Application of the Material Balance Method in Paleoelevation Recovery: A Case Study of the Longmen Mountains Foreland Basin on the Eastern Margin of the Tibetan Plateau

We applied the material balance principle of the denudation volume and sedimentary flux to study the denudation-accumulation system between the Longmen Mountains （Mts.） and the foreland basin. The amount of sediment in each sedimentation stage of the basin was estimated to obtain the denudation volume, erosion thickness and deposit thickness since the Late Triassic Epoch, to enable us to recover the paleoelevation of the provenance and the sedimentary area. The results show the following： （1） Since the Late Triassic Epoch, the elevation of the surface of the Longmen Mts. has uplifted from 0 m to 2751 m, and the crust of the Longmen Mts. has uplifted by 9.8 km. Approximately 72% of the materials introduced have been denuded from the mountains. （2） It is difficult to recover the paleoelevation of each stage of the Longmen Mts. foreland basin quantitatively by the present-day techniques and data. （3） The formation of the Longmen Mts. foreland basin consisted of three stages of thrust belt tectonic load and three stages of thrust belt erosional unload. During tectonic loading stages （Late Triassic Epoch, Late Jurassic-Early Cretaceous, Late Cretaceous-Miocene）, the average elevation of Longmen Mts. was lower （approximately 700-1700 m）. During erosional unloading stages （Early and Middle Jurassic, Middle Cretaceous and Jiaguan, Late Cenozoic）, the average elevation of Longmen Mts. was high at approximately 2000-2800m.

A New Material Balance Equation Model for Analyzing Dynamic Performance of C_2 Flooding

Implementing a CO2 flooding scheme successfully requires the capacity to get accurate information of reservoir dynamic performance and fluids injected. Despite some numerical simulation studies, the complicated drive mechanisms and actual reservoir performance have not been fully understood. There is a strong need to develop models from different perspectives to complement current simulators and provide valuable insights into the reservoir performance during CO2 flooding. The aim of this study is to develop a model by using an improved material balance equation （MBE） to analyze quickly the performance of CO2 flooding. After matching the historical field data the proposed model can be used to evaluate, monitor and predict the overall reservoir dynamic performance during CO2 flooding. In order to account accurately for the complex displacement process involving compositional effect and multiphase flow, the PVT properties and flowability of reservoir fluids are incorporated in the model. This study investigates the effects of a number of factors, such as reservoir pressure, the amount of CO2 injected, the CO2 partition ratios in reservoir fluids, the possibility of the existence of a free CO2 gas cap, the proportion of reservoir fluids contacted with CO2, the starting time of CO2 flooding, oil swelling, and oil flowability improvement by mixing with CO2. The model was used to analyze the CO2 flooding project in Weyburn oil field, Saskatchewan, Canada. This study shows that the proposed model is an effective complementary tool to analyze and monitor the overall reservoir performance during CO2 flooding.

The generalized method for estimating reserves of shale gas and coalbed methane reservoirs based on material balance equation

As the main unconventional natural gas reservoirs,shale gas reservoirs and coalbed methane(CBM)reservoirs belong to adsorptive gas reservoirs,i.e.,gas reservoirs containing adsorbed gas.Shale gas and CBM reservoirs usually have the characteristics of rich adsorbed gas and obvious dynamic changes of porosity and permeability.A generalized material balance equation and the corresponding reserve evaluation method considering all the mechanisms for both shale gas reservoirs and CBM reservoirs are necessary.In this work,a generalized material balance equation(GMBE)considering the effects of critical desorption pressure,stress sensitivity,matrix shrinkage,water production,water influx,and solubility of natural gas in water is established.Then,by converting the GMBE to a linear relationship between two parameter groups related with known formation/fluid properties and dynamic performance data,the straight-line reserve evaluation method is proposed.By using the slope and the y-intercept of this straight line,the original adsorbed gas in place(OAGIP),original free gas in place(OFGIP),original dissolved gas in place(ODGIP),and the original gas in place(OGIP)can be quickly calculated.Third,two validation cases for shale gas reservoir and CBM reservoir are conducted using commercial reservoir simulator and the coalbed methane dynamic performance analysis software,respectively.Finally,two field studies in the Fuling shale gas field and the Baode CBM field are presented.Results show that the GMBE and the corresponding straight-line reserve evaluation method are rational,accurate,and effective for both shale gas reservoirs and CBM reservoirs.More detailed information about reserves of shale gas and CBM reservoirs can be clarified,and only the straight-line fitting approach is used to determine all kinds of reserves without iteration,proving that the proposed method has great advantages compared with other current methods.

