Laboratory Testing Techniques Research Articles

Evaluation of Horizontal Well Performance After Drilling-Induced Formation Damage

It is well recognized that near-wellbore formation damage can dramatically reduce well productivities, especially for open hole completed horizontal wells. The economic impact of poor productivity of these wells has pushed toward significant efforts in recent years to study laboratory testing techniques and numerical modeling methods for predicting and controlling drilling-induced formation damage. This paper presents an integrated approach, combining a near-wellbore modeling with laboratory experiments for data acquisition as input for the model, to evaluate the performance of oil and gas wells after drilling-induced formation damage.

Evaluation of Fire Damage to a Precast Concrete Structure Nondestructive, Laboratory, and Load Testing

This article discusses the use of nondestructive and laboratory testing techniques and load testing in evaluation of fire damage to precast prestressed concrete members in a parking structure. The in situ evaluation phase consisted of nondestructive testing of concrete using ultrasonic pulse velocity and radiographic exposures to locate tendons prior to the removal of cores. Flexural strength of concrete and dynamic Young's modulus of elasticity and air permeability index of 25 mm (1 in.) thick disks sawed from the cores were determined in the subsequent laboratory testing phase. Analysis of concrete properties at small depth increments permitted assessment of whether a damage gradient was present and the nature of any gradient found, as expressed by changes in these properties. Based on the compromise in material properties indicated by nondestructive and laboratory testing, two affected double-tees were load tested. The deflection pattern observed during load testing confirmed the compromise indicated by the findings of the testing program.

Innovative laboratory testing

Abstract Three laboratory test techniques were developed to study and quantify damage development in loaded rock specimens and to provide data for use in the calibration and solution of numerical models. Damage-controlled tests involved incremental loading–unloading cycles with the stress at volumetric strain reversal (crack damage stress σ cd ) and elastic properties calculated for each successive cycle. Damage was quantified by measuring the irreversible volumetric strain upon unloading and the degradation of rock strength and elastic properties. In long-term loading tests, a creep stress greater than σ cd was applied to the specimen until failure. The time to failure was dependent upon the ratio of the creep stress to σ cd , and to confining pressure. It was shown that σ cd is a reasonable estimate of the long-term rock strength. Damage was quantified by measuring the degradation of elastic properties through periodic unloading–reloading cycles. The test data were used for the calibration of Itasca's PFC stress-corrosion model. Five types of thermoporoelasticity tests were designed to determine seven of the nine thermoporoelastic parameters required for the modelling of the thermoporoelastic response of rock. Tests were performed by applying increments of confining pressure, temperature or pore pressure on the rock specimen, and measuring the changes in confining pressure, specimen volume and pore pressure. The measured values of five parameters were found to agree reasonably well with the estimated values.

Review of Water Ingress Characteristic of Stressed Masonry

Studies have found that over 80% of total water ingress occurs at the brick/mortar interface and not through the brick unit or the mortar. The interface between the brick and mortar is influenced by the tensile bond strength between the two, which is highly affected by the applied load on the structure. However, numerous and often innovative laboratory testing techniques have been developed to assess water ingress under realistic weather conditions, but they consider only unstressed panels. One of the main objectives of this paper is to identify how crucial is the changing of loading direction and applied stress level on the formation of cracks and eventually on water ingress at the brick/mortar interfaces in masonry walls. The paper also presents some of the results from a research program carried out recently on stressed brickwork masonry, which shows that stressing has a fundamental and quantifiable effect on controlling water ingress.

On-site non-destructive test for sealants

The degradation of sealants is defined as a change in physical properties caused by chemical reaction involving bond breaking in the backbone of macromolecules, and hence causes deterioration in the functionality of the polymeric material properties, such as elastic recovery and hardness. Currently, there is still no successful technique of determining the elastic recovery of in-situ sealant on building facades. Specifications and standards available are basically concerned with quality control in the manufacturing, and testing of new formulated products, and the design and application of sealants. They do not reflect and give adequate indications of the status of working sealants. Furthermore, the conventional laboratory testing techniques are tedious, time consuming and often destructive, which make them unsuitable for in-situ testing. This paper discusses the development of an on-site non-destructive testing technique to assess the performance of sealants on building facades. Assessment was made of the sensitivity, reliability and applicability of the tester. This is achieved by carrying out tests on various generic types of high-performance sealants subjected to natural and artificial weathering.

