bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wax Removal and Prevention in an Old Well — Lessons learnt
Authors: Anyanwu Chinedu , Agbo Ejimofor , Olusola Bukola , Olowoyeye Oluwasola , Njoku Ben 
Published: August 2020

Abstract
Wax deposition in producing wells is one of the most challenging flow assurance issues which is worsened when not addressed during well design. EC-40 being the first and only well completed on reservoir X1.0, was completed without provisions for wax inhibition. It produced about 1,100BPD with intermittent mechanical wax cutting intervention every 6 months. However, as production continued, the start-up rate, FTHP and the duration of production continued to reduce thus increasing the frequency of the wax cutting until it became uneconomical. In this paper a combined approach involving the use of chemical solvent and a Wax Inhibition Tool (WIT) was used to remove and prevent wax formation. A Xylene – Diesel chemical solvent was used to dissolve the entire wax in the tubing and restore the well to production while the WIT which prevents wax deposition, was installed at the XN-Nipple of the tubing. The well was opened up to a potential of 1,000 BPD after successfully removing the wax and installing WIT and produced for about 4 months before getting waxed up again. This paper illustrates the lessons learnt from the case study and based on results proposes an optimized way of re-installing the WIT or a retrofit chemical injection valve for wax prevention.
Automated Production Network Model Calibration and Optimization in Agbami Field
Authors: Fagbowore Olufisayo , Okpani Olu , Oyewole Anthony 
Published: August 2020

Abstract
Agbami Field is a deepwater producing asset off the coast of the Niger Delta region in Nigeria. The production system comprises of 26 subsea production wells, 8 subsea production manifolds, subsea flowlines and subsea risers respectively. The production wells are intelligent completions made up of 22 dual zone well completions and 8 single zone well completions. Dual zone well completions are equipped with Interval Control Valves (ICVs) for zonal control & isolation. They are also equipped with several pressure/temperature (P/T) gauges from the sand-face completion to topsides for real time measurement.
Production commenced in 2008 and peak production was achieved a year later in 2009. Field production remained at peak for about 8 years. The stellar field performances have been achieved through several reservoir management best practices. These include, but not limited to, robust initial field development strategy, infill development, acid stimulation operations, Real Time Reservoir Management (RTRM) and production optimization using Intelligent Well Completion (IWC).
This paper demonstrates the development of an automated system which performs Production Network Model calibration and assessment of production optimization opportunities. The key considerations for automated calibration and optimization system workflow development will be presented. Since deployment, the automated calibration and optimization system has reduced the manhours spent with manual model calibration and optimization assessment by 85%.
Lessons learned during the development and deployment of the automated system as well as production gains realized from the solution will be highlighted.
Sustaining Production in Brownfield Assets by Adapting Existing Rigless Workover Technology to Create Well-Specific Solutions
Authors: Haastrup Adeyemi , Adeyinka Adeboye , Ajakaiye Olayinka , Fatile Olufemi , Aina Soji , Adegoke Oluwagbemiga , Aliyev Shahin 
Published: August 2020

Abstract
The changing landscape of global energy and fluctuations in commodity prices have driven companies to get more efficient means to sustain their businesses. With companies seeking more from their assets via rigless interventions, the trend has been that the low-hanging opportunities have been executed. The opportunities left are either too complex for rigless interventions or the expected production is too small to make major-rig workovers economic.
We discuss such complex opportunities that were revisited to ensure sustained production from mature fields. The first case study discusses a gas-lift opportunity that was suspended when tubing leaks were discovered. The three holes posed a challenge since they were quite shallow and not suitable to be used as the injection-point of the gas. The work-around was to use a tubing patch to cover the holes without significantly reducing tubing ID as much as a pack-off would to allow for future well re-entry.
The second case study discusses a well with a tubing restriction that prevented perforation addition. The job stalled when a gauge cutter (similar OD as the available gun) barely passed through the restriction during a dummy run. Even if the gun passed through and was detonated, the expended gun would be swollen and irretrievable due to the restriction. A modified perforating gun that disintegrated upon detonation was used, eliminating the need to retrieve the expended gun.
The third case study was a well completed with mud five decades ago. The mud had caked; preventing any chance of executing a poor boy gas lift. The solution was to adapt the cement-bond-log technique to identify regions of moveable mud in the annulus with the mud subsequently displaced out by pumping.
The lesson learned is that opportunities that have stalled due to their complexity can still be executed via rigless workovers by leveraging on existing technologies with slight adaptations to create well-specific solutions.
Re-positioning Mature Fields for Sustainability: Deriving Additional Value by Applying the Internet of Things via Remote Well Monitoring
Authors: Adeyinka Adeboye , Tsakporhore Abraham , Oduwole Ajibola , Jumbo Sandison , Odusote Femi , Aliyev Shahin , Adegoke Oluwagbemiga , Lapham John , Eme Titi 
Published: August 2020

