文、卫、马油田注水井最佳调剖适用条件初探

应用数理统计方法,研究了颗粒型调剖剂在文明寨、卫城、马寨三大复杂断块油田的调剖效果;以调剖后增油降水的增值系数大小作为效果评价依据,分析发现不同开发时期的注水井吸水厚度/层数占射孔厚度/层数的百分比、地质采出程度、累计注采比、启动压力为影响调剖效果的主要因素.并且确定了文、卫、马断块油田最佳的调剖适用条件,用以指导今后调剖选井、选层、效果预测.     

川西Q地区须家河组储层流体识别方法研究

川西Q地区须家河组储层作为川西坳陷中深层重要气层系之一为典型的致密碎屑岩储层,具有多层系、多类型、多组合的储集体系特点。该区致密碎屑岩钙质含量高,非均质性强,对地层电阻率影响大,储层物性具有低孔低渗高含水饱和度特点,测井解释孔隙度、渗透率参数误差大,气水纵向上间互分布、横向上邻井对比性差导致气水层识别不准确等问题。本文根据不同流体在测井响应上的差别,采用综合指数法（FTI）、电阻率与孔隙度交会图法、正态概率分布法（P1/2）进行流体识别,得到各方法的符合率分别为86.36%、68.19%和90.91%。综合各因素分析,综合指数法（FTI）和正态概率分布法（P1/2）能达到该区准确流体识别的要求,为川西地区须家河组储层的流体识别方法适用性提供了依据。     

Maneuvering Angle Rigid Formations With Global Convergence Guarantees

Angle rigid multi-agent formations can simultaneously undergo translational, rotational, and scaling maneuvering, therefore combining the maneuvering capabilities of both distance and bearing rigid formations. However, maneuvering angle rigid formations in 2D or 3D with global convergence guarantees is shown to be a challenging problem in the existing literature even when relative position measurements are available. Motivated by angle-induced linear equations in 2D triangles and 3D tetrahedra, this paper aims to solve this challenging problem in both 2D and 3D under a leader-follower framework. For the 2D case where the leaders have constant velocities, by using local relative position and velocity measurements, a formation maneuvering law is designed for the followers governed by double-integrator dynamics. When the leaders have time-varying velocities, a sliding mode formation maneuvering law is proposed by using the same measurements. For the 3D case, to establish an angle-induced linear equation for each tetrahedron, we assume that all the followers’ coordinate frames share a common Z direction. Then, a formation maneuvering law is proposed for the followers to globally maneuver Z-weakly angle rigid formations in 3D. The extension to Lagrangian agent dynamics and the construction of the desired rigid formations by using the minimum number of angle constraints are also discussed. Simulation examples are provided to validate the effectiveness of the proposed algorithms.      

Stabilisation of infinitesimally rigid formations of multi-robot networks

This article considers the design of a formation control for multivehicle systems that uses only local information. The control is derived from a potential function based on an undirected infinitesimally rigid graph that specifies the target formation. A potential function is obtained from the graph, from which a gradient control is derived. Under this controller the target formation becomes a manifold of equilibria for the multivehicle system. It is shown that infinitesimal rigidity is a sufficient condition for local asymptotical stability of the equilibrium manifold. A complete study of the stability of the regular polygon formation is presented and results for directed graphs are presented as well. Finally, the controller is validated experimentally.     

Improving Room-Temperature Li-Metal Battery Performance by In Situ Creation of Fast Li+ Transport Pathways in a Polymer-Ceramic Electrolyte

