Risk characterization plays a crucial role in ensuring safe and stable chemical processes. However, existing studies cannot mine the deep-level relationships between multi-variate process data, resulting in un-detailed characterization results. Hence a multi-variate data-driven modeling method of risk characterization networks is proposed for chemical processes in this paper. The method particularly combines the Spearman's rank correlation coefficient and Apriori algorithm. Firstly, the Spearman's rank correlation coefficient is used to analyze the correlations between multi-variate process data. Secondly, the Apriori algorithm is further applied to mine the internal association rules of process data. Thirdly, a risk characterization network model is established using the complex network theory. To illustrate its validity, the Tennessee Eastman Process (TEP) and a catalytic cracking process are selected as test cases. Results show that the risk states of chemical processes can be effectively characterized, and the risk roots can also be reasonably identified and traced.

Refined risk prediction must be achieved to guarantee the safe and steady operation of chemical pro-duction processes.However,there is high nonlinearity and association coupling among massive,complicated multisource process data,resulting in a low accuracy of existing prediction technology.For that reason,a real-time risk prediction method for chemical processes based on the attention-based bidirectional long short-term memory(Attention-based Bi-LSTM)is proposed in this study.First,multisource process data,such as temperature,pressure,flow rate,and liquid level,are preprocessed for denoising.Data correlation is analyzed in time windows by setting time windows and moving step lengths to explore correlations,thus establishing a complex network model oriented to the chemical production process.Second,network structure entropy is introduced to reduce the dimensions of the multisource process data.Moreover,a 1D relative risk sequence is acquired by max-min deviation standardization to judge whether the chemical process is in a steady state.Finally,an Attention-based Bi-LSTM algorithm is established by integrating the attention mechanism and the Bi-LSTM network to fit and train 1D relative risk sequences.In that way,the proposed algorithm achieves real-time prediction and intelligent perception of risk states during chemical production.A case study based on the Tennessee Eastman process(TEP)is conducted.The validity and reasonability of the proposed method are verified by analyzing distribution laws of relative risks under normal and fault conditions.Also,the proposed algorithm importantly improves the prediction accuracy of chemical process risks relative to that of existing prediction technologies.

Screen is a core component of the linear vibrating screen and is closely linked to the efficiency of drilling fluid recovery. This study aims to analyze the impact of different vibration frequencies and amplitudes on the fluid flow performance through screen with different weaving patterns. Analysis reveals that when the motion direction of the screen is opposite to the flow direction of the drilling fluid, higher screen velocity corresponds to increased drilling fluid permeation velocity and reduced pressure. Plain weave screen exhibits the highest fluid permeation velocity, maintaining the lowest negative pressure. Vortices concentrate mainly around the screen wires at the back of the screen, with herringbone twill weave screen showing improved vortex distribution compared to plain weave screen. Increasing vibration amplitude and frequency enhances screen motion, amplifying variations in pressure and pressure drop coefficients during the motion cycle. With increased amplitude and frequency, the average pressure drop coefficient of the screen rises, making it more challenging for drilling fluid to permeate through the screen. Herringbone twill weave screen demonstrate lower pressure drop coefficients than plain and twill weave screen, indicating superior drilling fluid permeation performance. Field experiments confirm that, compared to plain weave screen, drilling fluid filtered through herringbone twill weave screen results in significantly lower water content in cuttings. The findings of this study provide theoretical insights for the analysis and design of linear vibrating screen meshes in drilling fluid applications.

套管变形导致压裂工具串遇阻是胜利济阳页岩油压裂开发过程中面临的主要难题之一.压裂开采中套管载荷影响因素复杂,基于常规区块的页岩油套管变形研究理论不能有效适用于工程地质条件复杂的济阳页岩.为此,针对济阳首口页岩油井,在分析现场测井数据的基础上,采用有限元方法模拟了固井质量和压裂施工参数对套管变形的影响规律.研究结果表明:水泥环在缺失严重时(缺失角度大于50°或缺失深度大于25 mm)会使套管发生强度破坏,水泥环缺失的临界部位是最容易发生套管损坏的部位;套管的最大应力随水泥环弹性模量的增大而减小,而受泊松比影响较小;注入排量的增加与周围地应力差成正比,在排量为10～12 m3/min时可获得较好的裂缝宽度,注入时间在150 s时周围地应力差最小;随压裂段间距的增加,套管周围地应力差减小,在压裂间距大于18 m后,再增大压裂间距以降低套管应力作用已不大.研究结果可为济阳页岩油水平井下一步压裂施工提供理论依据.

