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- NAPL FLUTe Procedures | FLUTe
NAPL FLUTe Procedures NAPL FLUTe Installation in Open Boreholes NAPL FLUTe Installation Procedure in GeoProbe Rods Sonic Core NAPL FLUTe Procedure Contaminants that React with NAPL FLUTe
- FLUTe - Why Seal a Borehole?
Why Seal a Borehole? Sealing a borehole with FLUTe liners after drilling prevents cross contamination . With traditional practice, the borehole is left open for extended periods of time between the time the borehole was drilled and downhole characterization. Additionally, if straddle packer systems are used for characterization, large portions of the borehole remain unsealed during all portions of the investigation. The problems that can occur when boreholes remain open include mobilization of contaminants into the open borehole, contaminant adhesion to the borehole wall, and contaminated migration from the open borehole into previously uncontaminated fractures (See "Figure 1" and "Figure 2"). Additionally, when making measurements with straddle packers, which by default leave portions of the borehole open, leakage past the packer can result in exaggerated flow rates and contaminant distributions that are erred from cross contamination with mixed borehole water. By using FLUTe liners, the borehole is either sealed while all downhole measurements are collected or as the liner sequentially seals off flow paths. In the way, the data integrity is very high as cross contamination and cross flow measurements cannot occur. Figure 1. DNAPL confined to an isolated fracture Figure 2. DNAPL spread to other fractures as a result of the newly drilled borehole acting as a flow path between otherwise unconnected fractures.
- FLUTe - Water FLUTe
Water FLUTe A Trusted Technology for High Quality Multilevel Groundwater Monitoring Since 1996 The Water FLUTe is a depth-discrete multilevel groundwater monitoring and head measurement system for use in overburden and bedrock groundwater assessments. Product Highlights Water FLUTe System Specifications Figure 1. Water FLUTe Pumping System All system components are compatible with VOC and PFC Sampling! Easily purge all sample intervals at the same time. Simultaneous purging allows for discrete samples to be collected while saving time spent in the field. Each purge stroke pumps roughly 1 gallon of water. Installation: The Water FLUTe multilevel groundwater system is installed in open bedrock wells via eversion, in a similar process as a blank liner installation (Click Here f or a basic installatio n overview or for a detailed i nstallation PDF, C lick Here ) . The Water FLUTe can also be installed in the overburden or unstable bedrock via sonic drilling. The installation of a Water FLUTe is affected by the depth and diameter of the hole, the relative transmissivity of the hole, the depth to the water table, and the rate at which water can be supplied to fill the liner. The system can be used for artesian situations with a heavy mud fill. If the hole is too tight to allow the liner to push the water into the formation, the water can be pumped from beneath the liner using a pump tube emplaced in the hole before the liner installation. Water FLUTe systems are usually installed in uncased boreholes. Installations into multi-screened cased holes are also common. Varying borehole diameters are accommodated from 3-30 inches. The Water FLUTe can be installed through smaller casing into larger open holes below the casing, or into "telescoped" casing. The liner is completely heat welded without the use of any glues. Once the liner is fully extended in the hole, the geometry looks like that in Figure 1. Note, that due to the size of the large tubing and pumping hardware components of the system, the pump system is not everted into the borehole, but simply lowered as a tubing bundle following the liner to the bottom. Sample Intervals: All samples collected from the Water FLUTe are drawn directly from the formation, without the potential for cross contamination or leakage as possible with packer based multi-level systems. The Water FLUTe is capable of up to 15 ports per borehole depending on the hole diameter from 4 inches to greater and all intervals can be sampled and purged simultaneously. Sampling the System: After the Water FLUTe is installed, the formation water will flow from the formation into the screen, sample port, and up the tubing on the inside of the liner. The water then flows up through the first check valve and up both legs of the "U" shaped tubing (pump tube and sample tube) to a height equal to the head of the formation. The water level can then be measured in the pump tube from the surface prior to sampling with a water level meter. To purge and sample the Water FLUTe, a gas pressure is applied to the pump tube at a pressure greater than the head of the formation. Once the pressure is applied, the first check valve closes, and the pressure forces the water to flow through the second check valve and to the surface through the sample tube. This process is repeated multiple times to both purge the system and collect samples. Click Here