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Knowledge of bubblepoint pressure is one of the important factors in the primary and subsequent developments of an oil field. Bubblepoint pressure is required for material balance calculations, analysis of well performance, reservoir simulation, and production engineering calculations. New bubblepoint pressure correlation based on data from the Niger Delta crude oils has been developed. Both quantitative and qualitative assessments were employed to evaluate this correlation which is compared to the best existing bubblepoint pressure correlation for the Niger Delta crude. The new correlation outperformed the best existing correlation by the statistical parameters used with a rank of 7.3 and better performance plot. Introduction Knowledge of bubblepoint pressure is one of the important factors in the primary and subsequent developments of an oil field. Bubblepoint pressure is required for material balance calculations, analysis of well performance, reservoir simulation, and production engineering calculations. In addition, bubblepoint pressure is an ingredient, either directly or indirectly, in every oil property correlation. Thus an error in bubblepoint pressure will cause errors in estimates of all oil properties. These will propagate additional errors throughout all reservoir and production engineering calculations¹. Bubblepoint pressure correlations use data that are typically available in the field; solution gas-oil ratio, gas specific gravity, stock-tank oil gravity and reservoir temperature. None of the currently proposed correlations for bubblepoint pressure (for review of bubblepoint pressure correlations refer to References 2 to 9) are not particularly accurate for the Niger Delta crude; therefore, the purpose of this paper is to propose a more accurate bubblepoint pressure correlation for the Niger Delta Crude. Data used The data used for this study was obtained from conventional PVT reports that derive the various fluid properties through differential liberation process from different oil fields in the Niger Delta. A total of 250 PVT reports were validated for this study using material balance and Campbell plots. 250 data sets were used for the correlation development of the new bubblepoint pressure correlation. Table 1 shows the PVT input data range used for this study.

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This present study emphasizes the inhibition capacity of a local inhibitor, Plant Extract (PE) on structure I (sI) gas hydrate. The Plant Extract (PE) was screened using a mini flow loop made of 316 stainless steel of internal diameter of 0.5-inch encased in a 4-inch PVC pipe skid mounted on a metal frame work fitted with pressure and temperature gauges, mixer vessel, pumps and control switches. Pressure and Temperature readings were recorded for 120 minutes. Plots of Pressure and Temperature versus Time for 1, 2 and 3wt% of the local inhibitor alongside Pressure versus Time plot of PE and MEG were done as a way of comparison. Calculations for Inhibition Efficiency (IE) for local inhibitor PE and MEG was also done. 1wt% of the plant extract (PE) had a high inhibition efficiency of 84.21% while 2 and 3wt% had inhibition efficiency of 60.53% and 73.68% respectively. The overall inhibition efficiency of Plant Extract (PE) was higher than that of MEG for 1wt% (60.53%) and 2wt% (55.26%) but had the same efficiency at 3wt% (73.68%). The optimum weight percentage for PE is 1wt% because of its high efficiency. It is clearly shown that Plant Extract (PE) is a better gas hydrate inhibitor which is gotten from nature and is environmentally friendly unlike Mono Ethylene Glycol (MEG) which is synthetic and toxic to both human and aquatic life. It is therefore recommended for field trial.

Lipases are hydrolytic enzymes responsible for the hydrolysis of triacylglycerol into glycerol and free fatty acids. The biodiversity of crude oil contaminated soil was explored for the isolation of novel potent lipase producing microorganisms. In this current study, microorganisms isolated from crude oil contaminated soils were screened for lipase activity and expression. Six fungal strains namely: Yeast, Aspergillus flavus, Aspergillus niger, Verticillus sp., Penicillum sp., and Microsporum audouini demonstrated lipase producing potentials and the best two: Verticillus sp. and Penicillum sp. were selected for enzyme production and characterization. The lipase enzyme was produced in broth medium. Optimization of selected biochemical parameters reveal that optimum temperature for lipase activity was 40 ºC, pH 7 with an incubation time of 168 h for lipase expressed by Verticillus sp. and 40 ºC, pH 8 with an incubation time of 144 h was established for lipase expressed by Penicillium sp. The kinetic parameters of the lipase enzyme revealed that the enzymes had low Km (0.19 and 0.30 respectively) for the selected substrate.