南海北部神狐海域输导体系特征及其对天然气水合物成藏的影响

基于地震解释和二维盆地模拟,从输导体系的类型、断层的活动性、古压力演化历史等方面综合研究南海北部神狐海域输导体系的特征,并结合生烃条件和天然气水合物稳定域条件,综合探讨输导体系对天然气水合物成藏的影响,进而预测神狐海域天然气水合物有利聚集区。结果表明：神狐海域输导体系类型主要有＂断层＂型和＂气烟囱＂型2种,并以＂断层＂型为主;＂断层＂型输导体系主要分布在神狐海域北部和中东部,断层性质为正断层,组合样式包括鹿角状、反＂y＂字型和阶梯型,断层主要活动期为珠江期—韩江期;该区域经历了3期超压旋回,其中第3次超压旋回与深部烃类流体的生成排放有关;该区域浅层形成了较厚的天然气水合物稳定域,深部具备充足的气源;该区域主要生排烃期与断层主要活动期、第3次超压旋回匹配良好,有利于深部烃类气体通过＂断层＂型输导体系向浅层运移;该区域北部和中东部是未来天然气水合物勘探的有利区。     

A new method of predicting the saturation pressure of oil reservoir and its application

Saturation pressure is a vital parameter of oil reservoir which can reflect the oilfield characteristics and determine the oilfield development process, and it is determined by experiments in the laboratory in general. However, there was only one well with saturation pressure test in this target reservoir, and it is necessary to determine whether this parameter is right or not.In this work, we present a new method for quickly determining saturation pressure using machine learning algorithms, including random forest regressor (RF), support vector machine (SVM), decision trees (DT), and artificial neural network (ANN or NN). Using these approaches, saturation pressure was obtained by using the initial solution gas-oil ratio (GOR), temperature, API gravity and other reservoir-fluid data available in the oilfields. Compared with the empirical formula for saturation pressure calculation, the calculated result shows that the accuracy given from machine learning is higher than that from other formulas at home and abroad, and has a good match with the lab test. On the basis of the calculated saturation pressure, it can determine whether the reservoir enters into the stage of dissolved gas drive or not, which also provides the basis for maintaining the reservoir pressure by water injection in advance, rational development decision-making and work over measures.This approach above can provide technical guidance for predicting the saturation pressure in the development of different kinds of reservoirs, including the sandstone reservoirs and carbonate reservoirs.     

一种新型底流与浊流交互作用形成的储集砂体——以北礁凹陷为例

目前地质学家对垂直于大陆斜坡发育的浊积水道研究已较为成熟,而对平行于大陆斜坡水道的研究还处于起步阶段。在深水环境中,底流与浊流交互作用较为普遍,但研究少且程度较低,与这种交互作用相关的平行斜坡水道亟待深入研究。通过二维地震资料对北礁凹陷的古地貌进行研究,再利用三维地震资料的时间域构造、均方根振幅等,结合三维区的地震剖面和该区沉积环境及海平面升降、古气候等因素对平行斜坡强振幅水道进行综合研究。结果表明：北礁凹陷中中新世具有狭窄通道古地形特征,东北部发育一条近平行斜坡水道,且主要分布在该狭窄通道的右侧,该水道呈指状或锥状展布。沿水道方向有前积现象,且水道头部也有前积现象,而中部、尾部均以平行充填为主,该水道下方不发育大型断层。该平行斜坡水道是垂直于斜坡的浊流与沿斜坡的底流在狭窄通道处交互作用的沉积结果,该水道是一种新型的岩性储集砂体,具有潜在的高孔、高渗特征,该水道形成时的古气候和狭窄通道的古地形是其主控因素,并提出了这种新型储集砂体的沉积模式,丰富了我国深水砂体的类型。该水道具有重要的古海洋、古气候意义,可能在深水环境下的狭窄通道处广泛分布,是南海深水油气勘探的潜在接替新区,应引起石油地质工作者的重视。     