for a detailed sampling procedure PDF file. Head Measurements: The water table depth at each port can be measured with a water level meter in the pump tube or, for continuous head measurements at each port, an air couple transducer (ACT) system or downhole pressure transducers can be used. Click here for more information on the ACT system. Well Completion: There is no need for an exterior seal with grout, sand or bentonite. The liner seals the entire hole and the water is drawn directly from the formation. As such, there is no concern about the seal of granular materials in a slender annulus. Warranty and Removability : The Water FLUTe system is fully warrantied and removable for other use of the borehole or easy abandonment by grouting the borehole. Our experience with Water FLUTe multilevel groundwater monitoring system now spans 21 years. Water FLUTe systems have been installed in 48 states in the U.S., and many foreign countries. More detailed descriptions and publications are available on our publications page. Additional Uses: The Water FLUTe is well suited for detection of tracer arrivals in that the purge volumes are minimal and the sample is drawn directly from the formation. Because there is not an interior tubing bundle, a transparent liner version allows one to watch for the arrival of strongly dyed injections, such as potassium permanganate, using a borehole camera. That option requires a special polyester liner instead of the standard nylon liner. A FLUTe method called a precise gradient measurement is available in order to measure vertical gradients within ~ 1mm between any two ports in the liner. Because there is no field assembly and no annular sealing materials needed, and the system is fully removable by inversion from the borehole, the overall cost of the Water FLUTe system is often the least expensive multi-level sampling and head measurement option of the multi-level monitoring systems. Click Here for our Shallow Water FLUTe - A Peristaltic Pumping Based Sampling System SPACER
- FLUTe - Head Profiling
Reverse Head Profile The Reverse Head Profile is a technique developed by FLUTe for measuring the vertical head distribution in a borehole after completion of a FLUTe Transmissivity profile. Click here for the Groundwater Journal 2016 Paper on the Method. How does it work? The method involves the inversion (removal) of the blank liner in a stepwise fashion after the completion of a transmissivity profile. The blank liner is stopped between flow zones of interest as identified by the transmissivity profile. As the blank liner is inverted from the well, it uncovers discrete borehole intervals of interest that were sealed during the Transmissivity profile. A pressure transducer located beneath the liner in the borehole records the new steady state borehole equilibrium pressure, Bhi, after each interval is uncovered. As we already know the transmissivity of each interval and the previous steady state borehole equilibrium pressure, we can calculate the contribution of the newly uncovered borehole interval by using each new “blended head” beneath the liner and writing the flow equations for each increment that has been uncovered. We define the net flow into and out of the hole to be zero, and using the transmissivity, Ti, measured for each increment in the hole, one has only the formation head, FH as an unknown for each newly exposed interval of the hole. For the first open borehole interval beneath the liner: T1(Bh1-FH1) = 0 Hence the formation head, FH1, equals the blended head, Bh1, in the borehole. The transmissivity for each interval, Ti, is obtained from the continuous transmissivity integral (Fig. 1). Upon inverting the liner to uncover a second increment of the borehole: T1(Bh2-FH1) + T2(Bh2-FH2) = 0 Solving for FH2, FH2= [ T1(Bh2-FH1)+ T2 Bh2 ]/T2 Note that for each new position, a new blended head, Bhi, is measured. Figure 1. Continuous Transmissivity Integral Solving for the formation head each time the liner is inverted allows theoretical determination of the head distribution in the formation while removing the same liner that was used to measure the transmissivity and to seal the borehole. The equation for solution of the formation head of the current interval, i, is: FHi = [ T1(Bhi-FH1) + T2(Bhi-FH2) + ……. +Ti Bhi ]/Ti Where Ti is the transmissivity of the ith interval in the hole determined from the liner continuous transmissivity profile, FHi is the calculated formation head of the ith interval, and Bhi is the blended head measured in the borehole after each new ith interval is uncovered. Watching the transducer measurement beneath the liner allows one to judge when a steady-state head has been achieved beneath the liner. Results: Figure 2. Two Reverse Head Profiles conducted for a 30-Meter Borehole. The blue dots were measured from the 1st RHP values, while the black dots were measured during the 2nd RHP. Note that the vertical red line is the original blended head in the borehole and the red plot point at 30-Meters BGS denotes a measurement taken in a very low transmissive zone and therefore is a less reliable head calculation.
