巴东组岩石能量耗散规律的实验研究

岩石变形和破坏可以看作能量耗散和释放的过程,基于巴东县城西壤坡库岸巴东组岩石压缩实验数据,利用岩石能量学分析理论,分析了巴东组岩石能量的耗散规律,并探讨了巴东组岩石的破坏模式和库岸斜坡失稳机制。结果表明:(1)压缩试验得到了4类破坏模式,其中楔形剪-张破坏模式的平均能耗最大、沿弱面剪切破坏的能耗最小;(2)峰值前外荷输入能(E1)、峰值前岩块损伤能(ED)及单位长度裂纹耗能率均表明,巴东组岩石在垂向上硬度不均。在构造作用下,岩体内部广泛发育顺层滑脱带;(3)硬度高的岩石常表现为脆性破坏,破裂时能量耗散速度快。硬质岩斜坡在破坏前所集聚的弹性能,远大于破坏时所需的破裂能,易发生剧烈滑动;(4)在矿物成分变化处,巴东组岩石能量分析的各项指标表现出明显的波动,灰质高的岩石强度相对于黏土质高者的强度大。研究成果对于解释巴东组岩石强度特征和巴东城区内滑坡的失稳模式具有参考意义。

松辽盆地浅水三角洲沉积特征及模式研究——以卫星地区泉头组三、四段为例

利用研究区内26口预探井的岩芯精细观察资料以及100多口井的测井、录井资料,系统性地分析了研究区内沉积特征,建立松辽盆地北部泉头组三、四段地层理想的近似网状式浅水三角洲沉积模式。研究认为研究区是由浅水三角洲沉积体系向西南入湖而成,泉头组三、四段主要发育三角洲前缘、三角洲平原、浅湖亚相,可细分为(水下)分流河道、(水下)决口扇、支流间湾、天然堤、洪泛沉积等微相类型。研究发现,浅水三角洲中多发育较强水动力特征的层理,垂向上出现间断性正、反韵律变化,河道砂多为垂向加积型,形成了"大前缘、小平原"为沉积主体的沉积环境。在上述研究基础上,建立了整个松辽盆地北部地区近似网状式浅水三角洲沉积模式。

桂中坳陷下石炭统鹿寨组页岩气研究

桂中坳陷石炭系发现多处油气苗及沥青，具有良好的页岩气储集条件。对桂中坳陷下石炭统鹿寨组(C J )烃源岩进行了研究，认为烃源岩主要为台前盆地相暗色炭质页岩，鹿寨组下部页岩具有良好的生烃条件。烃源岩有机质丰度高，平均TOC含量为3.08°% ，干酪根类型为IIi 型和II2,来源于水生浮游生物和菌藻类母质，烃源岩最高热解峰温度460~560°C ，处于高成熟阶段，现今以生成天然气为主。页岩中脆性矿物含量为35.6% ~75.2%，粘土矿物含量为3.1%~62.1%，页岩硅质来源中生物成因硅质具有较大贡献，鹿寨组底部富有机质页岩段发育的有机质微孔隙和纳米级一微米级微裂缝是页岩气富集的主要空间。桂中坳陷经历多期叠加构造改造，抬升剥蚀对页岩气保存有重要影响，断层和岩浆热液活动对页岩气保存也不利。断层影响相对较小、盖层厚度超过1 8 0 m 的桂中坳陷西北部地区是下石炭统页岩气勘探的有利方向。

青海凯木都大湾东锌多金属矿地质特征及找矿前景分析

凯木都大湾东锌多金属矿区白沙河岩组中发育的大理岩、岩浆活动、岩体与围岩接触带构造为本区提供重要成矿条件。通过1:1万土壤测量圈定19个综合异常,异常主元素多以锌、铅、铜为主,最后圈定多金属矿化体5条,以此证明该区域具有较好的成矿地质条件,找矿前景良好。

Geochemistry of the Palaeo–Mesoproterozoic Tadpatri shales,Cuddapah basin, India: implications on provenance,paleoweathering and paleoredox conditions