不依赖子波的弹性波混合域全波形反演

震源子波的准确性直接影响全波形反演的建模效果,获取准确的实际子波十分困难。本文基于去子波影响的褶积法,提出弹性波混合域不依赖子波的全波形反演策略。基于二阶弹性波应力-位移方程的混合域反演理论,把观测地震记录与模拟记录的特征道、模拟记录与观测记录的特征道在频率域做乘积运算,构造了不依赖子波的弹性波混合域全波形反演目标函数,推导了反传震源的理论公式。最后,对Overthrust模型进行试算,得到了较好的反演结果,验证了该方法的可行性。     

沉积物中天然气水合物生成与分解过程的电阻率变化

测定天然气水合物在沉积物形成和分解过程中电阻率的变化对海底天然气水合物的勘探开采具有重要的意义。利用设计的水合物实验装置,以99.9%的甲烷气体—3.5%氯化钠溶液—南海沉积物为研究体系,模拟测量了温度周期变化下海底沉积物中天然气水合物形成与分解过程的电阻率。实验结果表明：当水合物在沉积物中生成时,沉积物电阻率增大。水合物初始成核时,沉积物的电阻率从4.493Ω·m减小至3.173Ω·m,随着水合物的大量形成、聚集,沉积物的电阻率增大至3.933Ω·m,最后随着松散的水合物逐渐老化致密,沉积物的电阻率逐渐减小趋于稳定至3.494Ω·m。当水合物分解时,沉积物电阻率减小。沉积物的电阻率随水合物的分解从6.763Ω·m减小到2.675Ω·m,最后趋于稳定至2.411Ω·m。温度震荡可促进沉积物中高饱和度水合物的形成,并且沉积物的电阻率随水合物饱和度增加而增大。样品的水合物饱和度从初次水合物生成时的21.80%增大到水合物再次生成时的82.17%,其电阻率从3.494Ω·m增到6.763Ω·m。     

Degradation of thiocyanate in aqueous solution by persulfate activated ferric ion

Thiocyanate formation from cyanidation of gold bearing ores is becoming a more common problem during gold processing. In this work, the application of an advanced oxidation process based on the use of persulfate (S₂O₈²⁻) as an environmentally friendly oxidant in the presence of ferric ion for destruction of a persistent and non-volatile inorganic contaminant, such as thiocyanate, in aqueous solutions is reported for the first time. The influence of various reaction parameters like ferric ion and persulfate dosage, initial thiocyanate concentration and the influence of radical scavenger are examined. An accelerated reaction using S₂O₈²⁻ to destroy thiocyanate can be achieved via chemical activation with Fe³⁺ to generate highly reactive sulfate anion-radicals (SO₄⁻). The results showed that degradation efficiency was negligible when persulfate was used alone, ferric ions significantly improved the degradation efficiency of thiocyanate at ambient temperature. Under the optimum molar ratios ([S₂O₈²⁻]:[SCN⁻] = 5:1 and [S₂O₈²⁻]:[Fe³⁺] = 1:0.2), 99% of thiocyanate present in aqueous solution at the initial concentration range of 1.72–17.2 mM was degraded within 60 min of reaction time. To evaluate the contribution of reactive free radicals generated through Fe(III)-mediated activation of persulfate to thiocyanate degradation, quenching experiments using methanol as the radical quenching agent were carried out. The obvious decrease in thiocyanate oxidation efficiency in the presence of methanol confirmed that the radical-based pathway was the dominant mechanism in Fe³⁺/S₂O₈²⁻ system. The degradation of thiocyanate was accompanied by the formation of cyanide as the main final product of the reaction. Thus the catalytic oxidation of thiocyanate makes it possible to return NaCN into the production process for leaching of precious metals. The work presents an efficient and environmentally acceptable wastewater treatment process applicable in mining facilities utilizing cyanidation of sulfide ores and/or concentrates.     

