Mobile Jammer-Aided Secure UAV Communications via Trajectory Design and Power Control

To further promote the achievable average secrecy rate for UAV-ground communications, a UAV-aided mobile jamming strategy was proposed in this paper. Specifically, an additional cooperative UAV is employed as a mobile jammer to transmit the jamming signal to help keep the source UAV closer to the ground destination, thus establishing more favorable legitimate link and enhancing the secrecy performance. We aimed to maximize the achievable secrecy rate by jointly optimizing the trajectories and transmit power of both source UAV and jammer UAV. To solve the considered non-convex optimization problem, we presented a block coordinate descent based iterative algorithm to address a sequence of approximated convex problems for the optimized parameter block by block to find a local optimal solution. Numerical results verify that the proposed algorithm can achieve significant secrecy rate gain compared to all the benchmark schemes.

Trajectory design and simulation in injection phase for hyper-velocity kinetic energy missile

A movement law of laser beam facula is designed for the injection trajectory of hyper-ve- locity kinetic energy missile to eliminate the influence of motor exhaust smoke on laser signal trans mission. Taking guidance loop of hyper velocity kinetic energy missile as plant, a closed loop control system with desired step response characteristics is constructed and the movement law of laser beam facula for the missile injection trajectory is designed based on the output signal of the closed loop controller under a step input. Six degree of freedom trajectory simulations show that by the guidance of the laser beam facula moving with designed law, the missile can finish transition from the initial trajectory to a stable tracking trajectory without overshoot within the required time.

Method of suspender line trajectory design

Based on the mechanical model of an elastic rod,a new trajectory design method was established.The advantages of the suspender line trajectory in reducing drag and torsion were compared,and the main controlling factors of drag and torque and their influence rules were analyzed.Research shows that the suspender line trajectory reduces drag and torque more effectively than the conventional trajectory in a certain parameter interval and has more controllable parameters than that of the catenary trajectory.The main factors affecting the drag reduction and torque reduction of the suspender line trajectory include the friction coefficient,vertical distance,horizontal distance,and deviation angle at the initial point in the suspended section.The larger the friction coefficient and deviation angle,the less the drag reduction and torque reduction.The suspender line trajectory has the best drag reduction effect when the horizontal and vertical distances are more than 3000 m and the ratio is close to 1.5.The drag in sliding drilling can be reduced up to 60%,and the torque in rotary drilling can be reduced by a maximum of 40%.Therefore,the trajectory design of the suspender line has unique application prospects in deep extended-reach wells.

Trajectory and Correction Maneuver During the Transfer from Earth to Halo Orbit

This article addresses the design of the trajectory transferring from Earth to Halo orbit, and proposes a timing closed-loop strategy of correction maneuver during the transfer in the frame of circular restricted three body problem （CR3BP）. The relation between the Floquet multipliers and the magnitudes of Halo orbit is established, so that the suitable magnitude for the aerospace mission is chosen in terms of the stability of Halo orbit. The stable manifold is investigated from the Poincar6 mapping defined which is different from the previous researches, and six types of single-impulse transfer trajectories are attained from the geometry of the invariant manifolds. Based on one of the trajectories of indirect transfer which are ignored in the most of literatures, the stochastic control theory for imperfect information of the discrete linear stochastic system is applied to design the trajectory correction maneuver. The statistical dispersion analysis is performed by Monte-Carlo simulation,

Joint Trajectory and Power Optimization for Securing UAV Communications Against Active Eavesdropping

Due to both of jamming and eavesdropping,active eavesdroppers can induce more serious security threats to unmanned aerial vehicle(UAV)-enabled communications.This paper considers a secure UAV communication system including both the downlink(DL)and uplink(UL)transmissions,where the confidential information is transmitted between a UAV and a ground node in the presence of an active eavesdropper.We aim to maximize the average secrecy rates of the DL and UL communications,respectively,by jointly optimizing the UAV trajectory and the UAV/ground node’s transmit power control over a given flight period.Due to the non-convexity of the formulated problems,it is difficult to obtain globally optimal solutions.However,we propose efficient iterative algorithms to obtain high-quality suboptimal solutions by applying the block coordinate descent and successive convex optimization methods.Simulation results show that the joint optimization algorithms can effectively improve the secrecy rate performance for both the DL and UL communications,as compared with other baseline schemes.The proposed schemes can be considered as special cases of UAV-assisted non-orthogonal multiple access(NOMA)networks.

