America, The Geology of North America, v. 0-2.

Valco, Peter and Economides, Michael J., 1995. Hydraulic Fracture Mechanics. John Wiley and Sons, West Sussex, England, 298 pp.

Williamson, W. H. and Woolley, D. R., 1980. Hydraulic Fracturing to Improve the Yield of Bores in Fractured Rock. Dept. of National Development and Energy, Australian Water Resources Councel Technical Paper No. 55, Canberra, Australia.

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