The development of unconventional resources, such as shale gas and tight sane gas, requires the integration of multi-disciplinary knowledge to resolve many engineering problems in order to achieve economic production ...The development of unconventional resources, such as shale gas and tight sane gas, requires the integration of multi-disciplinary knowledge to resolve many engineering problems in order to achieve economic production levels. The reservoir heterogeneit3 revealed by different data sets, such as 3D seismic and microseismic data, can more full3 reflect the reservoir properties and is helpful to optimize the drilling and completioT programs. First, we predict the local stress direction and open or close status of the natura fractures in tight sand reservoirs based on seismic curvature, an attribute that reveals reservoi heterogeneity and geomechanical properties. Meanwhile, the reservoir fracture network is predicted using an ant-tracking cube and the potential fracture barriers which can affec hydraulic fracture propagation are predicted by integrating the seismic curvature attribute anc ant-tracking cube. Second, we use this information, derived from 3D seismic data, to assis in designing the fracture program and adjusting stimulation parameters. Finally, we interpre the reason why sand plugs will occur during the stimulation process by the integration of 3E seismic interpretation and microseismic imaging results, which further explain the hydraulic fracure propagation controlling factors and open or closed state of natural fractures in tigh sand reservoirs.展开更多
Underground coal mining activities in the Quangninh coal basin (in the North ofVietnam) have been carried out at a depth of-130 m to-150 m,and in the near future thismining depth will become-300 m and-500 m.Together w...Underground coal mining activities in the Quangninh coal basin (in the North ofVietnam) have been carried out at a depth of-130 m to-150 m,and in the near future thismining depth will become-300 m and-500 m.Together with the increasing coal output,the quantity of methane and other mine gases emitted from coal beds during mining activitieswill grow bigger and bigger.According to the forecast of the coal mining industry,ifmines go deeper downward,all underground coal mines in the Quangninh basin will beclassified into the mine group with the dangerous level of methane bearings.Mine gascontrol and management operations with conventional ventilation are less effective andentail high expenses.One of the main solutions is to carry out short,medium and longboreholes for controlling and recovering methane and other mine gases from coal bedsbefore mining activities.Efficiency of drilling activities for methane gas recovery from coalseams with horizontal bore holes at underground coal mines depends on many factors includingthe mine gas draining borehole layout at the roadways,gas content in the coalbeds,technologies for mine gas draining boring activities,and so on.Methane gas existsin the coal beds under the adhesive state with stable physical and chemical bonds.In orderto recover these gases,it is necessary to carry out boreholes and create artificial joints(collecting pits) in coal beds with the impulse method (hydraulic separation method).展开更多
The ceramic coating technology of microarc oxidation (MAO) was utilized to modify surface properties of the movable endplate of a high pressure gear pump used in water-hydraulic system, which is made of aluminium allo...The ceramic coating technology of microarc oxidation (MAO) was utilized to modify surface properties of the movable endplate of a high pressure gear pump used in water-hydraulic system, which is made of aluminium alloy. A coMPact ceramic layer of more than 130 μm was developed on the movable endplate with the hardness up to HV1000 by means of microarc oxidation. A trial of tests conducted in a water power transmission system show that the maximum outlet pressure of the gear pump with the movable endplate treated by microarc oxidation, can reach 16 MPa. It is pointed out that the ceramic coating developed by microarc oxidation technology on the surface of aluminium alloy, is economical and feasible.展开更多
文摘The development of unconventional resources, such as shale gas and tight sane gas, requires the integration of multi-disciplinary knowledge to resolve many engineering problems in order to achieve economic production levels. The reservoir heterogeneit3 revealed by different data sets, such as 3D seismic and microseismic data, can more full3 reflect the reservoir properties and is helpful to optimize the drilling and completioT programs. First, we predict the local stress direction and open or close status of the natura fractures in tight sand reservoirs based on seismic curvature, an attribute that reveals reservoi heterogeneity and geomechanical properties. Meanwhile, the reservoir fracture network is predicted using an ant-tracking cube and the potential fracture barriers which can affec hydraulic fracture propagation are predicted by integrating the seismic curvature attribute anc ant-tracking cube. Second, we use this information, derived from 3D seismic data, to assis in designing the fracture program and adjusting stimulation parameters. Finally, we interpre the reason why sand plugs will occur during the stimulation process by the integration of 3E seismic interpretation and microseismic imaging results, which further explain the hydraulic fracure propagation controlling factors and open or closed state of natural fractures in tigh sand reservoirs.
文摘Underground coal mining activities in the Quangninh coal basin (in the North ofVietnam) have been carried out at a depth of-130 m to-150 m,and in the near future thismining depth will become-300 m and-500 m.Together with the increasing coal output,the quantity of methane and other mine gases emitted from coal beds during mining activitieswill grow bigger and bigger.According to the forecast of the coal mining industry,ifmines go deeper downward,all underground coal mines in the Quangninh basin will beclassified into the mine group with the dangerous level of methane bearings.Mine gascontrol and management operations with conventional ventilation are less effective andentail high expenses.One of the main solutions is to carry out short,medium and longboreholes for controlling and recovering methane and other mine gases from coal bedsbefore mining activities.Efficiency of drilling activities for methane gas recovery from coalseams with horizontal bore holes at underground coal mines depends on many factors includingthe mine gas draining borehole layout at the roadways,gas content in the coalbeds,technologies for mine gas draining boring activities,and so on.Methane gas existsin the coal beds under the adhesive state with stable physical and chemical bonds.In orderto recover these gases,it is necessary to carry out boreholes and create artificial joints(collecting pits) in coal beds with the impulse method (hydraulic separation method).
基金Sponsored by the National Natural Science Foundation of China(Grant No.60772077)
文摘The ceramic coating technology of microarc oxidation (MAO) was utilized to modify surface properties of the movable endplate of a high pressure gear pump used in water-hydraulic system, which is made of aluminium alloy. A coMPact ceramic layer of more than 130 μm was developed on the movable endplate with the hardness up to HV1000 by means of microarc oxidation. A trial of tests conducted in a water power transmission system show that the maximum outlet pressure of the gear pump with the movable endplate treated by microarc oxidation, can reach 16 MPa. It is pointed out that the ceramic coating developed by microarc oxidation technology on the surface of aluminium alloy, is economical and feasible.
