The use of inflow control devices (ICD) have been used to balance flux around wellbores and also delay breakthrough of unwanted fluid into completions.1-2. Inflow-control devices (ICDs) were developed to avoid coning problems in long horizontal wells. The model for the ICD consists of pressure-drop equations from the reservoir, through the screen, the flow conduit, the ICD nozzle, and into the production tubing, along with pressure drop through the lower-completion system.1-2. This technology has been a common practice in the petroleum industry for many years now. This procedure though has been beneficial especially in highly heterogenous small formations, but however causes some pressure drop which does not contribute to additional fluid inflow into the wellbore and this is seen to be an impairment to the productivity of horizontal wells to some extent. In wells that are equipped with ICD, a precise quantification of this additional pressure drop is of paramount importance to completely identify the existence of damage created around the well bore. Many authors have proposed mathematical solutions that can be used to estimate various pseudoskin factor caused by damage, partial completion, slanted well and perforation. No author has researched about productivity loss or skin that may result from the use of inflow control devices. In this work, a 3D numerical model which includes inflow control devices along horizontal wells was used to investigate reservoir and production performances of various ICD nozzle sizes. Different productivity losses from different nozzle sizes were seen as skin. Consequently, a simple equation for calculating this skin due to restricted fluid entry through ICD nozzles was derived. The skin results obtained from this new equation is compared with the result obtained using existing skin equation and the variance is within acceptable limit.
This work detailed the procedure employed in inverse calculation of gas composition using separator information. Starting with flash calculation, we develop a method to determine the separator measurement (Condensate gas ratio (CGR), Gas specific gravity (γ
Unlike previous methods such as described in [
Idowu, Joseph Adekunle (African University of Science & Technology) | Iledare, Omowunmi O. (Emerald Energy Institute, University of Port Harcourt) | Adeogun, Oyebimpe (Emerald Energy Institute, University of Port Harcourt) | Echendu, Joseph C. (Emerald Energy Institute, University of Port Harcourt)
The paper aims to; estimate relative technical efficiency (RTE) for each of the Nigeria 32 active Operators using vDEA model, rank the performance of the Operators considering output orientation, categorize each of the Operators into its respective return to scale (RTS) group using Non-Increasing Return to Scale model (NIRTSM) and suggest necessary policies that could improve the performance of the Operators.
The approach is based on variable return to scale assumption of DEA model framework (vDEA). Based on this, four variables were considered; two inputs, petroleum reserves in million BOE and Number of producing Wells and two outputs; total annual oil production in million BBLS, total annual gas production in million SCF. vDEA model assumes operational variability due to constraints such as: projects financing, competition, government policies, operational terrains, etc. A dual linear programming model (DLPM) is formulated and a Microsoft excel solver aided with a visual basic application (VBA) is used to generate RTE for each Operator simultaneously. RTS indexes are estimated using output oriented NIRTSM. The relationship between the two models' results is used to categorize each Operator into different production scale group.
The empirical results reveal a decreasing trend in the Operators' RTEs from 2010 to 2016. Twelve (12) of the Operators were operating on efficient production frontier within the period under investigation. Based on this, Operators were classified into three different production scale group. Eight (8 or 25%) were operating on decreasing return to scale (DRTS), Six (6 or 19%) on constant return to scale (CRTS) while the remaining Eighteen (18 or 56%) were on increasing return to scale (IRTS). Significantly, it is discovered that more than 80% of the JV Operators have been operating on DRTS.
Consequently, the paper provides information on RTEs of the 32 active upstream Operators in Nigeria considering more realistic assumptions as recommended, (
Echendu, Joseph C. (Emerald Energy Institute- International Institute for Petroleum, Energy Law & Policy) | Iledare, Omowunmi O. (EEI) | Akinlawon, Adeyemi J. (EEI) | Idowu, Adekunle J. (African University of Science and Technology)
The paper evaluates the impact of the single tax system at its current rate in comparison to the proposed dual tax system in the National Petroleum Fiscal Policy in Nigeria on project economic performances. The paper also expounds on the arguments between two schools of thought (single tax and dual tax proponents) towards understanding the rationale underlying the divergent viewpoints. The methodological approach applies the discounted cash flow modelling framework to evaluate the performances of terrain based projects using selected metrics such as internal rate of return (IRR), discounted payout (DPO), net present value (NPV) and government take (GT) under the two tax systems. It calibrates the unit technical cost (UTC) for typical deep water projects in Nigeria and imposes the current and proposed fiscal terms. Varying cost treatment options and alternative allowable/incentives are investigated in the modelling framework using global best practices. The paper concludes that whichever tax system is adopted, it is possible to achieve equivalent economic metrics. However, the dual tax system presents a better flexible option over the single tax system as one of the split rates – especially the hydrocarbon resource tax – could serve as an instrument to incentivize investment, promote conservation, expand resource base through technology innovation more easily without denying the mineral owner an outright revenue via taxation. In a classical case like Nigeria, where national fiscal budget is largely financed using hydrocarbon revenue, the dual tax system seemingly offers a better option for revenue sharing among the stakeholders – the resource owners and the Federal Government than the current single upstream tax system. This paper bridges the gap between the divergent viewpoints on taxation system in Nigeria by proffering a pathway. It suggests that the overall objectives of stakeholders could be achieved using the same metrics if the mechanics in designing a fiscal system is better understood. This will lead to progressive application in achieving the divergent expectations.
