Petroleum EngineeringThis collection contains theses of Petroleum Engineering Students from 2016-2022http://repository.aust.edu.ng/xmlui/handle/123456789/3692023-10-01T07:54:50Z2023-10-01T07:54:50ZIntegrated Modelling and Optimization of Options for Developing Thin Oil Rim Reservoirs: Niger Delta Case StudyAladeitan, Yetunde Mariamhttp://repository.aust.edu.ng/xmlui/handle/123456789/50902022-10-12T21:00:45Z2020-09-12T00:00:00ZIntegrated Modelling and Optimization of Options for Developing Thin Oil Rim Reservoirs: Niger Delta Case Study
Aladeitan, Yetunde Mariam
The goal of an oil field development project is to accelerate the hydrocarbon production and maximize recovery at the lowest cost. Optimizing the production of oil from thin oil rim reservoirs poses a major challenge in the oil and gas industry because of the water and gas coning tendencies which limit the ultimate recovery from such reservoirs. Development of oil rims generally requires a lengthy study to unravel the complex interplay of the subsurface uncertainties and to determine technical feasibility, development concept and economic attractiveness. Simulations and experimental methods coupled with simple analytical solutions or correlations are typically used to identify the oil rate that minimizes coning and maximizes recovery. This research aims to optimize oil recovery from oil rims by generating models to be used to forecast production rates and increase the ultimate recovery over a range of uncertainties.
In this work, a surrogate simulation model is developed to analyze oil rim dynamics and evaluate the impact of a range of subsurface uncertainties on the oil and gas recovery. Alternate development strategies have been considered, and the method of experimental design was used to obtain correlations for each development strategy. The lessons learned from the generic model were incorporated into a systematic study of an integrated reservoir management plan for developing an oil rim reservoir in the Niger Delta. Seven reservoir development strategies are evaluated using numerical reservoir simulation; and the optimum production strategy is selected.
The evaluation of the best strategy includes optimization of well placement and economic analysis using the cumulative oil and gas recovery from the various development strategies. In the economic analysis several profitability indices such as net-present value, internal rate of return, and discounted payout period were utilized to identify the optimum development strategies. The results show that well placement has a significant impact on water and gas coning and on oil recovery. It is concluded that the development of thin oil rim reservoir requires an integrated reservoir management plan. Proper reservoir management is achieved when the reservoir producibility factors, operational constraints and economics of the project are considered in the field development planning.
2020-09-12T00:00:00ZUpstream Petroleum Industry Performance Evaluation using Data Envelopment Analytic ApproachIdowu, Adekunle Josephhttp://repository.aust.edu.ng/xmlui/handle/123456789/50432022-04-26T21:01:21Z2019-06-23T00:00:00ZUpstream Petroleum Industry Performance Evaluation using Data Envelopment Analytic Approach
Idowu, Adekunle Joseph
Nigeria ranks among the top ten petroleum producers in the world with over eighty petroleum Investors in its upstream sector. This creates an enormous challenge for the upstream institutions’ managers especially in the evaluation of technical performance of the sector. One major problem is that there is hardly any quantitative empirical information on technical efficiency of the sector for effective performance evaluation and strategic policy formulation. It is this identified knowledge and information gap that this study aimed to fulfill by estimating the needed relative technical efficiency for each of the 32 selected upstream industry operators in Nigeria. The study adopts an output-oriented data envelopment analysis framework considering a constant return to scale, variable return to scale and non-increasing return to scale.
Consequently, an economic analysis was carried out using a panel data econometrics model to establish the determinants of technical efficiency in the Nigerian upstream sector. The results of the analysis revealed decreasing trends in the upstream sector operators’ technical efficiencies from 2010 to 2016. Additionally, the panel data econometrics model revealed that four of the selected independent variables were statistically significant determinants of the upstream technical efficiency in Nigeria within the period of the study.
In conclusion, this study recommends strategic policies towards minimizing bureaucracies and enabling new efficiency-oriented ideas for operators on decreasing return to scale frontier. It also recommends the formation of alliance among the operators on increasing return to scale frontier to boost internal growth and unlock significant values. As regards the six operators on a constant return to scale production frontier, it is specifically recommended that they should embark on serious reserves growth’s strategy to increase their reserves base.
2019-06-23T00:00:00ZGenetic Units Based Reservoir Characterization using a Normalized Pore Throat Radius for the Clastic System: Niger Delta as Field Case StudyOnuh, Haruna Mondayhttp://repository.aust.edu.ng/xmlui/handle/123456789/50412022-04-26T21:00:54Z2016-12-12T00:00:00ZGenetic Units Based Reservoir Characterization using a Normalized Pore Throat Radius for the Clastic System: Niger Delta as Field Case Study
Onuh, Haruna Monday
Globally, 30–50% of hydrocarbon volumes in silici-clastic reservoirs are contained within the thin-bedded pay. In the Niger Delta deep water assets, over 30% of in-place volumes are found within the complex turbidites. The presence of multi-pore architecture within such facies makes their description from petrophysics very complex. With the quest for hydrocarbon prospects in frontier deep water settings characterized by such complex rock fabric, detailed reservoir characterization is essential for accurate field management and production optimization.