During the chemical processes， major accidents frequently occur due to the danger of materials and the complexity of processes. It is necessary to reveal risk evolution mechanism to ensure the safe and stable operation of chemical processes， as well as to inhibit the spread， diffusion， or even evolution of secondary and derivative disasters. However， many traditional methods heavily rely on expert experience or prior information， which will cause the inaccuracy of risk assessment results. Although the community structure in complex network can be regarded as a highly abstract of risk evolution path， the existing algorithms cannot consider both of the rationality and accuracy division results. Therefore， a deep mining method of risk evolution path is proposed for chemical processes based on the DSAE-Louvain community structure. First， multi-source process data should be processed to establish a risk evolution network， and the Dijkstra and Hop-count algorithms are further applied to obtain a similarity matrix. Then， the deep sparse autoencoder （DSAE） and Louvain algorithm are combined to divide the community structure using sparse analysis. Finally， the risk weak nodes and critical evolution paths in whole chemical processes are deeply mined according to the ranking of node importance. To illustrate its validity， the Tennessee Eastman （TE） process is selected as a test case. Results show that the proposed DSAE-Louvain method are more refined and high-efficiency in the community structure division by comparing with the GN algorithm， Louvain algorithm， and DSAE-GN method; particularly， the mined risk evolution paths are more in accord with actual production processes.

In order to improve the flow state of the heater shell side and enhance the performance evaluation of the heater, this paper proposes a perforated plate-type heater model. Based on Fluent, numerical studies are conducted on the heat transfer performance and shell-side fluid flow characteristics of a perforated plate-type heater. The variations of the heat transfer factor Nu, friction factor f, and evaluation parameter Nu/f1/3 are analyzed for different helix angles β and ratios of the long and short semiaxes of the circular holes on the heating plate under different Reynolds numbers Re. The results reveal that under the same shell-side Reynolds number Re, the heat transfer factor Nu shows an increasing trend with the increase in the proportion of the helix angle β. The heat transfer factor Nu for the heating plate with the hole shape ratio a/b = 1 does not exhibit significant improvement compared to hole shape ratios a/b = 0.8 and a/b = 0.6, but it increases by 4.87 to 7.07% compared to the hole shape ratio a/b = 0.4 in the perforated plate-type heater. On the other hand, the friction factor f decreases as the helix angle β and the ratio of hole shapes on the heating plate increase. The lowest friction factor f is observed for the helix angle β of 25° and the hole shape ratio a/b = 1 in the perforated plate-type heater. When the helix angle β is 25° and the hole shape ratio is a/b = 1, the evaluation parameter Nu/f1/3 reaches its highest value, indicating the optimal overall performance of the perforated plate-type heater.

In order to accurately predict the fatigue life of oscillating bearings for beam pumping unit under actual variable load and variable speed conditions,a calculation method for fatigue life of the bearings based on variable load and variable speed conditions is proposed according to ISO 281:2007 standard and Miner linear damage theory.Taking cylindrical roller bearings for center shaft of CYJY12-4.8-73HB pumping unit as research objects,the dynamic analysis of the unit is carried out by ADAMS software to determine the oscillating load and oscillating speed of the bearings,and then the fatigue life of the bearings is calculated under actual operating conditions and compared with traditional calculation method for fatigue life of the bearings.The results show that the calculation method for fatigue life is reasonable,providing a reference for fatigue life prediction of the bearings.

与广泛使用的金属管道相比,粘接性玻纤增强柔性管具有耐腐蚀、柔性好、安装简单等特点,正在成为海洋油气输运新的管道型式.针对粘接性玻纤增强柔性管试验周期长、测试成本高以及试验结果受环境因素影响大等问题,采用Halpin-Tsai模型建立设计内径152 mm、设计内压30 MPa柔性管有限元模型,研究增强层玻纤带的缠绕角度、缠绕层数以及内衬层和外保护层壁厚等结构参数对柔性管承压性能的影响,结果表明:随着增强层玻纤带的缠绕角度、缠绕层数以及外保护层壁厚增加,柔性管的承压性能提高;随着内衬层壁厚增加,柔性管承压性能先提高后降低;确定理论条件下柔性管结构参数为增强层玻纤带缠绕角度±55°、增强层玻纤带缠绕层数40层、内衬层壁厚25 mm、外保护层壁厚25 mm.结合实际工程应用对结构参数进行优化,并开展爆破试验进行验证,最终得到柔性管实际结构参数为增强层玻纤带缠绕角度±55°、增强层玻纤带缠绕层数100层、内衬层最佳壁厚8 mm、外保护层最佳壁厚8 mm.

