Permeability Estimation Using Log Data, Abu Dhabi Offshore Field, UAE

摘要

One of the major elements used to evaluate an oilfield reservoir is the rock Permeability. It’s also used in many other aspects such as reservoir simulation, rock type definition, etc. There are many methods utilized to measure / predict formation permeability (Well Test, MDT, Core analysis…). Rock Permeability indicator significantly increases with porosity for the intergranular-type formation (not applicable for noninterganular rock, such as formation containing solution channels, vugs or fracture); however it is also quite dependent on the surface area presented by the grains. On the other hand, irreducible water saturation reflects the surface area. Therefore a function of porosity & irreducible water saturation can help in prediction of the absolute permeability. In our case study, the actual Sw (initial) were used in this function, hence the Permeability obtained actually represent the effective rather than absolute value. Through the petrophysical evaluation of an offshore oilfield in Abu Dhabi, it was noticed that by applying a function of Water Saturation, Porosity & other coefficients, there were a good match between the Permeability estimated using open-hole log data & Permeability measured from the core sample in the laboratory. A step further of this quality check to this function is taken by comparing these results to the wells test & having an overall comparison over the full field data in-hand. This paper focuses on establishing a correlation between open-hole log data interpretation & permeability measurement from the core sample that resulted in generating an empirical equation capable of predicting the permeability from the open-hole log data.