分层抽样方法在岩心柱取样中的应用

通过储层岩心实验得到的数据是地质研究、测井解释和油气藏工程计算的基础。岩心柱样品的选择是储层岩心实验的第一步,其取样精度对实验结果具有重要的影响。当岩心柱样品取样数量受限的情况下,传统的简单随机抽样方法难以满足测量精度的要求。针对传统抽样方法的局限性,阐述了分层抽样方法的原理,并探讨了分层抽样参数的选取标准。在实测数据的基础上,使用Visual Basic语言编程实现蒙特卡洛算法,对随机抽样和分层抽样的测量精度进行了比较。结果表明:在相同抽样数量的前提下,分层抽样的数据精度明显优于简单随机抽样。因此,根据不同岩心实验的要求,提出了基于分层抽样的岩心柱样品的选择方法。该方法可以预估取样精度,并据此设计合理的样品数量,当实验样品数量受限时,可以有效地提升取样精度。      

Calculation of average bed porosity

Results of various authors on the average porosity of different shapes of grains (spheres, cylinders, lumps, Rashing rings) are codified, and relationships are derived between the porosity of fixed granular bed and the ratios of vessel diameter to grain diameter and the shape of the grains. A formula is proposed for engineering evaluation of bed porosity, the accuracy of the calculation from which is improved as a result of the statistical representativeness of an array of experimental data. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 1, pp. 9–10, January, 2006.     

Development and evaluation on a RFID-based traceability system for cattle/beef quality safety in China

Beef has become a kind of important food in China because of its nutritional value perceived by consumers. With increasing consumers' awareness and governments' regulations on beef quality and safety, traceability is becoming a mandatory requirement in cattle/beef industry. This paper developed and evaluated a cattle/beef traceability system that integrated RFID technology with PDA and barcode printer. The system requirements, the business flow of the cattle/beef chain, and the key traceability information for the system were identified through a survey. Then a conceptual model was proposed to describe the process of traceability information acquisition, transformation and transmission along the supply chain. Finally, the system was evaluated and optimized in the sampled supply chain.The results show that the major benefits gained from the RFID-enabled traceability system are the real-time and accurate data acquisition and transmission, and the high efficiency of information tracking and tracing across the cattle/beef supply chain; the main barriers for implementing the system are the inapplicable method of inputting information, the inefficient sequence of data input and communication mechanism associated with RFID reader, and the high implementation cost.     

A model and prototype implementation for tracking and tracing agricultural batch products along the food chain

There is an increasing demand of traceability in the food chain, statutory requirements are growing stricter and there is increasing pressure to develop standardized traceability systems. Each event in the chain, like production of transportation, packing, distribution or processing results in a different product which can have its own information associated within the tracing system. From the raw material to the sale of goods, more and more information needs to be gathered and made available. Supplementary information may also be collected at any step, in order to provide data for analysis and optimization of production practices.Using web-based systems for data processing, storage and transfer makes possible a flexible way of information access, networking and usability. In this paper an architectural proposal is presented and the proposed solution is tested by the implementation of a prototype. The software architecture presented makes use of a series of standards than offer new possibilities in traceability control and management. For testing the prototype, information from precision farming together with the information recorded during the transport and delivery was used. The system enables full traceability and it complies with all existing traceability standards.     

Application and validation of a statistically derived risk-based sampling plan to improve efficiency of inspection and enforcement

The statistically derived risk-based sampling plan for surveillance sample assignments of chemical and biological hazards was designed using binomial probability distribution. The binomial statistics was applied to the past 3-year data to estimate a confidence interval and a sample size aiming to improve efficiency and effectiveness of the agency's sampling and inspectional activities. The accuracy of the statistical models and computed estimates were validated in the following years. The ranges of confidence interval and sample size appeared to be significantly influenced by a level of the violation rate of feed product samples, an acceptable error, a number of the analyzed samples, and a statistical significance level. The violation rates of feed products for target analytes (aflatoxins, fumonisins, Salmonella, and dioxin) in the validation data were lower than those of the average 3-year data in most feed products. Besides, the actual violation rates of the validation samples did not exactly fall within the anticipated range of the confidence interval estimates. Such a discrepancy is considered introduced by several factors such as sample size adequacy, skewed distribution of a target analyte in feed products, and unique analyte/product combination. The overall study results indicate that the risk-based plan of work would provide a more effective and efficient risk management tool to help improve the oversight of the feed industry and the compliance to feed safety standards.     

