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Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Design for inefficient well sidetracking of Bohai oilfield increased greatly recent years. Optimize sidetracking programs and reduce costs is important. Trajectory and window sidetracking tools were optimizing chosen for middle depth sidetracking to reduce costs. Horizontal casing well could solve mudstone and water contain problems for same layer sidetracking. For open hole completion well, window sidetracking costs lower for drilling platform working, and open hole sidetracking is suitable for workover rig. One to one design method for inefficient well sidetracking could reduce costs efficiently, good application results have been obtained. [ABSTRACT FROM AUTHOR]

Based on the orthogonal test design method, the expansive mudstone in the cutting of Jingxin expressway in Zhangjiakou city was tested, and the relationship between the expansion rate of mudstone samples under different overlying loads and the soaking time, initial water content and compaction degree was studied, and the sensitivity of various factors was analyzed by the range analysis method. The results showed that the curve of expansion rate with the soaking time presented an S-shaped trend, which can be roughly divided into initial expansion stage, accelerated expansion stage and slow expansion stage. Under the same initial water content, the expansion rate increased with the increase of the compaction degree. Under the same compaction degree, the expansion rate decreased with the increase of initial water content. The range analysis method showed that the soaking time of the sample was the main factor affecting the expansion rate. Water content and compaction degree were the secondary influencing factors, and the influence of water content on the sample expansion rate was obvious under small load, and the load continued to increase, the compaction degree exceeded the influence of water content on the sample expansion rate. [ABSTRACT FROM AUTHOR]

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Aiming at the design problem of inclined borehole wall in expansive mudstone formation in eastern Mongolia, a theoretical model of circular borehole wall under the combined action of uneven ground pressure and expansive contact pressure is established based on elastic mechanics theory. The analytical solution of borehole stress and displacement under the combined action of uneven ground pressure and expansive contact pressure is obtained. The influence of wall thickness on wall stress and displacement is studied. Based on the thermal coupling module of FLAC3D, the optimization scheme of different shaft thickness is simulated, and more reasonable supporting parameters are determined by optimizing shaft section and supporting form. The numerical results show that when the outer shaft wall reaches 600 mm and the inner shaft wall reaches 600 mm, the influence of increasing the shaft wall thickness on the displacement and deformation is not obvious. The optimized support scheme can effectively resist wellbore deformation in expansive mudstone formation.

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The swellability of mudstone has important influence on slope stability and other geotechnical engineering. Lianhuashan Formation of the Devonian is developed in Cenxi City, central of southeast Guangxi. It is mainly distributed in a small scale in the low hill area of the stripped and dissolved ridges and valleys geomorphologic area. In order to find out the dilatability of the mudstone in this area, this study has carried out geological mapping, drilling, field test, laboratory geotechnical test and X-ray diffraction analysis to determine the macro-characteristics and physical and mechanical properties of the mudstone. The swelling property of mudstone is studied by the comprehensive evaluation method of macroscopic preliminary judgment—physical and mechanical indexes quantitative initial judgment—Gaussian process quantitative detailed judgment. The physical and mechanical indexes are selected as effective montmorillonite content, < 2 μm colloidal content, liquid limit, plastic index and total swelling and shrinkage ratio, and the quantitative criterion of swelling property is given. The five indexes of mudstone in the study area are 22%-33%, 20%-33%, 46. 8%-78. 0%, 24. 1-42. 9 and 1. 3%-5. 2%, respectively. It is concluded that the mudstone in the study area has moderate to strong swellability. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the vertical bearing characteristics of dynamically driven piles on mudstone foundation, the vertical compressive static load test of single piles driven on mudstone foundation was carried out to analyze the sink penetration and bearing characteristics of the test piles, and to discuss the influence of groundwater on the bearing performance of the test piles, and to evaluate the applicability of the model by comparing and analyzing the calculated values of the ultimate bearing capacity of single piles from different theoretical prediction models based on the results of the static load test. Research shows that the ultimate bearing capacity of the test pile is related to the piling energy, and different piling energies cause different degrees of disturbance damage to the mudstone around the pile, which in turn affects the bearing performance of the test pile. Comparing the damage of the test pile with the mudstone around the pile in water, it is found that there is no direct relationship between the softening of the mudstone around the pile in water and the damage of the pile. Comparing the predicted ultimate bearing capacity results of different models, it is considered that the hyperbolic model is more suitable for the nature of the mudstone at this test site, and the predicted curve variation trend and the measured value are in good agreement. The reason for the large difference between the predicted value of the exponential model and the measured value is the abnormal damage of the test pile at the last level of loading. The pile driven into the mudstone foundation is affected by the super pore water pressure, soft and hard interlayer and the disturbance of the piling process, and the single pile bearing capacity has instability to a large extent. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

