疏松砂岩稠油油藏防砂介质的原油-地层砂协同复合堵塞机制与规律

针对稠油出砂井防砂介质堵塞问题,使用稠油与水混合液携带地层砂,开展单向驱替流动、热采交变吞吐流动两种模式下的挡砂堵塞驱替模拟试验,揭示不同条件下割缝、绕丝、复合滤网和砾石层等多类型防砂介质的稠油-地层砂协同堵塞机制与规律,根据堵塞机制和定量关系,构建稠油-地层砂对防砂介质堵塞程度和动态产能预测模型。结果表明:高黏度稠油对防砂层多孔介质具有明显堵塞作用,渗透率损伤可高达70%;稠油防砂井中,存在稠油和地层砂对防砂介质的协同堵塞机制,稠油以束缚油的形式占据介质空间,加剧内部分选桥架堵塞,最终造成90%以上渗透率损害,但同时挡砂效果得到提升;热采蒸汽交变吞吐生产方式对稠油-地层砂的协同堵塞具有明显的解除堵塞效应;但随着交替轮次的增加,解堵和渗透率恢复幅度逐渐下降;对于稠油油藏防砂,建议挡砂精度相比常规油藏防砂精度放宽1~2个等级。

Jet formation in shock-heavy gas bubble interaction

The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work. The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D. As a validation, the experiments of a SF6 bubble accelerated by a planar shock were performed. The results indicate that, due to the mismatch of acoustic impedance, the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition. With respect to the same bubble, the manner of jet formation is also distinctly different under different shock strengths. The disparities of the acoustic impedance result in different effects of shock focusing in the bubble, and different behaviors of shock wave inside and outside the bubble. The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation. Moreover, the analy- sis of the vorticity deposition, and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation. It is concluded that the pres- sure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

Modeling of flow of oil-in-water emulsions through porous media

Formation and flow of emulsions in porous media are common in all enhanced oil recovery tech- niques. In most cases, oil-in-water （O/W） emulsions are formed in porous media due to oil-water interaction. Even now, detailed flow mechanisms of emulsions through porous media are not well understood. In this study, variation of rate of flow of O/W emulsions with pressure drop was studied experimentally, and rheological pa- rameters were calculated. The pressure drop increases with an increase in oil concentration in the O/W emulsion due to high viscosity. The effective viscosity of the emulsion was calculated from the derived model and expressed as a function of shear rate while flowing through porous media. Flow of O/W emulsions of different concentrations was evaluated in sand packs of different sand sizes. Emulsions were characterized by analyzing their stability, rheological properties, and tem- perature effects on rheological properties.

Bayesian Markov chain Monte Carlo inversion for anisotropy of PP-and PS-wave in weakly anisotropic and heterogeneous media

A single set of vertically aligned cracks embedded in a purely isotropic background may be con- sidered as a long-wavelength effective transversely iso- tropy （HTI） medium with a horizontal symmetry axis. The crack-induced HTI anisotropy can be characterized by the weakly anisotropic parameters introduced by Thomsen. The seismic scattering theory can be utilized for the inversion for the anisotropic parameters in weakly aniso- tropic and heterogeneous HTI media. Based on the seismic scattering theory, we first derived the linearized PP- and PS-wave reflection coefficients in terms of P- and S-wave impedances, density as well as three anisotropic parameters in HTI media. Then, we proposed a novel Bayesian Mar- kov chain Monte Carlo inversion method of PP- and PS- wave for six elastic and anisotropic parameters directly. Tests on synthetic azimuthal seismic data contaminated by random errors demonstrated that this method appears more accurate, anti-noise and stable owing to the usage of the constrained PS-wave compared with the standards inver- sion scheme taking only the PP-wave into account.

