In this paper an experimental study on damage tolerance behaviour of composite panels with softening strips is carried out. A prediction method of residual strength of panels with softening strips is proposed. The com...In this paper an experimental study on damage tolerance behaviour of composite panels with softening strips is carried out. A prediction method of residual strength of panels with softening strips is proposed. The comparison between estimated and experimental results shows that the prediction method can be applied to design. In this paper the failure mechanisms are described.展开更多
Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate(CaCO3)particles,whose diameter is consistent with the size of pores or apertures in th...Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate(CaCO3)particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system(NLTDFS).Under the simulated condition of the well bottom during real drilling,NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours,respectively,and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability.The results showed that the permeability recovery rate of the core reached 90%or so,and the damaged depth was less than 1 cm,which demonstrates that NLTDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system.NLTDFS has been used to drill many horizontal wells,and four of them have obtained high yield of natural gas.The yield of natural gas of LP1 well reached 85×104 m3/day after completion with the rump pipe.The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.展开更多
In this paper, the coupled thermo-mechanical （TM） processes in the AEspoe Pillar Stability Experiment （APSE） carried out by the Swedish Nuclear Fuel and Waste Management Company （SKB） were simulated using both c...In this paper, the coupled thermo-mechanical （TM） processes in the AEspoe Pillar Stability Experiment （APSE） carried out by the Swedish Nuclear Fuel and Waste Management Company （SKB） were simulated using both continuum and discontinuum based numerical methods. Two-dimensional （2D） and three- dimensional （3D） finite element method （FEM） and 2D distinct element method （DEM） with particles were used. The main objective for the large scale in situ experiment is to investigate the yielding strength of crystalline rock and the formation of the excavation disturbed/damaged zone （EDZ） during excavation of two boreholes, pressurizing of one of the boreholes and heating. For the DEM simulations, the heat flow algorithm was newly introduced into the original code. The calculated stress, displacement and temperature distributions were compared with the ones obtained from in situ measurements and FEM simulations. A parametric study for initial microcracks was also performed to reproduce the spalling phenomena observed in the APSE.展开更多
文摘In this paper an experimental study on damage tolerance behaviour of composite panels with softening strips is carried out. A prediction method of residual strength of panels with softening strips is proposed. The comparison between estimated and experimental results shows that the prediction method can be applied to design. In this paper the failure mechanisms are described.
文摘Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate(CaCO3)particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system(NLTDFS).Under the simulated condition of the well bottom during real drilling,NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours,respectively,and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability.The results showed that the permeability recovery rate of the core reached 90%or so,and the damaged depth was less than 1 cm,which demonstrates that NLTDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system.NLTDFS has been used to drill many horizontal wells,and four of them have obtained high yield of natural gas.The yield of natural gas of LP1 well reached 85×104 m3/day after completion with the rump pipe.The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.
基金conducted within the context of the international DECOVALEX Project (DEvelopment of COupled models and their VALidation against EXperiments)financed by Japan Atomic Energy Agency (JAEA) who was also one of the Funding Organizations of the projectChrister Anders-son from Swedish Nuclear Fuel and Waste Management Co.(SKB),Sweden
文摘In this paper, the coupled thermo-mechanical （TM） processes in the AEspoe Pillar Stability Experiment （APSE） carried out by the Swedish Nuclear Fuel and Waste Management Company （SKB） were simulated using both continuum and discontinuum based numerical methods. Two-dimensional （2D） and three- dimensional （3D） finite element method （FEM） and 2D distinct element method （DEM） with particles were used. The main objective for the large scale in situ experiment is to investigate the yielding strength of crystalline rock and the formation of the excavation disturbed/damaged zone （EDZ） during excavation of two boreholes, pressurizing of one of the boreholes and heating. For the DEM simulations, the heat flow algorithm was newly introduced into the original code. The calculated stress, displacement and temperature distributions were compared with the ones obtained from in situ measurements and FEM simulations. A parametric study for initial microcracks was also performed to reproduce the spalling phenomena observed in the APSE.