Summary To improve the overall performance of continuous spiral baffle heating systems, we propose in this paper two different structural models of electric heaters for in-situ shale oil wells. The models are simulated using Fluent software to investigate the flow and heat-transfer characteristics under different mass flow rates. The variation in heat-transfer coefficient, pressure drop, and overall performance of the heating plate under different gas mass flow rates and heights of heating and shielding plates are analyzed. The performance of the two different heater structures is compared with Wang’s laboratory experiment. The results show that Model I of the heating system has the best overall performance when the gas mass flow rate is between 9.74×10−3 kg/s and 1.624×10−2 kg/s, and the height of the heating and shielding plates is 35 mm at a mass flow rate of 9.74×10–3 kg/s. Wang’s pressure drop (ΔP) is more than 2.48 times higher than that of Model I and more than 6.49 times higher than that of Model II, while the heat-transfer coefficient (h) of both Model I and Model II is increased by more than 15% compared to Wang’s experiment. The overall performance (g) of Model II is increased by more than 5.7 times compared to Wang’s experiment, and the overall performance (g) of Model II is increased by more than 1.68 times compared to Model I. These results provide a theoretical basis for optimizing the design of continuous spiral baffle heating systems.

A design idea of fidelity sampling cylinder while drilling based on surface nitrogen precharging and supplemented by downhole pressurization was proposed,and the working mode and optimization method of sampling parameters were dis-cussed.The nitrogen chamber in the sampling cylinder functions as an energy storage air cushion,which can supplement the pressure loss caused by temperature change in the sampling process to some extent.The downhole pressurization is to press the sample into the sample chamber as soon as possible,and further increase the pressure of sample to make up for the pres-sure that the nitrogen chamber cannot provide.Through the analysis of working mode of the sampling fidelity cylinder,the non-ideal gas state equation was used to deduce and calculate the optimal values of fidelity parameters such as pre-charged nitrogen pressure,downhole pressurization amount and sampling volume according to whether the bubble point pressure of the sampling fluid was known and on-site emergency sampling situation.Besides,the influences of ground temperature on fi-delity parameters were analyzed,and corresponding correction methods were put forward.The research shows that the fidelity sampling cylinder while drilling can effectively improve the fidelity of the sample.When the formation fluid sample reaches the surface,it can basically ensure that the sample does not change in physical phase state and keeps the same chemical compo-nents in the underground formation.

近年来发生的部分海洋油气泄漏事件主要由接头密封失效引起,因此接头密封性能对管道的安全运行极为重要.介绍了海洋玻纤增强柔性管用锥套连接型接头及其密封结构,并用ABAQUS软件建立密封结构的有限元分析模型,对接头密封性能进行校核;分析了海洋高压环境下O形密封圈的von Mises应力、剪应力及接触压力分布规律,确定了接头外护套的安装距离,并对接头的抗拉强度进行校核,为玻纤增强柔性管用接头的密封设计提供参考.

Formation sampling while drilling (FSWD) is one of the most advanced formation sampling technologies in the world. During the operation, a small probe with a cushion is pressed against the wellbore to reduce the pressure in the probe enough to break the cake seal and extract the fluid from the formation. The content of drilling mud filtrate (drilling filtrate or filtrate) in the extracted formation fluid is determined by pollution rate. When the pollution rate of the extracted formation fluid drops to the specified index, the valve in the sample chamber is opened for sampling. When the sampling volume is reached, the pump and valve are closed. The time from the pump opening to the pump closing is called sampling time. The shorter the sampling time is, the shorter the circulation time of drilling fluid will be, so as to reduce the sticking accidents. Due to the influence of wellbore radial space, the size of the suction probe is limited. In order to avoid phase change of the pumped formation fluid during the operation process, the suction pressure difference should not be too large, etc. In this paper, the finite element simulation method is used to analyze the relationship between the above changes of the suction probe and the sampling time in the simulation results from the aspects of changing the size, shape, structure and arrangement of the suction probe in the formation fluid sampling tool while drilling, so as to realize the optimal selection of the suction probe. The research results of this method have important guiding significance to the design of fluid sampling tool while drilling.

由于稠油黏度高、密度大、流动性差等特点,通常采用蒸汽吞吐或蒸汽驱2种方式开采,其作用原理是将高温(350℃)高压(21 MPa)蒸汽注入稠油层,使油层温度上升、黏度下降,流动性增加,便于开采.为降低海上平台作业成本,并满足在高温注热蒸汽环境下不提出泵的要求,设计了新型的注采一体用水力潜油泵,并对其整体装置、轴承等重要部件进行了设计计算、模拟及试验,研制出满足该泵使用寿命达到2a的止推轴承.满足了稠油注采一体工艺的要求.

