To investigate the effect of grain sizes on hydrogen embrittlement 4N-purity iron, miniature tensile tests were conducted after charging for ultrafine-grained specimens produced by high-pressure torsion and subsequent annealing. Hydrogen indexes defined from reduction area increased with decreasing size, shear-type fracture occurred fine dimples surface diagonally raptured specimen a smaller si...

Abstract A reasonable displacement method is essential to improve the oil efficiency of tight reservoirs. In this study, three different methods were utilized on core samples obtained from Yanchang Formation Chang 8 and 9 reservoirs: spontaneous imbibition displacement, various water flooding rate after imbibitions; furthermore, utilization degree residual in pores was discussed. The imbibition...