矩形断裂石香肠矿物成分体积分数与其流变学意义研究——以湖北铁山为例

以湖北大冶铁山地区发育的矩形断裂石香肠为例,从地质研究的角度探索了矩形断裂石香肠体的黏度与其矿物组成和体积分数之间的关系。结果表明,当矩形断裂石香肠体中透辉石的体积分数越大,则石英、绢云母和方解石等矿物的体积分数越小,对应的石香肠体的黏度就越大;它们的能干性排序依次为:透辉石>石英和绢云母>方解石。

改进的双矿物模型在川东北地区陆相致密储层测井评价中的应用

川东北地区大安寨段地层发育泥岩、砂岩和介壳灰岩,其中介壳灰岩是研究区储层的主要岩性。研究区储层为特低孔隙度特低渗透率微孔隙-微裂缝型储层,孔隙结构复杂,非均质性强。传统的双矿物模型利用岩性孔隙度测井曲线定量计算矿物成分和地层孔隙度,结果与录井描述和岩心分析结果符合较差。提出了改进的双矿物模型,利用对岩性敏感的电阻率测井曲线确定介壳灰岩和砂岩相对体积分数,根据混合矿物骨架值计算基质孔隙度。改进后的双矿物模型确定的矿物成分和基质孔隙度与录井描述和岩心分析结果基本一致。对比传统双矿物模型,改进的双矿物模型是一种对该地区复杂岩性微孔隙-微裂缝储层有效实用的测井解释模型。

多矿物处理方法在北美页岩油气藏测井评价中的应用

页岩油气储层与常规油气储层、泥质或灰质围岩的测井响应特征不同,通常呈高自然伽马、高中子孔隙度、高电阻率、高纵波时差、低体积密度和低光电吸收截面指数等特征。页岩油气储层较常规油气储层的岩石物理体积模型复杂,仅仅利用常规测井资料进行评价精度较低。为此,本文以美国德克萨斯州南西湾(Western Gulf)盆地的页岩储层F为例,综合利用常规测井与自然伽马能谱测井,建立了多矿物体积模型,采用最优化方法,利用多矿物处理模块对该页岩油气层进行处理,得到了地层岩性剖面、孔隙度、含水饱和度及总有机碳含量等参数,探讨了页岩油气储层参数测井评价方法,取得了较好的处理效果。

绿泥石缺失条件下盖层封闭性的变化规律

为进一步探究绿泥石对CO2-水-岩石相互作用的影响,结合鄂尔多斯盆地深部地层的黏土矿物组成,利用先进的数值模拟软件TOUGHREACT,研究了绿泥石缺失条件下盖层封闭性的变化规律,并揭示了其封闭性变化的机理。结果表明:绿泥石缺失使盖层中的地球化学反应发生了极大的变化,矿物体积分数的变化量减小,盖层的自溶蚀效应减弱;矿物的化学行为(由沉淀为主转化为以溶解为主或由溶解为主转化为以沉淀为主)发生了逆转;CO2-水-岩石的地球化学进程大幅减缓;CO2的矿化捕集作用明显减弱,且CO2矿化捕集量一直小于0,不利于CO2地质封存。

安棚深层系储层孔隙度计算方法研究

在低孔低渗储层中 ,声波时差测井对孔隙度响应较差 ,利用声波测井资料直接计算储层孔隙度误差较大 ,很难满足精度要求。在对中子孔隙度和密度孔隙度进行环境校正的基础上 ,根据双矿物体积模型(砂岩、碳酸盐岩 ) ,列出三孔隙度测井响应方程 ,求出这三组超定方程组的解 ,从而得到安棚深层系三孔隙度解释模型。用岩心分析孔隙度对该方法进行检验精度较高 ,能较好解决安棚深层系低孔低渗储层孔隙度计算的问题。