- FLUTe - Unique Applications
In one sense, all FLUTe applications are unique in that these methods did not exist before 1989. However, some methods have become so commonly used that they are no longer unfamiliar. Those common methods are: 1. Blank liners for sealing boreholes. 2. Transmissivity profiles of open boreholes for rapid high resolution measurements. 3. Water FLUTe installations for multi-level water samples and head measurements. 4. NAPL FLUTe installations to map LNAPL and DNAPL of many kinds. There have been extensions of these methods to smaller diameter holes, more artesian holes, and deeper holes. However, these are variations on the FLUTe systems commonly used. The following descriptions are of applications of FLUTe methods not so widely used and perhaps not known to many FLUTe users. Some are applications that should be used more frequently because of the advantages. Unique Applications Installations with Artesian Conditions In the early days of FLUTe methods, if the water table was very shallow or the well somewhat artesian, a heavy mud was used instead of water to pressurize the liner after it had been installed. The installation was usually done off of a scaffold to obtain a sufficient excess driving head to evert the liner. However, FLUTe has developed several designs, with patents pending, which allowed the installation of everting liners into boreholes with 20 ft of artesian head and flow rates out the top of the casing of 100-150 gal/min. Very good transmissivity profiles have been obtained in such holes. Such extreme artesian conditions often lead to a final liner fill of a bentonite/cement grout for a long term Water FLUTe installation. The liner is not then removable as are other FLUTe installations. Installations in Karst Terrain Installations in karst boreholes of many kinds for many purposes are drilled into karst formations. The boreholes are difficult to seal and therefore isolating sampling intervals, grouting of casing, and other common functions are more difficult to nearly impossible in karst. The continuous lining capability of FLUTe systems without the use of grout makes those difficulties much less of a concern. Sealing casing strings in karst formations Grouting the annulus can be very expensive in karstic limestone because large quantities of expensive grout are sometimes lost to the karst solution channels. Loss of returns while drilling is further evidence of the problem. The grout seal can be compromised by the loss of grout into the formation and subsequent leakage from the lower production zone to upper aquifers. The mixing of mud, which is used to support the borehole wall with the grout injected to seal the annular space between the casing and formation, can lead to a weak and permeable seal in the annulus. The annular grout can mix with formation fluids to degrade its in-situ chemistry and strength. A high pressure gradient on a grout column during curing may also lead to a porous and permeable grout. This difficulty can be encountered in water wells, oil wells, or “fracking” wells. A high strength, flexible FLUTe liner can be installed prior to or during the insertion of the casing, eliminating the above difficulties. The annulus can be grouted through a trimmie pipe in stages in order to not burst the liner with a high pressure grout column and without any loss of grout to the formation or mixing with the borehole fluids. This is done routinely in the installation of FLUTe liners in ground water investigations. The formation fluids and drilling muds are forced out of the borehole by the everting liner prior to the grout injection between the liner and the casing or the mud can also be pumped from beneath the liner during the liner installation. The neighboring drawing is a visual representation of the procedure. Well Development It has been observed that the removal of a flexible liner draws down the head beneath the liner by as much as 100 feet, especially near the bottom of the hole. That low pressure beneath the liner as it is being removed tends to extract mud and cuttings from fractures that may not otherwise be cleared in the normal well development procedures. This process and an explanation of why boreholes may not otherwise be well developed is described in the conference presentation titled: “Open Hole Well Development Problems and Solutions” in the publications section. Injection of Remediation Fluids Some FLUTe liners have been fitted with tubing much like that of a Water FLUTe but without any check valves and usually with larger diameter tubing than that used in the Water FLUTe sampling system. The tubing is then used to inject remediation fluids into discrete intervals. In some cases, some of the intervals are used for monitoring the arrival of remediation fluids. Special liners of more resistant fabrics than the standard nylon liner have been used to avoid damage by the fluids injected. For information on those designs, contact us. Liner augmentation of horizontal drilling (LAHD) Flexible liners were first tested