Accumulation process and model for the Ordovician buried hill reservoir in the western Lunnan area,the Tarim Basin

The Ordovician buried hill reservoir in the western Lunnan area, a type of dissolved fracture and cavernous reservoir, is mainly composed of heavy oil. The oil is the mixture sourcing from the Middle-Lower Cambrian and Middle-Lower Ordovician, with three stages of pool forming process: (1) the destruction and parallel migration/accumulation during the late Caledonian to early Hercynian; (2) the oil and gas accumulation during the late Hercynian characterized by adjustment upward along faults and parallel migration/accumulation; (3) the formation of heavy oil during the latest Hercynian. The Ordovician buried hill reservoir is affected by the diffusion of light oil and gas but had no hydrocarbon charging during the late Yanshan period to Himalayan period, but in this period, formed the association of heavy oil and dissolved gas cracked from crude oil with dry coefficient of 0.91-0.96. The study on accumulation process of the Ordovician buried hill reservoir has important implications for the exploration potential of early oil and gas accumulation in the cratonic area of the Tarim Basin.     

Accumulation process and model for the Ordovician buried hill reservoir in the western Lunnan area, the Tarim Basin

The Ordovician buried hill reservoir in the western Lunnan area, a type of dissolved fracture and cavernous reservoir, is mainly composed of heavy oil. The oil is the mixture sourcing from the Middle-Lower Cambrian and Middle-Lower Ordovician, with three stages of pool forming process： （1） the destruction and parallel migration/accumulation during the late Caledonian to early Hercynian; （2） the oil and gas accumulation during the late Hercynian characterized by adjustment upward along faults and parallel migration/accumulation; （3） the formation of heavy oil during the latest Hercynian. The Ordovician buried hill reservoir is affected by the diffusion of light oil and gas but had no hydrocarbon charging during the late Yanshan period to Himalayan period, but in this period, formed the association of heavy oil and dissolved gas cracked from crude oil with dry coefficient of 0.91-0.96. The study on accumulation process of the Ordovician buried hill reservoir has important implications for the exploration potential of early oil and gas accumulation in the cratonic area of the Tarim Basin.     

An Analysis of the Kinetic Features of Scissor Elevator Mechanism and Its Optimized Design

A mathematical model has been established for the research on scissor elevator for ship passenger stairs.The kinematical and kinetic simulation analyses were carried out with MATLAB/Simulink.The relative kinetic relation between hydraulic cylinder and other parts,as well as its rules of change has been found.A 3-D model of ship scissor elevator was established with Pro/E.The design of the mechanism was optimized in Pro/MECHANICA based on the findings from simulation analysis.Practice has proved that the design is scientific and reasonable and could serve as the theoretical guidance and reference for the design of scissor mechanism of other uses.     

Mass balance calculation of the pyrolysates generated from marine crude oil： A prediction model of oil cracking gas resources based on solid bitumen in reservoir

Oil cracking gas plays an important role in the resources of natural gas in the basins with high and over mature marine source rocks in China. The prediction of the oil cracking gas resources becomes nec-essary and urgent in the gas exploration in these basins. A marine crude oil sample was pyrolyzed using sealed gold tubes system. The pyrolysates including gas,liquid and solid were quantitatively analyzed. Based on the pyrolysis data and kinetic calculation,the yield correlativity among gas,liquid and solid products was regressed with high correlative coefficients to establish a prediction model suitable for the resource estimation of oil cracking gas. The verification formula for this model was also established on the principle of mass conservation. The affecting factors and the application precondi-tions of this prediction model were discussed. This model would enlighten and provide some new ideas for the resource assessment of natural gas in the high and over mature marine carbonate source rock areas in China. It is expected to be valuable in gas exploration.     

Experimental studies on interaction of water mist with class K fires

Interaction of water mist with cooking oil fires is studied experimentally and theoretically. A LDV/APV system is used to measure the velocity and diameter of water mist at different pressures in the experiments,and the effect of water mist velocity and diameter on fire extinguishment efficiency is investi-gated. The experimental results show that water mist has excellent surface cooling effect; it can control and extinguish cooking oil fires quickly without re-ignition. The critical temperature (Tfo) is calculated by energy balance equation,and the fire plume momentum is calculated and compared with that of water mist in order to determine the critical velocity (νwy) of fire extinguishment. This paper provides references for cooking oil fires extinguishment with water mist.     

