Velocity model and time-depth conversion for the northwestern South China Sea deepwater areas

There are rich natural gas resources in the northwestern South China Sea deepwater areas, with poor degree of exploration. Because of the unique tectonic, sedimentary background of the region, velocity model building and time-depth conversion have been an important and difficult problem for a long time. Recent researches in this direction have revealed three major problems for deepwater areas, i.e., the way to determine error correction for drilling velocity, the optimization of velocity modeling, and the understanding and analysis of velocity variations in the slope areas. The present contribution proposes technical solutions to the problems：（1） velocity correction version can be established by analyzing the geology, reservoir, water depths and velocity spectrum characteristics;（2） a unified method can be adopted to analyze the velocity variation patterns in drilled pale structural positions;and （3） across-layer velocity is analyzed to establish the velocity model individually for each of the layers. Such a solution is applicable, as shown in an example from the northwestern South China Sea deepwater areas, in which an improved prediction precision is obtained.

Time-depth conversion of transient electromagnetic method used in coal mines

Accuracy of time-depth conversion in data processing of transient electromagnetic prospecting always affects the accu- rate positioning of water bodies in coal mines. In order to improve the accuracy of time-depth conversion, we established a mathe- matical model of time-depth conversion for a transient electromagnetic method based on the theory of "double smoke ring effect" of full space transient electromagnetic field transmission. Using a 3-layer as well as a 4-layer geo-electric model for roadway floors, we performed the time-depth conversion of theoretical curves of apparent resistance varying over time. In these curves, the depth corresponding to extreme value points is nearly the same as the depth of a geo-electric model. The position of water body deter- mined by our time-depth conversion method agrees well with the result of borehole drilling, indicating that the established time-depth conversion model can clearly improve the accuracy of spatial positioning of water bodies in coal mines.

Velocity and Structural Modeling of Mesozoic Chiltan Limestone and Goru Formation for Hydrocarbon Evaluation in the Bitrisim Area, Lower Indus Basin, Pakistan

The present study focuses on building a workflow for structural interpretation and velocity modeling and implementing to Jurassic-Cretaceous succession （Chiltan Limestone and Massive sand of the Lower Goru Formation）. 2D-Migrated seismic sections of the area are used as data set and in order to confirm the presence of hydrocarbons in the study area, P and S-wave seismic velocities are estimated from single-component seismic data. Some specific issues in the use of seismic data for modeling and hydrocarbon evaluation need to deal with including distinguishing the reservoir and cap rocks, and the effects of faults, folds and presence of hydrocarbons on these rocks. This study has carried out the structural interpretation and modeling of the seismic data for the identification of traps. The results demonstrate existence of appropriate structural traps in the form of horst and grabens in the area. 2D and 3D velocity modeling of the horizons indicates the presence of high velocity zones in the eastern half of the study while relatively low velocity zones are encountered in the western half of the area. Two wells were drilled in the study area （i.e. Fateh-01 and Ichhri-01） and both are dry. Immature hydrocarbons migration is considered as a failure reason for Fateh-01 and Ichhri-01 well.

Photodissociation Dynamics of Dichlorodifluoromethane（CF2Cl2） around 235 nm using Time-Sliced Velocity Map Imaging Technology

Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.

Temperature Effect on Light Concentration Silicon Solar Cell’s Operating Point and Conversion Efficiency

It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (CPV). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (MPP) moves to the open circuit when the cell temperature increases.

AIR VELOCITY SENSOR

During the last twenty years there has been rapid progress in the use of automation in a wide range of industries,as well as in military, scientific application. However, the progress in the application of automatic control is often hindered by the lack of accurate, reliable measuring apparatus. An economic thermal couple air flow sensor with better linearity (accuracy is ±5% of full scale) has been successfully made at Trolex Ltd. Many other existing sensors fail in the application of industries because of non-linearity.

火炮角度参数计量装置关键技术研究与设计

针对现有手段无法满足火炮角度参数对高精度计量的需求,研究提出一种进一步提高火炮角度计量精度的方法,采用正、余弦函数电路及数字—舷角变换电路设计制作了18位高精度数字—舷角转换器,采用D/A转换、电机转速及传动比例换算的方式模拟角度、角速度信号,并制作基于该技术的火炮角度参数计量装置,通过实验验证了该装置的准确性。

大型硫回收装置多功能CO变换加氢催化剂应用总结

普光气田是国内成功开发的首个高含硫气田,原料气(天然气)碳硫比高,再生酸性气CO_(2)含量高,会反应生成CO继而生成COS、CS_(2)等有机物,成为影响装置达标排放的关键因素之一。研究开发了具有CO变换功能的克劳斯尾气加氢催化剂,并成功应用于中国石化中原油田普光气田天然气净化厂200 kt/a硫回收装置。工业应用结果表明:加氢反应器过程气CO变换率超过90%,在线炉制氢天然气消耗量减少279 m^(3)/h,催化剂加氢转化率、有机硫水解率均超过99%,烟气SO_(2)排放浓度降至200 mg/m^(3)以下,CO排放浓度降低了90%,效益显著。