in augmentation of horizontal drilling in Mustang, OK in 1997. The method is described in the publication LAHD presentation 2002 which describes the first commercial application of the method to emplace sampling intervals under a landfill in Indianapolis, IN. The basic advantage of the technique is that it replaced the mud cake of a horizontal drill hole with a flexible liner which liner can also carry a variety of instruments into position beneath buildings, highways, and landfills. The method has not been extensively used primarily because FLUTe has not advertised the option. Landfill monitoring in a prefabricated layered subsurface Many current landfill monitoring designs either monitor the landfill within the containment system (e.g., a leachate collection layer between the first and second liner) or outside the containment system in the ground water. For landfills located above deep vadose zones, a major leak will not be detected until a large portion of the vadose zone is contaminated if the monitoring system is ground water wells. FLUTe has designed a landfill monitoring design which has a much higher probability of detection of a leak early in the leak history. The same system provides many other a dvantages such as measurement of the leak rate, sampling the leak for composition, and even the remedy of the leak as part of the monitoring design. That system monitors the entire plane beneath the landfill outside of the landfill liners and does not include instruments which can fail in time so as to lose their monitoring capability. The design is described in the papers provided in the publications section under landfill monitoring . Monitoring beneath a landfill in vertical wells In some situations, the monitoring beneath a landfill or building is preferred in vertical wells. The ability of a propagating liner to travel horizontally and through turns in the piping was used in one situation and is planned for another. The first situation was in a brown field with an existing set of wells. A very large building was to be constructed on the site and it was desired to continue a soil vapor extraction remediation and monitoring of the same wells beneath the building. It was not desirable to have the vertical wells protrude through the floor of the building. In order to obtain water samples and make head measurements beneath the building, horizontal piping was installed in trenches beneath the building which ran from a vault outside the building, through various turns, to sweep elbows connecting to the vertical wells. FLUTe single sampling port systems were installed in the horizontal piping for distances of several hundred feet. The piping was 3 and 4 inch diameter with sweep elbows in the turns. In a more recent design, larger horizontal piping is to be installed beneath a landfill as it is being constructed to allow access to vertical wells beneath the landfill with multiple sampling intervals. Details of the horizontal path to vertical wells for monitoring are provided in the white paper “FLUTe Wells Under Landfills and Buildings” . FLUTe has numerical models which predict the driving pressure needed to overcome drag, gravity, and turn angles for tortuous passages of specified geometry and liner assemblies of various characteristics such as weight, length, friction coefficient and diameter of liner. The models have been well tested against actual installations (see "Installations in tortuous passages" in this section). These installations are easier than the installations in horizontal drill holes as the hole is being drilled in the liner augmentation of horizontal drilling used beneath existing landfills. Landfill monitoring in vertical wells down gradient Many current landfills have common water wells down gradient from the landfill for the purpose of monitoring leachate leakage from the landfill. Obviously, the more closely spaced the wells and the varied the depths of the wells, the greater the probability that the well system can intercept a leachate leak. However, the installation of many traditional screened wells is very expensive to construct and to sample. A more practical approach is to use multi-level sampling systems and to purge them sufficiently to develop a large draw down to capture even a long slender leachate plume. This requires multi-level sampling systems which can produce large purge volumes to draw ground water from a significant distance from the well. The Water FLUTe systems are well suited for that application in that the several sampling intervals can be purged simultaneously and produce a gallon or more per stroke of the system for each port. This allows realistic purge volumes as large as 55 gallons. Water FLUTes can be constructed with even larger production per stroke of each pumping system. The ability to purge all the sampling intervals simultaneously is due to the unique FLUTe design which has each pumping system at the same depth independent of the elevation of the sampling intervals. The ability to obtain a large volume per stroke is because