Composite polymer-ceramic electrolytes have shown considerable potential for high-energy-density Li-metal batteries as they combine the benefits of both polymers and ceramics. However, low ionic conductivity and poor contact with electrodes limit their practical usage. In this study, a highly conductive and stable composite electrolyte with a high ceramic loading is developed for high-energy-density Li-metal batteries. The electrolyte, produced through in situ polymerization and composed of a polymer called poly-1,3-dioxolane in a poly(vinylidene fluoride)/ceramic matrix, exhibits excellent room-temperature ionic conductivity of 1.2 mS cm⁻¹ and high stability with Li metal over 1500 h. When tested in a Li|electrolyte|LiFePO₄ battery, the electrolyte delivers excellent cycling performance and rate capability at room temperature, with a discharge capacity of 137 mAh g⁻¹ over 500 cycles at 1 C. Furthermore, the electrolyte not only exhibits a high Li⁺ transference number of 0.76 but also significantly lowers contact resistance (from 157.8 to 2.1 Ω) relative to electrodes. When used in a battery with a high-voltage LiNi_0.8Mn_0.1Co_0.1O₂ cathode, a discharge capacity of 140 mAh g⁻¹ is achieved. These results show the potential of composite polymer-ceramic electrolytes in room-temperature solid-state Li-metal batteries and provide a strategy for designing highly conductive polymer-in-ceramic electrolytes with electrode-compatible interfaces.     

Recent Advancements in Petroleum E & P Equipments in China

The role of equipments in oil and gas exploration and development had never been attached with so much importance as that in shale oil and gas boom in the U.S. With the help of massive hydraulic fracturing and horizontal drilling techniques, the U.S., the world＇s No. 1 oil importer even started to dream about energy self-sufficiency with its proudly high production of shale oil and gas from several major shale plays in the country. However, what behind this remarkable achievement are powerful multi-stage hydraulic fracturing machinery and smart tools for directional drilling.     

An adaptive learning and control architecture for mitigating sensor and actuator attacks in connected autonomous vehicle platoons

In this paper, we develop an adaptive control algorithm for addressing security for a class of networked vehicles that comprise a formation of human‐driven vehicles sharing kinematic data and an autonomous vehicle in the aft of the vehicle formation receiving data from the preceding vehicles through wireless vehicle‐to‐vehicle communication devices. Specifically, we develop an adaptive controller for mitigating time‐invariant state‐dependent adversarial sensor and actuator attacks while guaranteeing uniform ultimate boundedness of the closed‐loop networked system. Furthermore, an adaptive learning framework is presented for identifying the state space model parameters based on input‐output data. This learning technique utilizes previously stored data as well as current data to identify the system parameters using a relaxed persistence of excitation condition. The effectiveness of the proposed approach is demonstrated by an illustrative numerical example involving a platoon of connected vehicles.     

长庆低渗透油藏油层解堵技术综述

长庆油田三叠系延长组储层渗透率0.96×10-3μm2～6.43×10-3μm2,粘土矿物中酸敏、水敏性物质含量较高,地层水矿化度高达119g/L,部分油藏Ba2+含量1200～2400mg/L。因储层孔隙喉道细小,注水开发中因粘土颗粒运移,原油乳化液、结蜡、结垢所导致的油层堵塞十分严重。几十年来,油田不断深入研究并大规模实施了多种形式的油层酸处理、油层清防垢、油层压裂等解堵技术。在所统计的151口油井酸处理施工中,平均单井增油量由早期的142t上升到近期的391t,在所统计的48口油井清防垢施工中,低渗透层油井平均单井增油量由早期的321t上升到近期的338t,在所统计的92口油井压裂施工中,平均单井增油量由早期的112t上升到近期的161t。最近研制的油层综合解堵体系,又将单井增油量进一步提高到944t。相比之下,综合解堵、酸处理和清防垢的解堵效果优于油层压裂。将油层挤注防垢剂工艺与油层压裂工艺或油层酸处理工艺组合作业,可大幅度提高油层解堵效果。     

硬岩地层PDC钻头不良工况原因分析与改善措施

传统PDC钻头在硬岩地层钻进时,不良工况多,钻头寿命及钻进效率非常低。为了找出硬岩地层PDC钻头不良工况发生的原因,以四川元坝地区须家河组致密砂岩为例,建立单个PDC复合片切削岩层的模型,分别对模型中复合片及微小岩块进行受力分析,发现单个复合片受力随切入岩石弧长、岩石的内摩擦角及黏聚力的增加而增加。视所有复合片破岩的临界钻压及扭矩为整个钻头受到岩石的作用力,钻头受力超出转盘的输出钻压及扭矩会导致不良工况的发生。最后,从提高PDC钻头结构使其能适应硬岩钻进,及使用PDC钻头伴侣来改善PDC钻头的切削条件两方面提出了PDC钻头不良工况的改善措施。