Synchronous injection-production energy replenishment for a horizontal well in an ultra-low permeability sandstone reservoir: A case study of Changqing oilfield in Ordos Basin, NW China

It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir.To solve this problem,this study proposes to use packers,sealing cannula and other tools in the same horizontal well to inject water in some fractures and produce oil from other fractures.This new energy supplement method forms a segmental synchronous injection-production system in a horizontal well.The method can reduce the distance between the injection end and the production end,and quickly establish an effective displacement system.Changing the displacement between wells to displacement between horizontal well sections,and point water flooding to linear uniform water flooding,the method can enhance water sweeping volume and shorten waterflooding response period.The research shows that:(1)In the synchronous injection and production of horizontal well in an ultra-low-permeability sandstone reservoir,the water injection section should select the section where the natural fractures and artificial fractures are in the same direction or the section with no natural fractures,and the space between two sections should be 60?80 m.(2)In addition to controlling injection pressure,periodic water injection can be taken to reduce the risk of re-opening and growth of natural fractures or formation fracture caused by the gradual increase of water injection pressure with water injection going on.(3)Field tests have verified that this method can effectively improve the output of single well and achieve good economic benefits,so it can be widely used in the development of ultra-low permeability sandstone reservoirs.

A nonlinear model for aerodynamic configuration of wake behind horizontal-axis wind turbine

Determination of the aerodynamic configuration of wake is the key to analysis and evaluation of the rotor aerodynamic characteristics of a horizontal-axis wind turbine. According to the aerodynamic configuration, the real magnitude and direction of the onflow velocity at the rotor blade can be determined, and subsequently, the aerodynamic force on the rotor can be determined. The commonly employed wake aerodynamic models are of the cylindrical form instead of the actual expanding one. This is because the influence of the radial component of the induced velocity on the wake configuration is neglected. Therefore, this model should be called a "linear model". Using this model means that the induced velocities at the rotor blades and aerodynamic loads on them would be inexact. An approximately accurate approach is proposed in this paper to determine the so-called "nonlinear" wake aerodynamic configuration by means of the potential theory, where the influence of all three coordinate components of the induced velocity on wake aerodynamic configuration is taken into account to obtain a kind of expanding wake that approximately looks like an actual one. First, the rotor aerodynamic model composed of axial (central), bound, and trailing vortexes is established with the help of the finite aspect wing theory. Then, the Biot-Savart formula for the potential flow theory is used to derive a set of integral equations to evaluate the three components of the induced velocity at any point within the wake. The numerical solution to the integral equations is found, and the loci of all elementary trailing vortex filaments behind the rotor are determined thereafter. Finally, to formulate an actual wind turbine rotor, using the nonlinear wake model, the induced velocity everywhere in the wake, especially that at the rotor blade, is obtained in the case of various tip speed ratios and compared with the wake boundary in a neutral atmospheric boundary layer. Hereby, some useful and referential conclusions are offered for the aerodynamic computation and design of the rotor of the horizontal-axis wind turbine.

The Effects of Turbulence Intensity and Tip Speed Ratio on the Coherent Structure of Horizontal-Axis Wind Turbine Wake:A Wind Tunnel Experiment

The evolution laws of the large-eddy coherent structure of the wind turbine wake have been evaluated via wind tunnel experiments under uniform and turbulent inflow conditions.The spatial correlation coefficients,the turbulence integral scales and power spectrum are obtained at different tip speed ratios(TSRs)based on the time-resolved particle image velocity(TR-PIV)technique.The results indicate that the large-eddy coherent structures are more likely to dissipate with an increase in turbulence intensity and TSR.Furthermore,the spatial correlation of the longitudinal pulsation velocity is greater than its axial counterpart,resulting into a wake turbulence dominated by the longitudinal pulsation.With an increase of turbulence intensity,the integral scale of the axial turbulence increases,meanwhile,its longitudinal counterpart decreases.Owing to an increase in TSR,the integral scale of axial turbulence decreases,whereas,that of the longitudinal turbulence increases.By analyzing the wake power spectrum,it is found that the turbulent pulsation kinetic energy of the wake structure is mainly concentrated in the low-frequency vortex region.The dissipation rate of turbulent kinetic energy increases with an increase of turbulence intensity and the turbulence is transported and dissipated on a smaller scale vortex,thus promoting the recovery of wake.

