Ma G.,Henan Coal and Chemical Industry Group Co. |
Su X.,Henan Polytechnic University |
Lin H.,Henan Polytechnic University |
Guo H.,Henan Polytechnic University |
And 2 more authors.
Natural Gas Industry | Year: 2014
The existing reservoir stimulating technology is only applicable to hard coal but unsuitable for soft coal, which restricts the CBM industrialization in China. It is urgent to develop a universal stimulating technology which can increase the permeability in various coal reservoirs. Theoretical analysis and field tests were used to systematically analyze the mechanical mechanism of the formation of radial tensile fractures, peripheral tensile fractures, shear fractures and other multistage various fractures in hydraulic fracturing and to work out the mechanism of permeability enhancement by fracture network stimulating in adjacent rocks and coal reservoirs. It is shown that multiple perforation staged fracturing of horizontal wells, hydraulic-jet staged fracturing, quadruplex hydraulic fracturing and some auxiliary measures are effective technical approaches to achieving fracture network stimulating, especially quadruplex hydraulic fracturing that can stimulate the fracture network in vertical and cluster wells. The fracture network stimulating technology for adjacent rock mining layers has significant advantages, such as safe drilling operation, strong renovation, strong anti-stress sensitivity, and strong velocity sensitivity, so this technology is suitable for coal reservoirs with any coal structures. In addition to adjacent rocks with strong water sensitivity and a high water yield, the technology is also strong in adaptability. Thus, a successful industrial test conducted on ground and under coal mines proves that the theory and technical system of fracture network stimulating in adjacent rocks and coal reservoirs will play a role as a widely applicable measure in the CBM development in China.
Su C.,Henan Polytechnic University |
Fu Y.,Henan Coal and Chemical Industry Group Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014
Characters of failure, strength and deformation for red sandstone are analyzed with uniaxial compression, conventional triaxial compression and Brazil split tests by using RMT-150B rock mechanics test system. Five conventional triaxial strength criteria are fitted to the test data with least absolute deviation, and the predicted values of uniaxial compressive strength, tensile strength and fracture angle are compared to the test ones. Results show that the Mohr-Coulomb criterion presents large misfit which overestimates strengths at low and high confining pressures. The Hoek-Brown criterion, generalized Hoek-Brown criterion, Rocker criterion and the exponential strength criterion present uniaxial compressive strength just the same with experimental value of 68.0 MPa, but partial higher in tensile strength estimation. The value of prediction in generalized Hoek-Brown criterion is most closed to calculations of tensile strength and the fitting effect is better. Fracture angles of red sandstone are 52.5°-66.6° in test, which correlated with confining pressure negatively. Prediction of fracture angle in Mohr-Coulomb criterion is 65° which is larger than the actual one. The fracture angles predicted by other four criteria decrease with the increase of confining pressure and correspond with the test results.
Sheng T.-B.,China University of Mining and Technology |
Sheng T.-B.,Henan Coal and Chemical Industry Group Co. |
Wei S.-Y.,Henan Coal and Chemical Industry Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012
In China the thickness of freeze sinking through alluvial layer has exceeded 500 m and is close to 600 m. Multiple-ring hole freezing scheme and construction materials of the previous 10 mine shafts are collected. Data of the temperature field of the multiple-ring hole frozen wall of two super-thick layer freezing wells in Zhaogu No.1 Coal Mine are measured. The main reasons for rib spalling in shallow area, fully frozen in deep area, slow driving, and high expense of freezing in freezing shafts are that the frozen wall is too thick, the ring diameter of holes cannot adapt to each other, the middle-ring holes are excessive, and the inner-ring holes are too deep. The frozen soil extends more quickly to inside after the intersection of inner and middle ring holes, and adjustment capacity of the main frozen hole is poor during frozen period in middle ring. The method of frozen wall thickness and the matched hole-distributing method of three-ring hole freezing which makes the outside circle as the main frozen hole, the middle circle as the auxiliary hole and the inner hole as the prevention hole for wall caving are studied. The contradiction between the freezing, driving and lining is effectively solved, and technical and economic benefits have increased greatly after the proposed method is applied successfully in three frozen walls of 530 m extra-thick clay-strata in Zhaogu No. 2 Coal Mine.
Sheng T.-B.,China University of Mining and Technology |
Sheng T.-B.,Henan Coal and Chemical Industry Group Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2010
Freezing pressure of seven clay layers was measured for main shaft, auxiliary shaft and ventilation shaft 197~507 m in No.1 Mine of Zhaogu, Henan Province. The test results indicate that the freezing pressure increase with layer depth, freezing pressure on the same level is not evenly distributed and exist higher concentration stress locally. Analyzed the changes law and show characteristics of freezing pressure in extra-thick clay layer. According to Golden Section Theory, the freezing pressure value of measured layer was definited and freezing pressure reference value at different depths was recommended.
Deng D.,Henan Coal and Chemical Industry Group Co.
2011 2nd International Conference on Artificial Intelligence, Management Science and Electronic Commerce, AIMSEC 2011 - Proceedings | Year: 2011
Safe and reliable operation of electromechanical equipments in coal mines is an important guarantee to achieve safe and efficient production for coal mining enterprises. For this reason, this article brought in the coal mine electromechanical equipments closed-loop management system based on the current development of internet of things (IOT) and information technology. First of all, based on the foundation of coal mine enterprises integrated production automation control system, coal mine enterprise should create the basic electromechanical equipments and operating conditions database; then use GIS 3-D visualization electronic equipment management system to informationize-manage and visual-monitor the electromechanical equipments, consequently formulate a comprehensive assessment on the health status of the electromechanical equipments, and finally tracking the potential risks and weaknesses in these equipments and perform mandatory maintenance. © 2011 IEEE.