Effects of n-3 polyunsaturated fatty acids from seal oils on nonalcoholic fatty liver disease associated with hyperlipidemia

AIM: To investigate the efficacy and safety of n-3 polyunsaturated fatty acids (PUFA) from seal oils for patients with nonalcoholic fatty liver disease (NAFLD) associated with hyperlipidemia. METHODS: One hundred and forty-four patients with NAFLD associated with hyperlipidemia were included in the 24-wk, randomized, controlled trial. The patients were randomized into two groups. Group A (n = 72) received recommended diet and 2 g n-3 PUFA from seal oils, three times a day. Group B (n = 72) received recommended diet and 2 g placebo, three times a day. Primary endpoints were fatty liver assessed by symptom scores, liver alanine aminotransferase (ALT) and serum lipid levels after 8, 12, 16, and 24 wk. Hepatic fat inf iltration was detected by ultrasonography at weeks 12 and 24 after treatment. RESULTS: A total of 134 patients (66 in group A, 68 in group B) were included in the study except for 10 patients who were excluded from the study. After 24 wk of treatment, no change was observed in body weight, fasting blood glucose (FBG), renal function and blood cells of these patients. Total symptom scores, ALT and triglyceride (TG) levels decreased more significantly in group A than in group B (P < 0.05). As expected, there was a tendency toward improvement in aspartate aminotransferase (AST), γ-glutamyltranspeptidase (GGT), and total cholesterol (TCHO) and high- density lipoprotein (HDL) cholesterol levels (P < 0.05) after administration in the two groups. However, no significant differences were found between the two groups. The values of low-density lipoprotein (LDL) were significantly improved in group A (P < 0.05), but no significant change was found in group B at different time points and after a 24-wk treatment. After treatment, complete fatty liver regression was observed in 19.70% (13/66) of the patients, and an overall reduction was found in 53.03% (35/66) of the patients in group A. In contrast, in group B, only f ive patients (7.35%, 5/68) achieved complete fatty liver regression (P = 0.04), whereas 24 patients (35.29%, 24/68) had a certain improvement in fatty liver (P = 0.04). No serious adverse events occurred in all the patients who completed the treatment. CONCLUSION: Our results indicate that n-3 PUFA from seal oils is safe and effi cacious for patients with NAFLD associated with hyperlipidemia and can improve their total symptom scores, ALT, serum lipid levels and normalization of ultrasonographic evidence. Further study is needed to confi rm these results.

Limitation of fault-sealing and its control on hydrocarbon accumulation——An example from the Laoyemiao Oilfi eld of the Nanpu Sag

Based on previous studies on the internal structures of fault belts, the fault belts in the Laoyemiao Oilfield of the Nanpu Sag can be divided into three units, a crushed zone, an upper induced fracture zone and a lower induced fracture zone according to the log response characteristics. The upper induced fracture zone is characterized by the development of pervasive fractures and has a poor sealing or non-sealing capability. It therefore can act as pathways for hydrocarbon migration. The lower induced fracture zone consists of fewer fractures and has limited sealing capability. The crushed zone has a good sealing capability comparable to mudstone and can thus prevent lateral migration of fluid. Through physical modeling and comparing laboratory data with calculated data of oil column heights of traps sealed by faults, it is concluded that the fault-sealing capability for oil and gas is limited. When the oil column height reaches a threshold, oil will spill over from the top of reservoir along the lower induced fracture zone under the action of buoyancy, and the size of reservoir will remain unchanged. Analysis of the formation mechanisms of the fault-sealed reservoirs in the Nanpu Sag indicated that the charging sequence of oil and gas in the reservoir was from lower formation to upper formation, with the fault playing an important role in oil and gas accumulation. The hydrocarbon potential in reverse fault-sealed traps is much better than that in the consequent fault-sealed traps. The reverse fault-sealed traps are favorable and preferred exploration targets.

