| Popis: |
Oil base drilling mud is commonly used during drilling operations because of the associated advantages especially in terms of cost and time savings benefits. However, once there is excessive overbalance pressure in the mud column during drilling, the oil base mud will invade the hydrocarbon formation. And since base oil used in preparing the drilling fluid is miscible with the formation hydrocarbon fluid, it will contaminate the reservoir fluids and alter the fluid's properties. Hence for waxy fluids (paraffinic), when early time contaminated samples are collected down hole via open hole wire line sampling, erroneous fluid property data will be generated in the course of characterization. Such erroneous data can be quite misleading, especially when used for the early phase upstream facility design. And the cost implication can be enormous for the flow assurance engineer. In this work, a waxy crude sample was collected from an onshore field in the Niger Delta region. Subsequently, the sample was contaminated with various levels of oil base mud in order to investigate the errors induced by OBM on waxy crude properties such as the wax appearance temperature (WAT), pour point, density and viscosity. The result shows that the presence of OBM contamination, significantly impacts on the waxy crude properties with pour point temperature being the most affected by contamination. Hence caution should be exercised when using or interpreting experimental data obtained from waxy samples contaminated with oil base mud. |
