In order to achieve the purpose of improving the understanding of drilling bits performance at a particular depth in the Niger Delta region of Nigeria, a simple performance optimization model -'Matching the Area Average Performance' was used to ascertain the actual performances of selected drilling bits used in the region against their prevailing drilling variables in terms cost evaluation. In this model, Cost per Foot equation was used to compare the performances of the selected drilling bits on the basis of minimum Cost Drilling for two case study wells - Agbada 1 and Soku 56, located in the heart of the region with depth range of 3,000 feet to 20,000 feet respectively. The interpretation of graphs of the relationships between Depth, Cost per Foot and Total Run Cost of a particular drilling bit size gave a proper downhole drilling analysis of two the two wells in the region hence, illuminating the behavior of a drilling bit at a particular depth amidst the prevailing drilling variables in the region. This study, a research contribution to investigation, evaluation, analysis, comparisons and interpretation of field data, is of immense benefit to indigenous engineers and drillers.