The Palaeo–Mesoproterozoic Tadapatri formation of the Cuddapah basin is comprised of clastic sedimentary rocks with minor carbonates and mafic–ultramafic sill bodies. Geochemistry of the shale is used to study the provenance, paleoweathering and paleoredox conditions of this Tadpatri formation in order to better understand the development of the Cuddapah basin during Palaeo–Mesoproterozoic time. The higher CIA(average 74.39), PIA(average 85.94) and CIW(average 87.59) values of the Tadpatri shales suggest intensely weathered sources.Higher Al2_ O_3/TiO_2(average 30.78) and LREE/HREE ratio(average 8.80) with negative europium anomaly indicate derivation of the clastic sediments from a felsic source rock. The geochemical parameters like U, U/Th, Cu/Zn,Ni/Co, V/Cr ratios reveal that the Tadpatri shales are mainly deposited in an oxic condition.

河北省化学地层研究

以河北省区域岩石地层组44种元素含量为对象,以有序地质量最优分割方法为手段,进行化学地层界线划分。同时对地球化学异常层进行了梳理搜索,并对区域地层进行了地球化学对比,从而建立起区域地球化学格架。这是地层多重划分对比的重要组成部分,是现代地层学研究的重要步骤。

Study on damages constitutive model of rocks based on lognormal distribution

The damage constitutive relation of entire rock failure process was established using the theory of representative volume element obeying the Iognormal distribution law, and the integrated damages constitutive model of rock under triaxial compression was established. Comparing with triaxial compression test result, it shows that this model correctly reflects the relationship of stress-strain. At the same time, according to the principle of the rock fatigue failure that conforms to completely the static entire process curve, a new method of establishing cyclic fatigue damage evolution equation was discussed, this method form is simple and the physics significance is clear, it may join preferably the damage relations of the rock static entire process curve.

Characteristics of Metamorphic Rock Magnetic Fabrics in the Nyalam Area of the Southern Tibet and Its Geological Significance, China

This paper reports Precambrian rock magnetic fabrics in the Nyalam area of southern Tibet. The analytical results of magnetic fabrics show that the values of H are high （〉 10% in general）, so the ductile deformations of the Precambrian rock are strong. The orientation of the maximum principal stress inferred from the minimum magnetic susceptibility is nearly S-N, NE-SW and NW-SE. The Flinn diagram of the magnetic fabrics show that the strain pattern is oblate and constrictional type. Magnetic foliation of great majority of rock samples is well developed and the magnetic lineation is poor and the magnetic susceptibility ellipsoid is flattened. The magnetic lineation of the minority rock samples is well developed and the magnetic foliation is poor and the magnetic susceptibility ellipsoid is prolate. According to the geological field and the magnetic fabrics, there are 3 times tectonic stress field in SN directed extruding, NW-SE directed extruding, NW-SE directed extension. It shows that the Nyalam area has undergone process the orientation of SN, NW-SE nappe structure and NW-SE directed extension structure. The change of tectonic stress is reflected by the field characteristics of the Precambrian rock magnetic fabrics that is the direct responding result of the arc-continental, continent-continental collision between the India and Asian continents in the late part of the Late Cretaceous to Late Eocene and subsequently shifted to intra-continental convergent, the plateau uplifting and extension structure stage since the Late Eocene.

Shales in the Qiongzhusi and Wufeng–Longmaxi Formations:a rock-physics model and analysis of the effective pore aspect ratio

