Hydrogeologic Prospecting
If your groundwater exploration program budgets for failure using the "wildcat" method perhaps it is time to plan for success using OAI’s hydrogeologic approach to groundwater exploration.
Using a combination of skills acquired as a petroleum geologist with training in hydrogeology, OAI is uniquely qualified to reduce risks commonly accepted as part of the groundwater exloration process. Here are Case Studies of how OAI's hydrogeologic approach to groundwater exploration (prospecting) led to the development of successful wells for two OAI clients.
Petroleum cross section of sands of the Citronelle Oil Field
CASE #2: Mobile County Water, Sewer and Fire Protection Authority’s Boykin Road Well (Well #8)
In 1998, as part of Mobile County Water’s wellhead protection plan, OAI's Daniel J. O’Donnell, completed a comprehensive hydrogeologic study of the central Mobile County area. The study identified five distinct sand aquifers between ground surface and a depth of 600 feet in an area where formal published geologic reports identified only one aquifer present. These aquifers were correlated through the use of cross sections developed from electric and driller’s logs, then mapped by Dan to identify each potential target aquifer's depositional trend.
The aquifer maps were then used to identify six potential wellsites for consideration as the system expanded to meet increasing demand. One site, the Boykin Road site, was mapped showing the Upper Theodore Aquifer to be 125+ feet thick underlying land owned by the utility.
In 2000, on the recommendation of OAI, the Boykin Road site was drilled. The aquifer was present at the mapped depth and slightly thicker than mapped. The Boykin Road Well was drilled, completed and tested out at 1,900 gpm. The well was subsequently permitted at 1,000 gpm.
Hydrogoelogic prospecting allowed MCW to maximize their financial resources by targeting a well defined and mapped aquifer rather than shooting in the dark and hoping to hit an aquifer. With six sites to choose from, MCW followed OAI's recomendation to drill at a water tower site they owned eliminating land purchase and piping costs and successfully completed their most productive well with no "dry holes". In 2005 and again in 2016, this well's water was voted the best tasting water in the Alabama Rural Water Association's Taste Test Contest. At OAI we call that a success story!
Case #1 The Cost of Failure or the Savings of Success, Your Choice
A southwest Alabama municipal water system, typical of many public water systems, planned and budgeted for a new well without the input from an experienced hydrogeologist. Over the course of two years, the system drilled four 500 foot borings, one 700 foot boring and completed three test wells. The outcome of this very expensive effort was a single 600 gpm public supply well.
Behind in their water supply devlopment program, OAI met with the system's superintendent and introduced a radically different approach to their wildcat method to exploration and development of groundwater resources. In less than ten minutes using the dust of his vehicle as a chalkboard, the new concept was presented by Dan and accepted by the Superintendent for their next well. Rather than relying on rules of thumb or mis-informed understandings of regualtions governing public supply wells in Alabama, OAI's approached is based on the hydrogeology of the area and hydraulics of the area's aquifers.
An evaluation of system data for each well was completed, the area's hydrogeology was studied and a plan was presented to develop the next new well at an existing wellsite. While bucking the "that's the way we always did it" approach, OAI's plan was approved and the project was given the go ahead to proceed. Historical data supported the proposed plan and aquifer testing comfirmed its feasibility. The system's first well completed using this new hydrogeologic approach was completed and permitted within six months of the plan getting the go ahead.
The project, OAI's first with this water system, was completed with no test well and only limited land purchase associated with up-grading the treatment plant. The new well was permitted for 750 gpm. A second well, a 600 gpm well, was completed a year later under the same plan at the same location. The 28 year old treatment plant for the existing well was replaced with a new treatment plant capable of treating production from all three wells.
Estimated savings to this system were $700,000+ according to the superintendent over previous costs of exploring for and developing a new well under the "that's the way we always did it" method.
Since completing this first wellfield, OAI has gone on to complete two additional wellfields for this municipal system increasing the system's production capacity by 4.82 mgd with no test wells, with no dry holes, limited distibution additions, reduced treatment facility costs by three plants and with very limited land purchase costs.
