bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and Screening of Hydrocarbon Utilizing Bacteria for Biosurfactant Production: Application for Enhanced Oil Recovery
Authors: Sylvester Okotie , Onyekonwu Mike , Okpokwasili Gideon 
Published: July 2019

Abstract
Tertiary oil recovery techniques comprise miscible flooding, chemical, thermal and microbial injection into oil reservoirs to enhanced recovery. Several studies have been performed on the use of surfactants and polymers injection for enhanced oil recovery. But this study is focused on isolation and characterization of hydrocarbon utilizing bacteria for biosurfactants and biopolymers production. The concept of microbial enhanced oil recovery consists the injection of nutrients to activate indigenous microbes in the reservoir or injection of external hydrocarbon degrading microbes plus nutrients during field applications to ensure the organisms produce the required metabolites. These microbes have the ability to produce gases to increase reservoir pressure and displacement of immobile oil, bio-surfactants to reduce interfacial tension, biopolymer for mobility control, Injectivity profile and viscosity modification, solvent, acid and biomass. In this study, soil samples were obtained from hydrocarbon-contaminated site in Gio, Tai Local Government Area, in Ogoniland, Rivers State, Nigeria. The samples were transferred into a polythene bag, placed in an ice pack, and transported immediately to the laboratory for physicochemical and microbiological analyses such as emulsification index, haemolytic activity and oil spreading technique. 37 isolates were tested for biosurfactant production and 3 of the isolates were selected for biosurfactant production with strong ability to degrade hydrocarbon. The selected microbes (Bacillus sp, Pseudomonas sp and Enterobacter sp) were identified by biochemical characterization and subjected to ranges of temperature, pH, nutrient sources, salinity, and inoculum concentration to determine their optimum reservoir performance conditions. The result shows the optimum parameter ranges for the three microbes: pH 7-8, temperature within 25 – 35°C, salinity within 0.5% - 5%, the result shows that as the inoculum size increases, the more the emulsification index, the best nitrogen source is peptone and the best carbon source for bacillus sp is glucose and glycerol for Pseudomonas sp and Enterobacter sp.
Solution to Limited Pressure BHP Data in Brown Fields; Material Balance Equation Approach
Authors: Agbodike Bright , Osokogwu Uche , Achumba Gabriel 
Published: July 2019

Abstract
Reservoir performance analysis and forecasting poses a challenge in brown fields with limited Bottom Hole Pressure (BHP) data. Most brown Oil Fields in Nigeria have the problem of limited BHP data. Most fields from 1960 to 1970 are having the problem because they were not properly managed from inception as per their data storage and recording systems. In Nigeria, many farm-out assets to the Marginal Operators from the International Oil Companies are having such challenges and managing such assets is daunting and time-consuming because of limited BHP data. Reservoir management is central to the effective exploitation of any hydrocarbon asset and is heightened for the development of brown fields. The problem of limited BHP data also makes reservoir pressure history matching difficult. This study proposes a workflow implemented on an Excel VBA program for a brown field in Niger Delta region of Nigeria with limited pressure (BHP) data. The program, which was validated, was used to history match the observed field production data, the limited reservoir BHP data, predict reservoir performance and production profile within the specified timeframe. The tool is built on Material Balance Equation which is a zero-dimensional-tank model created for the reservoir. Pressure Volume Temperature (PVT) properties with correlations, fractional flow models and Corey correlation for relative permeability estimates were incorporated in the algorithm. The matched model calculates the likely parameters of the reservoir and aquifer, then the production history calibrates the pressure model. The following approach is used in resolving the problem for the field case study. Production data aggregation; Calibration of PVT laboratory data; Calibration of reservoir pressure model; Development of fractional flow model for the system; Calibration of the reservoir's last production date.
This approach gives an accurate reservoir pressure history prediction, and also good production forecast in field with limited BHP data.
Experimental Investigation of the Macroscopic Displacement Efficiency of Locally Sourced Locust Bean Gum and Gum Arabic
Authors: Eiroboyi I. , Ikiensikimama S. S. , Oriji B. A. , Okoye I. P. 
Published: July 2019