Mechanism and application of a newly developed pressure casting process:horizontal squeeze casting

Compared to traditional high-pressure die casting(HPDC),horizontal squeeze casting(HSC)is a more promising way to fabricate high-integrity castings,owing to a reduced number of gas and shrinkage porosities produced in the casting.In this paper,the differences between HSC and HPDC are assessed,through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences.Equipment development and related applications are also reviewed.Furthermore,numerical simulation is used to analyze the three fundamental characteristics of HSC:slow cavity filling,squeeze feeding and slow sleeve filling.From this,a selection principle is given based on the three related critical casting parameters:cavity filling velocity,gate size and sleeve filling velocity.Finally,two specific applications of HSC are introduced,and the future direction of HSC development is discussed.

Optimization of integrated geological-engineering design of volume fracturing with fan-shaped well pattern

According to the variable toe-to-heel well spacing, combined with the dislocation theory, discrete lattice method, and finite-element-method(FEM) based fluid-solid coupling, an integrated geological-engineering method of volume fracturing for fan-shaped well pattern is proposed considering the geomechanical modeling, induced stress calculation, hydraulic fracturing simulation, and post-frac productivity evaluation. Besides, we propose the differential fracturing design for the conventional productivity-area and the potential production area for fan-shaped horizontal wells. After the fracturing of the conventional production area for H1 fan-shaped well platform, the research shows that the maximum reduction of the horizontal principal stress difference in the potential productivity-area is 0.2 MPa, which cannot cause the stress reversal, but this reduction is still conducive to the lateral propagation of hydraulic fractures. According to the optimized fracturing design, in zone-Ⅰ of the potential production area, only Well 2 is fractured, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage;in zone-Ⅱ, Well 2 is fractured before Well 3, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage. The swept area of the pore pressure drop in the potential production area is small, showing that the reservoir is not well developed. The hydraulic fracturing in the toe area can be improved by, for example, properly densifying the fractures and adjusting the fracture distribution, in order to enhance the swept volume and increase the reservoir utilization.

沁水盆地南部煤层气地质工程一体化关键技术

沁水盆地南部煤层气资源丰富,但地质、工程条件复杂,樊庄成熟工艺技术推广邻区适应性较差,煤层气规模效益开发面临严峻挑战。为了解决沁水盆地南部煤层气“井位部署难度大、钻井周期长、裸眼井井眼易垮塌、单井产量低”等问题,开展了地质工程一体化技术攻关,形成了“三性”煤储层评价、可控水平井钻完井、分段压裂及疏导式排采等多项关键技术,并开展现场试验与推广。研究结果表明:通过地质与工程有机结合,实现了地质模型为工程技术优化提供技术支撑,工程实践不断校正地质模型,施工精度提高;水平井煤层钻遇率95%,单井钻井复杂平均减少40%,产能到位率达90%,单井平均日产量超过8000 m^(3)。

远探测声波测井处理解释方法发展与展望

远探测声波测井技术(亦称反射声波测井技术)能够从井中探测及评价井外数十米范围内的裂缝、洞穴和断层等地质异常反射体,大大拓展了测井技术的应用范围。在回顾该技术发展历程的同时,重点介绍了远探测声波测井处理解释核心方法、软件和现场应用效果。结合目前油田实际生产需求和现有技术面临的挑战,指出远探测声波测井处理解释方法有5个最重要的发展方向:继目前利用声波时差和密度通过反射系数褶积进行“测井约束下的地震反演”后,突破实现井下实测反射波和地面地震反射波正反演关系的直接建立,同时开展页岩储层裂缝成像、压裂效果评价、随钻地质导向研究及远探测声波测井仪器革新。