Research on soil multi-media environmental pollution around a Pb-Zn mining and smelting plant in the karst area of Guangxi Zhuang Autonomous Region,Southwest China

The method of principal component analysis was applied to systematical research on the soil multi-media environment, including soil, surface water, ground water, waterbody sediment and agricultural crops, as well as pollution-inducing wastewater, mullock (or waste ore) and slag in the periphery of a large-sized Pb-Zn mining and smelting plant in a karst area of Guangxi Zhuang Autonomous Region. The results revealed that soils in the area studied have been heavily polluted by Cd, Zn, Pb and Hg, and the levels of these metals in the samples of agricultural crop greatly exceed the standards. The above-mentioned pollutants exist in all soil-multi-media environments. The mullock, slag, wastewater, surface water, ground water, soil, and agricultural crops constitute a composite ecological chain. Therefore, the improper disposal of mullock and slag, and the use of polluted wastewater for agricultural irrigation are the main causes of soil pollution. Heavy metals in the soil have three transition progresses: point (improved soil with slag, ground water inflow plot), linear (river transition) and non-point transition (regional pollution by slag) patterns, and the tailing yard is the most important locus for heavy metals to release into the environment.

Fixed-Bed Column Adsorption Modeling of MnO4- Ions from Acidic Aqueous Solutions on Activated Carbons Prepared with the Biomass

Activated carbons calcined at 400˚C and 600˚C (AC-400 and AC-600), prepared using palm nuts, collected in the town of Franceville in Gabon, were used to study the dynamic adsorption of MnO4- ions in acidic media on fixed bed column and on the kinetic modeling of experimental data of breakthrough curves of MnO4- ions obtained. Results on the adsorption of MnO4- ions in fixed-bed dynamics obtained on AC-400 and AC-600 adsorbents beds indicated that the AC-400 bed appears to be the most efficient in removing MnO4- ions in acidic media. Indeed, the adsorbed amounts, the adsorbed capacities at saturation and the elimination percentage of MnO4- ions obtained with AC-400 (31.24 mg;52.06 mg·g-1 and 41.65% respectively) were higher compared to those obtained with AC-600 (9.87 mg;16.45 mg·g-1 and 17.79% respectively). The breakthrough curves kinetic modeling revealed that the Thomas model and the pseudo-first-order kinetic model were the most suitable models to describe the adsorption of MnO4- ions on adsorbents studied in our experimental conditions. The results of the intraparticle diffusion model showed that intraparticle diffusion was involved in the adsorption mechanism of MnO4- ions on investigated adsorbents and was not the limiting step and the only process controlling MnO4- ions adsorption. In contrast to AC-400, the intraparticle diffusion on AC-600 bed plays an important role in the adsorption mechanism of MnO4- ions.

四川某锂辉石废石重介分选

这是一篇矿物加工工程领域的文章。研究对象为四川某锂辉石废石,根据该锂辉石废石的矿物特性,对该锂辉石废石三种不同入料粒度(-15+0.5 mm、-10+0.5 mm、-5+0.5 mm)分别进行实验室重液分选实验,实验结果表明,该锂辉石废石采用重液分选效果较好,且以-10+0.5 mm作为后续重介实验的入料粒度范围,并选择2.70 g/cm^(3)作为分选密度时,重液分选指标相对较好,但根据实际生产重介分选实验结果,最终在入选粒度为-15+0.5 mm,介质密度为2.0 g/cm^(3)时,分选指标相对较好。

基于PLC的Fuzzy-PID分选密度控制研究

重介选煤工艺中,密度控制是保证产品质量的关键。密度控制过程中,由于被控对象具有不确定、非线性、干扰大等特点,常规的PID控制难以满足控制要求,造成生产质量的不稳定。针对这些问题,提出了一种基于PLC的复合模糊PID控制算法,利用模糊推理对PID参数KP,KI,KD进行在线整定。其中模糊决策器和PID调节器都通过PLC来实现,这样既保留了PLC控制系统灵活、可靠、抗干扰能力强等特点,又大大提高了控制系统的智能化程度。实践结果表明:该系统能有效抑制干扰的影响,调节快速、稳定。

