Envirotech has the equipment and experienced field personnel required to get your project done on time, on budget, and without safety incidents.
Monitor Well Installation
Double & Triple Cased Well Installation
Direct Push (Geoprobe) Drilling
Phase II Environmental Site Assessment Drilling
Envirotech’s experienced Project Managers can help you determine which drilling method is best suited for your need based on the site lithology and depth required in your drilling work plan.
In general, direct push (also called Geoprobe) drilling is the most efficient way to determine the absence or presence of a Constituent of Concern in the soil or groundwater (for Phase II Site Assessments). Direct push rigs use a hydraulic hammer to drive 2.25” OD samplers into the ground, and samples are collected from inside the tooling. Different diameters of samplers are available, but the most common is the 2.25” Macrocore Sampler. Sampling with this method is fast and inexpensive, the only downsides being that this method does not drill deep, or create a large enough borehole to create a good filter pack for monitor wells. All of our direct push rigs can also spin hollow stem augers to set shallow wells.
Hollow Stem Auger (HSA) Drilling – As a generality, when talking auger size, drillers think in terms of internal diameter while consultants think in terms of outer diameter. The reason for that is because consultants are generally thinking of the final product (for example, a 2” diameter monitor well with 2” of filter pack material all around it, which would require a minimum of a 6” on OD Auger Size). Drilling contractors are thinking in terms of how to connect the tooling to the rig spindle, where the ID of the HSAs must match your spindle connection exactly.
In general, for shallow (20 to 100 foot) wells that need to be installed in clay or sand, Hollow Stem Augers (HSA) are the most efficient method.
The standard HSA size that we use for 2” diameter monitor well installation has an internal diameter of 4.25” and an outer diameter of 8.25”. This size allows for a great compromise between getting a good filter pack, and minimizing waste generation. Additionally, it has sufficient room for both the 2” well casing and a 1” tremie pipe, which is of assistance for sites where flowing sands are encountered.
Envirotech also has HSAs that are 3.25” in ID (6025” in OD) for the installation of double cased wells inside 8” diameter casing. Augers that are 6.25”, 10.25” and 15.25” in ID are also kept at the facility for the installation of less common 4” diameter and 6” diameter wells, as well as the installation of 8”, 10” and 12” isolation casing for double and triple cased wells.
Mud Rotary Drilling – At sites on the Gulf Coast where wells deeper than 130 feet are required, Mud rotary drilling becomes a preferred method over HSA drilling because of the torque required to turn that length of HAS tooling.
Envirotech Drilling received delivery of a new, track-mounted Diedrich D-50 on the 11th of June. The D-50 rig has 9000 foot pounds of torque, and can drill as deep as 120 feet below ground surface using hollow stem augers, mud rotary, or air rotary drilling methods. The tracks prevent it from getting stuck on off road drilling sites, improving uptime and safety. This particular rig will be operated out of our San Antonio office, as Houston already has a similar rig operating out of it.