Design and operation problems related to water curtain system forunderground water-sealed oil storage caverns

The underground water-sealed storage technique is critically important and generally accepted for the national energy strategy in China. Although several small underground water-sealed oil storage caverns have been built in China since the 1970s, there is still a lack of experience for large-volume underground storage in complicated geological conditions. The current design concept of water curtain system and the technical instruction for system operation have limitations in maintaining the stability of surrounding rock mass during the construction of the main storage caverns, as well as the long-term stability. Although several large-scale underground oil storage projects are under construction at present in China, the design concepts and construction methods, especially for the water curtain system, are mainly based on the ideal porosity medium flow theory and the experiences gained from the similar projects overseas. The storage projects currently constructed in China have the specific features such as huge scale, large depth, multiple-level arrangement, high seepage pressure, complicated geological conditions, and high in situ stresses, which are the challenging issues for the stability of the storage caverns. Based on years’ experiences obtained from the first large-scale （millions of cubic meters） underground water-sealed oil storage project in China, some design and operation problems related to water curtain system during project construction are discussed. The drawbacks and merits of the water curtain system are also presented. As an example, the conventional concept of “filling joints with water” is widely used in many cases, as a basic concept for the design of the water curtain system, but it is immature. In this paper, the advantages and disadvantages of the conventional concept are pointed out, with respect to the long-term stability as well as the safety of construction of storage caverns. Finally, new concepts and principles for design and construction of the underground water-sealed oil storage caverns are proposed.

High Precision CAE Analysis of Automotive Transaxle Oil Seal Leakage

The manufacturing industry today due to worldwide competition is focused on shorter development cycle. In this situation, computer aided education （CAE） technology as a tool for simultaneous achievement of quality, cost and delivery （QCD） plays an important role. The hardware-software environment surrounding CAE has evolved. Though technological problems have been understood and general solutions have been derived and reflected in the CAE analysis software, research findings that boost the credibility of CAE have still not been incorporated fully enough into the development of design process. The real technical mechanism issue is not precisely capture. Therefore, it is important to clarify the real cause in CAE results through CAE simulation in order to assure product reliability and assurance. It is the aim of this study to realize the prediction of design analysis process through understanding of unclear technical mechanism in abnormal occurrences with the utilization of CAE simulation. In other words, it is the aim of this study to focus on issue in automotive transaxle oil seal leakage to understand, grasp, and visualize the main cause through usage of CAE analysis process. It is understood that the point of contact and pump volume was related and this could contribute towards seals quality design. Plus, the utilization of CAE analysis in prediction phase to realized design development is also possible

Effect of Sealing Air on Oil Droplet and Oil Film Motions in Bearing Chamber

Beating chamber is one of important components that support aero-engine rotors and research on oil droplet and oil film motions is an important part of bearing chamber lubrication and heat transfer design. Consid- ering the pressure of sealing air is an important operating condition that affects the oil droplet and oil film mo- tions, the effect of sealing air pressure on airflow in bearing chamber is investigated in this paper firstly ; and then based on the air velocity and air/wall shear force, the oil droplet moving in core air, deposition of oil droplet im- pact on wall as well as velocity and thickness of oil film are analyzed secondly; the effect of sealing air pressure on oil droplet velocity and trajectory, deposition mass and momentum, as well as oil film velocity and thickness is discussed. The work presented in this paper is conducive to expose the oil/air two phase lubrication mechanism and has certain reference value to guide design of secondary air/oil system.