the entire hole volume inside the liner is available for relatively large diameter tubing. The sealing liner occupies an insignificant portion of the hole volume. See the Water FLUTe sampling procedure for a more detailed description of the system. Mapping of subsurface flow One technique for doing that uses a transparent borehole flexible liner to observe in time the arrival of dyes or remediation fluids such as potassium permanganate injected into the formation in a nearby borehole. There are a number of interesting options for monitoring tracer arrivals with the Water FLUTe system which is well suited to monitor for both pressure changes or for tracer arrivals. The tracer arrivals are particularly easy since all the sampling systems can be short stroked simultaneously to “sip” on the medium with minimal perturbation of the natural flow state. The continuously sealed hole also makes the monitoring hole a minimum perturbation on the flow field. Leak detection FLUTe has a patented method which employs an advancing and a retreating liner (one everting, the other inverting) with a constant sampling interval between them. This allows, for example, a vacuum to be applied to the interval to extract any gas or liquid flowing through the hole wall or pipe wall into the interval between the two liners. The method is called “a progressive packer”. The advantages are several in that the liner travel is very gentle while providing an excellent isolation of the traveling interval from the rest of the borehole or pipe. Logging of boreholes The description of geophysical applications treats the method of towing longing sondes through open passages while the passage is supported and sealed with a blank propagating liner. This is especially attractive for sondes such as neutron moisture measurements. However, many kinds of sondes can be towed into passages that are relatively unstable or flowing fluids with minimal risk of loss of the tool. In other situations, contaminants in the borehole, such as coal tar, are incompatible with many sondes and the liner protects the sonde from contact with those fluids. See the Geophysical applications PDF for sondes that can “see” through the liner. Other uses for lining of piping and boreholes FLUTe has in the past installed cure-in-place liners, such as resin soaked carbon fiber liners, in tortuous passages from the basement 100 ft upward to the roof gutters of the Smithsonian Museum of Natural History. The purpose was to line and seal rotting cast iron piping. Those applications are not common for FLUTe, but do use the special art and science of flexible liners as developed by FLUTe and the unique ancillary equipment of FLUTe design. A much more common need is for deep boreholes drilled through karstic formations (e.g., oil and gas wells) to prevent the loss of the grout seal between the casing and the borehole wall. In karst formations, the sealing grout flows freely into the solution channels and caverns and prevents a high quality seal of the annulus which allows potential vertical leakage of brines, petroleum or gas into overlying potable aquifers. FLUTe has a design whereby the borehole is lined as the casing is being installed to prevent the loss of the sealing grout into the formation. Contact us for details. Installations in tortuous passages The ability to install a flexible liner by eversion into tortuous passages is particularly useful for the landfill monitoring, geophysical applications, relining of piping and other applications. The fact that the liner also seals the passage is an additional advantage as well as the ability to support the hole wall as a pressurized liner. This combination of characteristics allows many other applications and the customer is invited to consider these characteristics as they may be applied in novel applications. A video is available of a test of the FLUTe calculation model of liner propagation around numerous turns. The test showed excellent agreement with FLUTe’s model which was used to judge the feasibility of installations such as in the pipes in the walls of the Smithsonian. Installations in lakes and ponds and other uses Liners do not need a borehole or pipe to guide the eversion process. A liner can be everted across a cafeteria floor with many chair and table leg obstacles. The everting liner tends to deflect past such obstacles. It is also interesting that an air filled liner can be everted across a lake. A chain attached inside the liner can keep it oriented with a designated top side. In the same manner, a water filled liner with appropriate weighting can propagate across the bottom of a pond. The liners can be fitted with many kinds of instruments for sample collection, temperature measurements, etc…, in these applications. It is also interesting that a pressurized liner can be everted unsupported through the air for significant distances. The Geophysical applications presentation shows examples of that kind of propagation for small (2” diam.) liners. With reasonable guy lines built into the liners, a tower formed by an everting liner can be erected in a few minutes to 50-100 ft. from a small pressure canister. Liners filled with special fluids can be propagated for long distances for interesting uses. FLUTe has proposed the use of everting liners to quickly lay water lines for fighting forest fire. Contact us to discuss any novel applications. We may have already done it. Video: Pressurized liner eversion through a series of pipe bends SPACER