The shales of the Qiongzhusi Formation and Wufeng-Longmaxi Formations at Sichuan Basin and surrounding areas are presently the most important stratigraphic horizons for shale gas exploration and development in China. However, the regional characteristics of the seismic elastic properties need to be better determined. The ultrasonic velocities of shale samples were measured under dry conditions and the relations between elastic properties and petrology were systemically analyzed. The results suggest that 1） the effective porosity is positively correlated with clay content but negatively correlated with brittle minerals, 2） the dry shale matrix consists of clays, quartz, feldspars, and carbonates, and 3） organic matter and pyrite are in the pore spaces, weakly coupled with the shale matrix. Thus, by assuming that all connected pores are only present in the clay minerals and using the Gassmann substitution method to calculate the elastic effect of organic matter and pyrite in the pores, a relatively simple rock-physics model was constructed by combining the self-consistent approximation （SCA）, the differential effective medium （DEM）, and Gassmann＇s equation. In addition, the effective pore aspect ratio was adopted from the sample averages or estimated from the carbonate content. The proposed model was used to predict the P-wave velocities and generally matched the ultrasonic measurements very well.

Numerical simulation of dynamic fracture properties of rocks under different static stress conditions

When underground cavities are subjected to explosive stress waves,a uniquely damaged zone may appear due to the combined effect of dynamic loading and static pre-load stress.In this study,a rate-dependent two-dimensional rock dynamic constitutive model was established to investigate the dynamic fractures of rocks under different static stress conditions.The effects of the loading rate and peak amplitude of the blasting wave under different confining pressures and the vertical compressive coefficient(K_(0))were considered.The numerical simulated results reproduced the initiation and further propagation of primary radial crack fractures,which were in agreement with the experimental results.The dynamic loading rate,peak amplitude,static vertical compressive coefficient(K_(0))and confining pressure affected the evolution of fractures around the borehole.The heterogeneity parameter(m)plays an important role in the evolution of fractures around the borehole.The crack propagation path became more discontinuous and rougher in a smallerheterogeneity parameter case.

Study of the engineering geologic feature of weathering zone of bedrock in 810 producing area of Luling Mine

For a safe extracting of the mine resource of the razor thin capping rock, a study of waterproof, sand prevention, roof fall prevention must be made. As a result, it’s necessary to master the engineering feature of weathering zone of bedrock. According to the lithology appraisal and X diffract analyses, the mineral feature of weathering zone of bedrock in 810 producing area has been studied in this article. By testing the physical mechanics index of weathering zone, we have found out some features of physical mechanic quality. Utilizing the determined result of viscosity index and slaking test, we reach a conclusion of the water stability of weathering zone, that is the weathering zone rock belongs to the type that is easily slaked when encountered water and the water stability is weak.

Petrophysical characteristics of shale oil reservoirs in the Yanchang Formation,Ordos Basin

The mediate-low maturity continental shale oil reservoir in the 7th member of the Triassic Yanchang Formation is one of the main zones for shale oil exploration and development in Ordos Basin,China,but the seismic response mechanism of the reservoir remains unclear.Therefore,developing a new method for“sweet spot”seismic prediction combined with rock physics is necessary.To determine the petrophysical characteristics of continental shale in the 7th member of the Yanchang Formation in the study area,a series of tests,such as a systematic acoustic test on shale oil samples in the target segment,X-ray diffraction analyses,analysis of thin optical sections,and scanning electron microscopy,were conducted to summarize the patterns of seismic elastic property changes.Results show that the shale oil samples of the 7th member of the Yanchang Formation are primarily composed of lithic feldspar sandstone with feldspar dissolution and intergranular pores,widespread micron pores,and throats.Such composition indicates a positive correlation between porosity and permeability.The velocities of the samples are affected by their porosity and mineral composition.Velocity increases with the increase of the calcium content and decreases with the increase of the clay content,indicating a negative correlation with the porosity and total organic carbon(TOC)content on the condition of the same rock structure(quartz skeleton or clay skeleton).The elastic properties of the rock are horizontally isotropic(T1 medium),and the velocity is vertically anisotropic.In addition,the directional arrangement of clay controls the anisotropy of rock velocity.TOC is mainly distributed in the primary intergranular pores,and it has no contribution to the anisotropy of rock velocity.The results of this paper can provide a reference for the seismic prediction of continental shale oil reservoirs in the 7th member of the Yanchang Formation.