Ikwan, Ukauku (Emerald Energy Institute) | Egba, Amba Ndoma (Department of Petroleum Resources) | Dosunmu, Adewale (University of Port Harcourt) | Iledare, Wumi (Emerald Energy Institute, University of Port Harcourt)
The primary objective of an E & P company is to drill and produce hydrocarbon at minimum cost with high level of safety without compromising environmental standards. With the current global downward slide in oil prices most E & P firms are slashing costs to shore up profitability. Drilling operations are high capital-intensive projects that drive unit production cost northwards. This paper presents a comparative analysis of drilling costs in three geographical locations of the world petroleum provinces viz; North Sea, Gulf of Mexico and Niger Delta with sensitivities of the various elements that affect drilling cost with a view to assisting operators and rig owners on optimizing activities in a lean environment.
Relying on panel data sourced from databases of a global energy consultant and industry operators, historical absolute average cost and footage trends were compared during the period of 10 years (2005-2014). A randomly selected well cost data was used to carry out the sensitivity analysis to deduce key determinants.
It was found that although there are regional differences that reflect the local geology and some economic factors, drilling times and all costs rise sharply with increasing depth. Also drilling cost for the Niger delta province is highest compared to the other two regions. The sensitivity study showed that the highest contributor to high drilling cost is the intangible element in which the rig rate, hole problems and security issues should be the focus in drilling cost reduction and economics. Contract renegotiation strategy to drive down rig rates and establish new market equilibrium is recommended in this lean environment. Also tangible costs from tubulars can be reduced with favourable policy on reviving Nigerian steel industries to enable local sourcing of these tubulars, improve employment rate hence reduce insecurity in the Niger Delta area.
Ketebu, Promise E. (World Bank Center of Excellence, Instutute of Petroleum Studies, University of Port Harcourt) | Ajienka, Joseph J. (Department of Petroleum Engineering, University of Port Harcourt) | Ogbonna, Joel (World Bank Center of Excellence, Instutute of Petrolem Studies) | Ikiensikimama, S. Sunday (Department of Petroleum Engineering, University of Port Harcourt) | Ukwu, Austin K. (World Bank Center of Excellence, Instutute of Petroleum Studies, University of Port Harcourt)
Waxy Crude Oils deposit wax at temperatures below the wax appearance temperature (WAT), thus exhibiting non-Newtonian flow behavior. In this study, the viscosity of waxy crude oils from 20 oil fields in the Niger Delta were measured for temperatures above and below the WAT using the Cannon-Fenske viscometer in line with D445 procedure on 112 viscosity data points. Of these total data points, 100 were used to develop the models and 12 were used to validate and compare the developed correlation with other correlations. Models for waxy crude oil viscosity and wax appearance temperature were developed using multiple regression analysis. The input data to the models are pour-point determined in line with ASTM D97, API obtained with ASTM E126-76 methods. The developed viscosity and WAT models have average deviations of 5.83% and 2.48% respectively.
This study assessed air quality in selected oil operating areas in Rivers State of Nigeria with consideration to land use type such as oil and gas facilities, major bus stops, schools, Markets, hospitals, residential areas, vegetation and commercial centers. Air quality and meteorological parameters across 25 locations were monitored during the wet season (April to October) 2015 to ascertain major air pollutant sources. The parameters monitored were, Nitrogen dioxide (NO2), Sulphur dioxide (SO2), Carbon ii oxide (CO), Volatile organic compounds (VOCs), particulate matter (PM) 1, PM2.5, PM4, PM7, PM10, TSP, wind speed, humidity and temperature. Descriptive statistics, agglomerative hierarchical cluster analysis (AHCA), Principal component analysis (PCA), Multiple linear regression (MLR) and Principal component regression (PCR) were used in the data analysis and modeling of Air quality index. Results showed that SO2 values ranged from 0.04 ppm to 0.15 ppm, NO2 values ranged from 0.025 ppm to 0.162 ppm, CO concentration ranged from 0.24 ppm to 6.36 ppm, VOC values ranged from 0.18 ppm to 2.19 ppm across all study locations. Particulate matter also varied across the study locations. Three clusters were obtained from AHCA. The dendogram plot from AHCA showed that the observed variation can be attributed to the land use pattern in the study area. Three principal components were extracted from the PCA based on eigenvalue of >1 and from the biplot after varimax rotation revealed that the major sources of air pollution in the area based on land use type are markets, major bus stops, residential and commercial centers. Vehicular emissions, biomass burning and dusty roads are the major sources of air pollution in the study area. MLR performed better than PCR with MLR and PCR having an R2 of 0.967 and 0.930 respectively. PCA, AHCA, MLR and PCR proved to be useful tools in air quality analysis for source apportionment and prediction as this can aid in air pollution abatement planning. There is need to improve existing policies in other to proactively mitigate the impacts of air pollution from oil and non-oil operation sources.