为了解决传统的正循环或反循环冲砂工艺在漏失井和深井中清砂难度大、成本高的问题,提出利用射流泵在油井下形成局部反循环的清砂工艺,并对其进行工艺流程优化设计,通过多级沉砂而提高清砂效率.以某油田油井为研究对象,设计一套井下局部反循环和多级沉砂的清砂管柱系统,包括对其中清砂用射流泵、集砂器2个核心工具进行结构设计.选用固定式、正循环式的射流泵结构,计算得到其喷嘴出口直径为4.4 mm,喉管直径为7.7 mm.通过CFD数值模拟方法对清砂用射流泵内流场进行仿真分析,对其喉嘴距和喉管长度2个关键结构参数进行优化,并为现场清砂作业提供依据.对所设计加工的工具进行了下井应用试验,试验结果可为后续清砂工艺的持续优化提供参考.

针对热采井口装置在蒸汽驱和蒸汽吞吐两种工况下的热蠕变失效情况,进行了其材料30CrMo在390℃,四个不同应力下的蠕变试验,对试验结果进行了拟合,获得了复合时间强化模型参数.用短期的试验进行了验证,复合时间强化模型的计算值与试验值之间的误差小于15％.运用Ansys Workbench模拟了热采井口装置主要承压件在恒温恒载工况和断续加载工况下的蠕变失效过程,得到主要承压件在两种工况下的失效时间,对热采井口装置的使用寿命评估具有重要的意义.

In view of the evaluation of the service life of the thermal recovery wellhead in the oil field, the tensile and creep property of 30CrMo are studied. The tensile properties at room temperature and 390 °C are obtained by tensile test;The creep tests of the material at 390 °C and five different stresses are carried out. The Norton Bailey equation is used to fit the test data, and the creep constitutive equations of low stress zone and high stress zone are obtained;Scanning electron microscope and transmission electron microscope are used to observe the original samples and five samples after creep. It is found that when the material is kept at 390 °C for a long time, the diffusion of carbon element in the crystal result in the increase of carbide quantity and particle size on the matrix , resulting in the decrease of the strength of the material. The mechanism of creep microstructure change of 30CrMo in low stress zone and high stress zone is different. The creep mechanism in low stress zone is dominated by dislocation thermal climbing, and the mechanism in high stress zone is dominated by Orowan winding.

内衬层在玻璃纤维增强复合材料粘接柔性管制造过程中起支撑作用,为保证内衬层强度,通常采用增加壁厚的办法,这不仅会增加管道制造成本,还会降低管道柔韧性.为保证有限元模拟结果的准确性,本文通过力学性能实验测得内衬层所用材料的力学性能参数.根据内衬层受力特点,研究了缠绕方式、缠绕层数和加热温度对内衬层厚度的影响.利用ABAQUS有限元分析软件计算了直径为?65 mm的玻璃纤维增强复合材料粘接柔性管内衬层最小厚度,为内衬层厚度的合理选择提供理论参考.

Due to the special marine environment, it is difficult for the traditional electronic sensors to play a long-term real-time on-line monitoring role in the key equipment of offshore platforms under the environment of high humidity, high salt, high pressure, corrosion and electromagnetic interference. Based on the principle of fiber grating sensing and material properties, Based on fiber Bragg grating sensing principle and material properties, the fiber grating sensing technology is introduced to monitor the key equipment status of offshore platform in real-time, and the key and possible dangerous position location monitoring and establish the early warning system, which helps on-site staffs to find out the problems of equipment structure in time and take corresponding measures to ensure the safe production operation of the offshore platform. In this paper, combined with the monitoring cases of offshore platforms, such as jacket platform, workover rig derrick, dry-type transformer cabinet, etc. The status monitoring methods, advantages and existing problems of FBG sensing technology in the field of offshore engineering application are discussed, so as to provide basis for the future development of FBG sensing technology in the field of offshore engineering.

A single high-pressure water source by the throttling way to inject water into different pressure wells is often used in offshore water injection platform. It will cause huge energy consumption. Therefore, a new idea of using adjustable jet pump instead of pipeline valve was proposed. A water injection well in Bohai was regarded as the research object, and an adjustable jet pump was designed. The 3D model was established and the Realizable k-ε turbulence model was used in Fluent to analyze how the nozzle-to-throat clearance and throat length affect the working performance of the jet pump. The reasonable structural parameters of nozzle-to-throat clearance and throat length were determined as 19.75 and 98 mm, respectively. To simulate the water injection process, the experiments of characteristic of the water injection pressure and flow rate when the nozzle opening varies as 50, 60, 70, 75, and 90% were carried out. Results show that when the water injection pressure ranges from 1.4 to 4.0 MPa, the water flow change from 605 to 273 m3/d with the 50% nozzle opening and the water flow changes from 803 to 657 m3/d with the 90% nozzle opening. By adjusting the nozzle opening, the adjustable jet pump can basically achieve the multiple combinations of injection pressure and flow. Compared with the existing water injection method, the new method can reduce energy consumption about 715 thousand kW-h per year.