Assessment of residual oil saturation with time-differentiated variable multiple material balance model

This study aims to improve the evaluation of residual oil saturation in water flooded zones based on the material balance model(MBM)with variable multiple for injected water.We investigated the change patterns of rock-electro parameters during waterflooding through the analysis of displacement tests.Our work differentiated the waterflooding into numerous displacement processes and accordingly propose an improved time-differentiated variable multiple MBM.The calculation results of the improved model are more consistent with the displacement experiment data of cores.Furthermore,the improved method was integrated into the comprehensive interpretation platform of offshore logging to analyze water flooded zones of a well in the A oilfield.As a result,the residual oil saturation calculated is in close agreement with the results of experiments on cores.Our results indicate that the time-differentiation and variable multiplier for injected water can effectively enhance the assessment accuracy of the residual oil saturation of water-flooded zones.

Balance Theory and the Relationship among Teacher,Students and Teaching Material

The balance theory was supposed in 1950s,and it provides the theory basis for optimizing the classroom teaching.By applying this theory,we discuss how to keep balance among teacher,students and teaching material.This paper aims to keep these three factors in an open,dynamic and balanced system so as to guarantee the successful classroom teaching.

A novel energetic framework with the combination of 5,6-fused triazolo-triazine and nitropyrazole-tetrazole for energy-stability balanced explosive

In recent years,the introduction of fused rings own high density and low sensitivity has promoted the development of energetic materials.However,the development of energetic compounds containing fused and bridged rings by introducing multiple nitrogen heterocycles at different sites of fused rings is still difficult to progress,which seriously limits the emergence of advanced energetic compounds.In this study,a series of energetic materials choosing different nitrogen rich heterocycles at the vacancies of the fused ring,i.e.,neutral compound 5,6 and their ionic derivatives(compounds 7-12)were designed and synthesized.Compounds 5 and 6 were further confirmed by single crystal X-ray diffraction,while the crystal analysis and theoretical calculations were carried out to explore the relationship between crystal structure and physicochemical properties.All of the newly synthesized compounds(5-12)are insensitive to mechanical stimulation(IS>40 J;FS≥342 N)and they own the high detonation velocity(D:8322-9075 m/s).Notably,hydrazine salt 11 own the higher detonation velocity(9075 m/s)and powder density(1.83 g/cm^(3)),but exhibits lower sensitivity(IS>40 J)than the classical energetic compound RDX(8795 m/s,1.80 g/cm^(3),7.5 J).It is obvious that the combination of 5,6-fused triazolo-triazine and nitropyrazole-tetrazole may be a new energetic skeleton for synthesising the heterocyclic compounds with balanced energy-stability.

Nonlinear oscillations of sigmoid functionally graded material plates moving in longitudinal direction

Geometrically nonlinear oscillations are investigated on sigmoid functionally graded material （S-FGM） plates with a longitudinal speed. The material properties of the plates obey a sigmoid distribution rule along the thickness direction. Based on the D＇Alembert＇s principle, a nonlinear equation of motion is derived for the moving S-FGM plates, where the von K^rm^n nonlinear plate theory is adopted. Utilizing the Galerkin method, the equation of motion is discretized and solved via the method of harmonic bal- ance. The approximate analytical solutions are validated through the adaptive step-size fourth-order Runge-Kutta method. Besides, the stability of the steady-state solutions is examined. The results reveal that the mode interaction behavior can happen between the first two modes of the moving S-FGM plates, leading to a complex nonlinear frequency response. It is further found that the power-law index, the longitudinal speed, the exci- tation amplitude, and the in-plane pretension force can significantly affect the nonlinear frequency-response characteristics of longitudinally traveling S-FGM plates.