Abstract
In enhancing oil recovery through polymer flooding, the application of polymers have been basically structured around the use of commercial polymers like xanthan gum, scleroglucan, Hydroxyl ethyl cellulose, Polyacrylamide, Hydrolysed Polyacrylamide and its derivatives. The use of some of these polymer has led to negative environmental issues and also increased treatment cost prior to discharge. The cost of some of the polymers is another reason, their applicability have not been appreciated so much in the oil and gas industry. The adoption of the principles of green chemistry in the synthesis of chemicals is a sure way of ensuring pollution prevention rather pollution control.
Analysis carried on these polymers showed good rheology especially at higher concentrations. The displacement efficiency of Locust bean gum (LBG) and Gum arabic were evaluated using 0.2wt% and 0.5wt% in hard brine to recover trapped oil after water flooding, the results reflected significant incremental recoveries from both the use of LBG and Gum Arabic which also correlated with rheological characterisation carried out under different saline conditions. This analysis was extended by carrying a comparative study with commercial Locust bean gum and Xanthan gum. The efficiency of locally sourced LBG and Gum Arabic revealed that they are both candidates for polymer flooding.
Development of Two-Phase Compressibility Factor Correlations Using a Stochastic and Robust Gradient-Based Optimization Algorithm.
Authors: Sheriff Adeyemi Temitayo 
Published: July 2019

Abstract
Accurate estimation of two-phase compressibility factor is of great importance in predicting the performance of a gas condensate reservoir using the material balance approach. Over the years, several correlations for estimating gas compressibility factor have been developed. Some of these correlations are; the Standing and Katz, Rayes etal, Dranchuk and Abou-Kassem, Brill and Beggs’ and Hall-Yarborough’s correlations. However, these correlations have not been so successful in predicting the compressibility factor of gas reservoir fluids in the two-phase region (below dew point pressure) and this explains why the industry still relies on the expensive and time-consuming constant volume depletion (CVD) approach. Therefore, this paper presents two different correlations for estimating two-phase compressibility factor using stochastic and robust gradient-based Newton-Raphson optimization algorithm. The first correlation presents the two-phase Z-factor as a function of pseudo-reduced pressure, pseudo-reduced temperature and the specific gravity. The second correlation on the other hand presents the two-phase Z-factor as a function of the single-phase Z-factor (obtained using Standing and Katz approach). Both correlations were developed using over 50 constant volume depletion (CVD) data of reservoir fluid samples obtained from gas condensate reservoirs around the world. Furthermore, in order to develop these correlations, two different models were proposed and the heptane-plus (C7+) and acid gas fractions were accounted for using the Sutton’s and Lee Kesler correlations respectively. Moreover, using the expected values of the pseudo-reduced pressure, pseudo-reduced temperature, specific gravity and single-phase Z-factor (all obtained using appropriate probability distributions) as the input variables, the optimum values of the models’ fitting parameters that minimize the sum of squares of the errors (SSE) were obtained using the stochastic and robust optimization algorithm(an algorithm obtained from Taylor series expansion of the error function and implemented on Octave programming language for the purpose of this study). Finally, having developed the correlations using 70% of the available data, the performances of these correlations were evaluated using 30% of the available data and the results obtained shows that these correlations outperform other pre-existing correlations.
Evaluating the Potential of Bio-Derived Flow Improver and Its Effect on Nigeria Waxy Crude
Authors: Fadairo Adesina , Ogunkunle Temitope , Oladepo Adebowale , Adesina Adedapo 
Published: July 2019

