靖南区块41/2小套管固井工艺技术

靖南区块开发层位为上古的石盒子组和下古的马家沟组,天然气储层埋深一般为3300000m。应用小井眼井能够有效节约勘探开发成本30%以上[1],在目前低成本开发的形势下,使用41/2套管小井眼开发在该区块得到大力推广和应用。针对小井眼环空间隙小、封固段长、静液柱压差大、流动磨阻大等因素严重影响顶替效率及固井质量等固井技术难题,着手从选择合适的固井工艺、水泥浆的性能、提高顶替效率及制定现场施工方法等各个方面进行研究,总结出了一套靖南区块41/2小套管固井工艺技术,为该区块顺利开发提供了技术保障。目前已在靖南区块使用该工艺完成现场施工56口井,固井质量一次合格率100%。     

5(1/2)″套管内下4(1/2)″套技术的创新应用

本文针对日益增加的复杂井况进行分析,对各种类型的套损井,通过创新应用51/2″套管内下41/2″套工艺技术,有针对性的进行治理,加快了复杂井况井的治理速度,提高了复杂井况修复成功率,达到了完善注采井网、恢复长停井地质储量、降本增效的目的。     

小直径套管延迟固井工艺在长井段套损井中的应用

针对文中油田油水井套管损坏严重,常规工艺技术难以解决套管长距离多处损坏的问题,开展了在φ139．7mm套管内下φ101．6mm套管延迟固井技术的研究与应用。该工艺采用φ101.6mm无接箍套管及套管扶正器,并应用延迟固井工艺,确保了φ139．7mm和φ101．6mm套管间的固井质量。该工艺作为钻开发调整井的替代技术,具有良好的经济效益。     

套管固井无限级滑套多层压裂预处理技术

随着勘探开发的进一步深入,水平井已成为目前提高油田勘探开发综合效益的重要途径,套管固井滑套多层压裂工艺是目前水平井压裂主要的技术手段之一。本文通过对3口应用套管固井无限级滑套多层压裂井的对比分析,总结出套管固井无限级滑套多层压裂预处理技术的技术原理、预处理流程和处理决策,为以后套管固井无限级滑套多层压裂工艺的有效推广提供了技术保障。     

小直径膨胀管固井技术在老井改造中的应用

目前国内某些油田老区套损问题比较普遍,严重影响油田的稳产,为使套损井重新开发利用,开展了小直径膨胀管固井技术的研究与应用,采用0107．95／116．72mm膨胀管对老井进行侧钻,并采用精细的固井工艺以确保固井质量,使侧钻后的老井产量大幅度上升。实践证明该工艺具有良好的使用效果和经济效益。     

非常规小尾管固井技术在南海东部的应用

南海东部地区陆丰油田A井是一口水平井,该井下?177.8 mm尾管至2 840 m时发生卡钻,无法下至设计井深,就地固井,造成?215.9 mm井眼2 840～3 330 m着陆井段的油水层未能进行水泥封隔,油水互窜导致井眼报废风险极大。为救活该井,决定钻完?152.4 mm水平井段后,采用非常规?127 mm尾管管柱结构的固井方式,对着陆井段油水层进行有效封固。在海上油田创新性的采用特制盲堵尾管、打孔尾管、水泥伞等组成的非常规尾管柱结构进行固井施工,总结出了一套非常规尾管固井工艺技术,对于其他类似复杂油气井固井具有借鉴意义。     

正、反注水泥固井工艺在塔中油田的应用

塔中油田奥陶系油气储量丰富。为加快勘探开发进度、缩短钻井周期、降低生产成本,根据地层稳定性,简化井身结构,由开发初期的四开结构,简化为三开井身结构;由两层技套双级固井,改为单层技套正、反注水泥固井工艺。解决了超深井单级固井一次注水泥返至地面,封固段长,注水泥量大,施工液柱压力高,地层易漏,油气层易受污染;长封固段固井,上下温差大,浆体结构与性能调节困难等一系列问题。通过简化井身结构、改变固井施工工艺、优化水泥浆体系,实现了低成本、高效率的油气开发要求。固井质量有了显著提高,满足了油气开发作业要求。该工艺在塔中油田完成固井作业10井次,固井合格率100%。     

储气库苏203-6-9H井?244.5mm套管固井技术

本文介绍了位于鄂尔多斯盆地伊陕斜坡中部的苏203井区储气库的第一口完钻的试采试验井苏203-6-9H井的基本情况,分析了其盖层井段?244.5mm套管固井技术难点。针对该井的固井难点,提出了优化固井工艺、选用旋流套管扶正器、优选驱油去污前置液及三凝DRE膨胀韧性水泥浆体系水泥浆体系、使用前导低密度低黏切抗钙污染钻井液等技术对策,保证了?244.5mm套管的固井质量,盖层井段固井质量优质,优质率82%。对今后长庆地区储气库井的盖层固井施工具有一定的指导意义。     