Characterization of RDX-Based Thermosetting Plastic-Bonded Explosive by Cone-Beam Microfocus Computed Tomography

In this study microfocus computed tomography (μCT), a nondestructive technique, was used for 3D characterization of cyclotrimethylenetrinitramine (RDX)-based thermosetting plastic-bonded explosives. Quantitative information on RDX crystals including the packing status of the crystal and binder system, as well as the inner structure characteristics of partially solidified and fully solidified samples, was obtained using cone-beam μCT technology. The CT images show that the CT value of RDX crystal grains was obviously higher than that of crystal powder/binder. The results also show that after vacuum casting and thermosetting, the RDX grains were dispersed evenly and there were no air pores or cracks observed in the sample. Small pores exist inside the RDX grains with a porosity of less than 0.3%. The analysis results indicate high quality of the explosive part after employing thermosetting molding. The binder system and RDX crystals were integrated sufficiently, yet the grain packing was not maximum. The estimated average density and maximal difference in density of the sample were both in accordance with the testing results by Archimedes’ method and it was proven that complete curing may enhance the overall density and density uniformity of the product.     

Microsatellite markers for animal identification and meat traceability of six beef cattle breeds in the Chinese market

Microsatellite markers have been shown to be a useful tool in individual identification and meat traceability. Aiming at developing a genetic tracing system for beef cattle breeds in the Chinese market, this study identified a set of 16 specific microsatellite markers within six breeds, including Japanese Black, Anduo yak, Limousin, Jiaxian Red, Nanyang Yellow and Luxi Yellow. A total of 180 alleles have been detected with an average number of 11.2 per locus, and the average polymorphism information content (PIC) is 0.7696 for all loci. The 16-loci set could successfully distinguish all the individuals of the six breeds. When the six most polymorphic markers were chosen for each breed, the matching probability (MP) value was found to be about seven in one million, excluding the extremely high value in Limousin. As the number of markers increased, the MP value was gradually lowered, and the accuracy was also enhanced. Meanwhile, the traceability validation test was conducted with the seven most polymorphic markers (ETH10, ETH225, ILSTS006, INRA032, INRA035, INRA037 and TGLA122), the conforming probabilities of genotypes for 28 blood and corresponding tissue samples were 100%. The results of this study could partly prevent the food fraud incidence in the Chinese market, and they also showed further evidence in the applications of genetic markers to meat traceability based on animal identification to ensure food safety.     

中俄东线天然气管道天然气质量分析与计量技术

天然气质量涉及在输送和使用过程中与安全卫生、环境保护以及经济利益相关指标的要求，而天然气计量则直接与购销双方天然气气量结算的金额有关。因此，天然气的质量分析和流量计量在天然气工业中具有重要的作用和意义。在跨国管道天然气贸易交接中，购销双方除了关注天然气价格以外，还会重点围绕天然气质量分析和流量计量开展技术谈判。为此，分析了中俄东线天然气管道技术谈判过程中所关注的天然气质量分析与流量计量技术问题，并从采用的方法标准、气质检测项目及其指标、流量计和辅助设施配置及其指标、取样口设置、在线分析仪器配置和分析及计量结果溯源性等关键技术方面进行了归纳和总结。研究结果表明：①明确了天然气质量分析与流量计量采标原则，使得在确定计量协议中的具体技术内容时有标可依；②确定了天然气质量分析中涉及的检测项目及其指标、取样口的设置、在线分析设备的配置、分析结果溯源性和保证措施，确保了其结果的准确性与可靠性； ③确定了计量系统指标要求、计量管路布置、流量计量溯源性和保证措施，确保了天然气流量计量结果的准确性与可靠性。结论认为，该研究成果可以为未来我国跨国管道天然气计量站及国内大型天然气贸易交接计量站的建设和管理提供经验和借鉴。     