职业教育横向融通的双精准育人体系构建与实践路径

我国职业教育聚焦点正在从体量发展、解决规模问题向人才培养质量优秀率、企业对人才需要契合性进行战略转向,在此过程中出现优势资源协调难、育训管理差异多、利益诉求差别大等校企横向融通欠佳现象;为深化高职教育教学改革,适应国家经济结构调整和产业转型升级对人才培养需求,以个人职业生涯可持续发展的职业教育体系建设为目标,以精准聚焦社会服务与人才培养为实践路径,构建“三个对接、三种模式、两个平台”;打造多层次“订式培养”的双精准育人体系,促使校企技术技能人才培养适销对路,促进职业教育与职业培训相互融通。

陆相页岩油水平井开发合理生产制度优化——以苏北盆地A区块阜二段为例

为了最大限度提高陆相页岩油全生命周期的采收率,并建立其水平井开发的合理生产制度。选取苏北盆地A区块阜二段为靶区,利用井震资料开展储层发育特征研究,建立“地质—开发—地应力—裂缝扩展”的地质工程一体化模型,进而对页岩油水平井开发合理生产制度进行优化研究。研究结果表明岩石类型、裂缝分布、岩石力学参数和工程施工参数是影响页岩油地质工程一体化模型精度的关键因素,确定了压后合理开井时间为20 d、合理生产压差为10 MPa、CO_(2)合理吞吐时机为井口压力下降至1.5 MPa左右、CO_(2)合理吞吐焖井时间为15 d,形成了页岩油水平井开发合理生产制度优化流程。研究成果对陆相页岩油长期稳产和效益开发具有重要支撑作用。

“两纵一横”科技创新培养模式培育大学生核心素养的实践探索

通过创建“两纵一横”模式即以纵向科技项目立项和横向科技竞赛、大学生科技活动节和科技沙龙为激励,以双师双能型教师为保障,以双创能力为培养目标的新模式。提出构建“三个体系”和搭建“两个平台”模式,鼓励学生参与国家级和省市级别的纵向项目科技立项和开发与参加国家级、省市级横向科技竞赛相结合的方式,来实现大学生科技创新能力的提升和创新精神的培养。此外,通过建立“三库+三制度”保障体系,坚持以赛促学、以赛促教和以赛促改,实现赛教全方位融合,形成师生优势互补的新态势,培养一大批实践能力强、理论知识广的应用技能型工程师,最终实现应用型本科院校培养模式从“学历提升型人才”向“职业技能型工程师”的转变。该成果在校内和校外三年来的推广与应用证明“两纵一横”创新培养模式具有可操作性和可复制性,在应用型大学建设过程中取得显著效果,发挥引领示范作用。

地下室工程“桩墙合一”技术优化及应用

为解决基坑作业面狭小问题,兼顾减少土方施工工作量、节约资源、节省造价,论文基于重庆某工程实例,简述“桩墙合一”技术优化思路及应用,包括利用人工挖孔桩与旋挖灌注桩形成咬合桩,代替原方案地下连续墙,采用环形支撑,实现咬合桩与地下室外墙合一、水平支撑与地下室结构板合一、内支撑格构柱与结构柱合一等;同时,对优化方案进行工期和经济效益对比分析。实践表明,该“桩墙合一”优化方案保证了施工安全和质量,经济效益可观,可为同类工程提供参考。

论大中小学爱国主义教育一体化建设的理论内涵及实践探索

推进大中小学爱国主义教育一体化建设是理论和实践相统一的重要课题。大中小学爱国主义教育一体化建设的内涵重点在“大中小学”和“一体化建设”,其实质是对大中小学爱国主义教育体系的系统构建。深刻理解大中小学爱国主义教育一体化建设的内涵和实质,遵循整体性与层次性相统一、主导性和主体性相统一、思想性、理论性和亲和力、针对性相统一,以及理论与实践相结合、宏观与微观相统一等原则,从打造教育共同体的组织架构、建立健全各学段既有序衔接又螺旋上升的课程和教材体系、打造各要素同向同行的横向教育格局、牢牢占领网络阵地等方面着手,打造虚实相融的教育模式。