Gulong shale oil enrichment mechanism and orderly distribution of conventional–unconventional oils in the Cretaceous Qingshankou Formation,Songliao Basin,NE China

Through the study of organic matter enrichment,hydrocarbon generation and accumulation process of black shale of the Cretaceous Qingshankou Formation in the Songliao Basin,the enrichment mechanism of Gulong shale oil and the distribution of conventional–unconventional oil are revealed.The Songliao Basin is a huge interior lake basin formed in the Early Cretaceous under the control of the subduction and retreat of the western Pacific plate and the massive horizontal displacement of the Tanlu Fault Zone in Northeast China.During the deposition of the Qingshankou Formation,strong terrestrial hydrological cycle led to the lake level rise of the ancient Songliao Basin and the input of a large amount of nutrients,resulting in planktonic bacteria and algae flourish.Intermittent seawater intrusion events promoted the formation of salinization stratification and anoxic environment in the lake,which were beneficial to the enrichment of organic matters.Biomarkers analysis confirms that the biogenic organic matter of planktonic bacteria and algae modified by microorganisms plays an important role in the formation of high-quality source rocks with high oil generation capability.There are four favorable conditions for the enrichment of light shale oil in the Qingshankou Formation of the Gulong Sag,Songliao Basin:the moderate organic matter abundance and high oil potential provide sufficient material basis for oil enrichment;high degree of thermal evolution makes shale oil have high GOR and good mobility;low hydrocarbon expulsion efficiency leads to a high content of retained hydrocarbons in the source rock;and the confinement effect of intra-layer cement in the high maturity stage induces the efficient accumulation of light shale oil.The restoration of hydrocarbon accumulation process suggests that liquid hydrocarbons generated in the early(low–medium maturity)stage of the Qingshankou Formation source rocks accumulated in placanticline and slope after long-distance secondary migration,forming high-quality conventional and tight oil reservoirs.Light oil generated in the late(medium–high maturity)stage accumulated in situ,forming about 15 billion tons of Gulong shale oil resources,which finally enabled the orderly distribution of conventional–unconventional oils that are contiguous horizontally and superposed vertically within the basin,showing a complete pattern of“whole petroleum system”with conventional oil,tight oil and shale oil in sequence.

Organic matter transformation ratio, hydrocarbon expulsion efficiency and shale oil enrichment type in Chang 7_(3) shale of Upper Triassic Yanchang Formation in Ordos Basin, NW China

The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution.

稠油热采无机硅酸凝胶封窜剂的研究与应用

在稠油油藏热采过程中容易发生蒸汽地下窜流和地表汽窜,严重影响矿区产能,同时造成地面污染。以水玻璃与尿素为交联剂主体,通过与表面活性剂甘油三乙酸酯进行复配,研制了一种新型耐高温封窜剂。通过正交试验确定了最优封窜剂配方:60%水玻璃+4%尿素+0.2%甘油三乙酸酯+水;红外光谱(FTIR)及扫描电镜(SEM)分析发现,该体系中水玻璃通过一段时间的交联,形成单硅酸,后缩聚形成线性多聚硅酸,硅酸分子间相互作用发生缠结,形成的网状结构使得其稳定性较高,结构更稳定,有更好的耐温能力;实验室内填砂管性能评价结果表明,封窜剂段塞注入量为0.2 PV及候凝时间为5 d时,封堵率98.8%、突破压力梯度1.4 MPa/m、残余阻力系数83.32,经过21 PV 260℃的高温蒸汽冲刷后封堵率稳定在94%以上;现场试验结果表明,井F-109日产油从0.9 t增至5.5 t,含水率由89%降至50%,施工244 d,累计增油1122.4 t,F井区地面不再发生蒸汽窜漏,受地面窜漏影响的14口井恢复了正常注汽吞吐生产,累计增油15713.6 t,平均单井日注汽量100 m 3,注汽压力5.5 MPa。综合表明,该封窜剂体系具有良好的高温选择封堵性,对稠油热采高温蒸汽窜流的有效治理提供了理论指导和技术支撑。

炼化企业挥发性有机化合物减排的探索与实践

炼化企业加工过程有组织、无组织排放的挥发性有机化合物(VOCs)量较大,对大气环境中的颗粒物、臭氧浓度等产生重大影响。A公司自“十三五”以来对VOCs减排进行了探索与实践,通过采取油气回收、储罐浮盘高效密封改造、呼吸阀改型升级、无组织排放改为有组织回收、VOCs焚烧、常态化泄漏检测与修复工作等多种减排措施,VOCs排放量已从2015年的4230 t下降到2022年的2157 t,降低比例达到49%,取得了显著的成效。