Certification and uncertainty evaluation of flavonoids certified reference materials

Flavonoids are the most widely used in the field of the food, medicine, and cosmetic due to their pharmacological functions and biological activities, such as anti-tumor, anti-inflammatory and antioxidation. This work described the assignment of purity values to 3 flavonoids certified reference materials (CRMs) including baicalein, 5,7-dihydoxy flavones and naringenine which?were developed in this study according to the ISO Guides 34 and 35. The qualitative analysis was performed by liquid chromatography-mass spectrometry (LC-MS) and infrared spectroscopy (IR). The CRMs’ purity values were assigned based on the weighted average of quantitative nuclear magnetic resonance method and mass balance approach with high resolution liquid chromatography-VWD. All the three CRMs with following value mass fractions: baicalein at a certified purity P ± U (k = 2) of 98.8% ± 0.8%;5,7-dihydoxy flavones of 99.1% ± 0.7% and naringenine of 99.5% ± 1.0% respectively. The homogeneity of the CRMs was determined by an in-house validated liquid chromatographic method. Potential degradation during storage was also investigated and a shelf-life based on this value was established.

Preparation and Certification of a New Salvianolic Acid A Reference Material for Food and Drug Research

Salvianolic acid A(Sal A),a water-soluble ingredient in Danshen,has various biological activities.Sal A and its impurities have similar physical and chemical properties,as well as strong reducibility;therefore,they are difficult to prepare and purify.In this study,high-purity Sal A was obtained by purification of sephadex chromatography and preparative chromatography.Furthermore,HPLC-DAD tandem ECD and HPLC-DAD tandem MS methods were used for non-volatile organic impurity analysis,ICP-MS method was used for non-volatile inorganic impurities and mass balance method and quantitative nuclear magnetic resonance were employed to certify the product.The structures of Sal A and its relative impurities were validated by nuclear magnetic resonance spectroscopy and mass spectrometry,and their contents were quantified as well.Following the principles of ISO Guides 34:2009 and 35:2005,a Sal A reference material was certified,covering homogeneity studies,stability studies,characterization,and uncertainty estimations.

新增医疗服务价格项目管理政策回顾、实施难点及建议

比较各地新增医疗服务价格项目管理方案和主要做法,发现各地新增价格项目受理未区分难度、消耗和缓急,未明确绿色通道和加收情形;新增价格项目将耗材打包收费,难以客观体现技术劳务与设备物耗贡献;新增医疗服务价格项目要素不统一,影响区域间医院价格管理效果评价;新增价格项目成本测算表构成与计算口径各异,影响区域间数据的比较;价格政策执行情况检查结果与新增价格项目管理之间缺乏有效协同衔接。建议整合现行政策文件,出台国家新增医疗服务价格项目管理指导意见;公立医院要响应临床需求,加强新增价格项目申报、成本测算、执行情况管理,促进医疗技术创新发展和临床应用。

多参数回归物质平衡法在水驱气藏气井生产动态预测中的应用

物质平衡法在水驱气藏气井生产动态指标预测中面临2项难题,即产能方程的建立和水侵量计算,影响指标预测精度。针对存在的问题,通过理论推导及经验回归,研究产能方程系数和气层压力、水侵量和气层总压差、产水量与产气量之间的变化规律。建立一种新的多参数回归物质平衡法:包括3个基础方程(水驱气藏物质平衡方程、二项式产能方程、井筒管流方程)和4个经验关系式(二项式产能方程系数A与气层压力、二项式产能方程系数B与气层压力、累计水侵量与气层总压差、累计产水量与累计产气量)。结果表明,多参数回归物质平衡法立足气井的生产动态数据,简化了产能方程建立和水侵量计算过程。经过实践检验,平均误差在5%以内,该方法满足现场实际要求。

