Studies on stress sensitivity of relative permeability in the laboratory were mostly carried out by varying overburden pressure at constant pore pressure (PP). However, in a real oilfield situation, changes in net stress are induced by changes in PP rather than overburden pressure. This research presents the effect of PP variation at a confining stress of 25 MPa on water-oil and silica nanofluid-oil relative permeability curves. Results showed that, at low PP variations of 0.1, 2, and 5 MPa, two-phase flow parameters exhibited distinct trends. Thus, for water-oil relative permeability, initial water (S wi ) and residual oil (S or ) saturations both decreased as PP increased. End-point oil K ro (S wi ) and water K rw (S or ) relative permeabilities both increased for water flooding. Similar trends were observed for nanofluid flooding. End-point mobility ratio and displacement efficiency both increased with increase in PP within this range for water and nanofluid flooding. At 10 MPa PP, S wi decreased compared to low PP variations, while S or increased significantly. Similar observation was made for nanofluid flooding except for S or which had moderate increment. End-point mobility ratio increased significantly for water flooding, but had a slight increase for nanofluid flooding compared to low PP variations. Displacement efficiency decreased for both water and nanofluid flooding compared to low PP variations. At the same PP, water-oil and nanofluid-oil relative permeabilities showed similar S wi and K ro (S wi ) but differing S or and K rw (S or ). The findings provide insights into the effect PP variation on relative permeability and would be important in flooding design considerations.

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Solid-state reactions of titanium thin films on Si surfaces damaged and amorphized by CHF3/O2 plasma treatment were investigated. The formation temperature of the C49–TiSi2 phase increased due to plasma-induced damage and contamination from decomposed gas elements. The presence of a plasma-induced damage layer suppressed the interdiffusion of Ti and Si. The Ti5Si3 phase was formed initially at an annealing temperature of 400 °C when a plasma-induced damage layer was present at the interface. The increase of the C49–TiSi2 formation temperature may be caused by the transformation of the Ti5Si3 phase into C49–TiSi2 rather than by the direct nucleation of the C49–TiSi2 phase with a clean interface.