热液地质作用研究现状综述

文章从现代海底热液地质作用、热液成因白云岩、热液地质作用对油气储层的改造作用以及塔里木盆地热液地质作用等四个方面总结了国内外学者关于热液地质作用的研究方法和研究进展。介绍了热液地质作用的岩石学、矿物学和地球化学识别标志,最后提出热液地质作用的研究思路和发展方向。

塔东古城地区奥陶系碳酸盐岩中钠长石的发现及其地质意义

综合应用岩石薄片显微镜鉴定、电子探针分析、阴极发光显微分析及流体包裹体温度测试等，研究塔东古城地区奥陶系碳酸盐岩的岩石矿物学特征．结果表明：塔里木盆地古城地区中下奥陶统灰岩中发育钠长石自生矿物，钠长石的发育和分布具有独特性，集中发育于鹰山组灰岩地层，以偶见、分散状和沿缝合线富集3种产状分布，主要交代灰岩微晶方解石沉积组分及海底胶结物方解石等早期成岩组分；钠长石的流体温度较高，温度在340-440℃之间，与沉积时或沉积期后不久的浅海岩浆热液喷流作用有关；钠长石被晚期热液鞍状白云石交代，被缝合线及构造裂缝切割改造，为古城地区第一期热液地质作用．该地区钠长石的发现丰富塔里木盆地热液地质作用的矿物学标志，为研究热液地质作用期次和热液演化史提供依据．

Oxygen and hydrogen isotope exchange of geopressured thermal water in the central Guanzhong basin

Geothermal water of Xi'an and Xianyang in the central Guanzhong basin is typically geopressured thermal water in China. δ18O and δD data of geopressured thermal water in Xi'an and Xianyang, combined with data from the perimeter of the basin, are analyzed to study features of hydrogen and oxygen shifts. The results show that 18O exchange of geothermal water at the perimeter of the basin and in the non-geopressured thermal water in the center of the basin is not evident, while in most of the geopressured thermal water in the central basin, in cities such as Xi'an and Xianyang, significant oxygen exchange had taken place as well as hydrogen exchange, suggesting that isotope exchanges would slowly move the geothermal water system towards equilib-rium. Thermal water reservoirs in the central basin have passed through significant water-rock reactions. Moreover, the geothermal reservoir of Xianyang city is relatively much more enclosed than that of Xi'an city. It has been observed that the more enclosed the geological environment of geothermal water is, the more obvious the oxygen shifts are. With the increasing of the depth, residence time, total amounts of dissolute solids and temperatures of geothermal waters, the oxygen exchange accelerates.

注入诱发地震:利用高应力路径储层和温度诱发应力预处理降低诱发地震风险的策略

如果应力路径足够高,正断层应力机制下的流体注入可以稳定储层。当储层由于注入而显著冷却时,这种稳定性将消失。此外,本文还提出了一种新的激发剪切储层的策略,以减少诱发大震级地震的可能性。本文提出的方法适用于逆断层应力状态,包括初始应力预处理阶段,在该阶段,储层被冷却,压力增加受到限制。这一过程降低了水平总应力,从而也降低了差异应力。然后,储层受到孔隙压力快速增加的刺激,在较低的差异应力下导致剪切破坏,比储层中最初出现的差异应力要小。由于古登堡—里克特b值和差异应力之间的联系,以这种方式激发的储层将表现出更高的b值,从而也减少了发生大地震的可能性。该方法的适用范围包括正断层和走滑断层的应力机制。