非常规油藏蓄能体积压裂的合理压裂规模研究

蓄能体积压裂是致密油、页岩油主要增产改造技术并成为开发前期主要方式,压裂规模是影响开发成效的重要因素。根据物质平衡原理,建立了未饱和油藏蓄能体积压裂物质平衡方程。经实测数据检验,能够准确预测压裂后井控范围内地层压力和地层压力系数随入地物量的变化规律,解决了蓄能体积压裂入地物量、入地液量定量预测问题,有利于优化压裂规模。结合致密油、页岩油水平井体积压裂投产后平均日产油、无效排液量等开发指标统计和数模预测,认为进液强度15~17 m^(3)/m较为合理。成果认识对于致密油、页岩油蓄能体积压裂开发合理压裂规模确定具有借鉴意义,有助于非常规油藏经济效益开发。

深层页岩气吸附模型和物质平衡新方法

准确评价深层页岩气井单井最终可采储量(EUR)对页岩气的高效开发具有重要意义。调研深层页岩气吸附模型,基于各模型对吸附数据的拟合程度优选出考虑深层页岩气吸附因素的T-Langmuir模型。基于T-Langmuir模型表征的深层页岩气吸附特征和流动物质平衡方程基本原理,建立考虑深层页岩气吸附特征的流动物质平衡新方法,并计算了四川盆地某页岩气井的单井最终可采储量。研究结果表明:T-Langmuir模型在高压条件下拟合效果较好,可以作为深层页岩气的吸附模型。新方法计算的单井最终可采储量为1.397×10^(8) m^(3),比传统方法的计算结果大0.109×10^(8) m^(3),经过和其他方法对比,新方法计算结果更为准确。

双种群混合遗传算法求解航空复合材料柔性调度问题

考虑航空复合材料柔性车间调度中的运输约束,以最小化完工时间为目标,建立调度模型,提出一种改进的双种群混合遗传算法进行求解。根据问题特点,基于工序排序、机器选择和运输约束3个子问题,设计三层实数编码以及对应解码方案。采用混合初始化提高种群质量,进化过程中采用交叉算子执行全局搜索,为双种群设计基于机器负载平衡和变邻域的局部搜索,提高全局和局部搜索能力。与对比算法相比10个测试算例中BPRD指标取得9个最优,APRD指标全部取得最优,t检验显著性有明显差异,验证算法的优越性。将算法应用于航空复合材料车间中,实现实际生产的调度,验证算法的可行性。

基于物质平衡法的剩余油分布研究——吴起油田薛岔区块贺沟开发单元

为精准掌握研究区油层各层位剩余油储量分布情况,为开展贺沟开发区块潜力分析提供重要依据。利用物质平衡法,研究吴起油田薛岔区块主力油层剩余油分布状态,从纵向分布、各小层采出率、平面分布状况三个视角进行研究。在原有研究基础上,利用物质平衡法劈分小层剩余储量,有效提高了不同层位剩余储量的劈分精度。该方法动静结合,具有阶段性,解决了传统方法劈分误差较大的问题。

顺北油气田断溶体油藏产量预测模型研究及应用

Arps递减曲线方程是油气田开发初期产量预测中应用较为普遍的方法,基本是参考类似油藏拟合参数以定压差生产为开发政策指导进行产量预测,对于顺北断溶体油藏地层压力下降明显,且储集层在地饱压差内的非线性流动特征明显,存在唯一的非线性惯性阻力,无法通过描述线性流动特征的采油指数来表征,存在误差较大、产量预测结果单一的缺点。通过分析顺北油气田产量递减特征,基于物质平衡原理,构建动态储量模型,结合顺北油气田通用产能方程和产能评价指标成果,形成了新的断溶体油藏弹性驱产量预测方法,用于指导断溶体油藏弹性驱开发阶段的生产管理,有更高的适应性和准确率,也为断溶体油藏开展产能建设方案经济评价优化、指导油井开发政策奠定了基础、提供多开发政策方案决策支撑。