When traditional methods are used to test soil moisture migration of rock and soil, the undisturbed soil is often broken and reshaped, which will change the structure of rock and soil and affect the authenticity of the test results. In order to solve this problem, a new testing method is proposed by using the characteristics of nuclear magnetic resonance(NMR)technology for nondestructive measurement of moisture in materials. Firstly, the calibration experiment was carried out to establish a functional relationship between the NMR signal amplitude and the position of a soil sample with unit water mass in a non-uniform magnetic field of 0~0.05 T. Second, a one-dimensional infiltration experiment and NMR test were conducted to record the infiltration time, water mass increase and NMR signal under different test positions. Then, using the functional relationship obtained in the calibration experiment, approximations of the moisture mass and its spatial distribution in the sample were obtained by comparing the theoretical signal and the measured signals. Finally, the mudstone sample was cut into several parts to perform a verification experiment by oven drying, and the results showed that the error in water content was 4.05 % or less.

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the suitability of Saihan Formation mudstone in the Chuanjing Depression of Erlian Basin, Inner Mongolia, as an alternative surrounding rock geological condition for high-level radioactive waste geological disposal repository, 23 samples of Saihan Formation mudstone from borehole KZK2-6 in the study area were selected to carry out analysis and test on mineral composition and geochemistry and the mineral composition, sedimentary environment, source rock properties and structural background of Saihan Formation mudstone were discussed. The results show that the mudstone of the Saihan Formation is mainly composed of quartz, clay minerals, and albite, and the average mass percentage of clay minerals dominated by illite is 21. 2%. A certain mass percentage of analcime, dolomite, and pyrite highlights its advantages in nuclide adsorption as the surrounding rock of the repository. The major elements are mainly SiO2, Al2O3 and TFE2O3, and are poor in MnO, P2O5 and TiO2. Compared with the continental upper crust, trace elements such as Ga, Cr, and Cu are slightly enriched, while Ba and Sr are slightly depleted. Rare earth elements are characterized by obvious differentiation between light and heavy rare earth, enrichment of light rare earth, loss of heavy rare earth, obvious “right-leaning” trend of the distribution curve, and obvious negative anomaly of EU. The provenance is a mixture of the felsic and active continental margin, and the parent rocks are mainly sedimentary rocks and granite, which were formed in the tectonic background of the continental island arc. The sedimentary environment indicates that the Saihan Formation is a brackish lacustrine deposit with land-sea transition, and the overall anaerobic reduction environment is dominant, which is conducive to nuclide solidification. To sum up, the mudstone of Saihan Formation in Chuanjing Depression conforms to the geological and geochemical conditions of the alternative surrounding rock of the repository in terms of mineral composition and sedimentary environment and can be used as the key research object in the next research and development stage of the screening and evaluation of clay rock (mudstone) site in the geological repository of high-level radioactive waste. [ABSTRACT FROM AUTHOR]

