EVALUATION OF MASONRY GROUTING EFFECTIVENESS USING THERMOGRAPHY AND ULTRASONIC METHODS

One of the frequently used methods of stabilization and reinforcement of historic masonry is grouting, especially grouting of cracks and voids in masonry structures. Determination of the properties of the injected structure, both in terms of physico-mechanical properties (with regard to the subsequent compatibility of the grouting mixture) and in terms of its condition and failures (cracks, voids, cavities), is a prerequisite for correct design and realization of reinforcement grouting. Minimization of interventions into the historic structure while performing surveys and the associated use of non-destructive diagnostic methods is one of the requirements for the remediation of listed buildings. Within the experimental research of reinforcement of historic masonry structures, the possibility of using thermography and ultrasound methods was evaluated and conditions and limitations for the use of these non-destructive methods were formulated

Design and Fatigue Analysis of an LWD Drill Tool

Indiana University-Purdue University Indianapolis (IUPUI)Previous works suggest that 80% to 90% of failures observed in the rotary machines are accounted for fatigue failure. And it is observed that cyclic stresses are more critical than steady stresses when the failure occurred is due to fatigue. One of the most expensive industries involving rotary machines is the Oil and Gas industry. The large drilling tools are used for oil extracts on-shore and off-shore. There are several forces that act on a drilling tool while operating below the earth's surface. Those forces are namely pressure, bending moment and torque. The tool is designed from the baseline model of the former tool in Solidworks and Design Molder. Here load acting due to pressure and torque accounts for steady stress i.e., Mean Stress and loading acting due to bending moment account for fluctuating stress i.e., Alternating Stress. The loading and boundary conditions have been adapted from Halliburton’s previous works for the LWD drill tool to better estimate the size of the largest possible transducer. The fatigue analysis of static load cases is carried out in Ansys Mechanical Workbench 19.0 using static structural analysis. The simulation is run to obtain results for total deformation, equivalent stress, and user-defined results. The component is designed for infinite life to calculate the endurance limit. Shigley guidelines and FKM guidelines are compared as a part of a study to select the best possible approach in the current application. The width of the imaging pocket is varied from 1.25 inches to 2.0 inches to accommodate the largest possible transducer without compromising the structural integrity of the tool. The optimum design is chosen based on the stress life theory criteria namely Gerber theory and Goodman Theory

Digital Signal Processing

Contains summary of research and reports on sixteen research projects.U.S. Navy - Office of Naval Research (Contract N00014-75-C-0852)National Science Foundation FellowshipNATO FellowshipU.S. Navy - Office of Naval Research (Contract N00014-75-C-0951)National Science Foundation (Grant ECS79-15226)U.S. Navy - Office of Naval Research (Contract N00014-77-C-0257)Bell LaboratoriesNational Science Foundation (Grant ECS80-07102)Schlumberger-Doll Research Center FellowshipHertz Foundation FellowshipGovernment of Pakistan ScholarshipU.S. Navy - Office of Naval Research (Contract N00014-77-C-0196)U.S. Air Force (Contract F19628-81-C-0002)Hughes Aircraft Company Fellowshi

Applications of aerospace technology to petroleum extraction and reservoir engineering

Through contacts with the petroleum industry, the petroleum service industry, universities and government agencies, important petroleum extraction problems were identified. For each problem, areas of aerospace technology that might aid in its solution were also identified, where possible. Some of the problems were selected for further consideration. Work on these problems led to the formulation of specific concepts as candidate for development. Each concept is addressed to the solution of specific extraction problems and makes use of specific areas of aerospace technology

Stress orientation to 5km depth in the basement below Basel (Switzerland) from borehole failure analysis