An experimental investigation on the effect of grain size on oil-well sand production

Sand production in oil wells is closely related to the mechanical behavior and petrographical properties of sandstones reservoir. Grain size is one of the main parameters controlling the phenomenon, which is studied in this paper. Large-scale hollow cylindrical synthetic samples with the same rock strength but different grain sizes were tested by an experimental setup in the laboratory. Different external stresses and fluid flow rates were applied to the samples and produced sand was measured continuously. Results show two different trends between sanding stress level and grain size. For the samples with finer grain size (D50<0.3 mm), the required confining stress for different sanding levels decreased with an increase in the grain size and for the samples with the coarser grains (D50>0.3 mm) the required confining stress for different sanding levels dramatically increased with an increase in the grain size. Those two different trends were discussed and explained. The first one was production of individual grains and the second was bigger chunks in the slab form. In samples with large grains, plastic zones around hole were changed to a completely loose zone including interlocked individual grains or cluster of grains. In these samples after breakage of these interlocked zones sand was produced in the form of individual grains and clusters. Contrary to this, for samples with smaller grain size, shear bands were formed around the plastified hole and sand was produced in the form of big chunks or slabs.     

An improved traceability system for food quality assurance and evaluation based on fuzzy classification and neural network

Currently, the food safety incidents happened frequently in china and the customer confidence declined rapidly, then the problems related to food quality and safety have attracted more and more social attention. Considering the concern with regard to food quality assurance and consumer confidence improvement, many companies have developed a traceability system to visualize the supply chain and avoid food safety incidents. In this paper, we proposed an improved food traceability system which can not only achieve forward tracking and diverse tracing like the existing systems do, but also evaluate the food quality timely along the supply chain and provide consumers with these evaluating information, to mainly enhance the consumer experience and help firms gain the trust of consumers. For the food quality evaluation, the method of fuzzy classification was used to evaluate the food quality at each stages of supply chain while the artificial neural network was adopted to derive the final determination of the grade of food quality according to all the stage quality evaluations. A case study of a pork producer was conducted, and the results showed that the improved traceability system performed well in food quality assurance and evaluation. In addition, implications of the proposed approach were discussed, and suggestions for future work were outlined.     

微观泄漏机理在非API套管接头密封性能评估中的应用

将微观泄漏机理引入非API套管接头密封性能研究,旨在建立表面粗糙度和密封结构加工参数与微观气体泄漏率之间的函数映射关系。通过Monte Carlo随机正态分布抽样公式结合密封表面粗糙度加工参数,模拟得到服从正态分布和预设表面粗糙度值的粗糙表面轮廓曲线,依据不同样本容量和表面粗糙度下平均峰角、平均峰高和三角峰数目/样本容量等轮廓曲线形貌特征统计数据,分析得到模拟曲线几何共性特征。结合弹塑性力学接触理论和计算得到的粗糙表面几何形貌参数,建立具有几何共性特征的高硬度管体层锥体压入低硬度软金属镀层平面简化泄漏模型,将气体泄漏看作不可压缩稳定层流,推导出含有密封面微观几何形貌特征（平均峰角和平均峰高）的气泄漏率计算公式。将与套管接头主密封结构重要加工参数相关的总密封预紧压力代入微观气体泄漏率计算公式,得到适用于非API套管接头密封性能定量评估计算方法。泄漏率实例计算结果表明,不同表面粗糙度对应气体泄漏率相差一个数量级,且加工精度等级越高相差越明显。非API套管接头密封设计和性能评估必须考虑金属机加工表面粗糙度。     

Anti-counterfeit code for aquatic product identification for traceability and supervision in China