Key technologies and practice for gas field storage facility construction of complex geological conditions in China

In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storage construction technologies were established, mainly including UGS site selection and evaluation, key index design, well drilling and completion, surface engineering and operational risk warning and assessment, etc. The effect of field application was discussed and summarized. Firstly, trap dynamic sealing capacity evaluation technology for conversion of UGS from the fault depleted or partially depleted gas reservoirs. A key index design method mainly based on the effective gas storage capacity design for water flooded heterogeneous gas reservoirs was proposed. To effectively guide the engineering construction of UGS, the safe well drilling, high quality cementing and high pressure and large flow surface injection and production engineering optimization suitable for long-term alternate loading condition and ultra-deep and ultra-low temperature formation were developed. The core surface equipment like high pressure gas injection compressor can be manufactured by our own. Last, the full-system operational risk warning and assessment technology for UGS was set up. The above 5 key technologies have been utilized in site selection, development scheme design, engineering construction and annual operations of 6 UGS groups, e.g. the Hutubi UGS in Xinjiang. To date, designed main indexes are highly consistent with actural performance, the 6 UGS groups have the load capacity of over 7.5 billion cubic meters of working gas volume and all the storage facilities have been running efficiently and safely.

Technical Challenges and Countermeasures for Deep Shale Gas Drilling by SINOPEC

Deep shale gas reservoirs being developed by SINOPEC are characterized by significant buried depths, high rock strengths, high temperatures and pressures, multiple layers, low ROPs, prolonged drilling time and prohibitoryhigh costs. All of these factors may negatively affect the economic and effective development of shale gas. Under such circumstances, existing drilling techniques for deep shale gas around the world have been reviewed to highlight technical challenges in deep shale gas drilling in China. With consideration to the previous drilling operations of SINOPEC for deep shale gas, technical solutions for deep shale gas drilling have been proposed with regard to the optimization of casing programs, enhanced drilling, trajectory control, high-density oil-based drilling fluid, cementation for deep shale gas development and other aspects. Some of these research findings have been deployed with great successes in Pingqiao, Jiangdong Block in the 2nd Phase of Fuling Project, Dingshan Block and other blocks with deep shale gas development. Among them, Well JY-74-2HF has had a drilling time of only 54.25d, whereas Well JY-187-2HF has a TVD up to 4024.14m. Relevant research results may provide valuable guidance and references for the optimization of drilling programs andthe enhancement ofdrilling ef^ciency for deep shale gas development.

基于D-H参数的M-DOF机器人建模、规划与控制系统设计

对多自由度工业机器人设计中的运动学建模、轨迹规划与控制问题进行了系统性的工程研究。以6自由度协作机器人UR操作臂为例,建立了D-H参数坐标系,推导了其正逆运动学模型,通过Matlab数值解算与仿真,验证了模型的正确性。采用五次多项式插值算法实现了关节空间的轨迹规划,设计直线插补算法保证了笛卡尔空间轨迹规划的顺滑性。最后采用Adams和Matlab联合仿真技术,建立了仿真环境下的机器人模型和控制系统,并进行了验证。仿真实验证明了所提面向多自由度机器人系统性工程设计方法的有效性,其采用的联合仿真技术能够缩短机器人开发周期,具有较好的应用价值。