Abstract
A root cause of many oil industry production and flow problem is paraffin wax especially in cold and deep offshore fields which are at low temperatures. About 82 – 89% of the hydrocarbon produced in the world suffers when wax precipitates out and solidifies in the pore spaces and channels of flow, around the wellbore, in the production wells or tubing, perforations, pump strings, and rods, and the whole oil transport flow-lines systems. The flow capacity of waxy crude can be quantified and evaluated using the means of pour point measurement. However, the description of this property during the flow of waxy crude is insufficient because the waxy crude rheological properties depend on the viscosity history. Using gelation theory, viscosity – temperature data can be analyzed and used to characterize the temperature behavior of waxy crude as such crude has the tendency to gel at low temperature. This paper evaluates Nigerian Waxy Crude Oil using biodiesel based material as an additive. Laboratory measurements on rheology were carried out on the sample at low temperatures condition. The obtained data of shear rate and shear stress plotted. The dose of biodiesel derived additive in neat waxy crude oil was varied between 0.1 to 0.5 v/v at the operating low temperature. The experimental investigations furnish that there is significant decrease in rheological properties with the decrease in pour point and temperature upon the addition of biodiesel derived additive hence, significantly enhance the flow of waxy crude in a flow system.
Reservoir Architecture as a Driver for Effective Field Development Planning in an Un-Appraised Field; Kz field, Kazakhstan as a Case Study
Authors: Kakayor Omagbemi G. 
Published: July 2019

Abstract
Successful oil and gas field development in clastic reservoirs is usually dependent on the amount of subsurface data available to be evaluated during field maturation. The general rule is that more data reduces subsurface uncertainties. This invites expensive appraisal campaigns that invariably leads to delays in investment decisions and increased costs in development projects. The present study highlights how the understanding and definition of the architecture of the reservoir coupled with the use of analogue database as a methodology can be used to enhance hydrocarbon development in fields that are not fully appraised. The un-appraised Kz field is used as a case study.
Kz field, with an expectation In-Place oil of ca. 1150 MMstb is located SW of the Kashagan field in the Caspian Sea, Kazakhstan. The field consists of 11 stacked hydrocarbon-bearing reservoirs of varying thicknesses penetrated by a single exploration well. Due to the paucity of well penetration, subsurface uncertainty that impact on hydrocarbon volume and recovery is high. The methodology used was to combine the wells log and core data in addition to the use of sequence stratigraphic technique to derive sedimentological conceptual models. Analogue databases were then used to derive a geological meaningful range of dimensions for the geometry of the respective sand bodies. These ranges were then used an input for in-place volume ranges.
Evaluation results showed a volume range that could support a go-forward decision for further investment in the field. Based on these results, some preliminary field development decisions were taken prior to dynamic simulation. Decisions include; (i) Drill six wells (ii) Do Multi-zone Well Completions and (iii) use two drill centers to optimally develop the field (Phase-1). The key strength of this approach is that some key Field Development decisions can already be made before appraisal using basic sedimentological concepts and analogue database studies.
Considerations for Mitigating Early Water Breakthrough in Horizontal Wells in Heavy Oil Reservoirs in the Niger Delta - Ogini Field Case Study
Authors: Erivwo Ochuko , Ochai Josephine , Agbaroji Victor , Oke Oluwatobi 
Published: July 2019