4″套管延迟固井技术的现场试验与应用

针对中原油田油水井套管损坏严重 ,常规大修修套工艺难以修复套管长距离多处损坏的油水井 ,开展了中深井全井下 4″套管延迟固井技术的研究与应用。该工艺应用了 4″无接箍套管、套管扶正器 ,较好地解决了 4″套管的居中问题 ,确保了 5 1 / 2 ″～ 4″套管间的固井质量。该工艺作为替代开发调整井和大修技术的完善 ,具有重要的意义和良好的经济效益。     

浅谈小套管固井技术在张天渠套损治理中的应用

张天渠油田自1996年投入开发,至今已有18年历史,随着油田开发进入中后期,套损日益严重,已经严重影响了油田的可持续发展。为挖掘老油田潜力,该油田在套损治理工艺方面不断探索,最终选择小套管固井技术对油水井进行恢复。目前小套管固井工艺在张天渠油田已经成熟,使老油田开发水平连年攀升。     

Thermophysical performances of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)2Ce2O7 high-entropy ceramics for thermal barrier coating applications

In this study, a novel high-entropy oxide of (La_1/6Nd_1/6Yb_1/6Y_1/6Sm_1/6Lu_1/6)₂Ce₂O₇was prepared using a sol–gel and high-temperature sintering technology. Additionally, its lattice structure, micro-morphology, elemental composition, and thermophysical and mechanical properties were evaluated. The results revealed that the obtained oxide powder has a typical fluorite-type lattice with particle sizes in the range of～30–100 nm. The bulk sample has a dense microstructure and uniform elemental distribution. Owing to its low lattice order, the thermal expansion coefficient of (La_1/6Nd_1/6Yb_1/6Y_1/6Sm_1/6Lu_1/6)₂Ce₂O₇ is greater than that of Sm₂Ce₂O₇, which also exhibits excellent lattice stability up to 1200 °C. Further, owing to phonon scattering due to lattice distortion, oxygen vacancy, and cation substitution, the thermal conductivity of (La_1/6Nd_1/6Yb_1/6Y_1/6Sm_1/6Lu_1/6)₂Ce₂O₇ is lower than that of Sm₂Ce₂O₇, while its mechanical performance is inferior to that of 7YSZ.     

Crystallization and phase evolution in novel (Gd1/6Tb1/6Dy1/6Tm1/6Yb1/6Lu1/6)2Si2O7 environmental barrier coating

Design of multiple rare-earth (RE) principal elements is a practical strategy to optimize key property of RE disilicate environmental barrier coating (EBC). However, multi-RE component in the feedstocks may also introduce critical fabrication problems due to the different evaporating and crystallizing behaviors of the EBC containing various RE composition. We herein report the preparation of a novel multi-RE disilicate (Gd_1/6Tb_1/6Dy_1/6Tm_1/6Yb_1/6Lu_1/6)₂Si₂O₇ EBC by atmospheric plasma spraying (APS). The crystallization behavior of the as-deposited coating annealed at 1100°C–1300°C with different durations (5 and 20 h) in air and argon atmospheres were investigated through comprehensive characterization techniques. RE disilicate, RE mono-silicate, and RE apatite were detected in the as-sprayed coatings, and mono-silicate and apatite transform to RE₂Si₂O₇ with the increment of temperature and extension of annealing duration. Furthermore, the contribution of multiple RE to the formation of apatite phase is discussed. The results provide a fundamental understanding and may guide the controllable preparation of multi-RE disilicate EBC via APS method.     

High-rate, high capacity ZrO2 coated Li[Li1/6Mn1/2Co1/6Ni1/6]O2 for lithium secondary batteries

Recently, there have been many reports on efforts to improve the rate capability and discharge capacity of lithium secondary batteries in order to facilitate their use for hybrid electric vehicles and electric power tools. In the present work, we present a ZrO₂-coated Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂. The bare Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ shows a high initial discharge capacity of 224 mAh g⁻¹ at a 0.2 C rate. Owing to the stability of ZrO₂, it was possible to enhance the rate capability and cyclability. After 1 wt% ZrO₂ coating, the ZrO₂-coated Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ showed a high discharge capacity of 115 mAh g⁻¹ after 50 cycles under a 6 C rate, whereas the bare Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ showed a discharge capacity of only 40 mAh g⁻¹ and very poor cyclability under the same conditions. Based on results of XRD and EIS measurements, it was found that the ZrO₂ suppressed impedance growth at the interface between the electrodes and electrolyte and prevented collapse of the layered hexagonal structure.     