Sequence Stratigraphy Study of the Late Quaternary Activity of the Nankou-Sunhe Fault in Its Northern Segment,Beijing

A test drilling exploration was implemented across the northern segment of the Nankou-Sunhe fault in the Beijing plain,and a combined borehole section was built by sequence stratigraphy,lithologic facies analysis,magnetic susceptibilityand absolute chronology to investigate the episodic activities of the fault since 60 ka BP. The results show that the active stages of the fault are 60 ka to 47 ka BP,36 ka to 28 ka BP,and 16 ka BP to present. Other intervals are relatively stable. The average vertical slip rate is 0.35 mm/a from 60 ka to 37 ka BP,0 mm/a from 37 ka to 32 ka BP,0.78 mm/a from 32 ka to 12 ka BP,and 0.35 mm/a since 12 ka BP. Compared with the conventional analyses on lithology and sedimentary facies,the sequence stratigraphy method has certain advantages in the studies of borehole strata comparison and episodic activity of buried faults.

Diagenesis and reservoir quality of the fourth member sandstones of Shahejie formation in Huimin depression,eastern China

Petrographic analysis combined with various techniques, such as scanning electron microscopy and X-ray diffraction, was used to assess the timing of growth and original mineral cements, the controls on reservoir and reservoir quality of the fourth member sandstones of Shahejie formation (Es4). The Es4 sandstones are mostly arkose and lithic arkose, rarely feldspathic litharenite, with an average mass fraction of quartz 51.6%, feldspar 33.8% and rock fragments 14.6% (Q51.6F33.8R14.6). They have an average framework composition (mass fraction) of quartz 57.10%, K-feldspar 5.76%, sodium-calcium feldspar 13.00%, calcite 5.77%, dolomite 5.63%, siderite 0.95%, pyrite 0.30%, anhydrite 0.04%, and clay mineral 11.46%. The diagenentic minerals typically include kaolinite, illite-smectite (I/S), illite, chlorite, authigenetic quartz and feldspar, and carbonate and pyrite. Es4 sandstone has undergone stages A and B of eodiagenesis, and now, it is experiencing stage A of mesodiagenesis. Reservoir quality is predominantly controlled by the mechanical compaction, for example, 45.65% of the original porosity loss is related to compaction. The original porosity loss related with cementation is only 26.00%. The reservoir quality is improved as a result of dissolution of feldspar, rock fragment and so forth. The porosity evolved from dissolution varies from 3% to 4%.

Study on critical conditions for rock failure by means of group renormalization

A study of the characteristics of the accumulative rock failure and its evolution byapplication of the group renormalization method were presented. In addition, the interactionand long-range correlated effects between the immediate neighboring units was studied.The concept of mechanical transference for model OFC, employed in the study ofself-organized criticality, and the coefficient a were introduced into the calculation model forgroup renormalization. With the introduction, mechanisms for the drastic increase and decrease of failure intensity of rocks were investigated under similar macro-conditions.

Unconventional Story： A Future with Shale Gas and Other Unconventional Resources, A Look from Russia

The main achievements in the development of hardly-recoverable resources are currently associated with shale oil and gas. The result of the ＂shale revolution＂ was billions of dollars in losses for oil exporters. The question is how this situation w＇ill be long-lasting or ＂shale bubble＂ will burst. The success of the shale revolution can be not only an economic win or economic defeat of the United States, the question is about reputation as a global political leader and the country＇s ability to solve the most difficult technological problems. Everything at stake to extend the ＂shale gas revolution＂ as it is possible longer, in time to prepare the conditions and technologies for a new energy revolution and to maintain the usual high level of energy consumption. The situation is further complicated by the introduction in the game of OPEC （organization of petroleum exporting countries） causing oil prices dropped below the cost of shale oil. The future of high technology in the production of oil depends on whether exporters and importers to negotiate the best price for oil, to ensure the sustainable development of the world economy.

