Tissue engineered medical products (TEMPs) use state-of-the-art technologies and offer the patients with alternative clinical options for diseases that conventional treatments may fail or be incompetent. However promising, this technology is comparatively new with very limited hands-on experiences with both manufacturing and clinical therapy. Of great significance to products with such complexity and novelty is the establishment of a complete jurisdiction framework and a standardization database so that the safety of the technique in clinical treatment can be ensured. Although different regulatory routes are adopted in different countries, risks are generally considered to be derived from the cellular components within the product, the material scaffolds, and potentially from the final products. This article is to provide an insight of the regulatory considerations and the role of China Food and Drug Administration (CFDA) in the supervision of TEMPs.
Drilling activity has increased rapidly in Iraq over the last few years. With the lack of reliable downhole data to develop a solid strategy to optimize drilling operations, the drilling performance has been inconsistent with frequent failures of drill stem components. Without the aid of quality downhole data it is very difficult to identify the root cause of these failures, and more importantly, provide a means to identify a solution to improve performance. This paper showcases a project in South Iraq where modeling of the drilling BHA's using a unique Finite Element Analysis software package identified critical natural frequencies of the drillstring. The integration of high frequency downhole vibration data collected in multiple positions of the string provided the evidence to validate the vibration road map delivered by the BHA analysis.The objective of the project was to identify the primary vibration mode, evaluate the vibrations severity, cause and source in the 12 !" vertical section and provide recommendations to achieve performance improvement through controlled step changes in bit & BHA design, drilling parameters and operational procedures. The pre-well BHA model analysis identified that the premature bit failure was a direct result of lateral vibrations induced by operating in a critical lateral harmonic zone. This was validated with the downhole vibration data.A well-established optimization process including expert detailed analysis of the high frequency downhole vibration data provided a clear understanding of the relationship between the pre-well BHA model, the drilling parameters planed and the associated downhole drilling dynamics.The impact on performance was clear. Implementation of the new recommended drilling parameters derived from the BHA analysis applied to the same bit and BHA used in Well #1 resulted on a 26% increase in drilling performance in well 2. 2-IntroductionThere are multiple drillstring dynamics modeling software packages available in the industry that enable any drilling team to do a pre-well analysis of each BHA design and model the downhole behavior of the system. Most these packages provide the similar approach of using Finite Element Analysis of the entire string to calculate the combination of drilling parameters based on a proven, scientific approach that will most likely initiate downhole vibration and high impact loading that leads to premature bit and/or downhole tool failures.It should be a requirement to run such modeling analysis for every BHA for two main reasons. First it allows the drilling engineer to twick the BHA design to minimize the impact of the natural resonant frequencies on the system performance. And second, and in case the BHA design remains the same, it ensures that the drilling parameter combination selected (weight and surface RPM) will not initiate disruptive harmonics generated from the natural frequencies of the system itself.
Based on the working principles of various automatic vertical drilling systems (VDS), they are divided into rotary-pushing type and slide-pushing type. Then, the technical advantages and applicable scope of the two types VDS are analysed. Thirdly, the reliability of different VDS is presented based on the latest application statistical data. Fourthly, suitable VDS are selected for a certain deep well with high temperature and pressure. Finally, the development trend of the VDS is predicted based on the analysis of typical application cases. The results show that, the existing VDS could almost meet the technical needs of rapid drilling in the middle-deep sections with high formation dip angle, although the reliability of electronic components and wear resistance of the push pad still need further improvement. New type VDS, that is miniaturized (suitable for small boreholes) and resistant to high temperature and high pressure, is in urgent need to fill the gaps in the market segment recently. Domestic independent VDS have made great progress in achieving the technical goal of anti-inclination, some even surpasses imported products in key indicators such as temperature resistance. The research results can provide support for the drilling company to optimize the VDS based on engineering-geological conditions.
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