We Are a Nation of Lonely Molecules*

We Are a Nation of Lonely Molecules* Peter Drucker in Post Capitalist Society (1994) postulates that we are living through a period where, within a few short decades, society has rearranged its world view, basic values, social and political structures, arts, and key institutions. Medicine and healthcare are among those key institutions that have been rearranged. Profound advances have been made in biomedicine including magnificent work on human genome project. Laboratory testing and new imaging techniques seem to have substantially replaced traditionally lengthy history-- taking process and physical examination lamented by Brooke (1986) in his muscle medicine reference to interesting other things to do during history and physical examination. Gone with detailed history and physical examination is related human contact and touching. Evidence-based medicine has been demanded by elite science community who value over all else double-blinded, placebo-controlled, double-crossover prospective study with results decoded by persons different than those posing clinical hypothesis. Although many might not agree with high priority placed on such studies, academic and clinical pressure to comply ensures most reductionistic of clinical mind-sets. Medical holism and integrated medicine is simply too ill-defined, too large, and too multifactorial for evidence basers to get their hands around. Real scientists are encouraged to avoid such foolishness. Further, integrated medicine modality literature is unfortunately shallow even with later-day improvements at National Institutes of Health level. In meanwhile, consumers (including patients and potential patients) are actively involved in new computer age and have access to megatons of information. But how are consumers to know what is reliable, credible, and usable, and what is garbage? How does one resolve inevitable Tower of Babel of opinions? Edward Hallowell (1999) writes, ... patients have `toxic worry.' It stems from a lack of face-to-face contact in a business world where travel, voice mail, faxes, and email allow us to conduct business without ever being in same room as our colleagues and customers. Add to that confusing contradictory advice one can dial up on Net supplied both by well-intentioned and unscrupulous. The who-to-believe syndrome aggravates toxic worry. You cannot look Internet straight in eye. You cannot judge credibility of handshake, or genuine-ness of character providing information. Shorris (1994) opines, the global village predicted by seers of 1960s is being replaced by electronic cottages populated by isolated dreamers ... we are a nation of lonely molecules. Stephen Byrum, PH.D., in his Bowles Lecture at Memorial Hermann Healthcare System (2000), discussed axiologic disorders referring to disturbances in realm of ethics and spirituality. He identifies major symptoms: loneliness; inability to enjoy awesome-ness of beauties of nature, art, music, and life; and attitudes such as, I don't care anymore. Nobody cares. It doesn't matter. Nothing matters. This all adds up to axiopathy ... suffering. Suffering is a universal affliction different from signs and symptoms of disease in traditional Western sense. Investigation of suffering demands attention to mood and feeling. It requires a beyond-superficial relationship with patient to be comfortable asking and having answered necessary but often highly personal questions. Spirituality and suffering are hardly addressed in today's hurried ten-minute clinical visits, yet suffering accompanies disease in varied degrees in all or most illnesses, leaving a large gap in a patient's sense of fulfillment from a physician visit. Addressing these sufferers requires deeper levels of communication. When offered, treatment must include reestablishing attachments. …

Reconstructing Service Load

Frequency domain-based service load reconstruction is used in the automobile and other mainly mechanical engineering industries. It is a complex technique and consequently beset with a variety of practical problems. Often these problems prevent this useful laboratory testing technique from being successfully implemented. It is proposed that some intelligent user support could improve the productivity of such facilities, especially for novice users. This article describes a first step towards an intelligent load reconstruction system. An add-on fuzzy logic-based software module was developed to automatically optimize the excitation signals used for system identification. To demonstrate industrial feasibility, a real servo-hydraulic test rig was used. Experimental results and scope for future development are discussed.

