Crude Oil Importation and Exportation in Nigeria : An Exploratory and Comparative Study

Nigeria is an oil producing country and crude oil is an important asset to its economy. This research focuses on the analysis of importation and exportation of crude oil products (measured in million barrels). Comparisons between the total importation and exportation were made and descriptive analysis was performed on the crude oil components. Poisson regression was used to establish the relationship between total importation and the importation of the petroleum products under consideration. The results show that Nigeria makes more importation than exportation of these products. Keywords-crude oil; exploratory data analysis; exportation; importation; Nigeria


INTRODUCTION
Crude oil, often called unrefined petroleum, is a natural product.Just like other mineral resources, petroleum is found through drilling.Crude oil is processed through distillation and produces several other components.Table I shows the various components of petroleum and their boiling point [1].These components are useful as transportation fuel, road tarring materials, paints, cosmetics and so on.Various works on crude oil production especially in Nigeria are contained in [2][3][4].

Components
Boiling Point Fuel gas, LPG, refinery gas Below This research makes comparison between the importation and exportation of these products in Nigeria.Crude oil is found in several countries, but Nigeria is one of the countries that extract light and sweet oil, otherwise known as brent crude oil.

II. MATERIALS AND METHDOS
The data presented in this article represent the amount of imports and exports of crude oil products in Nigeria from 1986 to 2010.Total importation and exportation of crude oil, importation and exportation of kerosene, motor gas, jet fuel, distillate fuel and liquefied petroleum gasses were taken into consideration.The data was obtained from [5].Descriptive analysis was performed and Poisson regression model was fitted to the importation datasets.Total importation was the dependent variable while importation of kerosene, motor gasoline, jet fuel, distillate fuel oil and liquefied petroleum gasses were the independent variables.The software used in dataset analyzing was Minitab 17.The Poisson regression model is of the form: where β 0 is a constant and β 1 , β 2 ,...,β k are the regression coefficients.For the present study, Y is the total importation, X 1 , X 2 , X 3 , X 4 and X 5 are the importation of kerosene, motor gasoline, jet fuel, distillate fuel oil and liquefied petroleum gasses respectively.Analysis contained in [6][7][8] can be used to analyze the dataset.

III. RESULTS
The summary of the data used is provided in Tables II and  III.It is clear that Nigeria imports more than what it exports.Specifically, the highest importation regards motor gasoline while the highest exportation is for distillate fuel oil (among the considered variables).The lowest importation is for liquefied petroleum gasses while the lowest exportation is for kerosene.The comparison between total importation and total exportation between 1986 and 2010 is provided in Figure 1.The comparisons between importation and exportation of kerosene, motor gasoline, jet fuel, distillate fuel oil, and liquefied petroleum gasses for the period under study are presented in Figures 2, 3, 4, 5, and 6 respectively.

 Poisson Regression Analysis
The Poisson regression equation is obtained as: 1.124 0.02239 0.01535 0.0214 0.0044 0.067 where, Total importation equals

IV. CONCLUSIONS
Datasets on importation and exportation of petroleum products have been studied in this paper.The conclusion was that the amount of total importation was greater than the respective amount of total exportation in Nigeria.The bulk of the importation is on motor gasoline while the bulk of the exportation is on distillate fuel oil.There is a negative linear relationship between total importation and variables X 2 , X 3 , and X 4 (importation of motor gasoline, importation of jet fuel and importation of distillate fuel oil respectively).The results of the Poisson regression provided regarded only importation of petroleum products, further research can include analysis on the exportation of these products.

TABLE II .
CRUDE OIL IMPORTATION, 1986-2010 (MILLION BARRELS) standard errors are presented in Table IV.The result for the deviance is provided in Table V and the model summary for the deviance is provided in Table VI.The results for the goodness of fit test are provided in Table VII.