Abstract
Horizontal wells are susceptible to early water breakthrough (EWBT) due to reservoir heterogeneity and "the heel-toe effect", caused by frictional pressure losses along the well that lead to a non-uniform production profile. Also, with heavy oil reservoirs, early water breakthrough can occur because of viscous fingering due to an unfavorable mobility ratio caused by a difference in the viscosity of heavy oil and water. This ratio leads to a high inflow of water into the wellbore.
EWBT is undesirable as it brings with it negative implications; from low oil productivity to corrosion in the wellbore and water disposal challenges. There are different industry solutions to managing early water breakthrough including reservoir based improved oil recovery (IOR) or enhanced oil recovery (EOR) methods such as thermal EOR (steam flooding, cyclic steam injection), chemical EOR (polymer or alkaline flooding) or miscible EOR (with methane or ethane to reduce capillary resistance). These methods are however complex and broad field-based applications with varying experiences in the outcomes of the field implementation. There are also mechanical well specific solutions for mitigating EWBT and in this paper, we present the considerations and plans for the application of Autonomous Inflow Control Devices (AICDs) for the mitigation of EWBT in the Niger Delta. AICDs are relatively new and are known for autonomous selective choking of fluid phases. They restrict the flow of less viscous phases like water while allowing more viscous phases like heavy oil to pass through, with minimum pressure drop.
The paper examines the different causes of EWBT in Ogini field and the different solution options available. It presents the cost/benefit analysis and modeling considerations resulting in the selection of AICDs for EWBT mitigation. The paper concludes with the technology implementation plan developed for its successful deployment in the upcoming drilling campaign.
Practical Deployment of Fluid Contact Tracking During History Matching for a More Reliable Reservoir Simulation Model: A Niger Delta Case study
Authors: Ogbuagu Frank , Silpngarmlers Lynn 
Published: July 2019

Abstract
The reliability of dynamic simulation models can spell the difference between value creation or erosion during the development of a hydrocarbon reservoir. There is a strong need to use every available data during reservoir characterization, earth modelling and history matching of the production and pressure history of the reservoir. Of greater importance is the need to blind test the history-matched simulation model, to ascertain its reliability, especially when the model is to be used for further development of the reservoir.
This paper details an offshore Niger Delta case study in which saturation logging results were used to blind test a history matched model, with an objective to further validate the model. The saturated oil reservoir was fully characterized using high resolution sequence stratigraphy and the earth model developed with available static data. History matching of the dynamic model was carried out using the parameter estimation approach, incorporating available dynamic data and tracking of contact movement observed in post-production wells. Following the history match, a saturation log was run in one of the producers in the reservoir, as a blind test for the quality of the history match.
Results of the log matched the contacts in the dynamic model within 1 ft, in the subject well, providing additional confidence in the quality of the model. As a result, matched model has been used for the maturation of 2 new drill opportunities with significant estimated recoveries.
The Rise of Business Process Outsourcing in Nigeria's Oil and Gas Industry and Implications for Industrial Relations
Authors: Igbatayo Samuel 
Published: July 2019

Abstract
Business Process Outsourcing can be aptly described as the process of forging a contractual relationship with external supplier for the provision of capacity that has been previously undertaken within an organization. In the global oil and gas industry, Business Process Outsourcing (BPO) has emerged in contemporary times as a potent tool in their operational mix. This is particularly hinged on the imperatives to find a delicate balance between rising global demand, diminishing reserves in some of the world's major oil fields, while managing distribution and operating costs. The collapse of crude oil prices from US$100.00 in May 2014 to about US$30.00 and even below in early 2016 has reinforced outsourcing. Empirical studies reveal that outsourcing of non-core activities may result in 25% cost saving associated with on-/near-site operations and as much as 50-75% for offshore operations compared to the cost of engaging in same activities in-house. Apart from cost-cutting, other benefits associated with BPO include a stronger focus on core competencies; improved regulatory conformity and compliance; as well as access to a larger talent pool and novel technologies. The oil and gas industry has emerged as the cornerstone of Nigeria's economy, accounting for about 70% of annual government revenue and more than 90% of the nation's foreign exchange reserves. Since the 1990s, outsourcing has assumed an increasing dimension in the nation's oil and gas industry. Empirical studies reveal, for example, that up until the early 1990s, employees in the oil industry comprised about 70% and 30% of permanent and temporary employees, respectively. The temporary employees were initially focused on non-core activities. However, in recent times core activities are increasingly contracted to service providers, reversing the structure of employment in the industry by 2010, with 40% of permanent employees, while 60% were permanent employees. The increasing replacement of permanent employees with temporary ones has fueled concern in the industry, led by labour unions, which have expressed concern about the sub-standard welfare of contract workers. This development has led the Federal government of Nigeria to issue guidelines on staff contracting and outsourcing in the Nigerian oil and gas industry.
Strategic Responses to Social Demands: Some Lessons for Marginal Oil Field Operators in Niger-Delta Region
Authors: Oruwari Humphrey Otombosoba , Dagogo Opiribo 
Published: July 2019