基于真三轴试验装置的岩石渗流密封方式改进及实验研究

国内现有的非常规油气储层的渗透性测试大多采用圆柱试样,通过假三轴试验装置进行测试,而真三轴条件下立方体试件棱边大多存在棱边串流与端面密封不严的缺陷。基于现有真三轴试验装置,以及大量的实验经验,针对现有的立方体试件单橡胶套渗流密封方式进行改进。介绍了嵌套式“上下密封套”结构特征,特别对棱边区的密封进行了设计,提出了密封套顶-底端面凹陷型内嵌“单孔网槽导流板”结构设计,并对顶部传压板的尺寸进行了讨论。对100 mm×100 mm×100 mm立方体煤样进行了真三轴渗流试验分析,得到了不同入口渗透压力真三轴围压条件下的渗透率。该密封方法的改进有助于提高科研单位及测试中心对原位地应力条件下非常规油气储层渗透性测试精度,并提高高端科研人才的实践创新能力与科研素养。

基于似然函数筛选法的旋转轴唇形密封可靠性关键设计因素研究

基于油封的有限元和数值计算模型,分析油封的设计参数对其静态和动态密封可靠性的影响规律。将油封的初始安装过盈量、油侧唇角、空气侧唇角、腰厚、腰长、理论接触宽度、卡紧弹簧的弹性模量、油封主体橡胶的硬度8个设计参数的标准化数据作为输入向量,将油封唇口最大接触压力、泵吸率和摩擦扭矩的标准化数据作为输出向量,建立响应面模型,以输出向量方差得到各设计因素的似然函数值作为评判指标,确定各设计参数对油封密封可靠性的影响程度。结果表明:橡胶硬度、理论接触宽度、弹簧弹性模量、过盈量、腰长对油封动态密封可靠性的影响较显著,油封唇口最大接触压力对弹簧弹性模量、理论接触宽度、橡胶硬度、腰厚、油侧唇角较敏感。综合考虑旋转轴唇形油封的静态和动态可靠性,得到影响其可靠性的关键设计因素为理论接触宽度、弹簧弹性模量和橡胶硬度。

海上油气田机泵机械密封泄漏信号检测方法设计

为避免出现大型海上油气田开采事故,保证机泵机械密封装置正常运行,提出针对海上油气田机泵机械密封的泄漏信号检测方法。利用小波包分解细化海上油气田机泵机械密封振动信号高频部分,运用希尔伯特变换重构信号,归一化处理信号矢量提取机械装置异常信号,使用匹配追踪法去除信号噪声。计算油体流动规律,通过音波评估信号波动范围,以温度与压力为前提,将高斯函数作为分类核函数,采用支持向量机构建泄漏信号检测判断函数,完成机械密封泄漏信号检测。实验结果表明:所提方法信号降噪能力较强,在保证机械密封泄漏检测准确性的同时,检测耗时最短,有效提高了海上油气田开采效率,可带来可观的经济收益。

双端面机械密封在双螺杆原油泵上的应用

基于原油库拆建工程项目,对双螺杆原油泵原采用的单端面金属波纹管机械密封改造为新型的带泵效环的背靠背双端面机械密封,并配套冷却循环辅助系统,经现场工业考核,背靠背双端面机械密封在双螺杆原油泵上得到良好应用。结果表明,新改造的双端面机械密封彻底解决了原密封存在的摩擦副磨损严重、泄漏量大、使用寿命短等问题,实现了工艺介质的零泄漏并确保设备长周期安全稳定运行。

