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It is important that leaks are detected early in pipelines. The need for prompt and accurate leak detection becomes more crucial when the pipeline content is gaseous. Remedial actions require that the leak location be determined in any leak incidence. Accurate leak localization will not only save cost but will enhance remedial actions such as replacement and repairs of damaged pipeline sections, clean-up of affected ecological systems and direct inspection of degree of damage. This information will aid in understanding the causes and effects of the leak. This paper presents a mathematical model for determination of the location of leak in a natural gas pipeline. The mathematical approach employed a mass balance approach to the modification of the Weymouth's gas transportation equation in a horizontal natural gas pipeline. The pipeline under consideration was divided into two sections at the advent of leak. Before the leak point the pipeline cross section is represented as the upstream section while the downstream represents the section ahead of the leak point. The mathematical model herein was developed with reference to the downstream section of the pipeline. The results showed good accuracy with other leak location models available in literature and was also verified to be correct and within acceptable error limits when compared with actual field data.

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In this paper, the economic potential of using a mini gas-to-liquids (GTL) plant for monetization of stranded associated gas in Nigeria was extensively evaluated. Feedstock to the plant comprises 50 MMscfd of treated stranded associated gas from Assa North in the Niger Delta region of Nigeria. 5000 b/d of GTL diesel product was realized after simulation using Fischer-Tropsch (FT) type modular gas-to-liquids technology. Economic analyses were performed for a wide range of economic conditions to determine the economic potentials of the GTL project. From the result, it was realized that for base case, the net present value (NPV) of the project was US$32,421 barrel-liquid-per-day (BLPD) corresponding to US$162.1 million for 5000 b/d of GTL diesel produced. The payout time (POT) was 4.48 years while the net cash ratio (NCR) was US$81.83 million. The internal rate of return (IRR) was 22.2%. From the sensitivity analyses performed, it was realized that the variable having the most influence on the NPV was the GTL product price (the price of diesel) followed by the capital cost of the GTL plant and then the natural gas price. It was also realized that the operating cost of the plant has the least (negligible) effect on the NPV of the project. Furthermore, it was realized that GTL project remained profitable for diesel prices above US$80/bbl as long as the price of natural gas was maintained below US$2.2/Mscf at 15% discount rates. In general, it was realized that the mini-GTL project was profitable for diesel prices equal to or greater than US$80/bbl as long as discount rates remained below 20% for base CAPEX and OPEX. It was recommended that the government of Nigeria subsidizes the price of natural gas to increase the profitability of mini-GTL projects creating a greater participation by the private investors and thereby reducing the volume of associated gas flared.

The flaring of associated gas has become a global challenge. Aside the financial implication resulting from associated gas flaring, the environmental consequences are enormous and poses great threats to humans and the underlying ecosystem. The environmental implication is the degradation of the ecosystem resulting to loss of ecological lives, emergence of sicknesses, air, water and land pollution, release of poisonous gases that hamper human habitation, release of greenhouse gases resulting to global warming, severe respiratory diseases like asthma, bronchitis have been linked to flaring of associated gas in the host communities. The goal of the world health organization to completely eradicate gas flaring by 2030 has forced many countries to make laws that favour the utilization of associated gas and the further development of gas projects. Costly gas projects have undergone technological improvement, miniaturization and scaling to become portable and profitable ventures. In this paper, we propose means of utilising and monetising the flared associated gas in generation of electricity by a method known as gas-to-wire, this is the process of generating electricity from natural gas at or near the proximity of the field. The produced electricity is supplied to nearby host communities while surplus is supplied to the main electricity grid. Izombe production sites have been taken for case study. The turbine system used is a combined cycle gas turbine with a daily gas feedrate of 40MMscfd. The technical and economic parametres relative to the project are analyzed and discussed. The project promises a potential solution to the Nigeria electricity problem by diversification of electricity production and distribution and reduction in over-reliance on national grid.