bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Souring Assessment and Application of Design and Engineering Practice to Successfully Predict and Mitigate H2S Release in a Produced Water Well Intervention
Authors: Aniekan Obot A. , Basil Ogbunude C. , Imaobong Bassey P. , Eelah Muzan , Ihuoma Green , Conrad Ibekwe , Jonathan Mude , Onajite Taro , Gogo Oforiokuma 
Published: July 2023

Abstract
In-depth understanding of subsurface risk is critical to the safe execution of well intervention operations. One of such high potential subsurface risk is the uncontrolled release of hydrogen sulphide (H2S) which is considered a critical hazard in the oil and gas industry that can put lives and asset at risk. H2S is often generated in anaerobic environments by the activities of Sulphur reducing bacteria which may be introduced by injection of sea or produced water into a reservoir. In addition, H2S can be released during well stimulation interventions in produced water disposal wells. These two possibilities for the release of H2S were considered in the recent assessment, planning and execution of BZ071 acid stimulation intervention. BZ071 is a produced water disposal (PWD) well injecting into the S1000 sand in the BZ NAG facility, with initial injection capacity of about 6kbwpd and cumulative of &gt;2MMbbl disposed into the target reservoir. The initial reservoir souring prediction assessment carried out at the commissioning of the PWD facility showed a high potential of H2S proliferation in the reservoir, although with no chance of H2S release to surface since there was no producer on the S1000 sand. The planning and integrated risk assessment of the BZ071 acid stimulation intervention involved extensive integrated review of the initial souring assessment to keep any potential H2S gas release to As Low as Reasonably Practicable (ALARP). This paper presents the success story of the 1st experience of H2S Release in BZ well intervention operation, which was carefully managed without any HSSE exposure, achieving goal zero. It outlines the reservoir souring prediction assessment, collaborative roll-up of controls and the learnings which led to a successful execution and mitigation of H2S gas release.
Alpha-28 FastTrack Maturation to Execution – Securing Export Gas Supply
Authors: Obakhena O. F. , Biambo T. G , Alli-Oluwafuyi J. , Ikiliagwu C. 
Published: July 2023

Abstract
In the global aspiration to meet an ever-increasing energy demand, fossil fuel and indeed natural gas plays a vital role both in energy security and energy transition. Natural gas is also a key driver of industrialization, a requirement for national growth and development. In the Niger Delta, problems with security & sabotage of hydrocarbon liquid evacuation pipelines as well as slippages in gas drilling projects has also led to shortages in gas supply, creating challenges in meeting contractual obligations to customers with attendant loss of revenue in a high oil & gas price regime.
To harness Nigeria huge gas reserve in the current business climate, it is pertinent to arrest declining gas production caused by aging reservoirs & maximize utility of available ullage by accelerating maturation of gas resources. Quickly maturing a gas resource to market has become very important to meet contract shortfalls in the short term and to comply with the recent call for sustainable greener and cleaner energy for environmental reasons on a long term.
Typically, the maturation and development of a gas project/well takes a minimum of two (2) years from identification to execution.
Maturation of Alpha-28 well in the Alpha field, a brown field Niger Delta, Nigeria, took about 12 months from identification to execution. This was achieved by adopting a non-conventional project maturation. This leaner approach, which did not lose any aspect of the project assurance intents of the conventional approach, involved proper framing, risk assessment, scaling, flexibility, and proactive engagement of all relevant stakeholders to ensure alignment. This paper discusses what was done differently, the how and the learnings that are planned to be incorporated into future similar projects.
Sedimentary Facies, Depositional Environment and Reservoir Quality of Group-B Shallow Clastic Reservoir in the Malay Basin, Malaysia
Authors: Bashiron N. , Johari S. , Sidek A. , Agi A. , Ariffin M. H. , Supee A. , Ridzuan N. , Mahat S. Q. Aini 
Published: July 2023

Abstract
Shallow reservoirs in Group-B of MS-field in Malay Basin, Terengganu's offshore, Malaysia were explored for development. Poor understanding of depositional settings, stratigraphic context, lithofacies, reservoir geometry, reservoir quality, and heterogeneity are some of the difficulties encountered in developing these shallow reservoirs. In this study, these challenges were circumvented by performing reservoir architecture and quality analysis. This was achieved by integrating the interpretation from the cores, well logs, petrographic and petrophysical analyses for depositional model generation, lithofacies description, as well as reservoir geometry, continuity, and quality determination. Five lithofacies were identified in Group-B, namely: laminated mudstone (ML), bioturbated mudstone (MB), heterolithic mud dominated (MH), heterolithic sand dominated (SH), and bioturbated sandstone (SB). The sediments encountered in ML and SB lithofacies consist of moderate to good reservoir quality, while for SH and MH, they ranged from high to low quality. This study provides a better insight to the shallow reservoir heterogeneity in MS-field and the results obtained could also be applied to the other similar shallow reservoirs for characterization and modelling improvement processes.
An Improved Model for Accurate Description of Drilling Fluid Rheological Behaviour in Enhanced-Water and Low-Toxicity Oil-Based Muds
Authors: Johnson Folayan Adewale , Dosunmu Adewale , Boniface Oriji Aleruchi 
Published: July 2023