The strata in coal mines are often distributed in layers with coexisting lithologies. The precursory indicators obtained from the study of the rock instability of a single lithology can often be challenging to apply in practical engineering. Therefore, it is important to explore the relationship between the fracture process of different lithologic rocks in a coal mine and acoustic emission（AE）parameters and establish various lithologic rock stability evaluation mechanisms based on AE parameters. In view of this, an acoustic emission monitoring system was used to measure three sequential types of lithology rocks（fine sandstone, sandy mudstone and siltstone）taken from coal seams. Through examining the correlation of AE parameters, five AE parameters with low correlation, such as energy, b-value, dominant frequency, apparent stress and apparent volume, are selected as the precursor indexes of the rock failure, and a stability evaluation system suitable for these three lithology rocks is established. The research results provide a basis for coal mine disaster early warning and prediction based on microseismic monitoring in practical engineering. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the geological conditions of the anchorage for a suspension bridge, it is proposed to calculate the value with theoretical methods. The Hoek-Brown solution, Bell solution and the modified Hoek-Brown solution are respectively used for comparative analysis based on the side loading effect of overlying rock and soil within the buried depth of the foundation base and the confining pressure effect of surrounding rock mass in the passive area, so as to obtain the theoretical solution of the bearing capacity of the bearing stratum of the project. In order to evaluate the difference between the above-mentioned standard solutions and the theoretical solutions and the measured values, a total of 6 groups of bearing capacity measurement tests in the bearing stratum of deep rock mass were carried out based on the East and West anchorage sites of the suspension bridge. The test results show that the characteristic value of the bearing capacity of the moderately weathered mudstone in the West anchorage and the characteristic value of the bearing capacity of the moderately weathered argillaceous sandstone in the East anchorage of the bridge are 2131 kPa and 2461 kPa respectively, which are significantly higher than the recommended value calculated according to the shallow foundation method in the current specification, and are closer to the modified Hoek-Brown theoretical solution, which provides a reference for the design and value selection for the bearing capacity of the bearing stratum of similar projects. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Bozhong 13-2 block is located on the Bozhong 13 structural ridge and is controlled by NE and NE trending faults. Due to the complexity of geological structure, leakage mechanism, pressure system and engineering factors, the weak layer in this block is difficult to “avoid”, “identify”, “block”, “control” and “seal”. In this paper, weak layer is identified by “three three” method. Then,the bottom hole pressure difference during drilling in weak layer is carefully controlled by pressure analysis model and mudstone borehole instability model of plugging transition zone. Finally, the high strength plugging technology are used to improve the layer bearing capacity after drilling. After the application of this technology in three wells in Bozhong 13-2 block, no complex accidents, such as well collapse, well surge and well loss occurred in the drilling process, which saved the construction period of more than 45 days and the cost of about 90 million yuan. This technology provided technical support for the overall development of Bozhong 13-2 block. [ABSTRACT FROM AUTHOR]

Fast plugging of microfractures and micropores in the hard brittle shales and deep buried sandstone/mudstone interbeds is one of the challenges that needs to be dealt with in solving borehole wall collapse in drilling the shale formation and reservoir damage. Graphene materials, because of their excellent properties such as nanometer sizes and layered membrane structures, can be used to solve these downhole problems at low concentrations and with high efficiency. A graphene slurry with good stability is prepared in laboratory with graphite using rolling lift-off technique. Evaluation of the performance of the graphene slurry shows that the D50 of the graphene particles is ±5 μm. The graphene slurry has good filtration control property and shale swelling inhibitive capacity. PPA test results show that the graphene slurry is able to effectively seal off the micropores on the sand plate. The application of the graphene slurry on two wells shows that it has good compatibility with the water based drilling fluids used and improves the plugging efficiency of the drilling fluids. Using this graphene slurry, the borehole wall collapse problem previously encountered is successfully solved. [ABSTRACT FROM AUTHOR]