Abstract
Corporate social responsibility has become a business imperative as organization deliberately and strategically include public interest on corporate decision in an attempt to satisfy the demand of sustainable development. Balancing short term sight and long term perspective against triple bottom requirements in the face of rapidly changing social environment presents uncharted challenges and opportunities for businesses. For marginal oil field operators located in the Niger Delta, the region is characterized by poverty, underdevelopment and violent conflicts. The study investigated the strategies adopted by marginal oil field operators in the region to achieve competitive advantage and success. Combining several methodological framework through literature review and multiple firm level case study to examine the various strategies that marginal oil field operators in Niger Delta region adopts in their efforts to becoming social responsible corporate entity. Data gathering is through internet and review of existing literature. The study established that marginal field operators may apply different strategies in responses to social demands in their operating environment. It is observed that the dynamic response or interactive strategy have produced beneficial result by sustaining peace in their operating environment in the long run compared to reactive or adaptive strategy which might gain temporary benefits in the short run. The significance of the study is that it would benefit investors in marginal oil field development as it would provide an understanding of the challenges in the business environment and the different strategic responses needed to handle these challenges. The study recommends that investors in oil and gas business assess their operating environment carefully in order to develop strategies that would result in a cost effective way of managing business and bring about harmonious relationship between the host communities and the oil company.
Production Restoration Through Innovative Sourcing of Lift Gas - Jacket X Case Study
Authors: Ganiyu Adeyemi , Ochi Achinivu , Adebayo Olufemi , Oluwabiyi Awotiku , Chijioke Ibeh 
Published: July 2019

Abstract
Gas lift is one of the most common and economical methods of artificial lift deployed in mature oil fields in the Niger Delta. Availability of lift gas on the oil production jacket or platform is a critical enabler for gas lift initiation. Most mature fields do not have the luxury of gas lift supply on its jackets either because gas flowlines were not laid at inception or the gas flowlines are out-of-service due to integrity issues.
Jacket X had four active oil well streams producing on natural flow at inception. In early 2017, these wells stopped production one after the other due to low tubing head pressure (LTHP) because of increasing watercut and declining reservoir pressure. The wells were producing at a combined rate of over 1,000 barrels of oil per day (BOPD) prior to stopping production. Well diagnostic and preliminary Nodal Analysis revealed the need to place the wells on gas lift to improve the vertical lift performance. However, this could not be executed as jacket X was not on the field gas lift flowline network. Without conventional lift gas on Jacket X, it was imperative to source for the most economic means of getting gas on the jacket. This paper highlights the processes and methodology of sourcing lift gas through an existing idle wellbore.
During the bi-anual field review, the team of Operations personnel, Facilities Engineering and Asset Management reviewed and mapped out low cost strategy to restore production of the shut-in wells. Since most of these wells stopped production due to LTHP, improving vertical lift performance became the critical success factor. To address this issue economically, the asset team developed an ingenious method of sourcing the required lift gas on the same Jacket X through rigless well intervention on one of the existing idle wellbores. The innovative approach deployed involved identification of gas bearing reservoir in one of the idle wellbores, cement squeeze operations to provide zonal isolation, oriented perforation of identified gas reservoir, topside modification of existing wellhead configuration and eventual supply of lift gas to the casing of the shut-in wells.
Utilizing the lift gas, the wells were placed on gas lift with 1,100 barrels of oil and 3.5 MMScfd of gas restored to production. Significant cost savings were realized during the execution of this project through the application of rigless interventions which eliminated the requirement of laying new flowlines to deliver required lift gas to Jacket X.
Finally, this paper will share some of the challenges, lesson learned, and best practices adopted while executing this project.