四川盆地致密气水平井钻井关键技术

为搞清四川盆地致密水平井钻井工程技术难点,针对致密气水平井井眼轨迹设计复杂、地层易坍塌掉块、卡钻风险高、下套管困难以及钻井周期慢等技术难点,开展了地层压力预测及应力分析、井眼轨迹设计优化、钻井参数及钻井设备优选、优化钻井液体系及参数、下套管模拟预测和套管强度校核等多方面工作。研究结果表明:1)西南致密气水平井地层坍塌压力为1.55~1.60 g/cm^(3),当水平段钻井方位约为105°及15°时井壁稳定性较好,有益后期储层压裂改造;2)采用“双二维”轨迹设计,钻具组合扭矩降低15%以上,摩阻降低20%以上,定向钻井速度可提高45%以上;3)钻机配套DQ50DBS型顶部驱动装置,配置2~3台1600HP钻井泵和NC52非标钻杆,钻井排量控制在35 l/s以上,可保证井眼清洁度及携岩效率;4)使用白油基钻井液体系的同时加入“刚性粒子+树脂纤维+沥青胶粒”措施进行封堵,可保证井壁稳定;5)优选P110钢级、10.54 mm壁厚完井套管并采用旋转方式下入,在满足后期压裂施工的同时,降低套管下入摩阻12%以上。上述成果认识对加快四川盆地致密气勘探开发进程具有指导意义。

日本职普融通的核心理念、实践策略与经验借鉴

日本自20世纪80年代便致力于消除职业教育与普通教育彼此长期分离的壁垒,历经数十载探索,日本在本国教育体系基础上探索出职普融通的两种设计策略:横向融合策略和纵向贯通策略。横向融合策略主要依托课程这一载体,以能力重塑为锚点,通过职普课程的深入融合,确保普通教育系统的学生具备职业意识,职业教育系统的学生掌握普通教育的知识;纵向贯通策略则以教育要素作为媒介,为学生提供职普之间自由转换与衔接的制度保障。日本在消除职业教育与普通教育壁垒方面为学生的发展提供了更多机会,鉴于我国与日本地缘相邻,教育体系与文化传统具有相似性,其职普融通成功经验对我国具有借鉴意义。

泌阳凹陷页岩油水平井随钻定测录导一体化模式探索

水平井是油藏开发实现少井高产、一井多靶、降本提效的主要手段之一,但泌阳凹陷核三段页岩油藏地质条件复杂,不利于水平井钻井提速提效。文中以地震、测井、录井及分析化验资料为基础,通过对泌阳凹陷核三段页岩油藏地质特征剖析,梳理了页岩油水平井钻井施工难点,从一体化组织运行、一体化协调施工及一体化支撑保障等方面阐述了泌阳凹陷定测录导一体化模式的探索及应用。研究表明:泌阳凹陷核三段页岩油层存在局部微构造及断层发育、地层倾角变化快等特点,同时其地震资料品质差。这些导致钻井施工中靶点预测及井眼轨迹调整难度大,影响随钻资料评价的准确性。通过优选定向系统、钻具组合及高效钻头,应用正反演结合测井数据及校正后的元素录井资料综合评价,实现了井眼轨迹优化着陆及长水平段持续追踪。随钻定测录导一体化模式在YYY1HF井进行了应用,提高了机械钻速,目的层钻遇率达100%,助力了区域页岩油水平井优快钻井,对于水平井优快钻井技术的发展及页岩油高效开发具有重要的意义。