Mechanical Design and Dynamic Compliance Control of Lightweight Manipulator

In the existing modular joint design and control methods of collaborative robots, the inertia of the manipulator link is large,the dynamic trajectory planning ability is weak, the collision stop safety strategy is dependent, and the adaptability and safety to the changing environment are limited. This paper develops a six-degree-of-freedom lightweight collaborative manipulator with real-time dynamic trajectory planning and active compliance control. Firstly, a novel motor installation, joint transmission, and link design method is put forward to reduce the inertia of the links and improve intrinsic safety. At the same time, to enhance the dynamic operation capability and quick response of the manipulator, a smooth planning of position and orientation under initial/end pose and velocity constraints is proposed. The adaptability to the environment is improved by the active compliance control. Finally, experiments are carried out to verify the effectiveness of the proposed design, planning, and control methods.

深层、超深层定向钻井中若干基础研究进展与展望

深层、超深层定向钻井具有“垂深大与水平延伸远”的双重特征,受到复杂地层、高温高压、超长裸眼等多重因素约束,其安全高效作业面临着更大的全方位技术挑战。为此,着眼于深层、超深层定向钻井的提速提效问题,系统总结了定向钻井的发展概况与技术特点,选取了深层、超深层定向钻井中力学方面的几个重要基础问题,分析了国内外专家学者的相关研究进展和最新研究成果,最后展望了深层、超深层定向钻井基础理论研究发展趋势并提出相关建议。研究结果表明:①大小偏差融合控制算法兼顾了井眼轨迹的控制精度、光滑度等多目标约束,适应于深层、超深层条件下井眼轨迹实时控制要求;②合理优化振动减阻工具个数、安放位置及其激励力幅值,可显著降低井下管柱摩阻,并有效提高机械钻速;③基于误差补偿机制的机械钻速融合预测模型既保留了机理模型的可解释性,又具有较高的预测精度;④套管复合磨损预测模型突破了经典“单月牙”模式的局限性,实现了复合模式下套管磨损形状与深度的同步预测。结论认为,深层、超深层定向井和水平井是未来油气井工程的重要发展方向之一,需要加强多因素耦合机理、钻井延伸极限、机理与数据融合驱动等方面的基础研究,以推动复杂油气井工程基础理论的创新与发展,为深层、超深层钻井工程技术进步提供必要的基础理论支撑。

塔中奥陶系“串珠状”反射对应的缝洞体要素浅析

“串珠状”反射是塔中地区缝洞型储层典型的主要反射特征,实际钻遇储层显示的放空漏失或溢流位置与串珠状反射相位对应关系复杂,钻井轨迹设计多解性严重。本文总结分析了塔中地区钻遇缝洞体及其组合对应的地震串珠状反射特征类型,设计了纵横向尺度、充填速度、形态及空间组合方式等要素不同的缝洞体模型,基于波动方程正演模拟和地震响应特征分析,明确了钻井放空漏失位置与串珠状反射特征类型及反射相位的对应关系,指出其“串珠状”反射的强波谷和强波峰之间的零相位附近最有可能是单个溶洞发育中心位置,或者是多个纵横向缝洞体组合中心并偏向速度最低的缝洞体位置,这些认识可为钻井轨迹设计提供指导。

复兴地区页岩油优快钻井技术

川东复兴地区侏罗系湖相、河流相砂泥岩储层发育,油气类型为凝析油、页岩气同产,该区陆相页岩油气水平井具有大井眼、井段长、造斜困难、地层压力安全窗口窄、水平段可钻性差、轨迹控制难、水平段易垮塌等难点。通过井身结构、钻井方式、提速工具、轨迹控制、钻井液类型、完井方式等进行技术集成与优化。结果表明:通过二开井身结构、强化参数钻井、PDC钻头+预弯曲钻具组合、强封堵油基钻井液、旋转导向钻井、不承压防漏固井等关键技术,克服井壁失稳、水平段可钻性差、漏溢转换频繁等复杂情况,提高了钻井效率,节约了钻井周期,形成了一套适合复兴地区页岩区块的优快钻井技术,为该区后续水平井勘探开发提供了借鉴。

