Electrical conductivity measurement of serpentine at high temperature and pressure

The electrical conductivity of serpentine is measured at 1.0-3. 0 GPa and 300-870℃. The effect of frequencies on electrical conductivity measurement is analyzed. The conduction mechanisms of serpentine before and after dehydration are discussed. Our experimental results show that the electrical conductivity of serpentine increases significantly after dehydration of serpentine, through which highly conductive layers (HCL) can be formed in the Earth's interior.     

Experimental study on electrical conductivity of dunite at high temperature and pressure

The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation enthalpies of the dunite are smaller than 0.9 eV, the conduction mechanism in dunite may be attributed to the mixed electrical conduction involving grain interiors and boundaries. On the basis of the results of this experiment, we can deduce that there exists cold mantle in the area of Gaize-Lugu in the Qinghai-Xizang (Tibetan) Plateau by reverse methods from the magnetotelluric sounding data (conductivity-depths profile) available for western Tibet. The result provides the present cold mantle viewpoint with strong proof on the basis of high temperature and pressure experiments.     

Impedance spectra of hot, dry gabbro at high temperature and pressure

Impedance spectra of hot, dry gabbro have been studied at 1.0～2.0 Gpa and 593～1173 K.The experimental results indicate that complex impedance depends on frequency of altering current. Impedance arcs representing grain interiors and grain boundaries conduction mechanism are displayed in the complex impedance plane. The impedance arc corresponding to grain interiors occurs over the range of 102～105 Hz, and the impedance arc corresponding to grain boundaries occurs over the range of 12～102 Hz. Each element of equivalent circuit corresponding to grain interiors is fit for complex nonlinear least square program. When garnet occurs in gabbro, the electrical conductivity of gabbro abruptly changes.     

The electrical conductivity of H2O at 0.21– 4.18 GPa and 20–350°C

The electrical conductivity of H₂O in solid and liquid phases has been measured at 0.21–4.18 GPa and 20–350°C. The results indicate: (I) different phases of H₂O in solid have different relations between electrical conductivity and temperature and pressure. The conductivity changes continuously with temperature, but discontinuously with the pressure between 2.11 and 2.58 GPa, which corresponds to the transforming pressure between ice (VI) and ice (VII);(II) the amductivity of H₂O in liquid all increases with temperature and pressure, but there are discontinuities at pressures between 0.57 and 0.9 GPa, and between 2.11 and 2.58 GPa, which are also consistent with the polyrnorph of ice (ice (V), ice (VI) and ice (VII)). This reflects that H₂O in liquid at different pressures has quite different properties of electron chemistry. It is probably the important reason that causes the layers with high electrical conductivity and low velocity in the earth’s ceust and upper mantle.     

The electrical conductivity of H_2O at 0.21-4.18 GPa and 20 -350℃

The electrical conductivity of H2O in solid and liquid phases has been measured at 0.21-4.18 GPa and 20-350℃. The results indicate: ( i ) different phases of H2O in solid have different relations between electrical conductivity and temperature and pressure. The conductivity changes continuously with temperature, but discontinuously with the pressure between 2.11 and 2.58 GPa, which corresponds to the transforming pressure between ice (Ⅵ) and ice ( Ⅶ ) ; ( ii ) the con-ductivity of H2O in liquid all increases with temperature and pressure, but there are discontinuities at pressures between 0.57 and 0.9 GPa, and between 2.11 and 2.58 GPa, which are also consistent with the polymorph of ice (ice ( Ⅴ), ice (Ⅵ) and ice ( Ⅶ ) ) . This reflects that H2O in liquid at different pressures has quite different properties of electron chemistry. It is prob-ably the important reason that causes the layers with high electrical conductivity and low velocity in the earth's crust and upper mantle.     

Orientational phase transition in C60 single crystal under high pressure

By using a piston-cylinder type hydrostatic high-pressure unit, the electrical dc conductance of bulk C₆₀ single crystal was measured in the pressure range of 0 to 0.6 GPa at 290 K. Wlth increasing pressure, a discontinuous increase of the conductance was observed at the pressure of 0.176 GPa, which can be ascribed to. the orientational ordering phase transition. In the simple cubic phase, the increase of conductance with increasing pressure is faster than that in the face-centered-cubic phase.     