二氧化碳埋存条件下油井水泥石腐蚀的热力学模拟

水泥石腐蚀问题是导致CO2埋存失效的关键因素之一。基于热力学吉布斯能最小化方法,模拟CO2埋存条件下水泥石的腐蚀,研究腐蚀过程中水泥石矿物组成与矿物质量的变化、矿物体积的变化和孔隙溶液pH值的变化,分析温度和压力对腐蚀的影响。结果表明水泥石矿物中羟钙石最先受到腐蚀,方解石的耐腐蚀性能最好,其他矿物的耐腐蚀性能相似;在羟钙石被完全腐蚀之前,水泥石矿物总体积不会缩小,孔隙溶液pH值基本维持不变,完全腐蚀之后总体积减小、pH值会降低,其他矿物陆续受到腐蚀。温度和压力对水泥石矿物种类的影响较小,温度越高时腐蚀水泥石所消耗的CO2质量越大;压力主要影响方解石的腐蚀,压力越高方解石的腐蚀程度越严重。研究结果可为水泥石CO2腐蚀的防治提供指导和依据。

基于PSO-GRG的背散射模式扫描电镜的数字处理及应用

根据背散射扫描电镜中灰度信息的多元高斯分布特征构造目标函数,应用粒子群-广义简约梯度(PSOGRG)联合优化算法求解岩石不同成分的灰度阈值,结合形态学滤波和图像融合算法得到典型元素图,并定量计算矿物体积分数及孔隙度。结果表明:所得岩石成分信息与氦气法、X衍射法所得结果一致性好,可靠性高;在取柱塞样品困难和样品规则度差的地区具有较好的推广性,可以为定量计算岩石成分信息提供新的手段,充分挖掘背散射模式扫描电镜图像中所蕴含的丰富地质信息。

Self-adapting extraction of matrix mineral bulk modulus and verification of fluid substitution

Gassmann＇s equations are commonly used for predicting seismic wave velocity in rock physics research.However the input matrix mineral bulk modulus parameters are not accurate,which greatly influences the prediction reliability.In this paper,combining the Russell fluid factor with the Gassman-Biot-Geertsma equation and introducing the dry-rock Poisson＇s ratio,we propose an effective matrix mineral bulk modulus extraction method.This method can adaptively invert the equivalent matrix mineral bulk modulus to apply the Gassmann equation to fluid substitution of complex carbonate reservoirs and increase the fluid prediction reliability.The verification of the actual material fluid substitution also shows that this method is reliable,efficient,and adaptable.

Trace element composition of magnetite from the Xinqiao Fe–S(–Cu–Au) deposit, Tongling, Eastern China: constraints on fluid evolution and ore genesis

The Xinqiao deposit is one of several polymetallic deposits in the Tongling ore district. There are two types of mineralization in the Xinqiao： skarn-type and stratiform-type. The skarn-type mineralization is characterized by iron oxides such as magnetite and hematite, whereas stratiform-type mineralization is characterized by massive sulfides with small amounts of magnetite and hematite. We defined three types of ores within the strati- form-type mineralization by the mineral assemblages and ore structures. Type Ⅰ ore is represented by magnetite crosscut by minor calcite veins. Type Ⅱ is a network ore composed of magnetite and crosscutting pyrite. Type Ⅲ is a massive ore containing calcite and hematite. Type Ⅰ magnetite is characterized by highly variable trace element content, whereas Type Ⅱ magnetite has consistently higher Si, Ti, V, and Nb. Type Ⅲ magnetite contains more In, Sn, and As than the other two types. Fluid-rock interaction, oxygen fugacity （fO2）, and temperature （T） are the main factors controlling element variation between the different magnetite types. Type I magnetite was formed by more extensive fluid-rock interaction than the other two types at moderate fO2 and T conditions. Type Ⅱ magnetite is thought to have formed in relatively low fO2 and high-Tenvironments, and Type Ⅲ in relatively high fOe and moderate-T environments. Ca ＋ Al ＋ Mn and Ti ＋ V discrimination diagrams show that magnetite in the Xin qiao deposit is hydrothermal in origin and is possibly linked with skarn.

Volumetric Variation and Rheology of Cement Based Mineral Additions （Blast Furnace Slag and Silica Fume）

The partial substitution of clinker by mineral additions offers very significant, both economical and environmental benefits. This adds value to industrial waste, and contributes also in the preservation of natural resources, like clay and limestone, as well as the reduction of greenhouse gas emissions （CO2）. This study is interested in the simultaneous effect of BFS （blast furnace slag） and SF （silica fume） on setting time and water requirement of cement paste. The volumetric variations are tested in mortars, prepared in the same mixture of pastes, and the tests indicate that the addition of slag increase the fluidity, reduce the water demand, shrinkage and expansion, compared to the mortar, containing ten percent （10%） of Silica Fume only. The images of pastes obtained by SEM （scanning electron microscopy）, are indicated an improvement of the microstructure of the paste with a large amount of slag, which leads to improve durability.