雪峰弧构造带钻孔轨迹控制关键技术研究

随着近年来矿产资源勘查要求的提高,岩心钻孔的深度及地层复杂性也不断加大,为能精准的钻遇靶区矿体以实现地质目的,对钻孔轨迹控制的要求越来越高。雪峰弧构造带部分工作区地层倾角大、软硬交替频繁、地层破碎,实际施工中地层造斜情况严重,随着孔深增加导致终孔轨迹与靶区矿体偏差较大,影响矿产资源勘查的精度和质量。通过对该工作区地层造斜情况的深入分析,在ZK1001钻孔绳索取心钻进施工中采用初级定向孔技术和满眼钻具工艺,大幅度提高了钻孔孔身质量,较好地实现钻孔轨迹控制。并通过试验不同的岩心钻具组合,提出了满眼钻具组合的优化意见和建议,为工作区岩心钻孔轨迹控制提供技术参考。

旋冲钻进系统控制策略研究现状与发展趋势

深部硬岩地层钻进效率低、成本高等问题是深井、超深井钻井过程中长期面临的难点问题。旋冲钻进技术由于破岩效率高、能降低黏滑振动以及钻压传递效率高等优点,在深地资源勘探开采、应急钻孔救援、钻井工程施工等领域逐渐得到应用,呈现出广阔的应用前景。然而,旋冲钻进系统具有强耦合、高度非线性、参数时变性、负载工况多变、多源动力协同等特性,常规控制方法难以取得理想的控制效果。为提升深井、超深井高端钻进装备的可靠性和智能化水平,研究钻进系统的控制策略具有重要的理论研究价值和工程实际意义。对旋冲钻进系统的组成结构及功能进行介绍;从钻速、钻压、钻进轨迹控制等角度综述近年来国内外研究机构和学者的研究成果;最后,对旋冲钻进系统控制策略未来的发展方向进行分析与展望。

超深断控碳酸盐岩缝洞储集体地震预测与井轨迹设计——以顺北油田4号断裂带中北部为例

顺北断控缝洞型油气藏主要受走滑断裂控制,断裂带的活动强度控制了储层发育程度,储集空间主要为断裂破碎形成洞穴、孔洞、裂缝,储层的空间展布非均质性强,缝洞体的空间定位和量化表征是制约井位井型的选择和高效动用的关键。综合测井、地震、地质等资料对顺北4号带断裂北段碳酸盐岩储集体进行立体半定量化表征研究。结果表明,顺北碳酸盐岩储集体沿断裂带呈不规则分布,储集体纵向延伸大(高度50~800 m),沿断裂面非均质性强,走滑断裂带拉分段、平移段及挤压段不同分段的储集体规模、组成差异较明显。拉张段储集体体积空间最大,孔洞占比最高(35%)、裂缝(65%);平移段体积空间较小,洞穴占比较低(44%)、裂缝(56%)。并根据储层预测及储集体空间展布进行井轨迹分类设计,拉分段平面宽度较大、断裂面与储集体夹角在0~30°,采用垂向大斜度角顺穿断裂带,最大限度地钻遇储集体;平移段断面窄,储集规模小,断面与储集体夹角在30~50°,采用垂向中斜坡角斜穿断裂带,钻井揭示储集体长度相比横穿可提高1.8倍,实现高产稳产。上述技术方法取得了良好的钻探效果。

