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Light Hydrocarbons (light + hydrocarbon)
Selected AbstractsGeothermometry and geobarometry of overpressured environments in Qiongdongnan Basin, South China Sea,GEOFLUIDS (ELECTRONIC), Issue 3 2003Honghan Chen Abstract We demonstrate the use of PVT fluid inclusion modelling in the calculation of palaeofluid formation pressures, using samples from the YC21-1-1 and YC21-1-4 wells in the YC21-1 structural closure, Qiongdongnan Basin, South China Sea. Homogenisation temperatures and gas/liquid ratios were measured in aqueous fluid inclusions, and associated light hydrocarbon/CO2 -bearing inclusions, and their compositions were determined using a crushing technique. The vtflinc software was used to construct P,T phase diagrams that enabled derivation of the minimum trapping pressure for each order of fluid inclusion. Through the projection of average homogenisation temperatures (155, 185.5 and 204.5°C) for three orders of fluid inclusion on the thermal-burial history diagram of the Oligocene Yacheng and Lingshui formations, their trapping times were constrained at 4.3, 2.1 and 1.8 Ma, respectively. The formation pressure coefficient, the ratio of fluid pressure/hydrostatic pressure established by PVT modelling coupled with DST data, demonstrates that one and a half cycles of pressure increase,discharge developed in the Yacheng and Lingshui formations for about 4.3 Ma. In comparison, the residual formation pressure determined by 2D numerical modelling in the centre of LeDong depression shows two and a half pressure increase,discharge cycles for about 28 Ma. The two different methods suggest that a high fluid potential in the Oligocene reservoir of the YC21-1 structure developed at two critical stages for regional oil and natural gas migration and accumulation (5.8 and 2.0 Ma, respectively). Natural gas exploration in this area is therefore not advisable. [source] Interplay of Properties and Functions upon Introduction of Mesoporosity in ITQ-4 ZeoliteADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Danny Verboekend Abstract The introduction of mesoporosity in zeolites is often directly coupled to changes in their overall catalytic performance without the detailed assessment of other key functions required for the rational design of the catalytic process such as accessibility, adsorption, and transport. This study presents an integrated approach to study property,function relationships in hierarchical zeolites. Accordingly, desilication of the 1D ITQ-4 zeolite in alkaline medium is applied to develop different degrees of mesoporosity. Along with porosity modification, significant changes in composition, structure, and acidity occur. Relationships are established between the physicochemical properties of the zeolites and their characteristics in the adsorption and elution of light hydrocarbons (C2 to C5, alkanes and alkenes) as well as in the catalytic activity in low-density polyethylene (LDPE) pyrolysis. The recently introduced hierarchy factor can appropriately relate porosity changes to catalytic performance. [source] Pyrolysis of liquefied petroleum gas assisted by radicals desorbed from mesh catalyst surfaceINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2003Eugene B. H. Quah The purpose of this study is to understand the reactions on the catalyst surface and in the gas phase during the catalytic pyrolysis of light hydrocarbons. To avoid the complexity of internal pore diffusion and heat transfer limitation, nickel mesh without pore structure was used as a catalyst for the catalytic pyrolysis of a commercial liquefied petroleum gas (LPG) sample in a quartz tube reactor and in a wire-mesh reactor over a temperature range of 600,850°C. With a Ni mesh catalyst, no catalyst deactivation associated with coke formation was observed at high gas flow rate. Our experimental results indicate that the desorption of radicals from the catalyst surface is an important process in the catalytic pyrolysis of LPG using the Ni mesh catalyst. The desorption of radicals across the gas,catalyst interface is greatly facilitated by increasing gas flow rate passing through the mesh. The desorbed radicals would initiate and/or enhance the gas-phase radical chain reactions and lead to improved reaction rates for the pyrolysis of LPG although the product selectivities remained unchanged. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 637,646, 2003 [source] OIL POLYMERISATION AND FLUID EXPULSION FROM LOW TEMPERATURE, LOW MATURITY, OVERPRESSURED SEDIMENTSJOURNAL OF PETROLEUM GEOLOGY, Issue 3 2008D. D. J. Antia A mechanism for hydrocarbon expulsion from low temperature (T = <20 , 150° C), low maturity (Ro=<0.6), overpressured sediments (clays, shales and enclosed sands) with active hydrocarbon concentration and/or generation is outlined. Low temperature polymerisation of light hydrocarbons (e.g. biogenic methane) is considered to be a potential source for some oils found in association with hydrates (resulting from fluidisation discharges from overpressured zones), and some oils found in shales displaying suppression of vitrinite reflectance. It is observed that low temperature polymerisation will increase the potential pressure load retained within an overpressured zone and increase the overall volume of gas/fluids discharged on pressure release. Field observations, including measured recharge volumes and the fluid discharge volumes through a chimney from an overpressured zone, have been used to produce a triple porosity, poroelastic fluidisation expulsion model which links the discharge volume to pressure loading. The model predicts that expulsion from an active pressure mound will be cyclic and episodic. Published geochemical results from seismic chimneys in the Lower Congo Basin have been reinterpreted using the model to demonstrate that expulsion through a chimney is episodic, and to identify overpressured zones where the dominant fluid is oil and others where the overpressured zone contains both oil and gas. It is suggested that some of the oil in these overpressured zones, currently interpreted as thermogenic, may be derived from the polymerisation of biogenic gas. [source] Charge generation during filling of insulated tanksPROCESS SAFETY PROGRESS, Issue 3 2002Migvia Vidal This research involves charge generation measurements for various flammable fluids during filling of insulated tanks and relating static charging with flow rate and physicochemical parameters, especially changes in electrical conductivity. The objective is to correlate static charge measured inside baffled metal and polyethylene tanks as a function of impeller, Reynolds number, and the electrical conductivity of both the hydrocarbon and the dispersed water phase for a variety of flammable liquids. A product of the research is a correlation for polyethylene and other plastic insulated tanks for transfers of low conductivity liquid fuels. Also, a universal (dimensionless) correlation that relates the charging data to the colloidal nature of the mixture will be developed for static charge generation during impeller mixing of light hydrocarbons containing various concentrations of water in cylindrical tanks. The correlation of electrostatic data from this research will help make it possible to control electrostatic charges, and, as a result, greatly improve safety of operations involving flammable fluids in industry. [source] Gas-Phase and Surface Kinetics of Epitaxial Silicon Carbide Growth Involving Chlorine-Containing Species,CHEMICAL VAPOR DEPOSITION, Issue 8-9 2006A. Veneroni Abstract A detailed chemical mechanism for the silicon carbide epitaxial growth using light hydrocarbons, silane, and either chlorosilanes and/or HCl as the chlorine source is presented. The mechanism involves 153,gas-phase and 76 surface reactions among 47,gas-phase and 9 surface species, respectively. A comparison with the performances of the standard process using silane-hydrocarbons is presented, and the observed growth rate increase and the disappearing of the homogeneous silicon droplets in gas phase is explained. [source] | ||||||||||||||||