Abstract
In this study, a new rheological model was developed by the introduction of dimensionless plastic viscosity and shear rate correction factors (k and n) respectively to the plastic viscosity stress-term of the Bingham plastic rheological model with a view to correcting the under-estimation errors that are associated with the model at high shear rate condition in the pipe. Similarly, an effective yield stress τeff was also incorporated into the model to correctly describe the resistance to flow at low shear rate condition in the annulus by taking into account the effect of lowest shear rate stress on the yield-stress term of the model. The drilling fluid matrix consists of a low toxicity oil-based mud (LTOBM) and a high-performance, nanoparticle-enhanced water-based mud (EWBM). The rheological characteristics of these muds were evaluated at temperatures of 30°C, 60°C and 120°C and pressures of 14.7psi, 2500psi and 5000psi respectively. The experiments were conducted under API recommended standard equipment and procedures. Also, statistical tools were employed to quantify the degree of deviation of the model from experimental values.
Empirical results of the new model comparative rheological performance analysis with different existing models that are commonly used in the oil industries showed that the developed model accurately predicts fluid rheology better than the Bingham plastic model at both high and low shear rates conditions in the LTOBM and EWBM at all tested temperatures and pressures. The new model performed better than the Bingham plastic and the power law models at 30°C and 14.7psi for the EWBM with lowest standard error deviation of 1.5096 as against 4.4392 and 2.2573 for BPRM and PLRM respectively. Similarly, the average absolute error of the new model for EWBM at 30°C and 14.7psia is 1.6874 unlike BPRM and PLRM with (EAA) values of 5.3249 and 2.8704 respectively. The new model is not significantly temperature and pressure dependent at high shear rate.
Optimization of Two-Phase and Three-Phase Separator Designs
Authors: Olugbenga A. G. , Ochayi A. E. 
Published: July 2023

Abstract
Mechanical constraints and non-linear fluid dynamics are factors that determine the design of the primary separator units in an oilfield. This study comprehensively outlined the design procedures of a two-phase and three-phase separators focusing on the challenges encountered during separator designs. The designs were calculatively altered after which the results were simulated using the Aspen Hysys software. Theories and relationships of existing separator designs were also employed in the optimization of the model. They comprised of declarative set of equations which are not dependent on the method of solution thereby making modifications easier and assumptions clearer in the context of horizontal separator, the models were outlined and illustrated.
An Assessment of the Level of Awareness and Knowledge Towards the Dangers of Climate Change and Energy Transition: Northern Nigeria as a Case Study
Authors: Inuwa Haruna Muhd , Usman Abdullahi 
Published: July 2023

Abstract
Access to energy is a pressing issue in both developed and developing countries. To achieve socio-economic development, countries worldwide, including those in Africa, must carefully plan their energy transitions, considering the advantages and disadvantages of different approaches and learning from past experiences. In Nigeria, over 80% of the population in underdeveloped areas lacks access to energy, with cooking being the primary energy-consuming activity. As the oil-producing powerhouse of Africa, Nigeria is increasingly becoming a significant emitter of greenhouse gases, and without intervention, emissions are projected to rise dramatically by 2040. This study focuses on the status of energy transition and climate change awareness in the northern part of Nigeria. A research questionnaire was designed to gather responses related to our research questions, following a comprehensive literature review. The collected responses were analyzed to generate structured results. The findings indicate that the majority of participants (51%) fall within the 20-30 age bracket. Notably, 52% of respondents rely on firewood as their primary energy source, while gas usage (24%) is also relatively high but considerably lower than firewood. Encouragingly, our study reveals that 51.4% of respondents expressed a preference for switching from firewood to electric cookers as their home energy source, despite the significant investment required for power infrastructure and policy support. Overall, the results of this study contribute to addressing awareness gaps, framing communication strategies, and promoting public engagement in the campaign against climate change risks and the adoption of safer energy transitions.
Field Surface Planner Algorithm for Integrated Gas Asset Management
Authors: Adeeyo Y. A. , Abu A. M. , Adun G. O. , Lucciano-Gabriel M. 
Published: July 2023