农产品检测用脱氧雪腐镰刀菌烯醇纯度标准物质的研制

[目的]本文旨在研制脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)国家级纯度标准物质,为农产品中DON的检测等工作提供物质基础。[方法]利用质量平衡法和定量核磁共振法对DON纯度标准物质进行纯度定值。质量平衡法包括采用液相色谱面积归一化法测定DON主成分含量,采用卡尔费休库仑法测定纯度标准物质中水分含量,采用顶空气相色谱-质谱法测定挥发性杂质含量,以及采用电感耦合等离子质谱法测定无机离子杂质含量。定量核磁共振法采用苯甲酸为内标,选择合适的共振峰,内标法定量标准物质的纯度,并对标准物质进行均匀性、稳定性检测和不确定度评估。[结果]质量平衡法的纯度定值结果为99.47%,定量核磁共振法定值结果为99.45%,最终所研制的DON纯度标准物质的纯度为99.5%,扩展不确定度为0.4%,均匀性良好,且满足12个月以上的稳定性要求。[结论]本试验所研制的DON纯度标准物质符合国家标准物质技术规范,目前已被批准为国家一级标准物质,并已被用于小麦、玉米等农产品实际检测过程中。

一种新型饱和型煤层气藏物质平衡方程

对于临界解吸压力与原始地层压力相等的饱和型煤层气藏,King提出的经典物质平衡方程在实际应用中还存在一些不足,其未考虑吸附相所占据的孔隙空间。Ambrose修正了自由气体孔隙体积,建立了一种新的物质平衡方程,在实际中得到了有效应用。在King和Ambrose的基础上,文中首次同时考虑了吸附相视孔隙度、吸附相体积随压力变化及吸附相密度等因素,为饱和型煤层气藏储量计算提供了一种新方法。实例分析表明,考虑吸附相视孔隙度后,吸附气储量的计算值增加了59.92%,游离气储量减少了82.33%,计算得到的总储量增加了31.08%,新方程计算所得的总储量更接近容积法计算的储量。

浮球覆盖下水面能量平衡再建与蒸发模型研究

针对干旱区平原水库蒸发强烈导致水资源利用率低的问题,选用黑色高密度聚乙烯(HDPE)浮球作为干旱区平原水库节水材料。通过理论分析、建模与室外试验三者结合,对完整非冰冻期内浮球覆盖下水面蒸发、水体能量平衡组分变化分布的响应机理进行研究,并在此基础上建立相应的水面蒸发量计算模型。结果显示:相较于自由水面,73%的浮球覆盖率下的整体水面净辐射吸收率减小约12.6%,其月均蒸发所需潜热通量减少了61.8%,约为148.73 W/m^(2),水体的感热通量和蓄热通量也有较大的变化。通过对彭曼模型的能量项和空气动力项进行修正,建立的覆盖条件下的水面蒸发量计算模型具有较高的精度。

基于外源排查和工程改造的污水系统提质增效实践

分流制污水管网的外水侵入是造成管网高水位运行、污水浓度低的主要原因之一。针对某污水系统A、B污水厂进水水质浓度降低、污水处理总量波动较大的现象,坚持系统治水,在全面摸查管网的基础上,通过物料平衡法、水量平衡法初步判断进入系统的山水、河涌水、湖水、雨水的外水量和区域,再进行外水点实际踏勘、监测、验证,对外水进行溯源,精准定量、定位。结合4类水特点和基础条件,通过一系列工程实施有力地减少外水入侵,提高了污水厂进水水质浓度。上述研究成果为后续推进污水系统提质增效、营造健康的城市排水保障系统探索出一条实施路径。