Polyethylene thin-walled linings for water mains: development of structural design guidelines

The factors affecting structural performance of thin-walled linings, such as loading, host pipe characterisation and installation technique are first summarised, whence ability of the lining to span small gaps and voids in the existing pipe are identified as major design criteria. The performance of linings installed using the two most popular pipe grade polyethylenes (PE80 and PE100) is then investigated under both short-term and creep loading conditions. This is achieved using a combination of laboratory testing techniques together with two- and three-dimensional finite element modelling. The possible effects of longitudinal notches induced by the installation processes on spanning capacity are included in the investigation. Explicit design recommendations for the criteria considered are obtained.

Evaluation of fibre rope properties for offshore mooring

An examination has been conducted of fibre rope mechanical properties measured in laboratory tests on materials, constructions and terminations intended for deepwater mooring applications. This data, combined with field experience, provide a better understanding of rope behaviour and enhances the knowledge required to engineer fibre ropes for these demanding applications. This has also led to improved laboratory test techniques for measurement of mechanical properties relevant to mooring system response analyses required to meet regulatory requirements. Preliminary evaluation of the data also indicates that a post-test evaluation method to determine retained properties of insert strops removed from mooring lines may be possible.

Gas flow in porous media with Klinkenberg effects

Gas flow in porous media differs from liquid flow because of the large gas compressibility and pressure-dependent effective permeability. The latter effect, named after Klinkenberg, may have significant impact on gas flow behavior, especially in low permeability media, but it has been ignored in most of the previous studies because of the mathematical difficulty in handling the additional nonlinear term in the gas flow governing equation. This paper presents a set of new analytical solutions developed for analyzing steady-state and transient gas flow through porous media including Klinkenberg effects. The analytical solutions are obtained using a new form of gas flow governing equation that incorporates the Klinkenberg effect. Additional analytical solutions for one-, two- and three-dimensional gas flow in porous media could be readily derived by the following solution procedures in this paper. Furthermore, the validity of the conventional assumption used for linearizing the gas flow equation has been examined. A generally applicable procedure has been developed for accurate evaluation of the analytical solutions which use a linearized diffusivity for transient gas flow. As application examples, the new analytical solutions have been used to verify numerical solutions, and to design new laboratory and field testing techniques to determine the Klinkenberg parameters. The proposed laboratory analysis method is also used to analyze data from steady-state flow tests of three core plugs from The Geysers geothermal field. We show that this new approach and the traditional method of Klinkenberg yield similar results of Klinkenberg constants for the laboratory tests; however, the new method allows one to analyze data from both transient and steady-state tests in various flow geometries.

Chemistry, Toxicology, and Human Health Risk of Cyanide Compounds in Soils at Former Manufactured Gas Plant Sites

Cyanide-containing wastes are commonly found in soils at former manufactured gas plant (MGP) sites, also known as town gas sites. The complex forms of cyanide are responsible for the blue-stained soils and rocks found at these sites. Most concentrations of cyanide at MGP sites are below 2000 ppm, although concentrations greater than 20,000 ppm have been observed. An understanding of the chemistry of the MGP cyanide-containing compounds, their fate, and transport as well as their toxicology is critical to accurately assessing potential human health risks from these compounds. In this paper, the authors demonstrate that the most prevalent types of cyanide compounds found at former MGP sites are the relatively nontoxic iron-complexed forms, such as ferric ferrocyanide, rather than the highly toxic free cyanide forms. Moreover, the chemical conditions at most former MGP sites limit the extent to which free cyanide may be released into air and water from complex cyanides. Using a screening analysis, the authors estimate potential risks from a multiroute exposure to complex and free cyanides in soil, air, and groundwater at former MGP sites and demonstrate that such risks are likely to be insignificant. Unfortunately, the lack of readily available measurement techniques to characterize cyanides in soil can result in erroneous conclusions about potential risks from cyanide compounds in soils at former MGP sites, particularly if health-based soil criteria for free cyanide (e.g., the Massachusetts Department of Environmental Protection criterion for free cyanide is 100 ppm (MA. DEP, 1995)) are applied. The authors recommend development of routine methods for field sampling and laboratory testing techniques to demonstrate that cyanides in soil at former MGP sites are predominated by iron-complexed species and that free cyanide is less than levels of concern.