Experimental study to confirm the existence of hydrocarbon under high pressure and temperature of deep lithosphere

Previous studies indicated that the existence of over- pressure in sedimentary basins not only affects the as- sessment of oil and gas resources, but also closely re- lates to the accumulation and preservation of petroleumin deep reservoirs[1,2]. It is well known that there are more than 180 overpressure basins in the world. Be- cause fluid pressure is transient in sedimentary basin over geologic time, the effect of increasing pressure on organic matter metamorphism is difficult to determine, …     

α-石英在高温高压下的结构转变研究

以经高能机械球磨的α-SiO2粉体作为初始原料,考察了高压高温下柯石英的合成。使用XRD和Raman等表征手段对合成样品进行了结构表征,结果显示在2．5GPa的低压下就能够合成出少量小尺度柯石英。     

高温高压下钻井液循环流动摩阻实验研究

深层油气勘探开发过程中常面临高温高压的挑战,钻井液在高温高压等复杂工况下,其性能会发生改变,研究钻井液在复杂工况下的流动摩阻变化规律,能为特深井钻井提速及井控提供理论基础。根据实际工况要求,建立了高温高压钻井液循环流动摩阻测试装置,实验研究了温度、压力、固相颗粒及含气率对钻井液流动摩阻的影响,采用多元回归方法拟合并绘制温压摩阻系数图版,能更好阐述温压与钻井液流动摩阻的定量关系。结果表明：顺北区块钻井液流动摩阻随温度增大而减小,随压力增大而增大,摩阻系数图版能更准确体现摩阻系数与温压的定量关系,固体颗粒含量对流动摩阻影响不大,钻井液流动摩阻随着含气率增加而增大。该实验装置与分析方法,对于研究复杂工况下钻井液流动摩阻变化规律具有重要意义。     

高渗透水泥浆高温高压流变性研究

随着油气开采难度的增大,对固井质量和固井水泥浆添加剂的要求越来越高,需要研制开发出新型高渗透水泥浆体系。借助美国产Fann50流变仪,研究了温度和压力对高渗透水泥浆流变性的影响,并与常规水泥浆进行了对比。分析结果表明,一定压力下,高渗透水泥浆的动切力、表观粘度随温度的升高而逐渐降低,流性指数减小;一定温度下,压力对高渗透水泥浆体系流变参数的影响不如温度明显。高渗透水泥浆比常规水泥浆体系具有更好的热稳定性。运用宾汉、幂律、卡森、赫切尔巴尔克莱(H B)、带剪切稀释系数等5种模式对实验数据进行了拟合分析,结果表明,H B模式是描述高渗透水泥浆高温高压流变性的最佳模式。     

高温高压煤复电阻率各向异性实验研究

电阻率各向异性是影响煤储层电法勘探的重要因素,针对煤样复电阻率各向异性的参数评价,对焦作地区煤矿储层沿平行和垂直层理方向分别钻取了煤样,并在高温高压条件下测量得到了相应的复电阻率频谱。为了定量分析温度、压力对煤样复电阻率各向异性的影响,建立了煤样不同方向频散参数(界面极化频率、模值频散度、弛豫时间)与温度压力的对应关系,电阻率各向异性系数与温度、压力的对应关系。结果表明：平行层理方向频散参数均与温度、压力呈现良好的线性关系,垂直层理方向频散参数的线性关系不如平行层理方向好;任意方向煤样频散与温度、压力的响应关系都可以用弛豫时间来定量评价;随温度升高各向异性系数增大,随压力增大各向异性系数变化不明显。研究结果可为更精确地定量评价温度、压力对煤储层电各向异性的影响提供实验基础和理论参考。     

The effect of phase transition on the compressional wave velocity for a trachybasalt at high temperature and high pressure

Compressional wave velocities in a trachybasalt, from Yichuan County, Henan Province, have been measured at 2.0 GPa and up to 1 350℃ in a YJ-3000 t cubic-anvil high-pressure apparatus. The run products have been gained at the same pressure but different temperatures, the observation of the thin sections of the run products indicates that, corresponding to the variation of the compressional wave velocity in the trachybasalt, the phase transition has taken place. The relationship between the change of the compressional wave velocity and the hydrous mineral dehydration, solid-solid phase transformation and partial melting has been discussed. The experimental data presented here are of great importance to elucidating the geological process in the earth's interior.     

