Evaluation of the synergetic gas-enrichment and higher-permeability regions for coalbed methane recovery with a fuzzy model

Determination of the synergetic region with both coalbed methane (CBM) enrichment and higher permeability and its distribution is fundamentally crucial to optimize well design and pattern arrangement for CBM recovery from coal. To address this issue, a predictive model was developed based on fuzzy theory by taking into account the main geological factors that affect the gas enrichment and permeability in coal reservoirs. Following the statistical analysis on a number of geological parameters, Euclid approach degree (a comprehensive evaluation coefficient) and fuzzy matter-elements were determined and integrated into the model. The information entropy method was used to evaluate the effect weight of each geologic factor on overall object of the synergetic gas-enrichment and higher-permeability region. The model was applied to the coal seam No. 3 of a developing coal block in the south of Qinshui basin as an example. The results show that the geological factors such as coal rank, gas saturation, coping thickness, transitional coal structure, and volatile content determine the distributions of the synergetic gas-enrichment and higher-permeability region with higher weight coefficients over 9%. Compared with these key factors, the factors such as coal thickness, gas content, methane concentration, ash content, principal stress difference, fracture density, porosity, and burial depth have only the weight coefficients o

Block scale investigation on gas content of coalbed methane reservoirs in southern Qinshui basin with statistical model and visual map

This study performs a block scale investigation on gas content of a coal reservoir in Zhengzhuang Block of the southern Qinshui basin in China. The gas content of Coal Seam No. 3 in this coal reservoir was measured in field and laboratory in conjunction with tests on coal properties such as adsorption isotherm, maximum vitrinite reflectance, coal composition and maceral component etc. Total 36 coal cores collected from 3 adjacent coalmines in the southern Qinshui basin were investigated, including analysis of logging data from the drilling wells. The investigations provided experimental data for block scale modeling and visualization analyses on the correlation between gas content and the key factors such as coal properties and geological conditions of the coal reservoir. Data obtained by field and lab tests were analyzed by statistical models in order to correlate gas content and individual type of coal properties and geological variables. The statistical model was then used to map the gas content of the target coal seam in the studied area, resulting in a flood map of gas content at a 1:50000 scale. The flood map was further visualized with other variables in terms of the properties of coal and coal reservoir and its geological conditions. These visualized maps provide useful geological interpretation for block scale investigation of the comprehensive relationships between the gas content and the coal properties and regional structure in the given coal reservoir. The results show that gas content has little correlation with coal rank, maceral composition, coal thickness, cap and bottom lithology, while it is highly related to the structural properties such as burial depth and effective cover thickness. A stagnant hydrodynamic condition is favorable to the higher gas content on the whole but does not contribute to gas lateral and local variation. Canonical correlation and principal component analysis on the statistical model reveal the key factors that control the gas content are burial depth, effective thickness of overlying strata, groundwater level and moisture content in coal seam

Tetramethylpyrazine: A promising drug for the treatment of pulmonary hypertension

BACKGROUND AND PURPOSE: Tetramethylpyrazine (TMP) was originally isolated from the traditional Chinese herb ligusticum and the fermented Japanese food natto and has since been synthesized. TMP has a long history of beneficial effects in the treatment of many cardiovascular diseases. Here we have evaluated the therapeutic effects of TMP on pulmonary hypertension (PH) in animal models and in patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH). EXPERIMENTAL APPROACH: Three well‐defined models of PH ‐chronic hypoxia (10% O(2))‐induced PH (HPH), monocrotaline‐induced PH (MCT‐PH) and Sugen 5416/hypoxia‐induced PH (SuHx‐PH) ‐ were used in Sprague‐Dawley rats, and assessed by echocardiography, along with haemodynamic and histological techniques. Primary cultures of rat distal pulmonary arterial smooth muscle cells (PASMCs) were used to study intracellular calcium levels. Western blots and RT‐qPCR assays were also used. In the clinical cohort, patients with PAH or CTEPH were recruited. The effects of TMP were evaluated in all systems. KEY RESULTS: TMP (100 mg·kg(−1)·day(−1)) prevented rats from developing experimental PH and ameliorated three models of established PH: HPH, MCT‐PH and SuHx‐PH. The therapeutic effects of TMP were accompanied by inhibition of intracellular calcium homeostasis in PASMCs. In a small cohort of patients with PAH or CTEPH, oral administration of TMP (100 mg, t.i.d. for 16 weeks) increased the 6‐min walk distance and improved the 1‐min heart rate recovery. CONCLUSION AND IMPLICATIONS: Our results suggest that TMP is a novel and inexpensive medication for treatment of PH. Clinical trial is registered with about:blank (ChiCTR‐IPR‐14005379)