Abstract
Reservoir characterization involves computing various petrophysical parameters and defining them in terms of their quantity and quality so as to ascertain the yield of the reservoir. Petrophysical well log and core data were integrated to analyze the reservoir characteristics of Explorer field, Offshore, Niger Delta using three wells. The study entails determination of the lithology, shale volume (Vsh), porosity (Φ), permeability (K), fluid saturation and cross plotting of petrophysical and core values at specific intervals to know their level of correlation. The analysis identified twelve hydrocarbon-bearing reservoir from three different wells. Average permeability value of the reservoir is 20, 0140md while porosity value range between 18% to 39%. Fluid type defined in the reservoirs on the basis of neutron/density log signature were basically water, oil and gas, low water saturation values ranging from 2.9% to 46% in Explorer wells indicate high hydrocarbon saturation. The Pearson Correlation Coefficient and Regression Equation gave a significant relationship between petrophysical derived data and core data. Scatter plot of petrophysical gamma ray values versus core gamma ray values gave an approximate linear relationship with correlation coefficient values of 0.6642, 0.9831 and 0.3261. Crossplot of petrophysical density values and core density values revealed that there is a strong linear relationship between the two data set with correlation coefficient values of 0.7581, 0.9872 and 0.3557, and the regression equation confirmed the relationship between the two data set. Also the scatter plot of petrophysical porosity density values versus core porosity density values revealed a strong linear relationship between the two data set with correlation coefficient values of 0.7608 and 0.9849, the regression equation confirmed this also. Crossplot of petrophysical porosity density values versus core porosity density values in Well 3 gave a very weak correlation coefficient values of 0.3261 and 0.3557 with a negative slope. The petrophysical properties of the reservoirs in Explorer Well showed that they contain hydrocarbon in commercial quantity and the cross plot of the petrophysical and core values showed direct relationship in most of the wells. Â
Highlights
Hydrocarbon accumulations have been found to mostly occur in pore spaces of reservoir rocks
Geophysical well log interpretation and core description were done on the wells of Explorer field, concise qualitative and quantitative evaluation were done on the well by first identifying the sand and shale using the gamma ray log, and compare zones of sandstone with the corresponding resistivity log by identifying sandstone to be of high resistivity and shale to be of low resistivity, the porosity log was used in identifying the fluid contact
By using empirical petrophysical formula, the petrophysical values were computed which enables in differentiating the oil bearing reservoir from water bearing reservoir (Figure 3), the porosity log confirms the nature of the reservoir
Summary
Hydrocarbon accumulations have been found to mostly occur in pore spaces of reservoir rocks. To have an idea of the commerciality of a new accumulation or reservoir, some basic petrophysical parameters such as porosity, permeability, hydrocarbon saturation,and thickness etc., needs to be evaluated These parameters can be inferred from various well logs. Adaeze,et al(2012) presented their results from the evaluation of petrophysical properties of “Uzek”well, Niger delta using well log and core data with a view to understand their effects on the reservoirs hydrocarbon prospect and oil productivity of the field. They were able to reveal similarity in the porosity values of well log and core data using the pearson correlation coefficient and regression equations (Adaeze et a., 2012). Evaluating the distribution of these petrophysical parameters throughout the formation, knowing fully that well logs data cannot give a precise and unequivocal information about a reservoir, which have direct impact on the reservoir parameters estimated, coredata is use to complement this in other to enhance accurate estimation of reservoir properties and the eventual hydrocarbon in place
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