中国深水钻井关键技术与装备现状及展望

随着陆上和浅水区域钻井技术日渐成熟,石油行业将研究重心转向深水区域,近10年全球重大油气发现70%来自海洋深水区域。深水钻井具有高风险、高技术、高投入的特点,其关键技术和装备是世界油气强国竞相角逐的技术制高点。随着在超深水、深层、远海“两深一远”区域勘探开发的持续推进,深水钻井需要面对深水、海况恶劣、浅层土质不稳定以及深层地质条件复杂等挑战。通过多方联合技术攻关和工程实践,中国已成功构建了具有国际竞争力的深水钻井技术与装备体系,包括深水钻井工程设计关键技术、深水钻井安全控制及高效作业技术、深水钻井关键装备。对相关成果进行了系统介绍,提出了融合人工智能和大数据技术创新钻井技术、加快工程地质一体融合、促进工程装备和软件研发、加强深远海钻井作业应急能力等建议,进一步推动深水油气勘探向深远海发展,实现深水钻井作业的安全高效和自主可控。

钻进参数自适应调控数字孪生系统架构

智能化钻井背景下,传统的司钻调控钻进参数的钻井模式已经无法满足钻进参数自适应调控的需求,而数字孪生技术具有实时同步、真实映射和高保真度的特性,因而构建钻进参数自适应调控数字孪生系统,与智能钻井设备、智能终端相结合,可实现钻机自主送钻和自主定向。为此,在介绍钻进参数自适应调控技术架构及其工艺流程的基础上,设计了基于数字孪生技术的钻进参数自适应调控系统架构,包括物理钻井平台、虚拟钻井平台、钻井孪生数据、服务应用层和通信连接层5个要素;并从数字孪生系统的构建、演化及更新等3个方面阐述了钻进参数自适应调控数字孪生系统的运行机制,分析了关键理论技术需求。研究表明,钻进参数自适应调控数字孪生系统能够实现钻进参数自适应调控技术和智能钻机、智能设备的深度融合,推动数字孪生技术在钻井工程中的应用,对于实现智能化钻井有重要作用。

木材深孔钻床的开发与机电设计

为了解决传统数控系统和机床结构无法直接用于木材深孔加工的问题,研究深孔加工的原理,分析重难点问题,从特殊的工装夹具系统和机床主体结构设计、机床的柔性辅助装夹系统设计、整个机床的电气控制系统和PLC内部的进给插补逻辑算法等进行研究和阐述。使用木材深孔钻床预加工16 mm的孔,测得精度为15.99 mm,完全符合加工要求。木材深孔钻床的设计与研究解决了木材在自动化深孔加工的问题,为该行业提供了解决方案。

反扭矩定向系统研制及试验

现有旋转滑动钻井工具无法同时实现隔离上部钻具旋转和钻头破岩产生的反扭矩,且工具面角不可控。基于此,设计了分时动态隔离上部钻具旋转和承载下部钻具扭矩的反扭矩定向钻井系统;研制了反扭矩定向系统样机;利用该样机开展了实钻测试,实钻总进尺57 m,工具面角控制精度小于±5°、造斜率达23.0°/100 m,平均机械钻速约为6.5 m/h(泥岩)。研究表明:研制的反扭矩定向系统可同时隔离上部钻具旋转和下部钻具扭矩;能精确控制工具面角,实现了下部钻具自动精确导向钻井的功能,验证了反扭矩定向系统结构设计理论的正确性。相关成果有望解决滑动钻进钻柱“托压”和井眼轨迹控制难题,提高弯螺杆滑动导向钻井时效。

人工智能技术在钻井工程的应用与发展

人工智能技术在石油工程领域的研究应用已有几十年历史,近两年来,随着人工智能技术的进一步提升,成为新一轮产业变革和科技革命的新引擎,核心驱动力趋势愈来愈明显。人工智能技术将会是油气勘探开发降本增效的有效手段,也是实现关键技术升级换代,提高竞争力的有效途径。近年来,国内外各大石油技服公司都已将人工智能应用于钻井工程领域的钻井设计、钻井参数优化、井眼轨迹控制、风险预警、钻井程序决策等领域,实现了现场部分应用,显示了较好的应用前景。人工智能技术应用将会影响各企业在新一轮竞争中是否能争取到优势地位。