基于两相流的水封油库油气泄漏运移规律及控制措施

地下水封油库运行的关键是保持一定的水封厚度,为确定合适的水封厚度,基于气液两相流理论,采用有限元数值模拟方法,以我国某石油储备地下水封洞库为依托,模拟了地下水封石油洞库储油运行期油气的泄漏运移演变过程。结果表明:施工期不设置水幕系统情况下,洞室顶部出现了大面积的疏干区,造成后期无法储油;设置水幕系统情况下,洞库上方能够维持一定水封厚度,洞库周围岩层油气泄漏范围和泄漏量均与储油运行时间呈正幂函数关系;水封厚度越大油气泄漏范围和泄漏量越小,但过大的水封厚度会大大增加工程成本,所对应的案例在水封厚度为30 m时对油气泄漏控制最为经济合理,《地下水封石洞油库设计标准》推荐的水封厚度合理且有一定安全裕度。研究成果可为水封油库工程的设计及油气泄漏控制提供一定理论参考。

厚层盖层段断层垂向封闭性定量评价方法及其应用

断层和裂缝是导致油气垂向调整运移或散失(圈闭失利)的首要因素,但不同类型盖层段断层的垂向封闭性控制因素存在明显差异,制约着断层垂向封闭性评价。以厚层膏岩、泥岩盖层为研究对象,结合野外观察、岩石力学测试和室内油气藏解剖,建立了基于拜尔利摩擦定律、莫尔-库伦破裂准则和盖茨准则的盖层脆韧性转化量化评价方法,揭示出不同脆韧性盖层段断裂带内部结构的差异性,构建了不同盖层脆韧性条件下的断层垂向封闭性评价方法。结果表明:厚层膏岩、泥岩盖层段断层的垂向封闭性主控因素是盖层的脆韧性、断层在盖层段的变形机制及垂向封闭能力;采用断接厚度(HCJT)法量化表征准南地区安集海河组脆性域泥岩盖层段断层的垂向封闭性,其HCJT临界值约为400 m;采用泥岩涂抹系数(CSSF)量化表征库车坳陷东秋背斜南翼脆韧性域膏岩盖层段断层的垂向封闭性,其CSSF临界值为3.5~4.0。研究成果对中国沉积盆地断块油气藏三维立体勘探具有重要的指导意义。

高黏土陆相页岩实验技术及其应用

页岩储层“四性”实验评价是页岩油勘探开发的重要基础及核心。现有实验技术存在页岩含油量检测不准、微纳米孔隙测量视域小及代表性差、流动性直接测量参数缺乏等难题,不适应古龙页岩油生产需求。通过研发实验装备、确定实验条件,建立基于保压密闭岩心“四性”实验技术及流程。结果表明:古龙高成熟和成熟页岩含油量测定较国标法可减少损失71%和50%,应用新建不同成熟度页岩含油量恢复模型,恢复了国标法现场录井页岩含油量数据;高成熟与低成熟阶段页岩中干酪根有机质、不同赋存状态油和水定量特征差别明显,受干酪根有机质向页岩油转化及演化程度的控制;页岩孔缝组合构成规模储集空间及流动网络通道,储集空间分为2大类7亚类12种类型,总孔隙度高于粉砂质岩、灰质岩、云质岩;确定页岩油上部、中部、下部油层组含油性与流动性特征,圆柱状页岩样品驱替油率为16%~43%,同一地层温度(100℃)不同驱替压力(10~50 MPa)下的超临界CO_(2)驱替使孔隙度增加4.51百分点、渗透率增加0.53×10^(-3)μm^(2)。研究成果为页岩油规模增储和效益上产提供了实验依据。