Awe, S. O. (The Shell Petroleum Development Company) | Eze, N. (The Shell Petroleum Development Company) | Akhideno, M. (The Shell Petroleum Development Company) | Iyamu, I. (The Shell Petroleum Development Company) | Weli, I. (The Shell Petroleum Development Company)
The drive of Nigerian government to boost economic activities through local capacity utilisation, human capital development and empowerment of indigenous companies resulted in the implementation of Nigerian content development in the oil and gas industry which was previously exclusive to the multinationals. The Nigeria Oil and Gas Industry Content Development Act of 2010 provides the legal framework to facilitate and promote mandatory participation of companies owned by Nigerians in the high-risk and high-cost petroleum industry. Prior to the enactment of the act, insignificant number of Nigerian companies had the financial strength and technical know-how required to be competitive in the petroleum sector compared with the well established multinational operating and service companies. These factors made compliance with the requirements of the act a daunting challenge for the sector.
Historically, The Shell Petroleum Development Company (SPDC) has played important roles in the development of various aspect of petroleum industry in Nigeria owing to its visionary leadership position in the sector. The SPDC began the Nigeria dontent Development (NCD) implementation in various aspects of its business right from the time the idea was first muted in 2001. This disposition of the company to NCD ensured that by the time the act was enacted in 2010, competent local contractors in drilling operations, production maintenance, facilities construction and so on had been developed. The transition of the SPDC from the implicit period of NCD implementation to the period when compliance to the provisions of the law became mandatory was smoothened by the development of the local contractors ahead of time.
The approach taken by the SPDC contributed to the realisation of major success stories in various arms of its operations. One of such achievements is the degree of compliance of the drilling operations department with NOGICD Act requirements. This paper details various schemes that were employed by the drilling and contracting departments in conjunction with the National Petroleum Investment Management Services (NAPIMS) and the Nigeria Content Development and Monitoring Board (NCDMB) towards the realisation of the nation's aspiration of domesticating technology, human capital development, financial empowerment and economic development, and then leveraging the resources available in the oil and gas industry.
A review of many oil/gas fields in Nigeria shows that most structures are under-filled (the fluid contact is much shallower than the structural spill point). This could be explained in different ways. Hydrocarbon charge has been suggested as a possible explanation, but we do not believe this to be the main cause in such a rich hydrocarbon province, like the delta, and where there are excellent carrier beds and world class source rocks, all throughout the system.
Another possible cause could be what we call a "dynamic top seal," where there is some degree of leakage either due to capillary forces or facilitated by crestal faulting. An ongoing analysis on capillary entry pressure and mechanical strength of the top seal, shows that this could be the case in some shallow reservoirs, but a "leaky" top seal does not appear to be a major issue in relatively deeper reservoirs.
An updated seismic interpretation was carried out in field X where part of the focus was to understand what controls the current fluid contacts. This study has direct implications towards predicting fluid contacts in near field opportunities in undrilled blocks for proper placement of development wells. Field X has one single well but there are undrilled blocks with similar structural geometries. These learnings will also help to carry out predictions of in place volumes for near field development.
This work showed that more careful and detailed structural mapping of the fault systems provides a view of fault geometry where relay ramps clearly control the position of the fluid level. The position of the initially planned well changed. We are applying these learnings and testing if this observation can be replicated in other fields, once more detailed mapping is carried out.
This paper presents the results of a study for estimation of reserves in a highly complex naturally fractured reservoir off the Coast of California. The fractured reservoir at the Point Arguello Field, consisting of the siliceous rocks of the Monterey Formation, has produced more than 187 million barrels of oil during the last three decades primarily from fractures intersecting the extended reach and directionally drilled wells. This study was conducted to assess the economic viability of continuing production of the field and economic incentives for maintaining operations at the three existing offshore production platforms. In our study we examined the remaining reserves from the fracture controlled production and scrutinized the potential contribution of the tight matrix to primary recovery and for EOR processes. In this integrated and comprehensive study, we used a new interpretation of 3D seismic data, revisited extensive mud log data, prepared diagnostic plots of performance data and incorporated conventional logs, DST and core data to characterize the production system. From the analysis of GOR, WOR, and 3D seismic we identified 10 separate compartments and related the vast differences observed in well productivities to the compartment size, degree of fracturing and behavior of water influx. We also developed common sense reservoir forecasting solutions to examine the potential application of CO2 injection for extracting oil from the tight matrix. The economic forecasting indicates substantial opportunities by managing water influx, exploiting bypassed intervals by new perforations, and drilling infill wells in blocks using volumetric curvature analysis data. Lessons learned show the definitive significance of integrated reservoir characterization, importance of mud logs and 3D seismic, and fault characterization for defining compartments, and potential applications to other similarly fractured reservoirs.