黏弹性介质纵波反射系数近似

本文从黏弹性介质精确Zoeppritz方程出发,以黏弹性介质为背景,根据介质的分解理论,利用弱黏弹性近似和相似介质近似推导了黏弹性介质反射系数近似公式,该式分为实部和虚部,在实部中既存在弹性项,也存在黏弹性项,更精确地反映了实际地层介质中波的传播规律。特别地,当品质因子为无穷大、衰减角为零时,该式与以完全弹性介质为背景得到的反射系数近似公式(Aki-Richards近似公式)完全吻合,证明了公式的合理性。最后利用四类AVO模型,采用不同的黏弹性参数对黏弹性介质反射系数近似公式的有效性进行验证,结果表明,与Aki-Richards近似公式相比,以黏弹性介质为背景推导出的纵波反射系数近似公式的精度更高。     

黏弹性介质叠前地震反演方法

前人只是从理论上分析了黏弹性介质中各种波的传播特征和衰减特征,并未对黏弹性介质精确的Zoeppritz方程进行近似,无法用于实际反演;沈章洪等以完全弹性介质为背景,推导了黏弹性介质反射系数近似方程,由于该近似方程的实部为完全弹性项,虚部为黏弹性项,因此也无法用于实际资料。为此,本文以黏弹性介质为背景,推导了黏弹性介质反射系数近似公式,以此为基础,基于贝叶斯理论的叠前地震反演,将纵横波速度、密度的反演推广到纵横波速度、密度和地层品质因子(Q值)的联合反演,建立了黏弹性介质近似方程,再根据贝叶斯理论建立反演方程,最终利用共轭梯度法对方程进行求解,得到纵横波速度、密度和地层Q值。模型试算与实例分析结果表明,根据联合反演所得的纵横波速度、密度和Q值进行储层描述,可提高储层预测精度。     

国际锂矿开发技术现状、革新及展望

与国内的锂矿技术创新相比,国外的锂矿开发利用技术总体发展时间早,但区域发展极不均衡,欧美澳技术革新持续性强,近期颠覆性技术频频出现。锂矿山多矿种综合开发利用是趋势,是降低成本、提高效益和环境保护的重要方向。采选冶垂直一体化是创新增效、优化流程的重要选项。从地域上看,美洲是世界锂提取技术的摇篮,南美锂三角技术稳定,成本低,正处于技术革新的前夕。非洲资源量大,硬岩为主,受限于基础设施,云母型提取技术的创新和综合开发利用是出路。澳洲硬岩锂矿开发强度最大,技术娴熟,成本压力催生更多优化创新项目。欧洲市场需求带动本土锂矿开发,采选冶一体化项目增多。新型锂矿如盐湖卤水、硬岩采选、粘土沉积型、地热卤水的提取技术在近期都将有重大突破的希望。      

Reduction roast and magnetic separation of oxidized iron ores for the production of blast furnace feed

Low grade oolitic iron ore from the Aswan locality, assaying 45.23% Fe and 23.93% insoluble residue, was tested for concentration using reduction roasting and subsequent low intensity magnetic separation for the production of blast furnace feed. The ore is a low grade, high phosphorus, and high alumina oolitic hematite. Fine grinding of the ore was found to be imperative due to the fine dissemination characteristics of the ore. The application of reduction roasting-low intensity magnetic separation process for high grade concentrate production and minimum hot metal costs was investigated. The studies included the use of gaseous reductants such as H₂ or CO, and the different parameters affecting the process were verified. Optimization of the process was demonstrated on a bench scale. Quality magnetic concentrates assaying 59.6% FE with recoveries of about 90% were obtained from a run of mine ore assaying 45.23% Fe.Révaluésumévalué- On a évalué la concentration de minerai de fer oolithique de basse qualité de la localité dAswan, essayant à 45.23% Fe et 23.93% de résidus insolubles. On a utilisé le grillage par réduction et une séparation magnétique subséquente à basse intensité pour la production dalimentation de haut fourneau. Le minerai est une hématite oolithique de basse qualité, haute en phosphore et en oxyde daluminium. On a trouvé que le meulage fin du minerai était impératif dû aux caractéristiques de dissémination fine du minerai. On a étudié lapplication du procédé de grillage par réduction-séparation magnétiqué, à faible intensité, à la production de concentré de haute qualité et des coûts minimums de métal chaud.Létude inclue lutilisation dagents réducteurs gazeux tels que H₂ ou CO. On a vérifié les différents paramètres affectant le procédé. On a optimisé le procédé à léchelle du laboratoire. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.