Aquifer thermal energy storage: An attempt to counter free thermal convection

This is the published version. Copyright 1983 American Geophysical UnionIn previous Aquifer Thermal Energy Storage (ATES) experiments, appreciable free thermal convection was observed. In an attempt to counter the detrimental effects of convection, a dual recovery well system was constructed at the Mobile site and a third injection-storage-recovery cycle performed. Using a partially penetrating well, cycle 3-3 injection began on April 7, 1982. A total of 56,680 m3 of 79°C water were injected. After 57 days of storage, production began with a dual recovery well system. Due to the dominating effect of nonhomogeneities, the dual well system did not work particularly well, and a recovery factor of 0.42 was achieved. The degree of aquifer heterogeneity at the location of the present experiments was not apparent during previous experiments at a location only 109 m away, although pumping tests indicated similar values of transmissivity. Therefore aquifers with the same transmissivity can behave quite differently in a thermal sense. Heat conduction to the upper aquitard was a major energy loss mechanism. Water sample analyses indicated that there were no important changes in the chemical constituents during the third set of experiments. There was a 19% increase in total dissolved solids. At the end of injection, the land surface near the injection well had risen 1.39 cm with respect to bench marks located 70 m away

The social affordances of flashpacking: exploring the mobility nexus of travel and communication

The proliferation of digital devices and online social media and networking technologies has altered the backpacking landscape in recent years. Thanks to the ready availability of online communication, travelers are now able to stay in continuous touch with friends, family and other travelers while on the move. This article introduces the practice of ‘flashpacking’ to describe this emerging trend and interrogates the patterns of connection and disconnection that become possible as corporeal travel and social technologies converge. Drawing on the concepts of ‘assemblages’ and ‘affordances’, we outline several aspects of this new sociality: virtual mooring, following, collaborating, and (dis)connecting. The conclusion situates this discussion alongside broader questions about the shifting nature of social life in an increasingly mobile and mediated world and suggests directions for future research at the intersection of tourism and technology

Hot-water aquifer storage: A field test

The basic water injection cycle used in a large-scale field study of heat storage in a confined aquifer near Mobile, Alabama is described. Water was pumped from an upper semi-confined aquifer, passed through a boiler where it was heated to a temperature of about 55 C, and injected into a medium sand confined aquifer. The injection well has a 6-inch (15-cm) partially-penetrating steel screen. The top of the storage formation is about 40 meters below the surface and the formation thickness is about 21 meters. In the first cycle, after a storage period of 51 days, the injection well was pumped until the temperature of the recovered water dropped to 33 c. At that point 55,300 cubic meters of water had been withdrawn and 66 percent of the injected energy had been recovered. The recovery period for the second cycle continued until the water temperature was 27.5 C and 100,100 cubic meters of water was recovered. At the end of the cycle about 90 percent of the energy injected during the cycle had been recovered

Thermal energy storage in a confined aquifer: Second cycle

This is the published version. Copyright 1981 American Geophysical UnionDuring the first 6-month injection-storage-recovery cycle of the Auburn University Aquifer Thermal Energy Storage Project, water pumped from an upper supply aquifer was heated to an average temperature of 55°C with an oil-fired boiler and then injected into a lower storage aquifer. Injection and recovery temperatures, flow rates, and temperatures at six depths in 10 observation wells and hydraulic heads in seven wells were recorded twice daily. The second-cycle injection, which was performed in a manner similar to the first, began on September 23, 1978, and continued until November 25, 1978, when 58,010 m3 of water had been pumped into the storage aquifer. The major problem experienced during the first cycle, a clogging injection well, was reduced by regular backwashing. This was done 8 times during injection and resulted in a 24% average injection rate increase compared to the first cycle. A 63-day storage period ended on January 27, 1979, and production of hot water began with an initial temperature of 54°C. By March 23 this temperature had dropped to 33°C, with 66,400 m3 of water and 76% of the injected thermal energy recovered. This compares to 66% recovery during the first cycle over the same drop in production temperature. Production of hot water continued until April 20, at which time 100,100 m3 of water and 89% of the injected thermal energy was recovered at a final production temperature of 27.5°C. During the second cycle, measurements were made of relative land subsidence and rebound to a precision approaching 0.1 mm. The surface elevation near the injection well rose 4 mm during injection, fell during storage, and fell more rapidly toward its original elevation during production. This movement was due to thermal expansion and contraction rather than to effects caused by head changes in the storage aquifer

Active-distributed temperature sensing to continuously quantify vertical flow in boreholes

We show how a distributed borehole flowmeter can be created from armored Fiber Optic cables with the Active-Distributed Temperature Sensing (A-DTS) method. The principle is that in a flowing fluid, the difference in temperature between a heated and unheated cable is a function of the fluid velocity. We outline the physical basis of the methodology and report on the deployment of a prototype A-DTS flowmeter in a fractured rock aquifer. With this design, an increase in flow velocity from 0.01 to 0.3 m s−1 elicited a 2.5°C cooling effect. It is envisaged that with further development this method will have applications where point measurements of borehole vertical flow do not fully capture combined spatiotemporal dynamics