Lyme disease: laboratory diagnosis and serologic testing

Although identified less than 20 years ago, Lyme disease has proved to be the most common tick-borne disease in the United States: some 10,000 cases were reported in 1992. In some cases the disease may be transitory and of little consequence but in others it may become chronic and severely disabling. Accurate diagnosis is, therefore, of great importance but, as this article shows, laboratory testing techniques still need improvement.

In situ stress and stiffness at seven overconsolidated clay and weak rock sites — Part 3 : O'Brien, A S; Forbes-King, C J; Gildea, P A; Sharp, P Ground EngngV25, N8, Oct 1992, P24–28

For projects in urban areas the accurate assessment of ground movements is often of fundamental importance, and their prediction depends on the appropriate selection of in situ stress and stiffness parameters. During the early 1980s new sampling, laboratory and in situ test methods became commercially available. In the past five years the authors have gained considerable experience with these new techniques, in a wide range of ground conditions. This paper reviews the assessment and interpretation of data for the selection of appropriate ground stiffness and in situ stress parameters. Some of this data is compared with that obtained from routine ground investigation and laboratory testing techniques and also that obtained from recent research. The authors concentrate on data obtained from three sites - two in London Clay and one in Weald Clay. Additional data is also presented for other heavily over-consolidated clays (glacial till, Oxford, Gault and Kimmeridge clays) and a weak rock (keuper marl). This paper is to be published in three parts. Part 1 describes the sites which were investigated and data on in situ stress measurements is presented. Data on undrained stiffness is presented in Part 2. Part 3 presents data on drained stiffness, conclusions and references for the entire paper are also given.

Hypercoagulability and Thrombosis

Increased knowledge about basic physiology of hemostasis, the identification of new blood protein defects leading to thrombosis, coupled with development of new, simple, readily available laboratory testing techniques now allows the cause of thrombosis to be identified in most patients. Because of this, clinicians and laboratory scientists must not only be familiar with blood protein defects associated with thrombosis, but must evaluate patients in a cooperative manner. Identification of the etiology will depend on both clinical and laboratory evaluation and assumes major importance for designing appropriate therapy.

Testing Techniques for Evaluating the Shear Strength of Lime/Fly Ash Slurry Stabilized Soil

Abstract Lime slurry pressure injections have been successfully used to stabilize and control swelling and expansive soils and low-strength clay soils to depths of up to 40 ft (12 m). When the activity of soils is somewhat lower, or when soils have large void ratios, lime/fly ash (L/FA) slurry mixtures have been injected to fill voids. It has been postulated that this action creates stronger seams, helps to mend possible failure surfaces, and at the same time increases the overall stability of a slope by decreasing water infiltration. The investigation reported herein was undertaken to develop laboratory testing techniques suitable for evaluating the strength improvement realized by introducing L/FA into a soil mass in the form of seams. To accomplish this goal, six specimen configurations were conceived, and a total of 45 direct shear specimens, including 35 containing vertical and/or horizontal seams of L/FA, were tested. In addition to demonstrating the viability of testing techniques developed, the testing program resulted in a small data base on one soil stabilized with an L/FA slurry having a lime-to-fly ash weight ratio of 1:3.75 and a solids-to-water ratio of 7.6 lb to 1 gal (0.9 kg to 1 L).

