FORMATION OF GOLD-BEARING HYDROFRACTURING BRECCIA BODIES IN TECTONIC LENSES: A CASE STUDY ON SHUANGWANG GOLD DEPOSIT, SHAANXI, CHINA

Macro-microscopic tectonic analysis and lithologic features show that the gold-bearing breccia bodies in the Shuangwang gold deposit, for hydrofracturing of the deep-sourced and alkali-rich fluids in the Devonian sodic rock series, are identified as hydrofracturing breccia bodies. Since the Indosinian, intracontinental collisional orogenesis results in multiple fracturings and magmatic emplacements in the Qinling area. Deep-sourced fluids resulting from deep fractures and granitoid magmatic intrusion are of a supercritical nature. Joint action between the fluid-rock system and structures leads to hydrofracturing and ore formation of the gold deposit. Firstly, the progressive coaxial compression caused the competent sodic rock series and the incompetent pelitic rock series to be deformed and partitioned. Lens-like weak-strain domains are hence formed and distributed at the approximate equidistance zones and the linear strong-strain zones, respectively. Subsequently, the progressive non-coaxial shearing and right-lateral and high-angle oblique thrusting lead to the most developed fracture system in the core of the weak-strain domain to turn from compression to extension and to link up with the deep fracture systems. The periodical huge pressure decline in the pumping center causes the deep-sourced confined fluids to develop periodic tectonic pumping, hydrofracturing and precipitation-healing in the sodic rock series. The gold-bearinghydrofracturing breccia bodies are hence ultimately formed at near-equidistance tectonic lenses. On the basis of the above model, the predicted concealed gold-bearing hydrofracturing breccia bodies have been preliminarily validated by latest drillings.

钦杭结合带南段钦州‒灵山构造带中生代板内变形特征与构造转换

钦州‒灵山构造带位于钦杭结合带南段,是华南中生代形成的大型构造‒岩浆活动带。构造解析表明,钦州‒灵山构造带灵山段由走滑构造、逆冲推覆构造以及一系列伸展构造组成:早期,该段整体表现为逆‒平移性质,平面上呈一组平行或分支复合的断裂束,剖面上表现为向深部会聚的正花状构造;中期,构造带南东侧的六万大山花岗岩体逆冲推覆至古生代地层之上,其平面上呈向北西凸起的弧形复合断裂束,剖面上由前、后缘推覆型韧性剪切带及花岗岩断夹块组成的逆冲推覆构造;晚期,钦州‒灵山构造带由挤压‒推覆变形转入后造山伸展变形,沿乐民‒寨圩一带发育了张性岩墙群、伸展型韧性剪切带及大型张性断裂带。带内构造变形特征、转换及演化机制揭示:在晚古生代钦廉‒罗定裂陷槽关闭的地质背景下,扬子地块与华夏地块于中生代沿钦州‒灵山构造带灵山段发生斜向拼合‒板内造山作用。上述认识对理解钦廉‒罗定裂陷槽的闭合、扬子地块与华夏地块的分界与拼合过程、华南板内造山的动力学机制及演化、六万大山印支期花岗岩基的侵位机制、十万大山盆地的性质,皆具有重要的地质意义。

基于地表数据及产状数据的交切断层建模方法研究

三维地质建模是地质研究的有力工具,断层的三维建模比其他地质体建模具有更大的难度,其中一个主要难题是交切断层切割关系的处理。本文以广西珊瑚矿田为例,探讨了基于地表数据和产状数据的交切断层建模方法,采用地表断层线-剖面断层轨迹-系列断层线-断层面的技术路线进行切割断层建模,采用初始断层面-断后约束条件-交切处理-约束插值的技术路线进行被切割断层的建模,并与其他建模方法的建模效果进行对比和讨论。最终形成了如下建模方法:(1)以旋转法求取部分切割断层的错开部位约束,以平移法求取完全切割断层的错开部位约束;以断层错开部位约束、地表断层线约束及断层面边界约束为控制条件,进行断层面DSI插值,实现断层错动;(2)局部法建模、分段断层线的平移连接及过度追求完全切割关系建模可能分别引起断层面延展可控性差、断面整体偏移误差及沿走向过度延伸问题,与地质事实相悖,故本文优选采用了整体法建模、顺延连接分段断层线及遵从原有切割关系的处理方法,获得了较好的建模效果。

基于XGBoost的钻井液体系分类预测模型研究

根据钻井液体系设计的原则,结合实际钻井液设计资料,应用一种新的机器学习方法建立了钻井液体系分类预测模型。钻井液体系分类数据经过独热编码(one-hot)之后,通过灰色关联度分析方法,选择出钻井液体系分类预测的20个特征参数,其中压力的关联度最大,为0.8233。将选择的地质设计参数和工程设计参数,基于一种极端梯度增强算法(XGBoost)针对4种钻井液体系进行分类预测。结果显示,基于XGBoost的钻井液体系分类预测模型4类钻井液体系训练集的准确率都为100%,测试集的平均准确率为99.89%,精确率为99.97%,召回率为98.89%,F1值为0.98。将该模型应用于胜利油田M区块,分类结果符合实际钻井要求,能够辅助选择钻井液体系,为实现钻井液智能化设计提供了帮助。

