Papers by Keyword: Gas Content

Abstract: Based on the analysis of coring, logging and experimental data, fine evaluation on Fort Copper Coal Measures (FCCM) of Early Permian Blackwater Group in north Bowen Basin of Australia has been done. FCCM is a potential coal measure. Eight coal seams exist in FCCM. Laterally, they develop steadily. Seams of FCCM characterize interbedding with partings, high ash content, high gas content and mediate-low permeability. The content of partings, which are groups of siltstone, mudstone and tuff, ranges from 15% to 55%. The cumulative thickness of pure coal ranges from 40 to 60 m. The ash content ranges from 20% to 70%, averaging 45%. Coal seams gas content is as high as 7% to 15%, benefitting from the dense rock block effect on the top and bottom, as well as the interplayers. The permeability ranges from 0.1 to 10 mD laterally. Parameters above show FCCM has good developing potential. Western slope of Nebo syncline is suggested as the favorable area, considering its good developing factors such as shallow buried depth of coal seams, relatively high permeability and effective gas preserve environment. Meanwhile, gas in partings can be considered in collaborative development strategy. Developing gas along with ash will be the focus of future development evaluation.

Abstract: In this study, the well logging response of CBM reservoir have been analyzed, and discussing the factors that affect the gas content of coal seam. The well logging technology has been employed in connection with log data and gas content. Take one oilfield’s well logging data for example, statistical analysis method and Langmuir equation method are selected to calculate the gas content of one coal seam, the two calculated results are basically the same, the highest value are about 26 cm³/g, is a high-yield coal seam.

Abstract: Against the problem of calculating gas content rapidly, this article studied the desorption characteristics of coal by measuring the characteristic parameters of coal in the laboratory. With the actually measured amount of desorption and the desorption rule of the coal within the first 30min, through theoretical derivation and Multiple Linear Regression, the gas content desorbs within the first 120min and the residual amount after a 120min of coal desorption is studied and confirmed Based on the rapid determination model of gas content in the coal seam is established, and the new model is verified, whose accuracy rate reaches above 85%. If relevant electronic equipments were made, this method would be able to give a result within 40min, thereby realizing the rapid determination of gas content in the coal seam within the gas belt.

Abstract: The mathematic principles and numerical arithmetic of quantification theory Iare studied of gas content prediction model and actually measured data during geological prospecting and producing of Jincheng Hebi No.6 coal seam are collected. Thus, twenty-nine reliable data of gas content are gained. Then, the gas content prediction model is founded based on quantification theory by selecting bedrock thicknesscoal seam thickness as quantitative values and lithological character of coal roof as qualitative value. By results of calculation and estimation, the model precision can meet the desire of engineering precision, showing that using quantification theory to predict gas content is feasible.

Abstract: There are several geological factors affecting the accumulation of CBM, including tectonic condition, burial depth, coal thickness, coal rank, gas content, permeability, reservoir pressure, desorption pressure and hydrological condition, etc. This article analyzes the influence of tectonic characteristics on the accumulation of CBM in H area, combining the tectonic characteristics and the actual production data, finally conclusions can be drawn that the uplifting movement of crust after coal-forming period could break the original adsorption equilibrium, then CBM would escape under unfavorable preservation condition; different scales of fractures and folds formed by tectonic movements play an important role in the preservation and dissipation as well as in the enrichment and accumulation.

Abstract: The methods of shale gas content measurement and shale Gas-in-place calculation are introduced in detail. The shale gas content is form 1.05 to 1.84 m³/t. From Gas-in-place calculation the adsorption gas content is a little more than free gas content. The advantage of shale gas accumulation areas are high formation pressure, low water saturation, high porosity and high total organic content. There are some discrepancy between shale gas content testing and gas in place calculation and three reasons may cause this phenomenon.

Abstract: In the log interpretation, the CBM content evaluation methods include: regression, LAN’s equation, KIM method, neural network, and so on. This paper investigates the suitability of these methods for a CBM reservoir in Southern Qinshui Basin, Shanxi Province of China, and finds out the most reasonable interpretation model of CBM content in this area. The results show that the composite parameter(COMP) method and the LAN’s equation method are more suitable for evaluating the CBM content in this study area, while the other methods are not.

Abstract: Gas content is one of the most important factors in the process of exploration and development of coalbed methane (CBM). The relationships between gas content and characteristics of geophysical logs have been evaluated for the No. 5 coal seam in Weibei CBM field. It is found that the main well loggings that have good responses for gas contents are the compensating density, natural gamma-ray, compensating neutron, natural spontaneous potential and acoustic. A theoretical model was proposed to calculate the gas content by using these well logging data and as well as the burial depth. The calculated gas contents fits well with the measured data with a small relative-error of 0.38-5.05%. In the model, both tectonic movement intensity and the gas accumulation were taken into consideration. Key words: Coalbed methane, Weibei coalfield, Ordos Basin, Gas content, Geophysical logging

Abstract: The influence of the re-melting times on chemical composition, microstructure, and mechanical properties of revert alloy K452 were systemically investigated. It was shown that the key factor in the engineering application was the control of gas content and porosities level in revert alloy. By an advancing technology in combination with the superheat treatment, adding a small amount of alloying elements such as C, Al, Ti, and using ceramic foam filters during vacuum induction melting, the composition and mechanical properties of the revert alloy in addition of 50% scrap were similar to that in the virgin alloy, which has successfully been used in applications for nozzle vanes of some new gas turbines.

Abstract: Southern Shizhuang Block has simple structure characteristics, relatively thick coal seams (3.1-10.5 m, 6 m in average), and favorable burial depth (450-900 m). The gas content of the No.3 coal seam in the Shanxi formation ranges from 6-20 m³/t, and it increases from the southeast to northwest area in the southern Shizhuang Block. Gas content is high in the structural low in the area, which means the gas accumulation is controlled by the geological characteristics of local structure and hydrogeologic conditions.