Cuttings transport has a major impact on the economics of the drilling process. It is one of the major factors affecting cost, time and quality of drilling wells. In spite of the many technological advances that have attempted to prevent the cuttings transport along the fluid, one significant challenge remains predicting the effect of cutting transport on pressure drop. Many interdependent variables affect cuttings transport and the complexity of the phenomena present challenges to the production engineer whose tries to determine how the cuttings transport affect the pressure in vertical flow. Meanwhile, many correlations have been developed to determine the effect of cutting transport in vertical flow but there is little information related to effect of cuttings transport on pressure drop and cutting hold up along the vertical pipe. This paper presents comprehensive details of effect of cutting transport on pressure drop and the detrimental effect of drill cutting hold-up on fluid flow along the vertical pipe.

Scaling phenomenon is a major problem that occurs when water is injected for oil displacement and pressure maintenance in oilfields. This phenomenon of precipitation and accumulation of oilfield scale due to incompatibility between formation and injected water is induced around the well bore after water breakthrough at reduced reservoir pressure. The effect results in formation damage which may negatively impact on reservoir performance well bore performance and the success of water flooding project that depends on mobility ratio. This paper presents an analytical model based on existing thermodynamic models for predicting brine mobility, hydrocarbon mobility and mobility ratio of water flooded reservoir with possible incidence of scale precipitation and accumulation. The key operational and reservoir/brine parameters which influence the mobility ratio such as salt concentration in the brine, produced water rate, pressure drawdown, reservoir temperature were identified using this model. Results of the study shows that the mobility ratio of a water flooded reservoir remains constant until water breakthrough and achieves an increasing local maximum at 10% pore volume injected water as the flow rate of produced water increases with a significant jump beyond the critical flow rate observed at mobility ratio of 1. Similar results corroborating above were obtained with variation in skin factor. This model therefore can be used to diagnose, evaluate and simulate mobility ratio and skin factor in a water flood scheme enabling production engineers plan an economically efficient water flood scheme.

The limitation in the formulation and application of synthetic surfactants in petroleum industry is owing to their high cost of production or importation and their associated toxic effect which have been proven to be harmful to the environment. Hence it is vitally imperative to develop an optimum surfactant that is cost-effective, environmentally safe (biodegradable) and equally serves as surface acting agent. This study discusses the production of microbial produced bio-surfactant and its application in enhanced oil recovery. The bacteria Pseudomonas sp. were isolated from urine and allow to feed on neem seed oil as the major carbon source and energy. The crude bio-surfactant produced from the fermentation process was used to prepare three (3) solutions of bio-surfactants at different concentrations of 5 g/500 mL, 10 g/500 mL and 15 g/500 mL, and their suitability for enhanced oil recovery (EOR) was evaluated. Reservoir core samples and crude oil collected from the Niger Delta field were used to evaluate the EOR application of the microbial-derived surfactants. The sets of experimental samples were carried out using core flooding and permeability tester equipment, and the results obtained were compared with conventional waterflooding experiments. The three bio-surfactant concentrations were observed to recover more oil than the conventional waterflooding method for the two core samples used. Optimum performance of the produced microbial-derived surfactant on oil recovery based on the concentrations was observed to be 10 g/500 mL for the two samples used in this study. Therefore, eco-friendly bio-surfactant produced from neem seed oil using Pseudomonas sp. has shown to be a promising potential substance for enhanced oil recovery applications by incremental recoveries of 51.9%, 53.2%, and 29.5% at the concentration of 5, 10, and 15 g/500 mL and 24.7%, 28.7%, and 20.1% at concentration of 5, 10, and 15 g/500 mL for the two core samples, respectively.

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