There are not or weak anti-counterfeit functions in the current traceability system. As a result, the counterfeiters could imitate this system easily. This phenomenon had a large impact on the traceability system construction and on consumer trust in the traceability information. The aim of our research was to construct an anti-counterfeit code for aquatic product identification, for traceability and supervision of aquatic enterprises in the domestic market. The aquatic products batch code (APBC) was in the form of a segmented combination encoding an enterprise identification code, a product code and a check code, which implements a combination of traceability and supervision. An encryption algorithm based on the Advanced Encryption Standard (AES) was designed for decimal anti-counterfeit code based on the unique identification of the aquatic trace units. Simulation tests indicated that a diffusion rate of greater than 90% was achieved when the encryption was run four or more times, thereby leading to the implementation of an anti-counterfeiting technique for aquatic traceability, known as “one time, one code”. The anti-counterfeit code combined with GS1 was used in a product label, and the method has a high level of security and is used for supervision and tracing of aquatic products in China.     

地震采集面元尺度与成像横向分辨能力分析

在分析地震采集面元尺度一般性设计的基础上,通过地震模型不同采集道间距的正演模拟成像结果分析,验证了采用不同道距成像解释结果存在较大差异。道距越大解释难度越大,误差也越大,道距越小,成像解释结果与实际地质构造越接近。通过对实际不同面元尺度的地震成像结果分析,揭示了较大面元的断层成像存在同相串轴现象,准确判别解释难度大。小面元的断层成像面窄而清晰,易于判别与解释,不同程度地提高了地震横向分辨能力。结合以往勘探的应用情况,根据不同地震勘探阶段的地质任务需求,给出了在新区地震勘探、高精度地震勘探、滚动开发地震勘探阶段设计采集面元尺度时的建议,可供地震勘探采集面元设计时参考。     

Traceability technologies for farm animals and their products in China

The history of traceability reveals that nomadic herders as early as 1000 BCE marked livestock with irons and ear incisions in order to protect against thefts. Nowadays, we build traceability systems to document the origin of foods, and in order to ensure safer foods when tracking and recalling products. A holistic traceability system includes, as a minimum, identification elements, databases and an information flow. The animal identification elements refers to body marks, ear tags, Radio-Frequency Identification (RFID) tags, retina image recognition, or DNA fingerprinting. The product identification refers to barcodes (EAN UCC, PLU, and GS1), 2D barcodes (QR, VC, and DM) and RFID or Electronic Product Code (EPC). The present review describes existing and upcoming traceability technologies for farm animals and their products, to update the common methods for information collection and data inquiry, with the view to expound traceability policies and regulations between developed and developing countries. The benefits of the new technologies and their practical limitations are also discussed.     

高密度高分辨地震勘探技术在渤海PL地区的应用

随着地震勘探技术的提高,以高空间采样率为显著特征的高密度地震勘探技术取得了重大进展。为探索高密度高分辨三维地震采集技术在海上的应用,在渤海PL地区地震资料采集中首次在国内应用了横向鸟技术,缩小了资料的面元尺寸,同时优化了震源、电缆等施工参数。同时,通过针对性的高分辨处理,成果资料在横向和纵向分辨率上都有很大提高,反映的地质信息更为丰富,有助于提高对断裂系统的认识能力,增加了可供选择的钻探目标。     

An intelligent value stream-based approach to collaboration of food traceability cyber physical system by fog computing

Good advanced food traceability systems help to minimize unsafe or poor quality products in food supply chain through value-based process. From the emerging technologies forthcoming for industry automation, future advanced food traceability system must consider not only cyber physical system (CPS) and fog computing but also value-added business in food supply chain. Accordingly, this study presents a novel intelligent value stream-based food traceability cyber physical system approach integrated with enterprise architectures, EPCglobal and value stream mapping method by fog computing network for traceability collaborative efficiency. Furthermore, the proposed intelligent approach explores distributive and central traceable stream mechanism in assessing the most critical traceable events for tracking and tracing process. Successful case study, software system design and implementation demonstrated the performance of the proposed approach. Furthermore, experiment shows the better results obtained after the simulation execution for intelligent predictive algorithm.     