Insulation System of Power Transformers Behavior Comparison of Mineral Oils and Natural Ester Dielectric Fluids

Paper deals with a comparison of selected properties of several vegetable oil representatives along their accelerated thermal ageing at the temperature of 90 ℃. These properties are compared to two widely used and commercially available mineral transformer oils. A combined insulating system （an oil-paper system） was created with the usage of mentioned oils for measurement purposes. Dissipation factor, capacity and volume resistance are characteristics measured along a thermal ageing of the oil-paper systems. Infrared spectroscopy was used as an additional method. After 1,000 hours of ageing, the dissipation factor of all systems based on vegetable oils did not exceed the value of 0.015. The volume resistance of systems containing mineral oils was approx, twice as high as the volume resistance of those with vegetable oils. The capacity on the other hand was slightly lower in the case of mineral oils application. An experiment also showed that the paper combined with the vegetable oil dries more quickly than in combination with the mineral oil. Infrared spectroscopy has not shown any expressive changes in the chemical structure of aU tested oils yet （up to 1,000 hours of ageing）.

Ultradeep diamonds originate from deep subducted sedimentary carbonates

Diamonds are renowned as the record of Earth's evolution history.Natural diamonds on the Earth can be distinguished in light of genetic types as kimberlitic diamonds(including peridotitic diamonds and eclogitic diamonds),ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds.According to the inclusion mineralogy,most diamonds originated from continental lithospheric mantle at depths of 140-250 km.Several localities,however,yield ultradeep diamonds with inclusion compositions that require a sublithospheric origin(>~250 km).Ultradeep diamonds exhibit distinctions in terms of carbon isotope composition,N-concentration,mineral inclusions and so on.The present study provides a systematic compilation concerning the features of ultradeep diamonds,based on which to expound their genesis affinity with mantle-carbonate melts.The diamond-parental carbonate melts are proposed to be stemmed from the Earth's crust through subduction of oceanic lithosphere.Ultradeep diamonds are classified into a subgroup attaching to kimberlitic diamonds grounded by formation mechanism,and present connections in respect of carbon origin to eclogitic diamonds,ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds.

Nanoindentation characteristics of cement with different mineral admixtures

In order to determine the effects of different mineral admixtures including fly ash （FA）, blast furnace slag （BFS） and metakaolin （MK） on hydration product phases from the nanoscale structure perspective, nanoindentation characteristics of the samples with similar 28-day strengths have been investigated. The results indicate that the volume fractions of porosity in po- rosity and hydration product phases of the samples with the same kind of mineral admixture are almost equal to each other, and are greater than that of the sample without mineral admixture. Mineral admixtures especially MK can decrease remarkably the volume fractions of CH in porosity and hydration product phases, and there exists a good linear relationship between the （AI＋Si）/Ca molar ratio of cementitious materials chemical compositions and the volume fraction of HD C-S-H gel in C-S-H gel. Therefore, it is possible to predict the volume fraction change of HD C-S-H gel in C-S-H gel by simply calculating the （AI＋Si）/Ca molar ratio of cementitious materials with similar 28-day strengths under the constant water-binder ratio.

Experimental study of the electrical conductivity of hydrous minerals in the crust and the mantle under high pressure and high temperature

Hydrous minerals are important water carriers in the crust and the mantle, especially in the subduction zone. With the recent development of the experimental technique, studies of the electrical conductivity of hydrous silicate minerals under controlled temperature, pressure and oxygen fugacity, have helped to constrain the water distribution in the Earth's interior. This paper introduces high pressure and temperature experimental study of electrical conductivity measurement of hydrous minerals such as serpentine, talc, brucite, phase A, super hydrous phase B and phase D, and assesses the data quality of the above minerals. The dehydration effect and the pressure effect on the bulk conductivity of the hydrous minerals are specifically emphasized. The conduction mechanism of hydrous minerals and the electrical structure of the subduction zone are discussed based on the available conductivity data. Finally, the potential research fields of the electrical conductivity of hydrous minerals is presented.