- FLUTe - Transmissivity Profiling
Transmissivity Profiling FLUTe Transmissivity profiles quickly measure all significant flow paths in a borehole with 6 to 12" resolution in as little as a few hours How Does it Work? As a blank liner is installed and everts down the borehole, the water in the borehole is forced into the formation by whatever flow paths are available (e.g. fractures, permeable beds, solution channels, etc.). Figure 1 is a drawing of a simple everting liner with three additional features, (1) The FLUTe Profilier at the wellhead which measures the liner velocity and additional parameters which can influence the velocity of the liner descent, (2) the pressure transducer measures the excess head in the liner which is driving the liner down the hole, and (3) a pressure transducer measuring the head beneath the liner. From these features, all factors controlling the eversion rate of the liner are monitored. The liner descent rate (measured by the FLUTe Profiler) is therefore controlled by the rate at which water can flow from the hole via those flow paths. The everting liner is somewhat like a perfectly fitting piston sliding down the hole, except the liner doesn't slide in the hole, it grows in length at the bottom end of the dilated liner at the "eversion point" as we call it. As the liner everts, it covers the flow paths sequentially. When the liner begins its descent in the hole, all of the flow paths are open and the descent rate is at its highest. As the liner seals off flow paths, the rate that the borehole water can be displaced out of the borehole decreases and therefore, the liner descent rate decreases as well. A monotonically fit velocity profile is produced that measures changes in liner descent velocity with depth (Figure 2). The velocity multiplied by the borehole cross sectional area (refined by a caliper log) is the flowrate of the borehole at each interval (Figure 3). At the start of the profile, the flowrate calculated is of the entire borehole. As the liner seals off flow paths, the borehole flowrate is reduced. The depths in the borehole, which exhibit a decrease in flowrate, identify the location of flow paths and the magnitude of the change is the measure of the flow rate. From the flow rate profile, one can calculate a transmissivity profile for the borehole using the Thiem equation (Figure 4). FLUTe has performed hundreds of these profiles in boreholes to depths of 1000 feet. These boreholes were 3" to 12" in diameter. Publications and professional papers comparing the results to straddle packers can be downloaded on our publications page. In most cases, the FLUTe Transmissivity Profiler™ can map all of the significant flow paths in the hole in a few hours (10 percent of the time required to do the same mapping with a straddle packer). Furthermore, the detail (6" to 12" resolution) in the FLUTe Profiler measurement is not even possible with straddle packers. The direct measurement of the flow paths with the Profiler may also reduce the need for those geophysical measurements which are used to deduce possible flow path locations in a borehole. Another advantage is that the blank liner is often installed to seal the hole against vertical contaminant migration. When used in conjuncture with the FLUTe FACT method, the contaminant distribution can also be mapped using the same blank liner (Figure 5). This data can be used with the Transmissivity profile to develop a fate/transport CSM as well as design a multi-level sampling system (See Water FLUTe ). Given the continuous transmissivity profile, the head profile can be determined by removing the liner in a stepwise fashion using a technique described at head profile. Figure 1. Transmissivity Profiling Setup Figure 2. Velocity Profile Figure 3. Calculation of the flowrate Q from the velocity change of the liner Figure 4. Flow Rate Profile and Transmissivity Profiles. Figure 5. Transmissivity Profile and FACT data. Note the high TCE concentrations at 112' and 140' BGS in very low transmissive fractures compared to low TCE concentrations in high flowing fractures at 90' and 130'. The TCE concentrations at 140' and 112' are the same or twice as high, respectively, as the highest flowing fracture in the borehole at 130' despite the fact that they are two of the lowest flowing fractures in the borehole. This data emphasizes the need for high resolution methods rather than coarse measurements, to assure that all significant contaminant source zones are properly identified during characterization. Water Samples (green diamonds), validate the FACT concentrations.
