3D forward modeling and response characteristics of low-resistivity overburden of the CFS-PML absorbing boundary for ground-well transient electromagnetic method

This study used the stable and convergent Dufort-Frankel method to differentially discretize the diffusion equation of the ground-well transient electromagnetic secondary field.The absorption boundary condition of complex frequency-shifted perfectly matched layer(CFS-PML)was used for truncation so that the low-frequency electromagnetic wave can be better absorbed at the model boundary.A typical three-dimensional(3D)homogeneous half-space model was established and a low-resistivity cube model was analyzed under the half-space condition.The response patterns and drivers of the low-resistivity cube model were discussed under the influence of a low-resistivity overburden.The absorption boundary conditions of CFS-PML significantly affected the low-frequency electromagnetic waves.For a low-resistivity cube around the borehole,its response curve exhibited a single-peak,and the extreme point of the curve corresponded to the center of the low-resistivity body.When the low-resistivity cube was directly below the borehole,the response curve showed three extreme values(two high and one low),with the low corresponding to the center of the low-resistivity body.The total field response of the low-resistivity overburden was stronger than that of the uniform half-space model due to the low-resistivity shielding effect of electromagnetic waves.When the receiving-transmitting distance gradually increased,the effect of the low-resistivity overburden was gradually weakened,and the response of the low-resistivity cube was strengthened.It was affected by the ratio of the overburden resistivity to the resistivity of the low-resistivity body.

Logging-based assessment of low-resistivity oil zones:A case study from Sudan

The reservoirs in the N oilfield in Sudan feature a complex sedimentary environment,which has led to a widespread development of low-resistivity oil zones,accounting for as high as 37%of the total oil zones.In this case,a large number of oil zones will be misinterpreted using conventional methods.Based on the analysis of the core data and logging curves of the study area,this study concludes that the lowresistivity oil zones are formed mainly due to the high irreducible water saturation caused by the high content of illite and smectite and complex pore structure,the additional electrical conductivity induced by clay minerals,and the difference in formation water salinity between the oil zones and water zones.Furthermore,four methods are proposed to qualitatively identify these oil zones and water zones,namely the relationship analysis of five reservoir properties,cross-plotting of sensitive parameters,analysis of pressure testing data,and multi-well correlation.Furthermore,the study quantitatively calculates the initial oil saturation using the capillary pressure data,thus avoiding the conventional empirical saturation formulas depending on electrical resistivity and solving the difficulty in calculating oil saturation of low-resistivity oil zones.Finally,precise logging processing and interpretation of 95 wells in the study area are conducted using the above-mentioned comprehensive assessment system for low-resistivity oil zones.As a result,59 oil zones are newly discovered in 43 wells.Moreover,it is recommended that 17 oil zones in 12 wells should be tested,of which 11 oil zones have been tested as recommended,all proven to be high production oil zones after perforation.The coincidence rate of logging interpretation increases from 75%to 94.3%,and the original oil in place(OOIP)increases by 57.42 million barrels.All these indicate that the assessment system proposed is suitable for low-resistivity zones.

Easy Paying Optimizing payment options for international visitors to China

As of January 31,2024,China had concluded mutual visa exemption agreements covering different types of passports with 157 countries,reached agreements or arrangements on simplified visa procedures with 44 countries,and enjoyed comprehensive mutual visa exemptions with 23 countries including Thailand,Singapore,Maldives,and the United Arab Emirates.

Are You Willing to Pay to Go to the Supermarket?

In recent yea rs,t raditiona l offline supermarkets are facing big challenges,and warehouse membership superma rkets(hereinafter referred to as membership supermarkets)are quickly gaining p opu l a r it y.Ma ny t r ad it iona l supermarkets have become membership supermarkets,and even many retail enterprises have entered this field.

Digital Payments Bring Better Travel Experience in China

CHINA’S visa-free policy keeps expanding and the country has entered a new era of welcoming visitors from an increasing global reach.By January 1,2024,China had inked mutual visa exemption agreements with 157 countries,simplified visa procedures with 44 countries,and enjoyed comprehensive mutual visa exemptions with 23 countries,including Thailand,Singapore,the Maldives,and the United Arab Emirates.