A vertical profile of maximum horizontal principal stress, SHmax, orientation to 5km depth was obtained beneath the Swiss city of Basel from observations of wellbore failure derived from ultrasonic televiewer images obtained in two 1km distant near-vertical boreholes: a 2755 m exploration well (OT2) imaged from 2550 m to 2753 m across the granitic basement-sediment interface at 2649 m; and a 5km deep borehole (BS1) imaged entirely within the granite from 2569 m to 4992 m. Stress-related wellbore failure in the form of breakouts or drilling-induced tension fractures (DITFs) occurs throughout the depth range of the logs with breakouts predominant. Within the granite, DITFs are intermittently present, and breakouts more or less continuously present over all but the uppermost 100 m where they are sparse. The mean SHmax orientations from DITFs is 151±13° whereas breakouts yield 143 ±14°, the combined value weighted for frequency of occurrence being N144°E±14°. No marked depth dependence in mean SHmax orientation averaged over several hundred meters depth intervals is evident. This mean SHmax orientation for the granite is consistent with the results of the inversion of populations of focal mechanism solutions of earthquakes occurring between depths of 10-15km within regions immediately to the north and south of Basel, and with the T-axis of events occurring within the reservoir (Deichmann and Ernst, this volume). DITFs and breakouts identified in OT2 above and below the sediment-basement interface suggest that a change in SHmax orientation to N115°E ±12° within the Rotliegendes sandstone occurs near its interface with the basement. The origin of the 20-30° change is uncertain, as is its lateral extent. The logs do not extend higher than 80 m above the interface, and so the data do not define whether a further change in stress orientation occurs at the evaporites. Near-surface measurements taken within 50km of Basel suggest a mean orientation of N-S, albeit with large variability, as do the orientation of hydrofractures at depths up to 850 m within and above the evaporite layers and an active salt diapir, also within 50km of Basel. Thus, the available evidence supports the notion that the orientation of SHmax above the evaporites is on average more N-S oriented and thus differs from the NW-SE inferred for the basement from the BS1/OS2 wellbore failure data and the earthquake data. Changes in stress orientation with depth can have significant practical consequences for the development of an EGS reservoir, and serve to emphasise the importance of obtaining estimates from within the target rock mas

Stress characterization and temporal evolution of borehole failure at the Rittershoffen geothermal project

International audienceIn the Upper Rhine Graben, several innovative projects based on enhanced geothermal system (EGS) technology exploit local deep-fractured geothermal reservoirs. The principle underlying this technology consists of increasing the hydraulic performances of the natural fractures using different stimulation methods in order to circulate the natural brine at commercial flow rates. For this purpose, knowledge of the in situ stress state is of central importance to predict the response of the rock mass to different stimulation programs. Here, we propose a characterization of the in situ stress state from the analysis of ultrasonic borehole imager (UBI) data acquired at different key moments of the reservoir development using a specific image correlation technique. This unique dataset has been obtained from the open-hole sections of the two deep wells (GRT-1 and GRT-2, ∼ 2500 m) at the geothermal site of Rittershoffen, France. We based our analysis on the geometry of breakouts and drilling-induced tension fractures (DITFs). A transitional stress regime between strike-slip and normal faulting consistent with the neighboring site of Soultz-sous-Forêts is evident. The time-lapse dataset enables us to analyze both in time and space the evolution of the structures over 2 years after drilling. The image correlation approach developed for time-lapse UBI images shows that breakouts extend along the borehole with time and widen (i.e., angular opening between the edges of the breakouts) but do not deepen (i.e., increase in the maximal radius of the breakouts). The breakout widening is explained by wellbore thermal equilibration. A significant stress rotation at depth is evident. It is shown to be controlled by a major fault zone and not by the sediment-basement interface. Our analysis does not reveal any significant change in the stress magnitude in the reservoir

Digital Signal Processing

Contains an introduction and reports on seventeen research projects.U.S. Navy - Office of Naval Research (Contract N00014-77-C-0266)Amoco Foundation FellowshipU.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation (Grant ECS80-07102)U.S. Army Research Office (Contract DAAG29-81-K-0073)Hughes Aircraft Company FellowshipAmerican Edwards Labs. GrantWhitaker Health Sciences FundPfeiffer Foundation GrantSchlumberger-Doll Research Center FellowshipGovernment of Pakistan ScholarshipU.S. Navy - Office of Naval Research (Contract N00014-77-C-0196)National Science Foundation (Grant ECS79-15226)Hertz Foundation Fellowshi

CMUT Crosstalk Reduction Using Crosslinked Silica Aerogel

Inter-element acoustic crosstalk is one of the major concerns which restricts the potential deployment of Capacitive Micromachined Ultrasonic Transducers (CMUTs) in Nondestructive Evaluation (NDE) despite its superior transduction capabilities. This thesis investigates the causes of acoustic crosstalk in CMUTs and develops a novel method of CMUT crosstalk reduction by passivating the CMUT top surface by a thin layer of Di-isocyanate enhanced crosslinked silica aerogel. This powerful technique derives its inspiration from the Scholte waves attenuation techniques as used in boreholes at the permeable formations. Analytical and 3D finite element analysis in MATLAB and COMSOL Multiphysics, respectively, show that the developed technique can minimize the crosstalk due to Scholte waves at the fluid-solid interfaces by at least 5 dB more at the nearest neighbor as compared to other published techniques. An added advantage of the developed technique is that the level of Scholte wave attenuation can be controlled by altering the porosity of the aerogel layer. A simple and cost-effective fabrication process employing sol-gel and ambient pressure drying processes for the aerogel layer deposition has been developed that doesn’t interfere with the basic CMUT operation or fabrication techniques