The International Drilling for the Recovery of Aquifer Sands, or “IDRAS” Project, is a current DOSECC scientific drilling project that requires DOSECC’s unique capabilities of custom engineering and fabrication of a unique drilling tool. The DOSECC team was tasked with providing geoscience researchers the ability to drill core samples in soft sediments that are saturated with water, with the water left in situ and undisturbed in the sample. The ultimate goal of this tool is to allow researchers on the IDRAS project to better analyze high arsenic groundwater in Southeast Asia, including India, Vietnam, and Bangledesh, that poses a significant health risks.
Project Update: As of October, 2016, the custom-fabricated drilling equipment has been successfully tested at DOSECC headquarters and will next undergo a second test drill an area of the Great Salt Lake that offers similar soil saturation conditions as those to be tested in Southeast Asia. This proofing test will provide validation that the system will meet the goals on the ground in Asia. Earlier tests allowed the design team to make adjustments to the original tool design to optimize the performance of the tool and change some features before this next round of testing.
Elevated groundwater arsenic (As) concentrations impact the health of over 100 million villagers across Pakistan, Nepal, India, Bangladesh, Myanmar, Cambodia, Vietnam, and China who rely on tube wells as their main source of drinking water. This ICDP project, likely to be the first of several devoted to groundwater quality over the next decade, seeks to identify the limited set of parameters that need to be considered in order to make meaningful predictions about the vulnerability of a low-As aquifer in the absence of a full-scale study. This is a crucial question from a public health perspective because selectively tapping low-As aquifers is the most effective way of lowering As exposure.
As a first step towards this goal, proponents from 16 different countries will drill an unconsolidated aquifer in the US that is elevated in As. A new tool under development, the freeze-shoe sampler, will be deployed to recover groundwater in contact with aquifer sands from the same depth by sealing the bottom of a coring tube by in situ freezing. Participants, including 9 from affected Asia countries whose travel to the drill site is supported by the project, will process cores collected at three sites with the freeze-shoe sampler on-site in a mobile geomicrobiology laboratory where a suite of labile sediment and groundwater properties will be measured. In addition to setting the stage for future deployments of the freezeshoe sampler in Asia, the new data will shed light on the release of As to groundwater caused by the reductive dissolution of iron (Fe) oxyhydroxides, a process that is mediated by micro-organisms involved in the mineralization of reactive organic carbon.
The freeze-shoe sampler has been developed under separate funding from the U. S. National Science Foundation. DES has performed this work under a subcontract from Columbia University. Freeze-shoe technology is being adapted for use on DES’s suite of soft sediment sampling tools that have been used for many years to collect long cores in modern lakes. This project is the first field test of these new tools.
A Multi-Disciplinary Project
The DOSECC project is led by Lead Project Engineer and Project Manager Brian Grzybowski. He reports:
“I’ve enjoyed working on the project because it spans a pretty broad range of engineering disciplines. With the freeze properties, it involves the heat transfer and thermodynamics of freezing the core. It involves electrical control systems, integration, and thermal science and HVCF applications. Plus, the system has all equipment on board, so when we send it down-hole it is an independent assembly that functions remotely down there, so it must be designed as a stand-alone system. We have the added challenge of requiring that it be able to survive the downhole conditions of low temperature and high pressure. When we send the tool downhole on the wire line, and it acts as a hypodermic needle, so it collects a core sample below what the bit has disturbed. This allows us to collect a 5’ long core sample undisturbed by the drilling process. We freeze 6” at the tip contained inside of a plastic, polycarbonate liner, then we pull it off the drill coring system and transfer it to the researchers at that point. They then can employ a system that can freeze the top of the core and allow it to be put it into refrigeration storage vertically to avoid the water changing orientation.”
A number of key DOSECC staff members have collaborated on this effort to bring a wide array of expertise and backgrounds to bear in order to solve a unique geoscientific problem for the first time. From field and drilling experience and engineering design to fabrication capability and geotechnical experience, our wide range of staff members and associates enables DOSECC to bring a great deal of experience to bear for the development of the product.
http://dosecc.com/wp-content/uploads/2016/10/IDRAS-map.jpg630626adminhttp://dosecc.com/wp-content/uploads/2016/05/SLANT-logo.pngadmin2016-10-11 23:50:522016-10-31 22:06:39IDRAS - International Drilling for the Recovery of Aquifer Sands