Identification of low-resistivity-low-contrast pay zones in the feature space with a multi-layer perceptron based on conventional well log data

In the early exploration of many oilfields,low-resistivity-low-contrast(LRLC)pay zones are easily overlooked due to the resistivity similarity to the water zones.Existing identification methods are model-driven and cannot yield satisfactory results when the causes of LRLC pay zones are complicated.In this study,after analyzing a large number of core samples,main causes of LRLC pay zones in the study area are discerned,which include complex distribution of formation water salinity,high irreducible water saturation due to micropores,and high shale volume.Moreover,different oil testing layers may have different causes of LRLC pay zones.As a result,in addition to the well log data of oil testing layers,well log data of adjacent shale layers are also added to the original dataset as reference data.The densitybased spatial clustering algorithm with noise(DBSCAN)is used to cluster the original dataset into 49 clusters.A new dataset is ultimately projected into a feature space with 49 dimensions.The new dataset and oil testing results are respectively treated as input and output to train the multi-layer perceptron(MLP).A total of 3192 samples are used for stratified 8-fold cross-validation,and the accuracy of the MLP is found to be 85.53%.

Micro-geological causes and macro-geological controlling factors of low-resistivity oil layers in the Puao Oilfield

Low-resistivity oil layers are often missed in logging interpretation because of their resistivity close to or below the resistivity of nearby water layers. Typical low-resistivity oil layers have been found in the past few years in the Putaohua reservoir of the Puao Oilfield in the south of the Daqing placanticline by detailed exploration. Based on a study of micro-geological causes of low-resistivity oil layers, the macro-geological controlling factors were analyzed through comprehensive research of regional depositional background, geological structure, and oil-water relations combined with core, water testing, well logging, and scanning electron microscopy data. The results showed that the formation and distribution of Putaohua low-resistivity oil layers in the Puao Oilfield were controlled by depositional environment, sedimentary facies, diagenesis, motive power of hydrocarbon accumulation, and acidity and alkalinity of reservoir liquid. The low-resistivity oil layers caused by high bound-water saturation were controlled by deposition and diagenesis, those caused by high free-water saturation were controlled by structural amplitude and motive power of hydrocarbon accumulation. Those caused by formation water with high salinity were controlled by the ancient saline water depositional environment and faulted structure and those caused by additional conductivity of shale were controlled by paleoclimate and acidity and alkalinity of reservoir liquid. Consideration of both micro-geological causes and macro-geological controlling factors is important in identifying low-resistivity oil layers.

Living environment shaped residents’willingness to pay for ecosystem services in Yangtze River Middle Reaches Megalopolis,China

Profound understanding on the diversity of local residents’willingness to pay(WTP)for ecosystem services(ESs)may aid evaluation of policy impacts by uncovering trade-offs and synergies for achieving sustainable environmental resource management.However,the reasons for the spatial preference heterogeneity of WTP are still unclear.In this study,an extensive survey with 4,580 residents in the Yangtze River Middle Reaches Megalopolis(YRMRM),central China,was carried out to investigate the public’s WTP to maintain and improve ESs.We identified key influencing factors and explored how they shaped the preference heterogeneity in WTP by random forest model and surface fitting method.Our results showed that 81.4% of residents reported WTP for ESs greater than zero.Water supply,waste treatment,food supply and raw material supply were the preferred ESs for residents.Living environment factors(i.e.,extent of farmland,water and forest near the residence)were found as the key drivers of WTP.Proximity to farmland,water and forests resulted in high WTP values for a series of specific ESs.The reasons for the heterogeneity of WTP are(1)the difference in proximity to farmland,water and forest(i.e.,the contributor to ESs),(2)the divergence of local residents’preferences for ESs.This study disclosed the heterogeneity and causes of public preferences in YRMRM,which could help policy and decision makers to develop eco-compensation initiatives towards conservative and sustainable use of the environmental resources.