On the LiCo2/3Ni1/6Mn1/6O2 positive electrode material

LiCo_2/3Ni_1/6Mn_1/6O₂ layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal α-NaFeO₂ type structure. The Li||LiCo_2/3Ni_1/6Mn_1/6O₂ cell showed a discharge capacity of 199 mAh g⁻¹ when cycled in the 2.7–4.6 V potential range while the best cycling performances were recorded when the upper cut off is fixed at 4.5 V. Structural changes in Li_xCo_2/3Ni_1/6Mn_1/6O₂ with lithium electrochemical de-intercalation were studied using X-ray diffraction. This study clearly shows the existence of a solid solution domain in the 0.1 < x < 1.0 composition range while for x = 0.1, a new phase appears explaining the decrease of the electrochemical performance when the cell is cycled at high upper cut off voltage.     

锂离子电池正极材料LiNi1/2Co1/6Mn1/3O2的制备与性能

采用Co2+浓度递增的金属离子混合溶液分次共沉淀方法制备Ni1/2Co1/6Mn1/3(OH)2,以其为前驱体,通过高温固相反应得到具有Co含量梯度的层状LiNi1/2Co1/6Mn1/3O2,探讨了焙烧温度及Co含量梯度对材料的结构和电化学性能的影响. 通过X射线衍射、扫描电镜、热重分析及恒电流充放电测试对合成的样品进行了表征. 结果表明,700℃合成产物即具有类LiNiO2的六方层状结构,800和850℃合成产物阳离子排列有序度高,层状结构显著. 材料结晶度好,粒度均匀,粒径在亚微米级. 合成温度800℃的梯度材料具有最佳的电化学性能, 2.5~4.2 V, 0.1 C倍率充放电50次后,梯度材料的容量仍保持在171.2 mA×h/g. 相同的焙烧温度,梯度材料比均匀材料的电化学性能更加优异.     

Preparation and optimization of ZrO2 modified P2-type Na2/3Ni1/6Co1/6Mn2/3O2 with enhanced electrochemical performance as cathode for sodium ion batteries

Surface stabilization is necessary for cathode materials to gain a long-term cycling stability because of unfavorable side reactions and exfoliation caused by corrosive environment. To improve the cyclic stability of P2-type ternary cathode Na_2/3Ni_1/6Co_1/6Mn_2/3O₂ for sodium ion batteries, we prepare a ZrO₂-coated Na_2/3Ni_1/6Co_1/6Mn_2/3O₂ through a simple wet chemical method. The coating layer is distributed homogeneously on the surface, and the fraction of ZrO₂ (1 wt-%, 2 wt-%, 3 wt-%, 4 wt-%, 5 wt-%) helps control the thickness of the coating layer. It turns out that all the materials exhibit pure P2 structure without any impurities. The material with a 2 wt-% ZrO₂ coating exhibits the best electrochemical performance in rate capability and long-term cyclic stability. It delivers a superior initial discharge capacity of 140 mA h·g⁻¹ between 2 and 4.5 V at 20 mA g⁻¹. Even cycles at high current density (100 mA g⁻¹), it shows 106 mA h·g⁻¹ reversible discharge capacity with 88% capacity retention after 300 cycles. The improvement in electrochemical performance is attributed to the segregation of cathode materials from the corrosive electrolyte by the nano-sized ZrO₂ layer. The EIS results confirm that a thin ZrO₂ coating layer can effectively protect the electrode from dissolution and stabilize the SEI film. This study can be used to develop the electrochemical performance of cathode materials for sodium ion batteries by surface modification via ZrO₂.     

Structure and microwave dielectric properties of Li2Mg3Ti1-x(Al1/2Nb1/2)xO6 ceramics

