Proper Test Interpretation Research Articles

Detailed numerical evaluation of diffusion convection equation in layered reservoirs during tracer injection

Characterization of heterogeneous reservoirs such as multilayered or fractured systems is an important issue in different disciplines such as hydrology, petroleum and geothermal systems. One of the popular methods that can be used for this purpose is tracer tests. Better understanding of the mechanisms of mass transfer (convection–diffusion process) is essential for having a proper test interpretation. In this study, the solutions of different scenarios of tracer flow in a pair of high and low-permeable layered reservoirs including convection and diffusion mechanisms are discussed. Although analytical solutions generally provided exact solutions, they involve several assumptions and might be hard to use for complex problems. As a result, numerical methods are selected for the investigation of different scenarios and addressing cases that are beyond access of analytical methods. In this study, several scenarios of considering diffusion and convection in low and high permeable zones and effective parameters on tracer concentration are investigated. According to the results of this study, the higher the porosity ratio of low to high permeable layer, the more time is needed to get the final concentration value. Also, by increasing the value of the dispersivity coefficient, the time needed to increase the concentration decreases. In other words, the sharp increase in concentration for lower times is seen in higher dispersivity values. The concentration profile variation is affected by Peclet number. The difference among concentration profiles in different cases is considerable, especially in low Peclet numbers where the diffusion mechanism is dominant. This behavior is more common in low permeable mediums such as multilayered tight or shale reservoirs.

Telehealth Physician Oversight over Direct to Consumer Testing: Doctors Working with Patients Towards Patient Empowerment

Patient empowerment has increased the demand for direct to consumer (DTC) laboratory testing. Multiple professional societies and advocacy groups have raised concerns over how DTC laboratory testing is being offered to consumers without proper physician oversight. Physician telehealth services can properly oversee DTC laboratory testing in a safe and medically sound manner. Using telehealth protocols and standards established by professional health organizations and state regulators, physician telehealth oversight in DTC laboratory test ordering can be effective to increase patient access to healthcare services. With proper physician oversight in test interpretation, post-test counseling, and information collaboration, DTC laboratory testing can remain a reliable and convenient option for consumers. Working within the channel of distribution of most DTC laboratory testing, physician telehealth services can properly oversee DTC laboratory testing in a safe and medically sound manner to ensure that proper test interpretation, counseling, and information collaboration are achieved. Physician telehealth services can properly oversee DTC laboratory testing to ensure that proper test interpretation, counseling, and information collaboration are achieved.

Interpretation of diagnostic testing strategies for production and economic usefulness

Veterinarians providing reproductive services use a variety of diagnostic testing methods, including physical examination, laboratory testing, diagnostic imaging, and performance record evaluation. The diagnostic end point may be a physical diagnosis of pregnancy, attainment of puberty, or adequate quality and quantity of sperm; furthermore, it may be a medical diagnosis of reproductive tract pathology, presence of an infectious pathogen, or abnormal hormonal status. Proper interpretation of test results requires an understanding of how sensitivity and specificity (as measures of test accuracy), and prevalence of the condition, affect the interpretation of an individual result. For many diagnostic questions, the proper use of more than one test, either in series or in parallel, allows veterinarians to optimize their diagnostic accuracy and the economic return for the testing strategy.

Gas Well Test Analysis: Use of Normalized Pseudovariables

Summary Pressure data from gas wells are normally analyzed by use of pseudopressure, which is a transformation of measured pressure. When tests are associated with large pressure changes accompanied by a severe wellbore storage effect, such as in tight reservoirs, use is made of pseudopressure and pseudotime transforms. The purpose of the pseudovariables is to linearize "effectively" the governing diffusivity equation so that proper test interpretation can be made. In this study, normalized pseudovariables or transforms are introduced. Use of these new pseudovariables produces results identical to those obtained with the conventional pseudovariables. However, the proposed pseudovariables offer some distinct practical advantages. For example, units of pressure and time are retained, thus giving a physical "feel" for the pseudovariable definitions. Other features include use of liquid equations for solving the gas flow problems—i.e., constants of the working equations remain unchanged. This study also proposes two methods for estimating the rate-dependent skin, together with permeability, mechanical skin, and well deliverability. The first method involves logarithmic convolution of pressure with flow rate, both measured downhole, by use of a radial model. A trial-and-error approach is used to obtain the rate-dependent skin on a convolution plot. The second method requires a transient flow-after-flow test of short duration; a standard graphic technique allows the estimation of the desired reservoir parameters. Once the reservoir parameters are estimated with either method, the absolute open-flow potential (AOFP) of a well can be established by assuming a reservoir radius because the AOFP is relatively insensitive to this assumption.

Sensory conduction studies in the early recognition of nerve disorders

Early investigations into sensory conduction are reviewed and related to recent and ongoing research, specifically with relation to the early detection of nerve disorders. Current study on entrapment neuropathies and on the assessment of minor sensory conduction changes is presented. It is concluded that, in the early recognition of nerve disease, the clinical orientation of the electromyographer is essential to proper test interpretation.