高温高压条件下甲烷和二氧化碳溶解度试验

根据不同温度和压力条件下测得的甲烷和二氧化碳两种气体在碳酸氢钠型水中的溶解度数据,对两种气体的溶解度与温度、压力及地层水矿化度之间的关系进行研究。结果表明:在地层水中的溶解机制不同,导致两种气体的溶解度值随温度、压力条件的变化具有不同的演变特征;综合前人低温(小于90℃)测试的溶解度数据,可将甲烷溶解度与温度之间的演变关系划分为缓慢递减(0~80℃)、快速递增(80~150℃)和缓慢递增(大于150℃)3个阶段;二氧化碳溶解度随温度的升高而逐渐降低,随压力升高而逐渐增大,其溶解与析离能力受压力影响更为明显;实际地层中,两种气体间溶解度的差异演变影响了天然气的空间分布。     

TATB高温高压下初始分解反应的分子动力学模拟

在凝聚相含能材料的反应过程中,反应体系往往需要高温高压的反应条件,且其中原子、分子的反应往往具有不同于气态分子的反应路径.因此,除需对体系分子的结构及电子性质进行计算分析外,还需对体系分子做反应动力学分析.本文采用ReaxFF分子动力学方法模拟了凝聚相下1,3,5-三氨基-2,4,6-三硝基苯(TATB)分子的初始反应过程,通过对分子产物随时间的分布、分子产物在不同时间段内的分布等分析,总结了其在反应初期的一些反应过程.结果显示,C-NO2键的断裂及质子转移为引起更复杂化学反应的初始反应.     

高温高压旋风分离器的性能及其应用

以工业应用成熟的PV型高效旋风分离器为基础，从改善分离器的强度入手，对PV型分离器顶部及进气口等部位的结构进行改造，提出了一种拱顶、直切入口、升气管偏心的新型旋风分离器。介绍了新型分离器与PV型的冷模对比性能试验、分离效率与压降计算及其在粉煤灰熔聚流化床气化、聚丙烯聚合反应装置中的应用。结果表明，新型分离器结构强度和分离性能优良，适合在高温、高压工况下应用。     

烧结温度对高速压制制备弥散强化铜材料导电率的影响

弥散强化铜材料具有高强度和高导电性的特性,孔洞是影响导电率的重要因素.本文采用高速压制成形技术,对Al2 O3质量分数为0.9%的弥散强化铜粉压制成形,研究了压制速度对生坯的影响.当压制速度为9.4 m·s-1时得到密度为8.46 g·cm-3的生坯.研究了烧结温度对烧结所得Al2 O3弥散强化铜试样导电率的影响.当生坯密度相同时,烧结温度越高,所得试样的导电率也越高.断口与金相分析表明：烧结温度为950℃时,烧结不充分,颗粒边界以及孔洞多而明显,孔洞形状不规则;烧结温度为1080℃时,颗粒边界消失,孔洞圆化,韧窝出现,烧结坯的电导率为71.3%IACS.     

旋风分离器高温性能试验研究

为了预测温度对分离器性能的影响，选用一个直径为300mm的切流反转式旋风分离器在常温～973K的范围内进行了性能试验研究。试验用粉料为二氧化硅，其中位粒径为10μm；入口气速的变化为12～36m／s。试验测定了不同入口气速和温度下旋风分离器的分离效率与压降。结果表明，相同人口气速下，分离效率与压降均随温度的升高而降低。当气速达到最佳入口气速时，旋风分离器的分离效率最高，且最佳入口气速随温度的增加而增加。