煤矸石-土壤混合基质对小白菜生长的影响及Pb迁移规律

盆栽试验研究了施用不同量煤矸石(0%、13%、26%、40%、53%)对贫瘠土壤改良的效果和对小白菜生长品质的影响。结果表明:(1)混合基质中Pb的迁移能力较差,小白菜中Pb积累量与植物体生物量具有正相关关系;(2)小白菜的发芽率、根系长度、地面以上株高和生物量等均在煤矸石施入比例为26%时达到最佳,发芽率、地面以上株高和干重分别增加23%、23.05%和20.62%;施入煤矸石超过40%时将导致各项指标有所下降;(3)采用单因子污染指数法进行食品质量评价,加入煤矸石量分别为0%、13%和26%时,产品污染指数分别为0.69、0.79和0.93,属于清洁水平;而加入煤矸石量为40%和53%时,污染指数分别为1.12(轻污染水平)和1.38(轻污染水平)。煤矸石可增加植物生长过程所需营养物质而作为贫瘠土壤的改良剂,实现煤矸石资源化并改善矿区生态环境。

多孔介质高温高压多组分气体-原油分子扩散系数研究

目前气体-原油分子扩散系数的研究对象多为单组分气体-原油体系,而且多在低温或者低压下在PVT筒中进行实验,与实际的注气过程相差较大。在这种情况下,研究了多孔介质中高温高压下多组分气体-原油的扩散系数,测试了全直径岩心中多组分气体-凝析油、多组分气体-重质原油在60℃,20MPa条件下的扩散系数。研究结果表明:原油组分对扩散有一定影响,但对于最终扩散程度影响不大;气体在凝析油中的扩散系数高于其在重质原油中的扩散系数;扩散系数以幂函数形式逐渐增加,最终逐渐趋于平缓。

裂缝-孔隙油藏蒸汽辅助重力泄油过程的自适应网格数值计算

为提高裂缝-孔隙双重介质油藏蒸汽辅助重力泄油(SAGD)过程数值模拟的计算速度,根据温度、各相饱和度随空间变化的快慢在不同区域采用不同尺度网格,提出双孔双渗模型下的自适应网格算法及裂缝-基质方程的解耦方法。对给出的算例分别采用全精细网格及自适应网格算法进行计算。结果表明:自适应网格法处理这类带峰面非线性问题有很好的计算精度和计算速度;裂缝-孔隙双重介质油藏SAGD开采可能较早出现蒸汽窜顶这一不利于蒸汽能量利用率的现象。

无压三产品重介质旋流器的发展和展望

无压三产品重介质旋流器作为重要的选煤分选设备,具有结构简单、分选精度高、节能环保的特点。介绍了无压三产品重介质旋流器在国内的发展应用历程,分析了不同时期三产品重介质旋流器的性能特点和应用效果,并对三产品重介质旋流器选煤工艺及装备的发展进行了展望。认为,无压三产品重介质旋流器技术工艺应持续研究原煤及煤泥重介质旋流器工艺参数对分选过程的影响和磁选工艺参数对磁选作业工艺效果的影响,重视中煤磁选尾矿的分选工艺;而在重介质旋流器装备方面要降低分选下限、提高分选精度,进一步提高检测设备的精度及可靠性、提高旋流器的使用寿命。

典型重金属聚能侵彻体对水介质及后效靶的侵彻特性研究

针对不同材料密度的聚能侵彻体对水介质的侵彻特性和对后效靶的毁伤效果,提出了一种描述射流侵彻水介质过程中速度衰减和头部直径变化的理论模型。结合数值模拟和实验结果,对比了等壁厚或等重量条件下钽合金、钨铜合金和紫铜药型罩所形成的射流杆在穿过一定厚度水介质后对后效钢板的毁伤威力。结果表明:建立的理论模型能够有效描述射流杆的速度衰减和头部变形过程。与紫铜材料相比,钽合金射流杆在水介质中的速度衰减率和头部直径变化程度均相对较小。在射流侵彻和随进水介质的共同作用下,钽合金药型罩聚能战斗部对后效靶的破孔直径增大了20.5%,显著增强水中聚能战斗部的毁伤威力。