长三角一体化税收共享机制研究

“十四五”时期长三角地区的区域联动进入全面发展期,高质量地推进长三角区域一体化发展,要求在建立健全税收利益共享体制机制上实施更大力度的改革创新。长三角地区税收政策不统一以及税收分享机制缺失不利于一体化发展,减少不良税收竞争,保持税收与税源的一致性是构建税收共享机制、提升区域一体化水平的必然选择。在长三角一体化推进过程中,应依照纵横交错财税体制“双管齐下”的推进路径,通过协调实体税制要素、统一税收优惠政策、制定专门的协同发展政策确保施行共同税收政策,明确产业转移的税收归属,构建产业转移税收分享机制,根据消费地原则建立跨省市的增值税收入分享与清算制度,完善跨区域所得税税基分配制度。

智慧校园助推西藏干教事业高质量发展研究

随着数字技术的飞速发展,党校教育面临新的历史机遇。全区党校信息化建设已经取得一定成绩,但在发展理念、基础设施、管理手段、服务模式等方面仍有较大差距。为更好适应干部教育需求和提升教学管理效率,需要构筑“区市县纵向贯通、多部门横向协同、上下级业务指导、优质资源融合共享”的一体化干部教育新模式,促进数字技术和干部教育深度融合,走出一条符合自身实际、贴合地域特征的智慧校园建设新途径,在新起点上以智慧校园建设为契机推动西藏干部教育事业高质量发展。

计算思维在“土木工程”专业中的横向价值探讨与培养模式思考

该文探讨了计算思维在“土木工程”专业中的横向价值与融合培养模式。介绍了计算思维的一般特征,以及如何将之迁移并融入“土木工程”专业教育中。通过程序设计习得的计算思维,可赋能专业软件开发,赋能科学发现和技术创新,透视专业软件“黑箱”,促进软件学习和应用;或通过不插电的方式赋能专业学习,进行体系建构。通过计算思维的赋能,可更好地理解数字化时代的发展逻辑,适应和促进“土木工程”专业发展的范式变革。

地应力-岩石力学分析在东海低渗透致密砂岩气藏水平井压裂中的应用

明确现今地应力分布规律和岩石力学特征是提高水力压裂效果的重要基础。目前海上低渗透致密砂岩气藏地应力分布及岩石力学参数研究尚不充分,且海上测井存在声波时差曲线缺失及密度曲线易失真等问题。因此,采用东海西湖凹陷A区已压裂井Well-1和Well-A2的测井、地震及水力压裂技术资料,通过声波时差及密度测井曲线重构方法形成了井筒地应力及岩石力学参数分析技术,结合建立的地震驱动的构造应力场及三维脆性指数预测技术,形成了适合东海西湖凹陷低渗透致密砂岩气藏的地应力及岩石力学研究技术体系,并以东海西湖凹陷第1口多级压裂水平井Well-A4H作为应用对象,从钻井及水力压裂等方面对该技术体系进行了应用评价。研究表明,该技术体系可用于对东海西湖凹陷低渗透致密砂岩气藏多级压裂水平井进行钻前井位优化、钻后分析,以及指导压裂方案设计、优化及压后效果评价,保障东海西湖凹陷低渗透致密砂岩气藏多级压裂水平井顺利开展地质工程一体化施工。

Integrating Geology and Engineering for Viscous Oil Production Improvement—JX Oilfield, Bohai Bay, China

In this paper a case study is presented where refined 3D reservoir geology models, well pattern pilot test and Real-time GeoSteering tools have been integrated to optimize production performance of a viscous oil reserve. The viscous reserves were of high structural dip angle. In addition delta depositional system represented highly variable geomorphology, where stacked sandbodies and shale bedding are crossing each other frequently. In order to keep a higher production rate, using horizontal wells along with water injection was not enough;therefore, detailed reservoir characterization, well pattern pilot experiment and GeoSteering were used to optimize previous development strategy and keep horizontal trajectories safely landing into reservoir target zone. The stratigraphic sequence architecture that is derived from seismic interpretations captured the variation within these high dip structural backgrounds very effectively. The best combination of choices was “Injecting Water outside from OWC” and “Stair Shaped Horizontal Trajectories”. The borehole collision risks of these optimized strategies were then analyzed and controlled successfully by the GeoSteering tools during trajectory landing process. The reservoir development performance is improved tremendously as result of these renewed development strategies.