韧性剪切带型金矿三阶段构造成矿模式——以广东河台金矿床为例

基于对粤西河台韧性剪切带型金矿的构造解析,本文提出了韧性剪切带型金矿成矿的一种新构造模式,即:在大型韧性剪切带运动指向的前锋,当扩展弱化而出现分支糜棱岩带时,就会在韧性剪切带中出现由强变形带包绕的构造透镜体弱变形域。由于透镜体域中央岩石处于脆性环境,在变形分解过程中,强变形带中含金流体会通过岩石中的微破裂渗透到相对低压的弱变形构造透镜体域中央,并通过构造泵吸机制在其中产生周期性的液压致裂与裂开‒愈合,这为在韧性剪切阶段活动的金提供了一个理想的沉淀场所。上述构造机制很好地解释了河台金矿床中透镜状特富矿体的成因。河台含金韧性剪切带在韧性、韧‒脆性及脆性阶段在同位空间并列与叠加了不同类型金矿体,从早到晚分别形成细脉‒浸染型、石英脉型与破碎带蚀变岩型金矿体。河台韧性剪切带群为粤西深层次逆冲推覆构造前缘陡坡带的分支糜棱岩带,其韧性剪切阶段为左旋平‒逆剪切,韧‒脆性与脆性阶段转变为右旋平‒逆剪切,并依此讨论了金矿体的侧伏规律及隐伏矿体的预测方向。

载银磷酸盐玻璃的缓释及抗菌性能研究进展

载银磷酸盐玻璃是一种新型抗菌材料。通常磷酸盐玻璃的化学性质不稳定,在水中可溶且溶解速率可调。银离子具有优良的抗菌性能,载银磷酸盐玻璃由于其缓释性和抗菌性,在诸多领域具有潜在的应用前景。综述了近年来该材料的研究成果,概述了其合成方法,总结了其结构和性能,及其在水处理剂、洗衣机、肥料、塑料和医学实践等领域的应用进展,并对其未来的发展作出了展望。

Combustion characteristics of semicokes derived from pyrolysis of low rank bituminous coal

Various semicokes were obtained from medium-low temperature pyrolysis of Dongrong long flame coal.The proximate analysis,calorific value and Hardgrove grindability index(HGI) of semicokes were determined,and the ignition temperature,burnout temperature,ignition index,burnout index,burnout ratio,combustion characteristic index of semicokes were measured and analyzed using thermogravimetry analysis(TGA).The effects of pyrolysis temperature,heating rate,and pyrolysis time on yield,composition and calorific value of long flame coal derived semicokes were investigated,especially the influence of pyrolysis temperature on combustion characteristics and grindability of the semicokes was studied combined with X-ray diffraction(XRD) analysis of semicokes.The results show that the volatile content,ash content and calorific value of semicokes pyrolyzed at all process parameters studied meet the technical specifications of the pulverized coal-fired furnaces(PCFF) referring to China Standards GB/T 7562-1998.The pyrolysis temperature is the most influential factor among pyrolysis process parameters.As pyrolysis temperature increases,the yield,ignition index,combustion reactivity and burnout index of semicokes show a decreasing tend,but the ash content increases.In the range of 400 and 450 °C,the grindability of semicokes is rational,especially the grindability of semicokes pyrolyzed at 450 °C is suitable.Except for the decrease of volatile content and increase of ash content,the decrease of combustion performance of semicokes pyrolyzed at higher temperature should be attributed to the improvement of the degree of structural ordering and the increase of aromaticity and average crystallite size of char.It is concluded that the semicokes pyrolyzed at the temperature of 450 °C is the proper fuel for PCFF.

基于无功功率方向法的主谐波电流来源判别

针对目前谐波电流造成特定线路各元件损耗难以明确其来源的问题,提出一种基于无功功率方向法来判别引起公共连接点(point of common coupling,PCC)处的主谐波电流来源方法。通常情况下,系统侧和用户侧谐波源流过特定线路各元件造成的损耗大小,可由两侧各自贡献的谐波电流大小区分,故以谐波电流指标为判别依据。以电网中谐波阻抗基本性质为基础,结合PCC处谐波电压和电流实测信息,利用基本电路原理和不等式约束条件,在谐波无功功率方向法的思路与判别条件下,推导得出了仅根据谐波电压和电流的相角差,就可直接判别主谐波电流来源的方法。最后,通过多种实际工程场景的实测数据,验证了该方法的有效性,使用中的便捷性反映了该方法在工程实用中的价值。

热解长焰煤的孔隙结构演变及半焦吸附性能

为扩大水煤浆制浆用煤选择范围,以双鸭山东荣长焰煤为原料,采用马弗炉制备中低温热解半焦,选用木质素磺酸钠作分散剂进行吸附实验,通过氮吸附法测定长焰煤及半焦的比表面积、孔容积和孔径分布,分析热解过程中长焰煤孔隙结构演变对半焦吸附量的影响。结果表明,半焦及长焰煤对木质素磺酸钠的吸附均符合Freundlich吸附。随热解温度的升高,半焦的比表面积、平均孔直径和孔容积都呈先增大后减小的趋势,其中,微孔比例先减小后增大,大孔比例先增大后减小,中孔逐渐发育。热解过程中,半焦比表面积越小,其吸附量越大,且微孔减少、中孔及大孔发育是导致半焦吸附量增大的重要原因。该研究为水焦浆分散剂及低阶煤的开发利用提供了新途径。