各向异性对地震波勘探信号时-深转换的影响

基于Thomsen岩石各向异性参数,计算了各向异性对在地下岩层中传播的弹性地震波的相速、能速和时-深转换的影响。结果表明:在关于垂直轴对称的横向各向同性介质非对称轴方向传播的P波的能速可以小于对称轴方向的相速,而在非对称轴方向传播的SV波的能速始终大于或等于对称轴方向的相速;如果不考虑各向异性或考虑各向异性但忽略在地层中传播的地震波的能速和相速之间的差别,会引起对地震波勘探信号的时-深转换产生误差,即不能用地震波勘探信号的走时信息准确地反演地下岩层的地质结构。

Symmetric Brownian motor subjected to Lévy noise

In the past few years,attention has mainly been focused on the symmetric Brownian motor(BM)with Gaussian noises,whose current and energy conversion efficiency are very low.Here,we investigate the operating performance of the symmetric BM subjected to Lévy noise.Through numerical simulations,it is found that the operating performance of the motor can be greatly improved in asymmetric Lévy noise.Without any load,the Lévy noises with smaller stable indexes can let the motor give rise to a much greater current.With a load,the energy conversion efficiency of the motor can be enhanced by adjusting the stable indexes of the Lévy noises with symmetry breaking.The results of this research are of great significance for opening up BM’s intrinsic physical mechanism and promoting the development of nanotechnology.

位置可调转向管柱传动的运动学分析及应用

方向盘在前后伸缩或者上下角度调整之后,转向系统的不等速特性引起的力矩波动,方向盘幅角及转向管柱的摩擦力矩变化都会发生变化。通过建立局部坐标系,进行空间坐标转换,推导了输入轴和输出轴转角的关系式。使用该方法可以计算不同方向盘调节位置时转向管柱传动的不等速特性,转向管柱位置调节导致的方向盘幅角变化,转向管柱万向节的摩擦力矩变化。基于以上三个计算结果,提出了输出轴的初始相位的设定方法。

固定床渣油加氢技术及渣油高效转化技术应用

固定床渣油加氢技术一般不加工100%减压渣油,其装置混合原料中减压渣油质量分数一般不高于65%。A固定床渣油加氢装置6个周期运行结果表明:原料中减压渣油比例越高,装置运行周期越短。B固定床渣油加氢装置体积空速为0.20 h^(-1),若体积空速降低至0.15、0.10 h^(-1),反应器压力降预计分别增加至2.3、3.4 MPa。A固定床渣油加氢装置加氢重油产率高达93.25%,520℃以上馏分转化率仅为25.38%。沸腾床渣油加氢技术及浆态床渣油加氢技术可以加工100%减压渣油。C沸腾床渣油加氢装置和D浆态床渣油加氢装置反应器压力降稳定,其中D装置反应器压力降仅为0.42 MPa。典型沸腾床渣油加氢技术和浆态床渣油加氢技术的转化率可达85.87%和91.49%。

柴油氧化催化器性能的影响因素研究

基于发动机台架进行柴油氧化催化器性能试验,研究了在发动机正常运转时DOC温升特性,出口温度变化受到空速和DOC入口温度的影响。空速(Space Velocity)、DOC入口排气温度对NO、CO和碳氢化合物对转化效率的影响,结果表明,在NO转化效率上1#DOC在250~450℃下空速越低转化效率越好,其中在175~350℃下转化效率随着温度得升高而增加,在375~450℃中转化效率随着温度升高而下降。2#DOC中可以看出在低温区域(175~275℃)空速越高转化效率越好,在300~450℃下空速越低转化效率越好。不同类型DOC对CO的转化效率在各温度下均在90%以上。两种DOC的THC转化效率1#DOC在300~400℃转化效率最高为90%,2#DOC在275~400℃转化效率最高为80%。

综合处理工艺在西溪湿地清水入城中的应用

针对钱塘江来水含沙量高,水体浑浊、透明度低等特性,以西溪湿地清水入城为例,通过减缓水流流速、投放絮凝剂、底泥疏浚等综合处理工艺,加快悬浮质絮凝沉淀过程、提升来水透明度;并通过耦合来水量、浊度、流速与絮凝剂投放量之间的关系,提出变频投放系统,寻求最经济运行模式。