The focus of this work is to characterize complex reservoir pore systems at core scale based on genetic reservoir unit averages and to provide improved models for petrophysical evaluation using a normalized pore throat radius approach for clastic reservoirs. New methods are presented for modelling permeability in rocks with multimodal pore throat size distributions using Niger Delta field as case study. The statistical significance of the coefficients in the proposed relationships for various genetic reservoir units was verified using α-level of 0.05; and the results indicate that the proposed model is very unlikely to have occurred by chance. Two methodologies are presented for upscaling from core plug to log scale–genetic unit averages of pseudo normalized pore throat radius as input parameter to the proposed model. This study also presents improved methodology for generating capillary pressures from NMR T2 relaxation time using a genetic unit based averages of the kappa scaling parameter proposed by Volokitin et al. The improved methodology is also applicable to conventional geophysical logs for estimating capillary pressure in the absence of NMR T2 data.
Comparative analyses indicate that the proposed methodology is an excellent improvement over existing methods (e.g., Reservoir Quality Index, Leverett J-Function, Stratigraphic Modified Lorenz Plot) for characterizing hydraulic flow units. Additionally, efficiency of the proposed methodology is demonstrated by comparison of estimated permeabilities versus core permeabilities from four depobelts in the Niger Delta. Permeabilities were derived from existing methodologies including Genetic Unit Averages of FZI’s, Neural Network Permeability, NMR based Schlumberger Doll Research (SDR) and Coates correlations. It is concluded that the proposed methodology is a superior and practical tool for reservoir characterization.
2016-12-12T00:00:00ZDevelopment of a Thermodynamic Model for Wax Precipitation in Produced Crude Oil -- Case Study of Hydrocarbon Fluid from Niger-Delta, NigeriaAkinyede, Opeyemi Mayokunhttp://repository.aust.edu.ng/xmlui/handle/123456789/50402022-04-20T21:00:56Z2019-06-23T00:00:00ZDevelopment of a Thermodynamic Model for Wax Precipitation in Produced Crude Oil -- Case Study of Hydrocarbon Fluid from Niger-Delta, Nigeria
Akinyede, Opeyemi Mayokun
Wax is often precipitated out of solution in waxy crude oil found in most oil reservoirs around the world, especially as the production of oil and gas has moved from on shore to more challenging terrains offshore. Waxes are composed primarily of paraffin which are saturated hydrocarbons. Wax precipitation and deposition pose production and transportation challenges in the area of flow assurance in the oil and gas industry which is not uncommon in the Niger Delta. This problem can affect system selection and operational procedures which has enormous cost implications. It is therefore important for producers to identify potential candidate wells/fields for organic solids precipitation and deposition. This can be done by understanding the composition and the paraffinic nature of the reservoir fluid mixture in prediction so that a production strategy can be designed to prevent or mitigate problems of wax precipitation and deposition.
This research builds on thermodynamic principles to model wax precipitation using Niger-Delta petroleum fluids. Reservoir fluid characterization is very significant in modeling as it helps identify components of the mixture. Statistical methods are used for analyzing the molar distribution of components in petroleum fluids for the Heptanes plus components (C7+) which are usually lumped. Three probability distribution functions (Normal distribution, Exponential distribution and Weibull distribution) were used in analyzing the distribution of components in hydrocarbon fluid. Kolmogorov-Smirnov, Anderson-Darling, P-value, and L-RT statistical methods were then used to determine the goodness of fit of the distributions to petroleum fluid data. Exponential distribution is found to be the best fit for gas because gas components decline from C1 to the last heavy component, which is a continuous decline. Liquid hydrocarbon components usually increase from C1 to an intermediate component, for example C8 as shown in this study, and decline to the last heavy component. This makes exponential function unfit, for the entire distribution in liquid hydrocarbon. Weibull distribution is found to be the best fit for all hydrocarbon fluid (gas and liquid).
A statistical model which can be used to determine goodness of fit for any number of data set at any desirable significance level, is developed using Kolmogorov- Smirnov test data. Minitab statistical analytical software is used to further analyze the fluid data using the Anderson-Darling test, P-value and the L-RT. Wax precipitation has a strong dependence on temperature. For wax prediction, a new correlation for predicting temperature of melting 𝑇𝑖 𝑓 of heavy ends is developed using fluid data from the Niger-Delta. The correlation is validated with experimentally determined melting point data.
A reliable wax precipitation prediction model is desirable for the optimal production of reservoir fluids. The solid-liquid equilibrium parameter is important for developing a predictive thermodynamic model to determine the amount of wax precipitate and wax appearance temperature. The temperature dependent term is grouped as one and together with the composition dependent term, bivariate analysis is done. Bivariate analysis is used to mathematically remove correlations in the predictors such that the effects of these predictors on the response can be observed more clearly. A new set of independent predictor random variables is then developed with a reliable regression model whose R-square remains the same before and after removal of correlations. Multivariate analysis is also presented using multiple predictor on the equilibrium parameter, to better understand how each parameter affects the response. A Step by Step procedure of how this can be done is presented. A Correlation is also developed to determine the fluid component at various temperature and pressure. These components were then used to predict the wax appearance conditions of the fluid. This method is useful in determining the depth of wax appearance in the well bore.
2019-06-23T00:00:00Z