Low-resistance ohmic contacts on InAlN/GaN heterostructures with MOCVD-regrown n+-InGaN and mask-free regrowth process

This paper studied the low-resistance ohmic contacts on InAlN/GaN with metal–organic chemical vapor deposition(MOCVD)regrowth technique.The 150-nm regrown n-InGaN exhibits a low sheet resistance of 31Ω/□,resulting in an extremely low contact resistance of 0.102Ω·mm between n^(+)-InGaN and InAlN/GaN channels.Mask-free regrowth process was also used to significantly improve the sheet resistance of InAlN/GaN with MOCVD regrown ohmic contacts.Then,the diffusion mechanism between n^(+)-InGaN and InAlN during regrowth process was investigated with electrical and structural characterizations,which could benefit the further process optimization.

Tourists’Willingness to Pay for Recreation Services in Nyerere National Park,Tanzania:Are We Overvaluing or Undervaluing Our Nature Recreation Resources?

This study estimated tourists’Willingness to Pay(WTP)per day for recreation services in Nyerere National Park(NNP)and compared these values with daily travel costs that are incurred by tourists to visit NNP in order to inform whether recreation resources in the park are overvalued or undervalued.The study revealed that tourists’WTP per day for recreation services was estimated at$237.4 and$1521 for resident and non-resident tourists,respectively.The estimated tourists’WTP values exceed the daily travel costs currently incurred by tourists,which are$201.04 and$1517.97 for resident and non-resident tourists,respectively.This indicates that tourists are willing to spend more to enjoy recreation services in NNP,which signifies that recreation resources in NNP are slightly undervalued.In addi­tion,the findings disclosed that the largest share of tourist daily travel expenses is allocated to transportation services,and very little is paid to the park as a conservation fee.It was revealed that out of the daily travel expenses incurred by non-resident and resident tourists,only 4.62%and 2.23%are respectively paid directly to NNP as conservation fees.This study considers that allocation is not very fair;thus,NNP,in collaboration with TANAPA,needs to adjust the current entrance or conservation fee and reduce the transportation costs charged by tourist companies.The travel costs incurred by tourists,age,education,monthly income,site visited,substitute site,and quality of park were identified as significant factors in influencing tourists’WTP for recreation services in NNP.Thus,policies oriented to reduce tour­ists’transportation costs and improve the quality of national parks would attract more tourists to NNP.

活力巴塞罗那 Clearpay办公室

本案为Clearpay公司巴塞罗那办公室的扩建项目,业主租下了与原办公室相邻的2个空间。原办公室和新办公室均由studioMADD设计。作为一家年轻的、富有创造力和雄心勃勃的公司,Clearpay的目标是打造一处能够体现这些品质的工作场所。这个空间需要激励员工、促进新的工作方式,因而创新性、可持续性、包容性,以及对所有人的热烈欢迎至关重要。最终的结果不仅达到了这些目标,而且超出了预期。

可信执行环境标准在金融支付场景下的应用

围绕金融支付创新,以GB/T 41388—2022《信息安全技术可信执行环境基本安全规范》和GB/T 42572—2023《信息安全技术可信执行环境服务规范》两项可信执行环境标准为基础,开展了在金融支付场景下的手机Pay与手机POS产品创新实践,在手机这类消费类电子设备上提供了既安全又便捷的产品体验,为标准在金融领域中的实施发挥了引领作用。

Identification and Evaluation of Low Resistivity Pay Zones by Well Logs and the Petrophysical Research in China

This paper presents an overview of petrophysical research and exploration achievements of low resistivity pay （LRP） zone by well logs in China. It includes geological characteristics and characteristics of well log response of the low resistivity pay zones discovered and evaluated in recent years, as well as the problems in recognizing and evaluating low resistivity pay zones by well logs. The research areas mainly include the Neogene formations in the Bohai Bay Basin, the Triassic formations in the northern Tarim Basin and the Cretaceous formations in the Junggar Basin, The petrophysical research concerning recognition and evaluation of the low resistivity pays, based on their genetic types, is introduced in this paper.

基于PayWord的WWW微支付模型

在 Pay Word微支付机制的基础上 ,通过对支付协议的深入分析和研究 ,对协议进行了必要的扩展和改进 ,使其更适合应用于 WWW中的信息付费和访问控制 .最后对系统的具体实现给出了建议 .