观测系统面元细分问题分析

建立了均匀性判别法则,利用总道数和炮检距统计数据,说明了细分面元比固定面元有更好的均匀性。针对当前对面元细分方法的不同认识,提出了最小面元是实面元而其它大面元均是虚面元的观点,最小面元和覆盖次数有一定的匹配关系。最小面元应该有足够的但又不能过高的覆盖次数,覆盖次数与信噪比存在一定的函数关系;最小面元越小,分辨率越高,实际资料解释中应该采用最小面元。以面元细分观测系统在MC,YX和SH地区的应用为例,对于不同复杂地质情况及信噪比,分析了面元和覆盖次数的细分程度和效果,指出了前两个观测系统存在过于追求小面元而导致覆盖次数偏低的问题,实际资料解释无法采用最小面元而采用大面元资料,降低了分辨率;而SH地区观测系统的最小面元和覆盖次数搭配合理,覆盖次数在合适范围内,实际资料解释时使用了最小面元,应用效果较理想。     

Testing improvements in the chocolate traceability system: Impact on product recalls and production efficiency

The primary aim of food traceability is to increase food safety, but traceability systems can also bring other benefits to production systems and supply chains. In the literature these benefits are extensively discussed, but studies that quantify them are scarce. In this paper we propose two hypothetical improvements of the traceability system within the chocolate production system and supply chain and we illustrate the resulting benefits by using a case study. Based on the case study, we quantify the influence of these improvements on production efficiency and recall size in case of a safety crisis by developing a simulation tool. These results are aimed to illustrate and quantify the additional benefits of traceability information, and could help food industries in deciding whether and how to improve their traceability systems.     

基于地震波形指示的碳酸盐岩储集体反演方法——以塔河油田中-下奥陶统为例

塔河油田奥陶系碳酸盐岩岩溶储集体埋深大,分布不均,类型复杂,具有较强的非均质性,储集体类型识别一直是该区油气勘探和开发的难题。为此,基于贝叶斯判别理论和马尔科夫链蒙特卡洛抽样算法,实现了一种新型波阻抗反演方法。在储集体类型识别、地震反射特征和岩石物理分析基础上,利用地震波形相似性优选样本井,参照样本空间分布距离和曲线分布特征建立初始阻抗模型。通过建立建议分布与先验信息之间的关系,实现先验解空间的有效采样,同时采用Metropolis-Hastings抽样算法对贝叶斯后验概率分布抽样,从而获得最大后验概率解。将该反演方法应用到塔河油田奥陶系岩溶储集体类型识别中,在反演精度得到明显提高的同时,充分利用了地震波形横向变化特征反映岩溶储集体空间分布位置和横向展布规律,有效识别了岩溶储集体类型,为非均质极强的岩溶缝洞储集体的精细表征提供有力支撑。     

Multivariate statistical log log-facies classification on a shallow marine reservoir

Sedimentary facies are important in reservoir characterization because flow properties are commonly assigned using facies-specific correlations. Multivariate statistical methods provide a powerful vehicle to extract facies responses from different well logs, to predict facies in uncored wells and evaluate uncertainty.Previous study shows a difficulty in bin selection to accurately reproduce the samples' conditional probability distribution. In this paper, a new method uses empirical beta distributions to model the distribution of petrophysical properties conditional to facies. Petrophysical property distributions are assumed conditionally independent, simplifying the use of Bayes rule.Three multivariate statistical methods (beta-Bayesian, multinomial logistic regression, and discriminant analysis) are examined in this paper using log and facies data from a western African sandstone reservoir. Three derived probability logs compare the prediction performance of the statistical methods as well as illustrate influences of log combinations and sample size. Two-way analysis of variance compares prediction accuracy of the models. For a given dataset, there are no significant differences (with 90% confidence) in predictions by the three methods. Additional logs improve prediction accuracy from 30 to above 80%. Final prediction accuracy is 82 to 90% for these three algorithms. Including 20 to 25% of the complete core and facies data in model construction provides accurate predictions; models were validated against the data not used in model construction. The fitted classification models can generate three-dimensional log-derived facies distributions for geologic modeling and reservoir simulation. The three methods are straightforward, efficient, and have quantifiable prediction errors.