Abstract
As the world transitions towards a more sustainable energy landscape, the need for a less environmentally harmful transition fuel becomes increasingly crucial. This has led to renewed interest in developing previously abandoned natural gas fields. In this paper, we present Field Surface Planner Algorithm (FSPA), a DCA-based model implemented in Python, which aims to generate an effective investment timing strategy for bringing new wells online in large gas fields. The model considers various surface facilities and commercial constraints, while prioritizing the fulfillment of contractual gas demand.
FSPA's algorithm revolves around a sales error concept, which quantifies the disparity between the current sales gas rate and the nominated gas demand. By comparing this sales error against a predetermined error tolerance, the model determines the optimal timing for introducing new wells into production. This approach ensures that the gas field's total sales gas rate remains in line with the nominated gas demand, while minimizing any potential environmental impact.
To ensure efficient operation, FSPA operates within the bounds of nominated gas demand constraints and facility constraints. Nominated gas demand constraints serve as a limit against which the on-stream dates and DCA forecasts for future wells are optimized, minimizing the need for flaring gas. Facility constraints restrict the volume of gas supply that the algorithm optimizes, aligning it with the capabilities of the surface facilities.
During a well's initial contribution, FSPA generates accurate DCA forecasts based on several key factors, including the exact amount of sales gas required to close existing gaps, the well's reserves, and economic limitations. This information aids in making informed decisions regarding short-term production shortfalls and facilitates effective negotiation with customers, ultimately delivering substantial value for the organization involved in gas field development.
By providing an efficient solution for well sequencing, the proposed model significantly reduces gas flaring costs, minimizes opportunity costs associated with production shortfalls, and assists in short-term decision-making processes. Overall, it offers a valuable contribution to sustainable energy transition efforts and promotes responsible development in the gas industry.
How Affordable is Minigrid Power for Sustainable Electricity Supply in Nigeria
Authors: Iwegbu Michael , IBE Anthony , Osokogwu Uche 
Published: July 2023

Abstract
The current conventional electricity model based on a central national power generation and long-distance transmission grids with its attendant losses is no longer sustainable particularly in isolated rural communities where the cost of building transmission lines and transporting fuels is high. The utilization of minigrids to provide an efficient source of power in Nigeria with a population of over 200 million people have begun. However, it appears this is not sufficient to stimulate the growth of minigrid adoption in Nigeria especially as there is a large disparity between the present minigrid and the national grid price of electricity (N250 - N300/kWh versus N53-N76/kWh), this currently serves as a deterrent to minigrids adoption, viability, and sustainability in Nigeria.
This paper examined the factors that contribute to the high cost of electricity generation from minigrids as well as provided recommendations to reduce the cost of electricity generation from minigrids by carrying out a technical and economic simulation of an existing 85KW solar based renewable energy minigrid project in Nigeria. This paper used HOMER software for the simulation using Solar PV (PV), Storage Battery(B), Diesel Generator (DG) and Converter as the basecase scenario and other alternative scenarios were also modelled using CNG (Compressed Natural Gas) and LPG (Liquified Petroleum Gas) as alternate sources of fuel
A structured analysis of the results obtained from the model show that fuel costs accounts as one of the key drivers of the minigrid systems tariff cost, the use of LPG as a source of fuel reduced the tariff cost by about 14% and CNG by about 38%. Based on these findings, this paper proposes the use of LPG and CNG as substitute fuels instead of diesel to reduce the current minigrid systems tariff costs.
Harnessing Value from Mature Offshore Asset: Successes from Recent Acid Stimulation Campaigns in Field X
Authors: Ganiyu Adeyemi , Burgess Matthew , Eyeregba Aghogho , Vesters Jules , Festus Chukwu , Adebayo Olufemi , Anthony Oyewole 
Published: July 2023

Abstract
Field X is a mature offshore field in the Niger Delta. In 2013, several wells in field X experienced significant production decline and a study conducted by cross-functional team identified fines migration as the primary cause of sandface impairment and acid stimulation was recommended as remediation for the damage. This technical work highlights the strategies and methodology adopted in implementing acid stimulation in field X.
The approach to candidate selection involved screening of historical well test data and pressure transient analyses (PTA) database for impaired/at-risk completions. Typical selection criteria are productivity index (PI) degradation (&gt; 50%), pressure drop due to near wellbore skin (DP skin &gt;500psi), violation of flux constraint, Interval Control Valve (ICV) integrity (dual completion) and water-cut evolution (&lt;5.0%). The team also piloted diversion agents in the field to improve stimulation in wells with high water-cut. A novel method of using dynamic positioning marine vessel with Remotely Operated Vehicle (ROV) and customized dual conduit Coil Tubing (CT) have been deployed to bullhead acid into the formation.
In the last two campaigns executed in 2020 & 2021, this ingenious way of harnessing value from field X has resulted to combined incremental Initial Production (IP) gain of approximately 10,000 bopd and safeguarded completion of a critical oil producer (~11,000 bopd). The total project cost for the two campaigns was ~$25.4 million resulting in significant cost savings (&gt;$51.6 million) compared to rig operations. The use of cross-functional team, robust candidate selection, continuous lookback and adoption of best practices were critical to successful execution. Some challenges being experienced in the field are lack of adequate injectivity, formation lock-up, increasing gas oil ratio (GOR) and increasing water-cut. The team plans to deploy diverters across additional high water-cut wells in future campaigns.
Integration of Technologies for Heavy Oil Production – An NNPC E&P Ltd Approach
Authors: Ifeduba E. A , Ijomanta H. U. , Hamza S. M. , Ayeni O. M. , Udo N. A. , Niyang A. S. , Okoh O. M. , Akinnurun Y. S. , Ogweda M. , Emetoh T. , Esene J. O. , Ojeaga B. 
Published: July 2023