A large number of shield tunnel construction practices have shown that the assembled tunnel segments just detached from the tail of the shield machine are prone to various defects such as ring displacement, crack propagation, and local damage. The reason for these defects is that the tunnel segments tend to float locally or as a whole during the construction process between the connecting rings. To investigate the reasons for the floating of tunnel segments during the construction period, a combination of theoretical derivation, numerical simulation, and on-site monitoring were used to roughly divide the floating force into two parts: "static floating force" and "dynamic floating force" for different strata and stages. The study focused on the theoretical derivation and analysis of the dynamic floating force magnitude and distribution during the grouting process at different stages. With the support of numerical simulation and on-site monitoring of the tunnel segment floating condition in the shield tunnel section from Sanyuanqiao station to Taiping Temple station of Chengdu metro line 9, the correctness of the formula and distribution pattern of the dynamic floating force calculation were verified for the poorly permeable and weathered mudstone stratum. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the shield muck in the mudstone stratum of Chengdu area, using cement as the solidification agent, fly ash as the active reinforcement material, and fine sand as the grading material, the mudstone muck unburned brick was prepared by pressing and molding, and was cured for 14 days in a concrete standard curing room. Using the compressive strength as an indicator, the effect of different mixing ratios on the compressive strength of the unburned brick was studied. The results show that the ratio of cement to fine sand has a positive linear relationship with the compressive strength of unburned bricks; Fly ash cannot be replaced with cement in an equal amount to improve compressive strength; When the mix design is 58% slag soil, 22% cement, 15% fine sand, and 5% fly ash, the compressive strength and softening coefficient of unburned bricks meet the MU15 grade requirements of JC/T422--2007 "Non fired Rubbish Gangue Bricks", and the appearance quality basically meets the specification re¬quirements. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND As an oil and gas geochemical detection and analysis technology, rock pyrolysis is widely used in oil and gas exploration. Moreover, this technology is fast, economical, and effective in evaluating the hydrocarbon-generating potential of source rocks and identifying the oiliness of reservoir rocks. Rock pyrolysis standard materials are used for the calibration and quality monitoring of rock pyrolysis instruments, as well as being the key material basis for quantitative calculation of rock pyrolysis analysis parameters for source and reservoir rocks. At present, rock pyrolysis standard materials are relatively scarce, and most of the on-site mud logging rock pyrolysis tests use value transfer samples for instrument calibration and quality control, which brings uncertainties to data quality. At the same time, the rock pyrolysis standard material in China lacks the important parameter S4 for source rock evaluation, while the rock pyrolysis standard material in foreign countries has only one value and cannot be used for gradient calibration. Therefore, it cannot meet the application and development requirements of rock pyrolysis analysis technology in oil and gas exploration. OBJECTIVES To develop five kinds of reference materials for rock pyrolysis, with a certain gradient value of each parameter, which can satisfy the needs of conventional oil and gas testing in petroleum exploration. METHODS Candidate samples were collected from dark mudstone, oil shale and carbonaceous mudstone in the Triassic Yanchang Formation, Permian Shanxi Formation, Taiyuan Formation and Carboniferous Benxi Formation in the Ordos Basin. After impurity treatment, jaw crushing, ball mill fine grinding, powder sieving 200 mesh, mixer mixing, 60Co irradiation disinfection and sterilization, and passing the preliminary homogeneity test, the samples were packed and numbered. RESULTS For each candidate, 5×30 bottles of samples were randomly selected for uniformity testing, and the measured values of F were all less than F0.05(29, 60). There was no significant systematic difference within and between groups of samples, and the uniformity was good. Short-term stability and long-term stability were tested by the straight line fitting method, and the slope of the fitting line |b1| < t0.05·S(b1), had good stability. Eight laboratories adopted the rock pyrolysis analysis method for collaborative determination. All of the determination analysis data conformed to the normal distribution, and the determination results and corresponding uncertainties were obtained. The fixed value parameters are S2, Tmax, S4 and reference value S1, wherein the value range of S2 is 2.01-11.90mg/g, the value range of Tmax is 437-442℃, the value range of S4 is 9.5-29.9mg/g. CONCLUSIONS In accordance with the national standard material research standards and specifications, five reference materials for rock pyrolysis, GBW(E)070323, GBW(E)070324, GBW(E)070325, GBW(E)070326 and GBW(E)070327, were successfully developed. The value of each parameter presents a certain gradient, which basically covers the content range of conventional pyrolysis analysis.

Under low confining pressures, a hard brittle mudstone is easy to dilate before the stress acted on the mudstone reaches its peak value. When the stress is greater than the dilation strength of the shale, the weakening of the mudstone by the hydration of the drilling fluid becomes fast and outstanding, resulting in borehole collapse. To avoid borehole collapse, a reasonable mud weight should be used. Through laboratory experiment and theoretical analysis, studies were conducted on the factors such as the fabric characteristics, hydrophysical properties, deforming patterns and strength criteria of hard brittle mudstones, as well as the change of strengths of mudstones after unloading prestress in a drilling fluid. A computation model and parameter computing method based on rock dilation strength criteria were developed for the collapse pressure of a borehole penetrating hard brittle mudstones, and a case study was conducted. The study results show that the mud weight is greater than the collapse pressure calculated on the basis of peak strength criteria and is lower than the collapse pressure calculated on the basis of dilation strength criteria, the formation around the borehole is in a state of dilation, and stress-induced micro fractures are generated around the wellbore, which stimulates drilling fluid hydration, and this is the root cause for borehole collapse. Based on this knowledge, mud weight determined on the basis of dilation strength criteria is more reasonable. [ABSTRACT FROM AUTHOR]

