Environmental Measurement While Drilling (EMWD)
The primary objective of this technology is to distinguish contaminated from non-contaminated areas in real-time while drilling beneath suspected hazardous waste sites. It can be used to improve the placement of extraction and monitoring wells, and it can be used to characterize sites quickly. Information on environmental conditions, drill bit location, and temperature during drilling is required in many environmental restoration operations. The Environmental Measurement While Drilling (EMWD) System obtains real-time data during drilling. Down-hole sensors are located behind the drill bit and linked by a high-speed data transmission system to a computer at the surface. Windowsª-based software is used for data display and storage. As drilling is conducted, data is collected on the nature and extent of contamination, enabling on-the-spot drilling and sampling decisions. The initial sensor developed by the Department of EnergyÕs Sandia National Laboratories (SNL) was a simple gamma radiation detector.
Limitations and Concerns
As is the case with most technologies that rely on sensors, the results are limited by sensor performance. For example, sensors may become clogged or damaged while drilling, leading to inaccurate results.
EMWD may substantially reduce drilling costs and lead to the more accurate placement of wells. This technology helps to characterize the extent and location of contamination in soil and groundwater, and it permits faster turn around. It is not specific to any single contaminant. However, Sandia National Laboratories, which developed the technology, has utilized a sensor that detects radionuclides. As sensor technology is developed, this tool may become more versatile.
Technology Development Status
The technology has been demonstrated in conjunction with horizontal drilling at the Rocky Flats Environmental Technology Site.
Other Resources and Demonstrations
See http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2001/011809.pdf for Characterization of Under-Building Contamination at Rocky Flats Implementing Environmental Measurement-While-Drilling Process with Horizontal Directional Drilling, prepared by Sandia National Laboratories. At Rocky Flats characterization is required under buildings. Sandia deployed the EMWD in conjunction with horizontal directional drilling to characterize contamination under two buildings and evaluate the performance and applicability for future characterization efforts. The Gamma Ray Spectrometer (EMWD-GRS) system produced real-time environmental and drill bit data during drilling operations. No gamma emitting contamination was detected. These real-time measurements provided technical data for steering the drill bit in and out of contaminated zones. There were time, cost, and safety advantages to using the EMWD systemÕs approach. It gathered data on the nature of contamination in minutes, as opposed to weeks or months for offsite confirmatory analysis; it had substantial cost savings by minimizing the number of samples; and it enhanced worker safety, minimizing waste generated during drilling.