| dc.description.abstract | The main objective of primary cement job is to provide complete isolation of the permeable zones behind the casing. This can be achieved by having an efficient cement displacement process. The challenge is always to have a displacement process which is as efficient as possible and one that cannot leave drilling mud in between the casing and cement sheath-formation interfaces. The present thesis focuses on cement displacement efficiency. It addresses the influence of the flow profiles and local turbulence due to wall roughness on the cement displacement process during laminar flow.
The study involved theoretical review and testing of the displacement model by Skalle (2014). It also involved analysis of experimental data from laboratory work by Ferizi (2014). The flow model was tested against the experimental data by plotting displacement efficiency curves and comparing them with theoretical curves for different cases of pipe roughness. The three cases, of water displacing oil were studied for water displacement in a slick pipe, in a medium rough pipe and in a very rough pipe. Three additional cases of viscous fluid displacing oil in pipes of different roughness were considered.
Theoretical analysis of the model showed that, at constant flow rate and pipe diameter, the parameter C in the model which accounts for the intensity of local velocity did not show any effect on the velocity profile. Adjustment of the original model to include the effect of local turbulence in the velocity profile. Analysis of experimental data by Ferizi (2014) showed that, the more viscous the displacing fluid was and the higher the wall roughness the higher the displacement efficiency became. Also, comparison of displacement efficiency curves from the model and experiments showed similar trends, thus indicating that the model is acceptable. | |