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The sedimentary sequences and geochemistry characteristics of mudstone contain much geological information and are widely used in sedimentology and provenance analysis. The Upper Carboniferous Benxi Formation in Gongyi area, the western Henan is rich in lithium resources. However, the source rocks, deposition conditions, and other controlling factors of lithium resouces and the occurrence minerals are not clear. Based on the field outcrop and the characteristics of major, trace and rare earth elements, the comprehensive analysis of Upper Carboniferous Benxi Formation in the western Henan were carried out. The lithium enrichment characteristics of Benxi Formation was illustrated, the source rocks, weathering degree, sediment sorting and recycling, paleoenvironment of Benxi Formation were discussed, and then the controlling factors of lithium enrichment were analyzed. The results show that lithium is mainly concentrated in mudstone with the average content of 1487×10-6, and the content of lithium in bauxite is low; Benxi Formation is mainly composed of fine-grained sediments, and the sedimentary sequences indicate that the sediments are deposited in lagoon; B/Ga ratio indicates that the sea water is brackish during the sedimentation; Sr/Cu ratio and other parameters show that the sediments are deposited in a warm humid-dry hot climate under anoxic conditions; the different diagrams of trace and rare earth elements in Benxi Formation indicate that the source rocks are mainly felsic igneous rock, and secondary limestones and mudstones; the chemical index of alteration and weathering index of parker parameters and related diagrams show that the source rocks have undergone strong weathering and sedimentary recycling. Lithium enrichment in Benxi Formation is closely related to the content of clay minerals (such as kaolinite and chlorite). Source rocks provide materials for lithium enrichment, and sedimentary characteristics such as sedimentary recycling processes and sedimentary environment, affect the enrichment of lithium resources. [ABSTRACT FROM AUTHOR]

The dark mudstone of Upper Paleozoic, which is one of the main source rocks in Huanghua depression of Bohai Bay Basin, has important exploration value. In order to further clarify the environment and formation mechanism of organic matter accumulation from the dark mudstone of Upper Paleozoic in Huanghua depression, the petrological, element geochemical and organic geochemical analyses were carried out. The results show that the dark mudstones of Upper Paleozoic in Huanghua depression of Bohai Bay Basin are near source deposits, which are in the transition period from hot and humid to warm and moist climate; the parent rocks are mainly felsic rocks, which are generally in medium to high weathering degree; the sedimentation sorting and recycling are weak, so the source information is well preserved; the enrichment of organic matter of the dark mudstone of Upper Paleozoic in Huanghua depression from the sedimentary period of Taiyuan Formation to the sedimentary period of Lower Shihezi Formation is not controlled by a single factor, but is the result of the joint control and mutual coupling of many factors, such as oxidation-reduction conditions, paleo-productivity, paleo-climate, and sedimentation rate; during the sedimentary period of Taiyuan Formation, the surface water has higher productivity and a relatively reductive sulfurizing underwater environment, which is conducive to the enrichment and preservation of organic matter; during the sedimentation period of Shanxi Formation, the surface water body also maintains high primary productivity under hot and humid conditions, and the higher sedimentation rate is conducive to the preservation of organic matter; during the sedimentary period of Lower Shihezi Formation, the warm and humid climate is conducive to the enrichment of organic matter, but the low deposition rate results in the dilution of organic matter by clay minerals and other inorganic minerals, which is relatively difficult to be preserved. [ABSTRACT FROM AUTHOR]

Several problems have been encountered in the development of the Sulige gas field, for example, the caving and sloughing of the hard and brittle mudstones of the Shuangshi formation of the Permian system, borehole instability of the black mudstones as well as difficulties in exerting weight to the bit in horizontal slide drilling, to name but three. Environmental protection requirements have limited the use of conventional shale inhibitors. In previous drilling operation, long time reaming, sidetracking after plugging the abandoned hole have been the norm for some time. To deal with these problems, an environmentally friendly cellulose shale inhibitor CQYJZ-3 was developed through chemical modification of a hemicellulose derivative, and an environmentally friendly drilling fluid named HCG-1, which is suitable for through-casing sidetracking of horizontal wells in Sulige gas field, was developed. Laboratory experimental results show that HCG-1 drilling fluid has stable rheology and good properties such as inhibitive capacity, lubricity, contamination resistance and corrosion inhibition. It is a non-toxic easy-to-degrade drilling fluid. This drilling fluid has been successfully used on 10 wells in the Sulige gas field. Field operation showed that HCG-1 had stable properties, good inhibitive capacity and lubricity. Wireline logging was successful at the first try. No downhole troubles were encountered during drilling. The HCG-1 drilling fluid can be also recovered for re-use. Good application achievements were obtained with the use of the HCG-1 in the Sulige gas field. [ABSTRACT FROM AUTHOR]

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