浅槽重介质分选机上升流系统结构改造研究

针对永安煤矿选煤厂W26F54浅槽重介质分选机上升流系统频繁发生堵塞问题,导致精煤产品质量下降、人工成本增加等问题,在对堵塞问题原因分析基础上,对上升流系统结构从系统管路改造、布流孔板结构改造、上升流介质斗缓冲版改造进行了系统改造。实践应用表明:改造后上升流系统堵塞频率降低了95%,对分选效果无影响,经济效益显著。

选煤厂末煤系统技术改造分析

针对选煤厂末煤系统存在的高硫份及低硫份末煤混合分选、部分产末煤产品混入到动力煤中销售,导致末煤产品未能充分发挥经济效益等问题,结合现场情况合理确定改造工艺以及改造技术方案。主要通过超级重介旋流器增加末煤系统处理能力并实现高硫份、低硫份末煤单独分选,同时充分利用超级重介旋流器分选效率高、处理能力大等优点洗选低硫份末煤,增加喷吹精煤产量;采用原有的跳汰系统分选高硫份末煤,满足动力煤配煤需要。末煤系统改造完成后,选煤厂末煤系统可多生产约17.75万t喷吹精煤,年增加经济效益约2850万元,技术改造取得较好效果。

张家峁选煤厂智能重介分选系统的研究与应用

随着“双碳”目标的提出,煤炭洗选加工的清洁化和智能化显得尤为重要。重介浅槽分选工艺作为我国绝大多数动力煤选煤厂的洗选工艺,其智能化改造是提高分选效率的重要保障。通过对张家峁选煤厂重介分选系统的智能化建设进行分析,重点介绍了分选模型和加介控制对重介分选系统模块的智能化建设方案。改造方案有利于提高全厂经济效益,也可为同类选煤厂提供新的思路,起到了示范作用。

选煤厂分选方案研究及工业试验效果评价

基于某选煤厂吨原煤介耗较高、分选精度低的问题,结合生产实际对重介质旋流器浮选方案进行优化改进,并进行工业试验效果检验。经过不断优化,吨原煤介耗大幅降低,重介精煤灰分质量分数也降低了2%左右,产率大幅提高,方案优化效果显著。

选煤厂工艺系统改造工业试验及评价

为进一步提升选煤厂的处理能力时期与煤矿生产能力相匹配,同时保证所设计的分选工艺与原煤特征相符才能够达到最佳的生产效益。在对选煤厂基本情况进行概述的基础上,重点分析其当前所存在的问题,在对工艺系统进行改造的同时,对炼焦配煤和动力用煤在不同分选下限开展工业性试验,试验结果可指导实践生产。

无压三产品重介质旋流器内介质颗粒分布研究

以WTMC1500/1100无压三产品重介质旋流器为例,介绍一种基于无压三产品重介质旋流器内介质颗粒分布的分析方法。该方案利用UG软件构建设备三维模型,并通过ICEMCFD软件对三维模型进行网格划分,之后以此为基础,分别对旋流器悬浮液的密度分布与轴向速度、切向速度、介质颗粒分布情况展开分析,以掌握旋流器内介质颗粒分布特点,为无压三产品重介质旋流器的设计提供支持,确认有限元分析法的应用价值。

煤矿深度筛分与重介质选煤技术结合工艺研究

优化洗选工艺设计,提高商品煤质量是提高煤矿经济效益的关键技术,针对煤泥全粒级洗选中存在的褐煤提质技术难题,以山西省镇城底矿为例,提出了深度筛分与重介质选煤技术结合工艺,结果表明,合理调整工作频率和张紧力可显著提高3 mm弛张筛的筛分效果,筛分效率达到81.77%,筛下率仅为2%,频率的最佳范围为46~50 Hz,张力的最佳范围为-6~0 mm。对于重介分选机,发现分选后的灰分偏析主要受给料位置、水平流与上升流流量比和给料速率的影响。当给料位置为15 cm,水平流向上升流流量比为2.75,给料速率为27.5 kg/min时,灰分偏析值最大,为0.746。