Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and p...Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and poor sealing performance.To enhance the performance of nylon cord rubber,a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined.The Plackett-Burman test,the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure.Using genetic algorithms,optimal structural parameters of nylon cord rubber were determined depending on field operation.The reliability of the optimized results was verified by laboratory tests.It was shown that after optimization,the bearing capacity of the expandable packer increased by 25%while the sealing performance increased by 66%.In addition,the bearing pressure was 70 MPa while the sealing pressure was 50 MPa.These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.展开更多
Effects of transverse loads on longitudinal stress strain behaviors and longitudinal constant tensile loads on transverse stress strain behaviors of single ply of nylon cord rubber composite are studied respectively u...Effects of transverse loads on longitudinal stress strain behaviors and longitudinal constant tensile loads on transverse stress strain behaviors of single ply of nylon cord rubber composite are studied respectively under biaxial tensile condition with cruciform specimen. Effects of transverse constant tensile load on longitudinal tensile mechanical properties are indistinctive compared with corresponding uniaxial longitudinal tensile mechanical properties. It can be relative to larger difference between longitudinal and transverse mechanical properties. Its dominating failure mode is typical fiber dominated mode; However, Experiment results indicate that transverse mechanical properties of nylon cord rubber composite with longitudinal constant tensile loads are distinct from its uniaxial transverse tensile mechanical properties. It can be attribute to action of longitudinal tension that makes material rigidify in the direction perpendicular to fiber, Mode of failure is representative of matrix dominated failure. For the measurement of large deformation up to 50 percent, a special CCD imaging method is employed in the experimental investigation that makes measurement of large deformations more precise.展开更多
An experimental research was made to have a grasp of the overall thermo-mechanicalproperties of nylon 6 and nylon 66 tire cords. The strength, fatigue, thermal shrinkage, therm-al aging and dynamic-mechanical properti...An experimental research was made to have a grasp of the overall thermo-mechanicalproperties of nylon 6 and nylon 66 tire cords. The strength, fatigue, thermal shrinkage, therm-al aging and dynamic-mechanical properties of both were measured, investigated and corn-pared. So far as their comprehensive performance is concerned, and favoritism to nylon 66cord for tire cord fabrics is perhaps unwarranted. And the effect of twist on the tensile proper-ties and fatigue behavior also have been measured and analyzed.展开更多
基金National Science and Technology major projects(2016ZX05042-004)Graduate Innovation Project(YCX2019059)for the financial support。
文摘Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and poor sealing performance.To enhance the performance of nylon cord rubber,a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined.The Plackett-Burman test,the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure.Using genetic algorithms,optimal structural parameters of nylon cord rubber were determined depending on field operation.The reliability of the optimized results was verified by laboratory tests.It was shown that after optimization,the bearing capacity of the expandable packer increased by 25%while the sealing performance increased by 66%.In addition,the bearing pressure was 70 MPa while the sealing pressure was 50 MPa.These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.
文摘Effects of transverse loads on longitudinal stress strain behaviors and longitudinal constant tensile loads on transverse stress strain behaviors of single ply of nylon cord rubber composite are studied respectively under biaxial tensile condition with cruciform specimen. Effects of transverse constant tensile load on longitudinal tensile mechanical properties are indistinctive compared with corresponding uniaxial longitudinal tensile mechanical properties. It can be relative to larger difference between longitudinal and transverse mechanical properties. Its dominating failure mode is typical fiber dominated mode; However, Experiment results indicate that transverse mechanical properties of nylon cord rubber composite with longitudinal constant tensile loads are distinct from its uniaxial transverse tensile mechanical properties. It can be attribute to action of longitudinal tension that makes material rigidify in the direction perpendicular to fiber, Mode of failure is representative of matrix dominated failure. For the measurement of large deformation up to 50 percent, a special CCD imaging method is employed in the experimental investigation that makes measurement of large deformations more precise.
文摘An experimental research was made to have a grasp of the overall thermo-mechanicalproperties of nylon 6 and nylon 66 tire cords. The strength, fatigue, thermal shrinkage, therm-al aging and dynamic-mechanical properties of both were measured, investigated and corn-pared. So far as their comprehensive performance is concerned, and favoritism to nylon 66cord for tire cord fabrics is perhaps unwarranted. And the effect of twist on the tensile proper-ties and fatigue behavior also have been measured and analyzed.
