Numerical Evaluation of Formation Damage Models for Application in Niger Delta Oil Reservoirs

Abstract

The frequent random application of formation damage models in the assessment of oil well deliverability has prompted the critical evaluation of these models to streamline their applicability in specific reservoir types. Coupled with the unconsolidated nature of the Niger Delta Agbada formation, the establishment of a unique damage model which will take into account, the textural and structural configuration of the formation sand in its damage estimation is most paramount. In this work, four formation damage models were numerically evaluated and matched to the conventional pressure buildup skin model using reservoir and well production data from five (5) different Niger Delta locations assigned ND-1, ND-2, ND-3, ND4 and ND-5. Result showed that the Frick & Economides model, if adopted within the region can be dreadful for all reservoir cases as it tends to underestimate formation damage implications as well as skin magnitudes since it is primarily a function of the altered permeability and damaged radius only, recording an average skin of 1.30 as against 3.36 for the reference model. The models of Behr & Raflee, Ozkan and Furui et al with reference to the buildup skin model showed promising results in skin magnitude estimation. Further damage analysis revealed that the Furui et al model was most appropriate as it yielded an average Flow Efficiency of 69.40%, an average skin induced pressure drop of 193.98 psi and an average damage factor of 0.3