Aiming to establish relationships between intrinsic structure factors and dielectric characteristics, a series of Li₂Mg₃Ti_1-x(Al_1/2Nb_1/2)_xO₆ (x = 0.0, 0.04, 0.08, 0.12, 0.16, 0.20) ceramics were synthesized to investigate the influences of (Al_1/2Nb_1/2)⁴⁺ substitution on the dielectric properties of Li₂Mg₃TiO₆ ceramics. The XRD and SEM results revealed that the pure rock salt phase (space group: Fm-3m) with a dense microstructure could be obtained with increasing the (Al_1/2Nb_1/2)⁴⁺ concentration, which is accompanied by an increase in the grain size from 11.69 to 22.81 μm. Meanwhile, some intrinsic factors, such as the average ionic polarizability, bond energy, packing fraction and lattice energy were calculated according to the complex chemical bond theory and refinement results. The unusual change in the dielectric constant (ε_r) was explained by the combined effects of the average ionic polarizability and relative density. The variation in the quality factor (Q × f) was ascribed to the packing fraction and lattice energy. The temperature coefficient of the resonant frequency (|τ_f|) reduced gradually with the increase in the octahedral bond energy, which enhanced the system thermal stability. Particularly, the Li₂Mg₃Ti_0.92(Al_1/2Nb_1/2)_0.08O₆ sample exhibited outstanding dielectric characteristics:ε_r = 15.256, Q × f = 174,300 GHz and τ_f = −19.97 ppm/°C.     

The PagKNAT2/6b-PagBOP1/2a Regulatory Module Controls Leaf Morphogenesis in Populus

Leaf morphogenesis requires precise regulation of gene expression to achieve organ separation and flat-leaf form. The poplar KNOTTED-like homeobox gene PagKNAT2/6b could change plant architecture, especially leaf shape, in response to drought stress. However, its regulatory mechanism in leaf development remains unclear. In this work, gene expression analyses of PagKNAT2/6b suggested that PagKNAT2/6b was highly expressed during leaf development. Moreover, the leaf shape changes along the adaxial-abaxial, medial-lateral, and proximal-distal axes caused by the mis-expression of PagKNAT2/6b demonstrated that its overexpression (PagKNAT2/6b OE) and SRDX dominant repression (PagKNAT2/6b SRDX) poplars had an impact on the leaf axial development. The crinkle leaf of PagKNAT2/6b OE was consistent with the differential expression gene PagBOP1/2a (BLADE-ON-PETIOLE), which was the critical gene for regulating leaf development. Further study showed that PagBOP1/2a was directly activated by PagKNAT2/6b through a novel cis-acting element “CTCTT”. Together, the PagKNAT2/6b-PagBOP1/2a module regulates poplar leaf morphology by affecting axial development, which provides insights aimed at leaf shape modification for further improving the drought tolerance of woody plants.     

Crystal structure analysis and high-temperature phase transitions of complex rare-earth perovskite,La2(Al1/2MgTa1/2)O6

In situ high-temperature powder X-ray diffraction analysis (HT-XRD) was carried out in the temperature range from 25°C-1430°C to investigate the crystal structure of double perovskites, La₂(Al_1/2MgTa_1/2)O₆ (LAMT) and its phase transitions. This complex perovskite is a promising candidate for application in thermal barrier coating systems. Rietveld analysis shows a rock-salt type ordering of the B-site cations in the monoclinic space group symmetry, P2₁/n at room temperature. Upon heating, a structural phase transition occurs at ~855°C, and the crystal structure becomes rhombohedral with the space group symmetry . On further heating, LAMT transforms to the ideal cubic phase at ~1390°C with the space group symmetry . Both of the structural phase transitions are completely reversible, and were confirmed through complementary differential scanning calorimetry and thermogravimetry measurements. With increasing temperature, the degree of the octahedral tilting decreases and the variance of the different B–O bond lengths is reduced, until in the cubic phase, no tilting is present, and almost equal B–O bond lengths are obtained.     

Enhanced energy storage properties of Bi(Ni2/3Nb1/6Ta1/6)O3–NaNbO3 solid solution lead-free ceramics

Sodium niobate energy storage ceramics with good environmental performance are widely used in electric power conversion and pulse power system, large energy storage density and high efficiency, huge power density and charge and discharge faster. In this work, (1-x)NaNbO₃-xBi(Ni_2/3Nb_1/6Ta_1/6)O₃ [(1-x)NN-xBNNT] (0.12 ≤ x ≤ 0.18) ceramics system were prepared by solid state reaction method. By introducing Bi(Ni_2/3Nb_1/6Ta_1/6)O₃ (BNNT), a relaxation strategy was constructed, which significantly improved the energy storage properties of NaNbO₃ (NN) based ceramics. Finally, comparatively high recoverable energy density (W_rec) of 3.43 J/cm³ and large energy storage efficiency (η) of 83.3% were obtained in 0.86NN-0.14BNNT ceramics. Besides discharge energy density (W_d) of 0.69 J/cm³, ultra fast charge-discharge rate (t_0.9) of 55 ns, the power density (P_D) of 70.66 MW/cm³ and the current density (C_D) of 883.23 A/cm² were also observed in ceramic.