Premium Connections Fatigue Assessment Methodology Fit for Multi-stage Hydraulic Fracturing Operations

Objectives/Scope During casing installation and drilling operations, Oil Country Tubular Goods (OCTG) strings are often rotated inside deviated wellbores, generating cyclic bending loading that could lead to fatigue damage. This phenomenon has been previously studied and understood. The completion of multistage fractured horizontal wells (MFHW) involves tens of fracture operations (an ever growing number) as part of the stimulation program in order to maximize production. These fracture operations involve a combination of cyclic pressures and tension loading in the production casing, through which they are conducted, with maximum loads often repeatedly reaching the upper limit of the pipe body performance ratings. This process of cyclic pressure and tension loading near the upper limit of the pipe body performance is the subject of this work. In unconventional plays, where MFHW are the standard approach, both cyclic bending due to rotation and cyclic burst and tension due to multiple fracturing operations are applied on OCTG strings. This combination may lead to a failure mode in which a crack opens due to material fatigue during rotation or fracturing cycles, and subsequently propagates (to failure) during the demanding fracturing stages. Methods, Procedures, Process As it would be expected during any technological evolution, the industry has seen an increase in casing failures during hydraulic fracturing, often not explainable by the current understanding of loads scenarios present in wellbores. Some of these events could be associated to the failure mode described above. Despite the potential risk introduced by this failure mode, to date, there is no standardized testing methodology available to evaluate the resistance of pipes and connections to this loading sequence. Results, Observations, Conclusions In order to cover this gap, a testing sequence aimed at replicating actual operating conditions was developed and deployed by the authors. This includes evaluating the resistance of a premium connection to rotation through a curved hole, and subsequent burst and tension cycles. The methodology and results are presented in this paper. Novel/Additive Information Through this testing approach, operators, manufacturers, and laboratories alike, can ensure the performance and reliability of OCTG, which are key elements in the well construction process. As main observations, all tested specimens successfully passed this very demanding testing sequence, aimed to replicate operative conditions during installation and subsequent stimulation operation.

Development and Application of Computerized Risk Registry and Management Tool Based on FMEA and FRACAS for Total Testing Process

Background and Objectives: Risk management is considered an integral part of laboratory medicine to assure laboratory quality and patient safety. However, the concept of risk management is philosophical, so actually performing risk management in a clinical laboratory can be challenging. Therefore, we would like to develop a sustainable, practical system for continuous total laboratory risk management. Materials and Methods: This study was composed of two phases: the development phase in 2019 and the application phase in 2020. A concept flow diagram for the computerized risk registry and management tool (RRMT) was designed using the failure mode and effects analysis (FMEA) and the failure reporting, analysis, and corrective action system (FRACAS) methods. The failure stage was divided into six according to the testing sequence. We applied laboratory errors to this system over one year in 2020. The risk priority number (RPN) score was calculated by multiplying the severity of the failure mode, frequency (or probability) of occurrence, and detection difficulty. Results: 103 cases were reported to RRMT during one year. Among them, 32 cases (31.1%) were summarized using the FMEA method, and the remaining 71 cases (68.9%) were evaluated using the FRACAS method. There was no failure in the patient registration phase. Chemistry units accounted for the highest proportion of failure with 18 cases (17.5%), while urine test units accounted for the lowest portion of failure with two cases (1.9%). Conclusion: We developed and applied a practical computerized risk-management tool based on FMEA and FRACAS methods for the entire testing process. RRMT was useful to detect, evaluate, and report failures. This system might be a great example of a risk management system optimized for clinical laboratories.

Variable Selection in Regression Models Using Global Sensitivity Analysis

Global sensitivity analysis is primarily used to investigate the effects of uncertainties in the input variables of physical models on the model output. This work investigates the use of global sensitivity analysis tools in the context of variable selection in regression models. Specifically, a global sensitivity measure is applied to a criterion of model fit, hence defining a ranking of regressors by importance; a testing sequence based on the ‘Pantula-principle’ is then applied to the corresponding nested submodels, obtaining a novel model-selection method. The approach is demonstrated on a growth regression case study, and on a number of simulation experiments, and it is found competitive with existing approaches to variable selection.

Aircraft Gas Turbine Engine Testing

The paper deals with testing of aircraft gas turbine engines. The main goal of the research is to propose and design testing sequence for a new or rebuilt engine. All factors and circumstances are described, including surroundings of the engine under test. Prerequisite knowledge is introduced, including the theory of testing, description of test beds, the methods of measurement of engine parameters and special factors that affect engine performance. Some examples of real testing facilities are mentioned. The result of the work is a proposal of test cycle, that can be modified according to engine purpose and specification.

Design and In-Water Testing of a Fault-Detection System for Unmanned Underwater Vehicle Actuators

We discuss the design of a fault-detection system for an unmanned underwater vehicle (UUV) actuator and present the results of in-water testing. We first discuss the design of the system, then its integration onto the UUV, the in-water testing sequence, and finally the analysis of the test results –- missed detection and false-alarm rate. This system serves as a platform for UUV fault detection and isolation research, enabling the development of system requirements, and providing the opportunity to compare the merits of the centralized vs decentralized fault-detection design approaches.

Treatment of Diabetes Type II Using Genetic Algorithm

<p>Chronic diseases is an important research field because of the growth of the number of affected people around the world. When someone has diabetes, the body either does not make enough insulin or cannot use its own insulin as well as it should. This causes sugar to build up in blood leading to complications like heart disease, stroke, and neuropathy. Poor circulation leading to loss of limbs, blindness, kidney failure, nerve damage, and death. Diagnosis plays vital role in diabetes treatment otherwise it leads to long term complications in terms of costs of the treatment of the patients and leads to many risks over the patient himself as mentioned above. In this research we propose new methodology to extract the best testing sequence evaluation mechanism for helping doctors to evaluate their patient’s cases and make the best decisions about the medicine being given. We managed to create chromosomes population each of which consists of binary decision tree, as this implementation considered being the best scenario of our problem. The system proves its efficiency by applying it on 50 patients and the results shows accuracy percentage of 95.4%.</p>

A Different Look at Cointegration Relationship between Quarterly Inflation Rates and Growth via Seasonal Integration Tests

Detecting the direction of inflation-growth relationship has been a controversial issue in terms of the theoretical framework, notedly since the rise of Mundell-Tobin effect which is based upon the assumption of substitutability between money and capital. In this study, it has been aimed to investigate the cointegrating relationship and its direction between inflation and economic growth covering the period 1998Q1:2014Q4 for Turkey as grounded on the testing sequence that is illustrated by Ilmakunnas (1990) in order to handle unit root testing in a seasonal context by testing the appropriate order of differencing and concerns with the case where SI(2,1) (seasonally integrated of order (2,1)) is the maximum order of seasonal integration. It has been also utilized from ADF unit root test and DHF, HEGY & OCSB seasonal unit root tests in seasonal integration analysis. In the study, five cointegration regressions have been considered in the level, seasonally averaged, quarterly differenced, first differenced and twice differenced forms and two series have been found to have the same degree of seasonal integration as SI(1,1). Applying various residual tests have revealed the presence of a cointegrating relationship between two variables. In addition, the inflation-growth relationship in Turkey has been concluded to perform in an opposite direction.