Environmental boundary and formation mechanism of different types of H<Subscript>2</Subscript>S corrosion products on pipeline steel

To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide (H₂S) corrosion products, theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H₂S corrosion conditions were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably, a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results, we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H₂S corrosion mechanism in the oil and gas industry.     

Low-temperature magnetic anomalies of oxygen-doped T′-type 214 compounds

A new low_temperature anomalous magnetism at about 29 K for the oxygen doped (Eu 1- x Y x ) 2CuO 4 and Sm 2CuO 4, prepared under high pressure, has been investigated. This anomaly originated from different mechanisms to weak ferromagnetism (WF) behavior of T′ phase, and should be assigned to the ferromagnetic clusters formed by doped holes.     

Oil cracking： An important way for highly efficient generation of gas from marine source rock kitchen

The potentials of gas generation by kerogen in the late period and by crude oil cracking are closely related to the origin of natural gas in the high- to over mature marine area and their exploration perspectives. The carbon structure of kerogens, with different types and at different evolution stages, have been experimentally studied using the high magnetic field solid ^13C nuclear magnetic resonance technique in order to determine the oil and gas potential of kerogens. Results show that the contents of gas potential carbon（GPC） of types Ⅰ, Ⅱ, Ⅲ kerogens at the high- to over mature stage are very low, indicating their weak gas-generating capacity and limited gas production; however, the content of oil potential carbon（OPC） of the low mature type Ⅰ kerogen is much higher, implying that a large amount of crude oil generated during the oil-generating period will be the material for later gas generation by oil cracking. The kinetic experiment of gas generation by crude oil cracking shows that, when the temperature is about 160℃（R0=1.6%）, the crude oil will start to produce large amounts of gas; the temperature range for major gas generation of crude oil is higher than that of the kerogens, and the gas production is 2 to 4 times higher than that of kerogens. The natural gas derived from oil cracking （called oil-cracked gas） is much abundant in methyl hexamethylene, which is quite different from the natural gas produced by thermal degradation of kerogens （named kerogen degradation gas） at high- to over mature stage.     

Experimental evidence for formation water promoting crude oil cracking to gas

Crude oil cracking to gas is the key to determining the exploration potential and strategy for deep hydrocarbon resources.Identifying the factors that affect the threshold and potential of crude oil cracking to gas as well as other possible influencing factors will provide the scientific basis for deep hydrocarbon exploration.A comparison of pyrolysis simulation experiments of crude oil,hydrous crude oil,and various water media under a constant temperature(350℃) and pressure(50 MPa) shows that water plays a large role in crude oil cracking to gas.(1) When water is added,the gas yields increase significantly,including those of alkane gases and non-hydrocarbon gases:the yield of alkane gases increases 1.8-3 times;the yields of H2 and CO2 also increase significantly.This means that water takes part in the process of crude oil cracking to gas,and supplies hydrogen.Therefore,the presence of water will dramatically enhance the potential of crude oil cracking to gas.(2) Mg2+ ions in the formation water promote the crude oil + water reaction to some extent and increase the total yield of alkane gases and the yields of both H2 and CO2 ;more interestingly,the i-C4/n-C4 and i-C5/n-C5 ratios increase significantly.This indicates that Mg2+ ions in formation water act as a catalyst,and a disproportionation reaction is involved in the crude oil + water reaction.This study helps us to understand the factors influencing crude oil cracked gas and to evaluate the hydrocarbon resources in deep sedimentary basins.     

Simulation experiments on the reaction system of CH_4-MgSO_4-H_2O

H2S-rich gas in carbonate reservoirs is usually attributed to thermochemical sulfate reduction (TSR). In this paper, thermal simulation experiments on the reaction system of CH4-MgSO4-H2O were carried out using autoclave at 425℃―525℃. The threshold temperature for initiating TSR is much lower than our previous studies (550 ℃ ). Properties of the reaction products were analyzed by microcoulometry, gas-chromatography (GC), Fourier transform-infrared spectrometry (FT-IR) and X-ray diffraction (XRD) methods. Thermodynamics and reaction kinetics of TSR processes were investigated on the basis of the experimental data. The results show that thermochemical reduction of magnesium sulfate with methane can proceed spontaneously to produce magnesium oxide, hydrogen sulfur, and carbon diox-ide as the main products, and high temperature is thermodynamically favorable to the reaction. Ac-cording to the reaction model, the calculated activation energy of TSR is 101.894 kJ/mol, which is lower than that by most previous studies. Mg2 may have played a role of catalytic action in the process of TSR. The elementary steps of TSR and reaction mechanism were discussed tentatively. The study can provide important information on the explanation of geochemical depth limit for natural gas and on the generation of high H2S gas in deep carbonates reservoirs.     