Ted Schultz' contributions to aircraft acoustics

Ted Schultz' contributions to aircraft acoustics began in 1955 during the initial design of the DC‐8 jet transport airplane at the Douglas Aircraft Company in Santa Monica, CA. As Assistant Chief of the Acoustical Engineering Staff, he was directly involved in theoretical and environmental work in interior and exterior acoustics and provided challenging leadership to other Douglas employees. Ted's work in aircraft cabin acoustics included design and testing of: fuselage sidewalls with high sound transmission loss against the pressure fluctuations in the turbulent boundary layer (whose characteristics were not well understood at that time); interior sound‐absorbing surfaces; and methods to control the noise produced by aircraft equipment items (e.g., hydraulic pumps, fans, venturi flow‐control devices, and air‐conditioning system components). During much of this experimental work, he found it necessary to develop unique acoustical laboratory test facilities and techniques which became an expertise widely sought after throughout his later professional career. In exterior acoustics, he worked closely with Alan Powell (consultant to Douglas Aircraft Company) to develop theoretical descriptions of the characteristics of noise resulting from the mixing processes in aircraft jet engine exhausts, as well as in the boundary layer along an aircraft fuselage. He provided insight and guidance in evaluation of results from model and full‐scale jet noise suppressor concepts. Ted also helped in the early development of methods to evaluate community noise impact from operation of jet aircraft. His expertise on rating community noise response considering aircraft and other exterior sounds is recognized worldwide. His highly developed skills in aircraft acoustics were called upon again in the 1984–1988 period as a consultant to McDonnell Douglas in the design of state‐of‐the‐art acoustical test facilities to study methods to minimize cabin noise levels in propfan‐powered transport aircraft. Ted's innovative contributions to all aspects of aircraft acoustics formed technical foundations that will be utilized in establishing acoustical designs for commercial transport aircraft for years to come.

Modelling of flow through potash tailings piles

Modelling the flow of brine through potash tailings requires that the saturated and unsaturated hydraulic properties of the tailings be established; in particular, the relationships of fluid content and permeability to matric suction are required. The in situ and laboratory testing techniques used for determining these properties are described and the results are presented.Numerical modelling techniques for the flow of brine through potash tailings are demonstrated by performing a computer simulation of an open-trench infiltration test conducted at the Lanigan Division Potash Mine in Saskatchewan. The responses of the field instrumentation during the infiltration test were compared with the results of the simulation. The simulation utilizes the measured fluid content versus suction curves and the calculated permeability versus suction curves as input parameters. Good agreement was observed between the measured and simulated field responses. The effects of varying the hydraulic properties of the tailings are examined to arrive at a better understanding of the flow mechanism involved. Key words: saturated–unsaturated, seepage, finite element modelling, brine, potash, tailings, infiltration.

Evaluation of laboratory testing techniques in soil mechanics : Saada, A S; Fries, G; Ker, C C Soils FoundV23, N2, June 1983, P98–112

Evaluation of laboratory testing techniques in soil mechanics : Saada, A S; Fries, G; Ker, C C Soils FoundV23, N2, June 1983, P98–112

The Investigation of Aquifer Parameters Using Multiple Piezometers

ABSTRACTIn order to investigate the aquifer parameters of a fissured layered sandstone aquifer, it was found necessary to construct and test an abstraction borehole using laboratory, double packer, geophysical and pumping test techniques. Good correlation was found between the techniques when the aquifer was represented by a fissured layered aquifer with low permeability bands separating layers of higher permeability. The use of multiple piezometers proved to be the only way of obtaining sensible results for field pumping tests and has given storage coefficients for both the confined and unconfined sections of the aquifer.

An Evaluation of Laboratory Testing Techniques in Soil Mechanics

ABSTRACT An extensive soil testing program was conducted on clay and sand materials using three different devices, namely the standard triaxial, the N. G. I. simple shear device and the thin long hollow cylinder. Both monotonic and cycling loadings were used and led to results that dramatize the influence of the boundary conditions present in each device. The use of the simple shear test to simulate the conditions that prevail during landslides or earthquakes is found to lead to erroneous results when compared to the thin hollow cylinder. For both static and dynamic tests the triaxial tests is definitely an improvement over the simple shear one. The thin hollow cylinder is shown to be the most desirable configuration to be used in the soils laboratory for studies related to strength and stability under both static and earthquake situations.