- FLUTe - Shallow Water FLUTe
Shallow Water FLUTe The Shallow Water FLUTe is an economical version of the Water FLUTe for use in environments with shallow water tables (<25 FT). Sys tem Overview: The system consists of a continuous borehole liner, spacers defining the sampling intervals, and tubing directly to the surface from each sampling interval (see the drawing). The SWF depends on the ability to pump the water sample to the surface using a peristaltic pump, so the maximum water table depth at any sampling interval is < 25 ft. The SWF is shipped on a small plastic reel and hence the shipping and installation is similar to a blank FLUTe liner. Installation: The Shallow Water FLUTe can be installed in the overburden and unstable rock formations through sonic casing and everted into open bedrock wells. Sampling Intervals : All samples collected from the Shallow Water FLUTe are drawn directly from the formation, with no potential for cross contamination or leakage as possible with packer based multi-level systems. The Shallow Water FLUTe is capable of up to 10-20 ports per borehole depending on the hole diameter from 4 inches to greater and all intervals can be sampled and purged simultaneously. Head Measurements: The water table depth at each port can be measured with a FLUTe vacuum water level meter system. For continuous head measurements at each port, an air couple transducer (ACT) system can be used with a simple surface connection. The transducers are located in the surface casing for easy access for reuse, replacement or repair. More information on the ACT can be found on our Ancillary Equipment page . Well Completion: There is no need for an exterior seal with grout, sand or bentonite. The liner seals the entire hole and the water is drawn directly from the formation. As such, there is no concern about the seal of granular materials in a slender annulus. Warranty and Removability : The SWF system is fully warrantied and removable for other use of the borehole or easy abandonment by grouting the borehole. The system can be used for artesian situations with a heavy mud fill. Whereas the system can be used for a variety of borehole depths, the Standard Water FLUTe system is better suited for boreholes more than 200 ft deep or for deeper water tables. Additional Uses: The SWF is well suited for detection of tracer arrivals in that the purge volumes are minimal and the sample is drawn directly from the formation. Because there is not an interior tubing bundle, a transparent liner version allows one to watch for the arrival of strongly dyed injections, such as potassium permanganate, using a borehole camera. That option requires a special polyester liner instead of the standard nylon liner. A FLUTe method called a precise gradient measurement is available in order to measure vertical gradients within ~ 1mm between any two ports in the liner. Because there is no field assembly and no annular sealing materials needed, and the system is fully removable by inversion from the borehole, the overall cost of the Shallow Water FLUTe system is often the least expensive multi-level sampling and head measurement option of the multi-level monitoring systems. SPACER
- FLUTe - Benefit of FLUTe Liners
Benefits of Using FLUTe Liners 1) Provide a continuous seal of a borehole or pipe, and prevent migration of formation fluids through the open hole. No sealing grouts or bentonite seals are needed. 2) Quickly map borehole transmissivity and vertical head distributions while displacing the borehole water. Equivalent to conducting packer testing on a 6" to 12" scale with higher resolution and no issues of leakage or packer bypass. 3) Map contaminant distribution in the pure phase (NAPL FLUTe ) and dissolved phase (FACT) . 4) Collect multiple discrete groundwater samples directly from the formation via a positive displacement gas driven sampling liner (Water FLUTe ) and a peristaltic pump driven liner (Shallow Water FLUTe ). 5) Reduce cost and field time for the client while delivering high resolution data. 6) Carry many useful devices such as tubing, instruments, absorbers, reactive covers, etc. into place in the borehole while maintaining a continuous seal of the borehole. 7) Support the borehole wall against slough and collapse. 8) Custom fabricated to meet demands of many different diameters and materials for many applications. 9) Propagate through tortuous passages of varying diameters inaccessible to rigid piping or push rods. 10) Warrantied and fully removable without the liner touching any other portion of the borehole wall.
- FLUTe - Vacuum Water Level Meter
FLUTe Vacuum Water Level Meter The vacuum water level meter (VWLM) is a very simple device that allows one to measure the depth to the water table (DTW) in a slender tube that cannot accommodate an electric water level meter. The VWLM is advantageous for any system that uses peristaltic pumping (DTW is less than ~25 feet below the ground surface). How does the VWLM work? The VWLM works similarly to the process of drinking a beverage through a straw. If you reduce the pressure at the top of the straw, the liquid rises into your mouth. The VWLM uses the same principal by applying a partial vacuum to the top of the sample tube. A vacuum pump is connected to the sample tube and a vacuum is applied. The magnitude of the vacuum applied determines how high the water level can be raised above the water table. The vacuum is increased until the water is visible in the sight glass (Figure 1). Once the water rises into the sight glass, the vacuum increase is halted by closing the valve to the vacuum source. The vacuum gauge (VG) displays the vacuum applied in units of feet of head that were required for the water to rise to the sight glass. Note, the level in the sight glass is well above the ground surface and therefore one must subtract the distance from the water level in the sight glass to the ground surface to find the DTW. To calculate the DTW, simply follow the equation below: Figure 1. Vacuum Water Level Meter Design. Depth to Water (DTW) = Vacuum Applied (VG) – Height of Water in the Sight Glass Above Ground Surface (H). DTW = VG (vacuum in feet of water) - H (height of water level in site glass above the ground surface).
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