基于Pay Word的微支付机制及改进分析综述

综述了电子支付中基于Pay Word的微支付机制,具体分析了Pay Word协议,并指出了该协议的优缺点。根据不同方面的改进对现有的基于Pay Word的改进微支付协议进行详细分类,最后讨论了当前基于Pay Word的改进微支付协议所存在的问题及进一步研究的方向。

支付产品的主要类型与对标研究——基于信用卡、Apple Pay和微信支付、支付宝、百度钱包、京东白条等主要第三方支付产品的比较

近年来,随着网络金融的兴起,多种场景和信用支付产品的开发与应用方兴未艾,第三方支付产品大行其道。在实践中,支付宝、微信支付、京东白条、百度钱包、Apple Pay等满足了不同客户对支付场景、支付技术、安全便捷等需求,得到了不少客户的认可和选择。本文选取信用卡和上述支付产品,基于服务范式与客户需求、运营成本与客户体验、风险管理与业务赢利三类双元类型,分析并定位六大主要支付产品。通过多维对标发现:支付宝、微信支付、百度钱包和京东白条在基于服务范式与客户需求的双元定位中具有一定差异化的特色;银行卡和支付宝在基于运营成本与客户体验的双元定位中具有一定优势;支付宝和Apple Pay基于风险管理与业务赢利的双元定位中具有比较优势。研究发现:第三方支付产品特别是互联网支付产品借助自身先天平台拓展了应用场景,将支付场景从金融领域延伸到消费领域,形成了客户选择范围较广、操作相对便捷、依附度较高的"产品生态系统",进而实现了消费方式的一站化、对象选择的平台化和生活方式的便捷化。本文针对支付产品的特征,提出了基于支付场景与业务范围的双元定位,并就信用卡的发展提出了若干建议。

Apple Pay与国内移动支付工具的比较分析及启示

近年来,移动支付市场迅猛发展,在线上、线下交易中均得到广泛普及。2016年2月,苹果公司与中国银联达成合作协议,银联云闪付开通支持苹果支付(Apple Pay)服务,Apple Pay正式登陆国内市场。论文从梳理移动支付发展的三阶段入手,比较分析了Apple Pay与微信支付、支付宝等移动支付工具在支付手段、安全性能、便利性等方面的优劣势,指出Apple Pay目前在国内市场面临缺乏消费生态场景支撑、消费者支付习惯难以改变,银联POS终端数量、近场支付等硬件环境仍有待于完善等制约因素,短期内虽然不会改变现有移动支付格局,但对加快我国近场支付市场发展具有重要的借鉴和启示意义。

Apple Pay与国内互联网支付工具的比较分析及启示

本文从梳理移动支付发展的三个阶段入手,比较分析了Apple Pay与微信支付、支付宝等互联网支付工具在支付手段、安全性能、便利性等方面的优劣势,指出Apple Pay目前在国内市场面临缺乏消费生态场景支撑、消费者支付习惯难以改变,银联POS终端数量、近场支付等硬件环境仍有待于完善等制约因素,并阐述其对加快我国支付市场发展的重要启示。

SUMMARIES OF TOP EVENTS IN CHINA AND AFRICA

China Increases Payment Convenience for Foreigners China has recently intensified efforts to enhance the convenience of payment services for foreigners,who primarily rely on bank cards and cash,while mobile payment is emerging as the predominant method of payment in China.

Review of Women’s Employment in Greece in the 20th and Early 21st Centuries

In the early 20th century,the role of Greek women in the working environment was considered complementary,and the type of work they would do should fit their Review of Women’s Employment in Greece in the 20th and Early 21st Centuries gender stereotypes.Therefore,they were low-paid workers and employees,and they were the first to be laid off.Despite the fact that the number of Greek women participating in the labor market has increased,many of them were obliged to work due to the high rate of men’s unemployment since there was no other way to sustain the living level of the household(Alpha Bank,2018).Greek women’s participation in the labor market was accompanied by an increase in flexible types of employment along with the pay gap between men and women,which remained persistent due to the existence of discrimination.