Porosity estimation using RHG approach and well log data from southern Niger Delta, Nigeria

Abstract

Raw well data from oil wells A₁₁, A₂₂ and A₃₃  in the southern parts of the Niger Delta (AXXField) were used for porosity estimation using the Raymer Hunt Gardner (RHG) technique. Using Microsoft Excel for analysis and computation of results, gamma ray log, sonic log with respect to depth were generated. The results of these curves were used to estimate porosity. The major outcomes resulting from this porosity estimation revealed that porosity ranges from 22.0% to 41.0%, 25.0% to 37.0% and 16.0% to 38.0% for wells A₁₁, A₂₂ and A₃₃ respectively, with average values of about 33.5% for well A₁₁, 30.1% for well A₂₂ and 27.1% for well A₃₃. Therefore, the average porosity obtained gives 30.2% in the AXX field. The result of this estimation belongs to the excellent class of porosity estimation. It shows that the available pore spaces in the oil reservoir zone are adequate for migration, that is, it can store and transmit fluid. These results show that an increase in sonic gives rise to an increase in porosity irrespective of the lithology.