A breakthrough of researching reservoir adsorption gas and its significance

GC-C-MS on linear isotope analysis equipment makes it possible to measure the hydrocarbon gases at the level of 10 -3-10 -2 μL- By applying this technique the carbon isotopes of C1-C3 of the adsorbed gas from the Triassic oil sand bed of the Aican-l Well in the Turpan-Hami basin were analysed. The δ13C values of C1-C3, are -55.1‰, -38.6‰ and -35.0‰ respectively. In terms of geochemical characteristics of natural gases and crude oils, in combination with basinal geological backgrounds, it is considered that the reservoir adsorbed gas was formed by crude-oil biodegradation, absorbed by reservoir rocks and its oil-gas source is related with the Permain (perhaps including the Carboniferous). The adsorbed gas is obviously different from the Jurassic coal-generated oil and gas.     

The controlling factors and distribution prediction of H_2S formation in marine carbonate gas reservoir,China

Generally, there are some anhydrites in carbonate reservoir, as H2S is also familiar in carbonate oil and gas reservoirs. Nowadays, natural gas with high H2S concentration is usually considered as TSR origin, so there is close relationship between H2S and anhydrite. On the contrary, some carbonate rocks with anhydrite do not contain H2S. Recently, researches show that H2S is only a necessary condition of H2S formation. The reservoir porosity, sulfate ion content within formation water, reservoir temperature, oil/gas and water interface, hydrocarbon and some elements of reservoir rock have great controlling effects on the TSR occurrence. TSR deoxidizes hydrocarbon into the acidic gas such as H2S and CO2, and the H2S formation is controlled by TSR occurrence, so the relationship among reaction room, the contact chance of sulfate ion and hydrocarbon, the reservoir temperature has great influence on the TSR reaction. H2S has relatively active chemical quality, so it is still controlled by the content of heavy metal ion. Good conditions of TSR reaction and H2S preservation are the prerequisite of H2S distribution prediction. This paper builds a predictive model based on the characteristic of natural gas reservoir with high H2S-bearing. In the porosity reservoir with anhydrite, the formation water is rich in sulfate and poor in heavy metal ion. Oil and gas fill and accumulate in the gas reservoir with good preservation conditions, and they suffered high temperature later, which indicates the profitable area of natural gas with high H2S-bearing.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower ()rdovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as “oil families“, although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any “oil family“. Despite their close stratigraphic proximity, it is evident that the oils of the/rower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new “oil family“ within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

Magnetic properties of surface soils across the southern Tarim Basin and their relationship with climate and source materials

The magnetic susceptibility (χ) of surface soils on the Chinese Loess Plateau (CLP) has strong positive correlation with mean annual precipitation.It is widely accepted that ultrafine magnetite/maghemite grains produced during pedogenesis are responsible for the enhancement of χ,and loess χ on the CLP has been widely used as a proxy for the intensity of the East Asian summer monsoon.However,few works have investigated mechanisms for the enhancement of χ in the case of surface aeolian sediments in westerly-dominated inland China,north of the Tibetan Plateau.Here detailed rock magnetism and grain size studies of 49 surface samples taken across the southern Tarim Basin for different rainfall/temperature/altitude conditions are presented.The results show that samples taken from desert have the lowest χ values and that χ of loessic sand and loess samples decreases with increasing altitude.In addition,the rock magnetism studies suggest that the magnetic properties of surface soils across the southern Tarim Basin are mainly controlled by the concentration of coarse aeolian ferrimagnetic minerals.The contribution of ultrafine pedogenically produced magnetic grains to χ is very limited.     

Magnetic and mineralogical characteristics of reservoir rocks in the Yakela oil field, northern Ta rim Basin and their implications for magnetic detection of oil and gas accumulations

The evidence about hydrocarbon migration within reservoir rocks in two wells has been obtained according to results of magnetic and mineralogical analysis of the Kapushaliang Group reservoir rocks from wells S15 and S4 located at the Yakela oil field, Tarim Basin. Results show that the secondary alteration associated with oil and gas accumulations above oil and gas field is predominantly magnetite mineralization, and that sulfur alteration occurs commonly at oil-water boundary and their products are generally pyrite and pyrrhotite, except for magnetite alteration which is closely related with hydrodynamical conditions in situ. The spherical magnetite grains of cauliflower microtexture on surface extracted from oil-bearing cores are secondary magnetite related with hydrocarbon microseep-age and their diameters are usually less than 50 μm.     

Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome based on NMR techniques

Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome has been performed by comparison with those of normal rats based on NMR techniques. The relative contents of formate,creatinine,2-oxoglutarate(2-OG) ,citrate,taurine,trimethylamine-N-oxide(TMAO) ,succinate and hippurate in the urine of the rats with Qi deficiency and blood stasis syndrome have been changed. These results have provided evidence for understanding the mechanism and the therapy of Qi defi-ciency and blood stasis syndrome.     

用毛细管电泳电感耦合等离子体原子发射光谱法分析铁的形态

During the last 20 years,metal speciation has attained great interest. The main reason for this is that the toxicity of an element and its biological role are critically dependent on the chemical form[1]. Especial ly,in recent years,various methods for the speciation of metal with different oxidation states have been introduced. Previous methods using different separation techniques such as gas chromatography (GC) and high performance liquid chromatography (HPLC) have been commonly used for element speciation.Consequently,capillary electrophoresis (CE) has shown considerable developments owing to its high separation efficiency,low sample and electrolyte consumption.     

Wavelet domain adaptive filtering algorithm for removing the seamless pipe noise contained in the magnetic flux leakage data

With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise （SPN）. SPN can in some cases completely mask MFL signals from certain type of defects, and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.     

Pyrolysis of oil at high temperatures: Gas potentials, chemical and carbon isotopic signatures

Although the gas cracked from oil has been believed to be one of the important sources in highly ma-tured marine basins, there are still some debates on its resource potentials and chemical and isotopic compositions. In this study a Cambrian-sourced marine oil sample from the Silurian reservoir of well TZ62 in the central Tarim basin was pyrolyzed using sealed gold tubes with two different pyrolysis schemes: continuous pyrolysis in a closed system and stepwise semi-open pyrolysis. The results show that the maximum weight yield of C_1–5 gases occurs at EasyRo=2.3% and the residual gas poten-tial after this maturity is only 43.4 mL/g, about 12% of the yield of 361 mL/g at EasyRo=2.3%. Combined with the results of kinetic modeling, the main stage of gas generation from oil cracking is believed within the EasyRo=1.6%―2.3%. The increase in the volume yield of C_1–5 gases at EasyRo>2.3% in a closed system is mainly related to the re-cracking of previously formed C_2–5 wet gases, not the direct cracking of oil. The stepwise pyrolysis experiments show that the gas from the cracking of residual oil at EasyRo>2.3% is characterized by very high dryness index (higher than 92%) and heavy methane carbon isotopes ranging from -28.7‰ to -26.7‰, which is quite different from the gases from the con-tinuous pyrolysis in a closed system. The kinetic modeling of methane carbon isotope fractionation shows that the carbon isotopes of methane within the main stage of gas generation (EasyRo<2.3%) are far lighter than the carbon isotopes of the precursor oils under a geological heating rate of 2 ℃/Ma. The above observations and results provide some new clues to the accurate recognition and objective re-source evaluation of oil cracking gas in highly mature marine basins.     

Kinetics of Nitrogen Removal from Molten Steel under Vacuum and Gas-Blowing Conditions

The kinetics of nitrogen removal from molten steel under vacuum and gas-blowing conditions has been studied during the VIM process. The experimental results indicated that vacuum affected the kinetics of nitrogen removal in the range of 67~5 360 Pa. At 67 Pa, the rate of nitrogen removal is controlled by the liquid phase mass transfer of nitrogen in molten steel. At 2 680Pa, the limited step for nitrogen removal from molten steel is the chemical reaction at the metal/gas interface. Under the present experimental conditions, the type (Ar, CO, CO₂) and quantity of gas flowed have no evident influences on the rate of nitrogen removal. The ratio of nitrogen removal of gas bubbles is less than 3%. Based on the experimental results, the mechanism of nitrogen removal during the VD process with argon blowing and the other melting or secondary refining processes with carbon-oxygen reaction have been discussed. Some new viewpoints are proposed.