Small drill-hole, gas mini-permeameter probe

The distal end of a basic tube element including a stopper device with an expandable plug is positioned in a pre-drilled hole in a rock face. Rotating a force control wheel threaded on the tube element exerts force on a sleeve that in turn causes the plug component of the stopper means to expand and seal the distal end of the tube in the hole. Gas under known pressure is introduced through the tube element. A thin capillary tube positioned in the tube element connects the distal end of the tube element to means to detect and display pressure changes and data that allow the permeability of the rock to be determined

Simulation of Turbulent Flocculation and Sedimentation in Flocculent-Aided Sediment Retention Basins

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Thermal energy storage in a confined aquifer: Experimental results

This is the published version. Copyright 1979 American Geophysical UnionTo aid in testing the idea of storing thermal energy in aquifers, an experiment was performed by Auburn University in which 54,784 m3 of water was pumped from a shallow supply aquifer, heated to an average temperature of 55°C, and injected into a deeper confined aquifer where the ambient temperature was 20°C. After a storage period of 51 days, 55,345 m3 of water were produced from the confined aquifer. Throughout the experiment, which lasted approximately 6 months, groundwater temperatures were recorded at six depths in each of 10 observation wells, and hydraulic heads were recorded in five observation wells. In order to prevent errors due to thermal convection, most of the observation wells recording temperature had to be backfilled with sand. During the 41-day production period, the temperature of the produced water varied from 55° to 33°C, and 65% of the injected thermal energy was recovered. At no time was an appreciable amount of free thermal convection observed in the storage formation. The dominant heat dissipation mechanisms appeared to be hydrodynamic thermal dispersion and possible mixing of cold and hot water induced by clogging and unclogging of the injection-production well. On the basis of laboratory and field studies, it was concluded that clogging of the injection well, which constituted the major technical problem during the experiment, was caused by the freshwater-sensitive nature of the storage aquifer. Due to the relatively low concentration of cations in the supply water, clay particles would swell, disperse, and migrate until they became trapped in the relatively small pores connecting the larger pores. Surging the pump and back washing the injection well would dislodge the clogging particles and temporarily improve the storage formation permeability. The phenomenon seems largely independent of temperature because it was reproduced in the laboratory with unheated water. It may, however, depend on pore velocity. Future research should be directed toward procedures for selecting storage aquifers that will have minimal susceptibility to clogging and other geochemical problems. Procedures for overcoming such difficulties are needed also because clogging and related phenomena will be more the rule than the exception. Designing an aquifer thermal storage system for maximum energy recovery would involve selecting an appropriate aquifer, analyzing the effects of hydrodynamic thermal dispersion and thermal convection if it is predicted to occur, anticipating geochemical problems, designing the optimum supply-injection-production well configuration and injecting a sufficiently large volume of heated water to realize economies of scale related to increasing volume-surface area ratio

Aquifer thermal energy storage : A well doublet experiment at increased temperatures

This is the published version. Copyright 1983 American Geophysical UnionThe two main objectives of this communication are to present a study of potential advantages and disadvantages of the doublet supply-injection well configuration in an aquifer thermal energy storage (ATES) system and to report on aquifer storage problems with injection temperatures in the 80°C range. A 3-month injection-storage-recovery cycle followed by a 7.3-month cycle constituted the main experiment. The injection volumes were 25,402 m3 and 58,063 m3 at average temperatures of 58.5°C and 81°C respectively. Unlikely previous experiments at the Mobile site, no clogging of the injection well due to clay particle swelling, dispersion, and migration was observed. This is attributed to the fact that the supply water used for injection contained a cation concentration equal to or slightly greater than that in the native groundwater. For cycles I and II, the fraction of injected energy recovered in a volume of water equal to the injection volume was 0.56 and 0.45 respectively. Both groundwater temperature and tracer data support the conclusion that this relatively low recovery was due to the detrimental effects of free thermal convection, possibly augmented by longitudinal zones of high permeability. Construction of a partially penetrating recovery well improved recovery efficiency but is not thought to be an adequate solution to thermal stratification. A maximum increase of 1.24 cm in relative land surface elevation was recorded near the end of second cycle injection. The engineering implications of such an elevation change would have to be considered, especially if an ATES system were being designed in an urban environment. A third cycle was started at the Mobile site on April 7, 1982. This final experiment contains a partially penetrating, dual-recovery well system which is expected to maximize energy recovery from a thermally stratified storage aquifer

Quantitative Methods for Reservoir Characterization and Improved Recovery: Application to Heavy Oil Sands

The first twelve months of the project focused on collecting data for characterization and modeling. In addition, data from Coalinga Field was analyzed to define the fractal structure present in the data set. The following sections of the report parallel the first four subtasks of the investigation were: (1) Collect and Load Property Data from Temblor Outcrops in California, (2) Collect and Load Property Data from Temblor Reservoir Sands, West Coalinga Field, California, (3) Collect and Load Property Data from Continuous Upper Cretaceous Outcrops in Utah, and (4) Define Fractal Structure in the Data Sets and Apply to Generating Property Representations