Modelling the Sorption of 63Ni to Granitic Materials： Application of the Component Additive Model

The component additive modelling approach is based on summing the results from models already calibrated with pure mineral phases. The summation can occur as the sum of results for thermodynamic surface speciation models or as the sum of pseudo-thermodynamic models for adsorption on individual mineral phases. Static batch sorption experiments of 63Ni are with different granitic rocks and component minerals. XRD analyses have been used to calculate the percentage mineralogical composition of the granitic rocks. Sorption data has been modelled using non electrostatic correction models to obtain Rdfor the granitic rocks and mineral. Ra values for the granitic rocks predicted from the component additive model have been compared to experimental values. Results showed that predicted Rd values for granite adamellite, biotite granite and rapakivi granite were identical to the experimentally determined values, whereas, for graphic granite and grey Granite, the predicted and experimentally determined Ra values were much different. The results also showed a greater contribution to the bulk Raby feldspar while quartz showed the least contribution to the Rd.

LA-ICP MS Characteristic of Geochemical Composition of Veins Rocks from the Central Part of the Khibina Massive in Kola Peninsula, Northern Russia

This paper discusses the vein rocks located in the central part of Khibina Mts.. These rocks are located on the border of two zones： ore and external. In the ore, zone is present titanite-nepheline bodies whilst in the outer zone are massive-syenites ＂khibinites＂. The veins can be divided into： mikrosyenites, melteigites and other rock types （e.g., tinguaites）. The results of LA-ICP MS （laser ablation of inductively coupled plasma mass spectrometry） indicate that these rocks are associated with deep zones which formed as a result of injection of primary magma and contamination of fluids during migration, where there have hydrothermal processes. Rock-forming minerals, their corrosion and accessory minerals indicate these processes, too.

不同试验条件下深部下组煤底板水岩相互作用特征

为探讨济北矿区深部下组煤底板岩石与水相互作用规律,以岱庄煤矿首采面底板5种不同类型岩性的岩样为研究对象,在自来水与饱和食盐水浸泡后并结合自然浸泡与湿–干交替循环浸泡条件下两两组合进行为期52 d的水稳性和相关电导率试验。研究结果表明:(1)根据20个岩样掉渣、表面裂隙、岩样开裂、饱水后强度和崩解等现象统计对比分析,发现不论是自来水还是饱和食盐水在自然浸泡条件下5种岩样的水稳性均相对较好,浸水后基本不崩解,但在湿–干交替循环作用条件下均会发生崩解现象;(2)通过对自来水浸泡岩样在自然与湿–干交替条件下电导率测试,发现所有岩样溶液中电导率增加幅度随时间均表现出比较明显的3个阶段,但同一岩样在不同条件下电导率增加幅度随时间变化具有较大差异性,湿–干交替岩样的电导率增加幅度明显大于自然浸泡岩样的;(3)电导率和岩样质量损失率基本呈正相关关系。研究结果对深部水岩相互作用导致岩石劣化的微观机制研究提供参考。

云南盘溪剖面泥盆系-石炭系界线地层及其沉积环境

云南盘溪剖面是华南泥盆纪浅水相代表性剖面之一,本文对盘溪剖面的在结山组及其上覆的石炭系地层进行了综合研究。首次在在结山组内发现了无洞贝类Desquamatia? sp.、综合珊瑚及层孔虫等化石证据,表明在结山组属于弗拉斯期。在在结山组之上的石炭系下部地层内,首次发现维宪期的有孔虫。根据有孔虫等生物推断盘溪剖面最早的石炭系应是维宪阶岩石岭组的沉积地层,相当于华南旧司组的一部分,大致与湖南石磴子组的中上部相当,时代约对应早石炭世维宪期Endothyranopsis compressa-Archaediscus krestovnikovi有孔虫组合带。因此,盘溪剖面在结山组之后缺失了上泥盆统法门阶至下石炭统杜内阶。微相分析表明在结山组为弗拉斯期晚期形成的一套局限台地礁后潟湖相的碳酸盐岩沉积,而岩石岭组则代表维宪期的一次正常海平面上升过程,属于碳酸盐开阔台地环境。