Abstract
NNPC E&P Ltd (NEPL) recently successfully drilled, completed and tested the Abura 6ST well which integrated multiple Improved Oil Recovery techniques to develop some heavy oil reservoirs in the Abura field. The 1AB6 and 2AB6 reservoir fluids have viscosities of 10 and 17 Centipoise and API gravity ranging from 16 – 20API° which is a marked variation from NEPL's conventional resources. NEPL is estimated to have over 1.2B barrels of heavy crude oil in her portfolio therefore an attempt to unlock the potential from these reservoirs had a lot of implication for the company. Conventional methods of producing this reservoir were not economically viable mainly due to the high oil viscosity and consequent preferential flow of water rather than oil.
The NEPL team resorted to integration of multiple improved oil recovery IOR techniques to ensure an economically viable well.The first of such improved oil recovery techniques was the use the ESP as the Abura field did not have any gas source for gas lift. Artificial lift was to eliminate flow assurance issues that such a hydrocarbon system would have. Another IOR technique was the combination of horizontal and deviated well bores to drain the reservoirs through a single wellbore in a commingled fashion. The well cuts across the shallowest reservoir as a high angle section and lands in the deeper reservoir as a horizontal well. To ensure preferential flow of oil from the reservoir into the wellbore, Autonomous Inflow Control Device AICD was deployed for both the horizontal and vertical sections of the completion which uses viscosity differences to prevent early water breakthrough and reduce water production.
To meet NUPRC's back allocation requirements, hydrocarbon fluid samples were collected during the drilling operation and unique fingerprint markers were identified which will aid in the determination of each reservoir's production contribution for proper hydrocarbon accounting. In the completions aspect of the design, Swell packers for zonal segmentation, Micro-emulsion breaker system for near well-bore remediation and improved permeability, downhole gauges & sensors and a Y-Tool assembly for alternate access in rigless intervention mode. The Abura 6ST well produced circa 2900 BOPD on choke 28/64 and ESP frequency of 40Hz.This paper seeks to elucidate on some of the IOR technologies and how they were integrated to facilitate the delivery of the first heavy oil ESP well in NEPL's direct operations.
Improving Well Construction/Intervention Time and Cost Estimation Accuracy Via Historical Performance Data Analysis
Authors: Orji Mirian Kosi , Arowosafe Toyin , Agiaye John 
Published: July 2023

Abstract
Time and cost estimation and the accuracy of it, are central to engineering design and forms the basis for economic analysis of projects. There are several factors that could result in cost or schedule overruns ranging from unplanned non-productive time, inefficiencies, changes in macro indices etcetera; however, one often overlooked factor is deficient time and cost estimation. Hence in addition to factoring prevailing market and contract rates for materials and services, it is important to critically analyze and benchmark plans against known performance for higher accuracy around estimations.
Well project time and cost models generally consist of estimating in modules or sub-phases and aggregating these modules to makeup the total. This can either result in a single discrete estimate or in ranges based on probability and statistical performance - inherently implying that some form of historic performance is crucial to the estimation accuracy. This paper describes a structured approach to developing a probabilistic estimation tool by analyzing past performance data at a phase or subphase level. This tool can be domiciled on a range of computation platforms using similar methodology, which comprises data collection from execution reports, data cleanup and organization to harmonize terminologies and group operation types, and finally statistical and mathematical data analysis. Statistical analysis develops probabilistic relationships in the dataset and correlation between performance variables such as depth and time; while mathematical analysis incorporates numerical correlations and multiple variables to generate estimates in modules and finally aggregates the discrete phase estimates.
The estimation has two major components – Time and Cost.
The analysis of time component considers the productive and non-productive time by phase; determines depth dependent operations and their correlation to time and assigns a mathematical function to each phase The cost component is broken down into two sub-components – recurrent cost which is highly time-dependent and non-recurrent (material and services) cost which are usually based on pre-defined contractual rates An additional end function is benchmarking, for comparison between estimates and historic performance
The aggregate of the probabilistic estimate of each module gives the total estimate of time and cost for a given well construction or intervention scope, with the overall objective of improving and maintaining estimation accuracy to avoid overruns and over-estimation of drilling, completions, workover and intervention projects.