利用反推法速度建场技术提高储层地质建模精度

针对常规方法下地震速度建场进行时深转换后存在的井点误差和断裂带构造畸变的现象,提出了反推法速度建场技术。该技术利用开发阶段已有的高精度构造层面和地震时间层面,将深度构造面与时间面一一对应,通过层间深度差和时间差逐层求取层间平均速度,并将各层平均速度纵向叠加生成空变速度场,进而进行时深转换。该方法适用于由目的层段、纵向可靠转换层段控制的层位间纵向范围,操作方法简单、高效,适用于构造简单区域和断裂复杂带,井点近于零误差,断裂带内构造形态保持较好,已得到推广应用。

两相厌氧系统中产甲烷相有机酸转化规律

研究了两相厌氧系统产甲烷相中有机酸转化规律 .以产酸相、产甲烷相COD负荷分别为 41 5kg/(m3·d)、6 0 5kg/(m3·d)的连续流试验装置培养种泥 ,运行稳定后 ,进行静态试验 .采用气相色谱仪 (GC 1 2 2型 )分析有机酸组成及含量 .结果表明 ,反应器相同位置的微生物降解转化有机酸速率快慢依次为 :乙酸 >乙醇 >丁酸 >丙酸 ;利用乙醇产乙酸的微生物与产甲烷菌所需最佳pH值范围相近 ;乙醇型发酵是充分发挥两相厌氧系统功能的最佳发酵类型 ;在产甲烷反应器中 ,大部分挥发酸的最终降解都要经历乙酸降解途径才能完成 ,造成乙酸的降解转化相对缓慢 。

巴楚夏河工区的三维速度建模方法

本文结合巴楚夏河工区的实际情况,详细探讨了该区三维速度建模方法。此法以地震速度平衡建模思想为指导,以随机模拟法为基础,采用离散平滑插值技术构建三维离散空间建模。与其他建模方法相比,此法的建模步骤及应用效果具有以下优点:1采用由点到面到体的建模过程,充分细致地反映了三维空间离散结构;2在建模过程中提供了大量插值、数值模拟方法,保证了建模的可靠性;3充分利用测井与地震信息,保证了建模的准确性;4所求速度模型能准确反映速度空间变化规律。文中具体介绍了建模步骤。在巴楚夏河地区的应用结果表明,此法能够较好地解决地震资料处理与解释中的速度问题,尤其是复杂地区的速度问题,可为油气田勘探开发提供准确的速度资料。

井巷断面内单点风速与平均风速转换机制

准确测量一点风速并将其转换为断面平均风速是矿井通风领域的一项技术难题。对其中涉及的单点风速测不准问题和单点风速与平均风速的转换机制进行了研究。结果表明,湍流充分发展的圆管断面上任一点（黏性底层除外）风速与平均风速为非线性关系,但在井下常见风速0.25~15 m/s,两者可近似为正比关系。为验证这一结论的普适性,在实验室采用激光多普勒测速仪对矩形非充分发展湍流断面上单点风速与平均风速的关系进行了测试。结果表明：当平均风速在0.78~6.2 m/s变化时,单点风速与平均风速仍表现为正比关系,比值k可作为该点风速与平均风速间的无因次转换系数;k的空间分布反映了断面速度场结构,当断面速度场结构变化时转换系数失效。在单点风速测不准问题上提出,测试传感器在提高数据采集频率的基础上应对速度信号进行时间平均处理,且时间平均尺度要大于湍流各态遍历假设。

水平界面上P-SV转换波转换点的精确解

转换波共转换点的叠加和道集选取都需要准确地计算转换点的位置.Tessmer和Behle、Taylor分别给出了水平单层介质中P-SV转换波转换点坐标的解析解,由于其表达式的复杂性,在应用中几乎不被采用.在本文中,运用Snell定律重新建立了在水平反射界面上反射的P-SV转换波的转换点坐标的四次方程,并严格地推导出与纵波速度、横波速度、炮检距和反射深度有关的转换点坐标的解析解,确定了惟一的解析表达式.将这一结果应用于P-SV转换波的速度分析和叠加处理中.简化的公式有较好的应用价值.

地震滑坡启程动力学机理

为深入揭示地震滑坡的启程动力学机理,探讨了地震诱发滑坡的启动机制.在分析滑坡滑动前聚集的临床弹性应变能的基础上,同时考虑地震水平加速度和竖向加速度,运用能量转化原理,导出了地震滑坡启程速度的计算公式.研究结果表明,地震触发斜坡破坏,主要是其"波动振荡链"综合效应所致;地震滑坡启程阶段经历了"先启动,后加速至启程"的过程;汶川地震东河口滑坡启程速度的计算结果与用动量传递法计算的结果相比,误差约3%.