This work evaluates the economics of GTL plant using two synthesis gas methods. The first method called the base case utilizes oxygen as fuel for combustion of natural gas, while the proposed case uses steam/CO 2 instead of Oxygen. The aim is to ascertain a more economically viable GTL configuration for an optimal GTL process. The associated flare gas at Egbema production sites in the Niger Delta has been chosen as case study. The gas flowrate is 50MMscfd of raw natural gas which was pre-treated before being fed into the main GTL plant. The liquid yield result shows that the proposed method has a liquid yield of 5730b/d over the 5430b/d gotten from the base case representing an increase in product yield of 5.5%. The economic analyses show a quicker pay-out time of 4.9 years from the proposed model compared to 5.9 years from the base case. Using the proposed method gave an annual cashflow increase of 20.9% and NPV increase of 59.7% at 10% discount rates. Also the DCF-ROR from the proposed method was 20.3% compared to 16.6% gotten from the base method. Thus the proposed method is more profitable in terms of NPV. The project is recommended for application in the Niger Delta stranded and remote gas locations that have before now been subjected to flaring.

Mathematical model for leak location in natural gas pipeline has been developed in this paper. The model employs an isothermal steady state approach. Leak occurrence in the pipeline divides the pipeline into two sections-the upstream and downstream sections respectively. Analyses of leak incidences were carried out in the two pipeline sections giving rise to two equations being developed to address the leak localization. The first leak equation was developed by considering the upstream section of the pipeline while the second leak equation was developed by considering the downstream section of the pipeline. The two equations were analytically developed by slight modification of the Weymouth's equation for gas flow in horizontal pipeline. Matlab software was used in the model simulation. Seven field data were used in the model simulation. The results from the Matlab simulation of the mathematical models developed gave the leak locations for each of the field cases. Comparison of the simulated results with actual results of leak locations determined experimentally revealed high level of accuracy with an average error of only 0.377% which is below the minimum acceptable limit. Furthermore analyses of results show that the two leak equations yield same results when used in the Matlab simulator. The model is highly suitable for accurate detection of leak in natural gas pipeline especially where economics and reliability is of essence.

The precipitation and deposition of wax has remained a major challenge that the oil industries is faced with during the production of waxy crude. This problem is simply an issue from the wellbore to the surface facilities. As a result of this, millions of dollars has been invested in remedial operations. In this research, a predictive model that uses thermodynamic relationship in predicting precipitation of wax has been developed. K-values for the solid-liquid equilibrium is described using solubility parameter, melting point temperature, enthalpy of fusion, and the molar volume for the components. The weight fraction was used to describe the wax mixture. Experimental data from three oil mixtures were used in comparing the model predicted wax appearance temperature (WAT). For oil mixA, the experimental value is 294.15K; Pauly et al predicted 302.15K while this work predicted 301.21K. For oil mixB, the experimental value is 300.15K; Pauly et al predicted 310.15K while this work predicted 308.91K. For oil mixC, the experimental value is 298.15K; Pauly et al predicted 302.15K while this work predicted 300.38K. The obtained results from this research confirmed the capability of the model in predicting Wax Appearance Temperature. A more conservative value for the WAT was predicted which is an improvement.

Oil companies'dealing with drilling operations in Nigeria often spends millions of dollars in importation of bentonite for its operations as a result of its importance and high demand. As a result of this, attempt to source for local substitute has been initiated, which if successful would save the nation from this huge capital flight. In this study, a sample of Umuna local clay deposit was evaluated for drilling fluid application. The viscosity and filtration loss was analyzed and it's far below that of the imported bentonite. The properties of the local clay was improved by addingmaterials such as HV-CMC, Drispac polymer and bentonite extenders to the formulated mud to enhance its viscosity and filtration loss Also the shearing speed was increased, but the used speed is limited to practical shearing speed. Theclay yield and characterization of the beneficiated samples show that the treated local clay is slightly comparable to the imported bentonite. The Calcium Exchange Capacity (CEC) result for the clay samples fall within the 70 -150 Meq/100g. This result further suggests that the analyzed clay is of montimorillonite family, with traces of illite which is good for drilling mud production. The obtained results from this study indicates that the filtration loss and plastic viscosity for the analyzed clay samples were generally far from comparing with the imported bentonite, but through beneficiation, they were able to compare with the imported bentonite.

Oil rim reservoirs present unique problems during production. This is because of the proximity of the water and/or gas to the oil in the pay zone leading to phase distortion due to pressure disequilibrium during production of the oil. The resultant effect is early water/gas breakthroughs which ultimately lead to increased well operational cost, damage to production equipment and eventually to early loss of the well. Production rate becomes crucial as it directly or indirectly affects the overall recovery efficiency from the well. Low rate production signifies longer well production period due to delayed breakthrough time but at the expense of higher well operational cost per unit volume of oil produced, while higher rate production signifies higher oil volume per unit cost of well operation but with increased risk of losing the well due to water/gas breakthrough. Operators produce at a rate deemed economic in order to make profits. Most economic rates are higher than the critical rate which is the rate considered that coning would be maximally delayed. To optimize production, it is necessary to recover most of the fluid from the reservoir before abandonment. Higher recovery factors means that less volume of fluid is left in the reservoir at abandonment. The optimum oil production rate is the best economic oil rate that would result to the highest recovery factor obtainable from that well. The question is what rate is considered optimal and how can it be calculated? This work presents a mathematical model solution for the calculation of the optimum oil production rate. It takes cognizance of the recovery factor and the time value of money and present an analytical model to calculate the optimum oil production rate. From the work the optimum oil production rate was calculated to be 918.63stb/d while the critical oil rate was calculated to be 20.17stb/d.