发电机轴承油槽密封结构对油雾泄漏的影响

大型水电站轴承油槽总是不可避免地发生油雾泄漏问题,改善密封结构通常是解决水电站轴承油槽甩油雾问题最简单有效的措施.为了降低油雾泄漏对发电机内部造成的污染,文中围绕某抽水蓄能电站发电机轴承油槽甩油雾问题,对油槽密封盖进行改型,并开展密封腔油雾多相流数值模拟研究.通过Mixture模型和SST k-ω模型解析了原密封结构和2种改进密封结构的流场分布特性,并评估了不同密封结构下的油雾泄漏情况.研究结果表明:相比于原设计模型,改进模型Ⅰ,Ⅱ的油雾泄漏量平均减少了18.9%,88.6%,改进模型Ⅱ抑制油雾效果最为显著;高压气体的注入会破坏密封腔原有的环形涡流,从而抑制油雾逸出;对于下部密封腔而言,提高进口压力,减小进口流速都有助于改善密封性能.文中的研究可为油槽密封改良以及轴承油雾泄漏控制措施提供一定的参考,提升电站的经济效益以及运行的安全稳定性.

结构和材料参数对旋转轴唇形密封可靠性影响

基于流量因子统计学方法建立油封密封区域的混合润滑数值模型,利用有限元软件进行求解,分析结构和材料参数对油封密封可靠性的影响规律。结果表明:在研究的参数范围内,静态密封可靠性随腰厚、腰长、空气侧唇角、弹簧的弹性模量、橡胶硬度的增加而提高,随过盈量、油侧角和理论接触宽度的增大而减小;当过盈量为0.4~0.55 mmm、理论接触宽度为0.3~0.6 mm、油侧角为35°~50°、空气侧唇角为15°~30°、腰厚为1.0~1.3 mm、腰长为0.9~1.2 mm、弹簧模量为1 175~1 250 MPa,橡胶硬度为70HA~85HA时有利于油封可靠性的提高,且在此取值范围内,动态密封可靠性随过盈量、油侧唇角、橡胶材料硬度、腰厚和理论接触宽度的增加而增大,随弹簧弹性模量、腰长、空气侧唇角的增大而减小。

松辽盆地古龙页岩油富集耦合机制

大庆油田生产实践证实松辽盆地青山口组古龙页岩油具有巨大的勘探开发潜力,但页岩油富集的耦合机制仍不明确,制约了页岩油成藏理论及油气富集区的认识。通过岩心精描、古地温恢复、常微量元素分析、场发射环境扫描电镜分析、二维核磁分析等技术,明确了古龙页岩油富集的耦合机制。松辽盆地古龙页岩油富集受宏、微观多因素耦合控制:宏观上,古龙页岩油富集受控于43.99~77.28℃/km古地温梯度的高温热盆、大规模发育的富氢高有机质页岩、温湿淡水-微咸水还原水体环境及较强的顶底板封存能力4个地质因素;微观上,古龙页岩油富集受控于以有机质成熟度为主线的生烃与成储同步演化耦合,随着页岩成熟度不断增高,干酪根不断裂解,生烃量增加,有机缝孔的占比逐渐增大,无机孔占比逐渐减少,生成的油气由重质向轻质转化,吸附油占比减小,游离油占比增大。当Ro大于1.3%时,孔壁表面润湿性由亲水性向亲油性转变,原油不断从小尺度孔隙向大尺度孔隙渗流。研究成果可为古龙页岩油成藏理论认识的深化及富集区优选提供重要依据。

温度对组合型织构油封密封性能的影响

耦合流体力学、变形分析、接触力学、能量守恒方程和黏温黏压方程,建立具有表面组合型织构油封的密封区域混合润滑数值模型,研究温度对表面组合型织构油封密封性能的影响;通过有限差分法对数值方程离散求解,得到不同表面织构油封唇口的温度分布及不同转速下油封唇口的最高温度,对比分析温升对油封泵吸率、油膜厚度、摩擦扭矩等密封性能的影响。结果表明:油封最高温度位于唇尖处,无织构油封最高温度略高于织构油封,随着转速的增加,油封最高温度也都随之增加;织构的存在会引起油封泵吸率的增加和平均油膜厚度变大;随着温度的升高,油封泵吸率、摩擦扭矩、油膜厚度都会逐渐减小,油封密封性能明显下降,温度升高至一定程度,油封泵吸率会变为负值。