Abstract
Mature fields typically require a considerable amount of attention and manpower to keep their production going. Typical daily operational challenges include identifying wells that quit, reactivating such wells and gathering wellhead/casing pressure data that are used for well integrity, surveillance and optimization studies.
These challenges are further compounded for mature assets that have a significant number of wells spread across wide geographical areas, leading to a never-ending cycle of data gathering while reactively chasing wells that have quit to minimize lost-production opportunities (LPO).
One way to manage these challenges is to install sensors that leverage on the Industrial Internet of Things (IIoT) on wells to achieve remote well monitoring. The sensors are used to monitor critical well parameters (pressures, temperatures) remotely, thereby reducing Opex incurred via helicopter trips to diagnose well problems. The solution was also configured to report shut-in wells via email/texts helping to narrow down the culprit well, reduce reaction time and minimize LPO.
More value can be derived beyond gathering surveillance data and reducing LPO reaction time. The data can be delivered real-time to the Asset Engineers in the office to drive engineering analysis on wells. Such analysis could lead to proactive solutions such as optimizing wells that are already on gas-lift or quicker decision-making to initiate gas-lift on a well just before it quits.
In this paper we demonstrate the value that was created by implementing remote well monitoring in mature fields using case-studies that capture the daily field operational challenges and how they were resolved leading to significant cost savings.
Log Hierarchy and Calibration with Other Data for Net Sand Definition in Poorly Developed Reservoir with Limited Log Data Within Niger Delta Depositional Environment
Authors: Anyaehie James , Iyowu Olakunle 
Published: August 2020

Abstract
Huge hydrocarbon volumes in the Niger Delta are potentially screened out as non-reservoirs due to conventional net sand definition that precludes complex lithologies (silty, laminated and heavy mineral formations). The situation is usually prevalent in reservoirs with legacy logs (vintage wells without Density, Neutron, NMR, etc.). Netsand determination is one of the key uncertainties when evaluating resource volumes. This uncertainty elevates in complex lithologies especially with limited suite of logs.
This report unravels the steps to adopt in selecting/ ranking input logs for net sand definition, its validation with reservoir production data (Production log), reservoir sampling (formation fluid & pressure) core data (full bore and/wall sample) drilling cutting etc. In addition, two case studies (fields with vintage and another with more recent well data set) resulting in circa 450% and 40% increase in HCIIP from a recent evaluation with application of the hierarchical process. This translated to increase in ultimate recovery and improved project economics (Net Profit Value and Uith Development Cost).
Investigating How Capillary, Viscous and Gravity Forces Impact the Matrix–Fracture Transfer Mechanisms in Fractured Oil – Gas Systems
Authors: Abubakar Mahmud , Abdulkadir Usman 
Published: August 2020

Abstract
By investigating how capillary, viscous and gravity forces impact the matrix–fracture transfer mechanisms in fractured oil – gas systems, this paper aims to deepen our understanding on the modeling of fractured reservoirs with the intention of creating more predictive and more realistic dual porosity – dual permeability reservoir simulation models.
The hypothesis of this study is that first order differential equations may be able to capture and approximate the total transfer realistically, however it has to be known to which extent the individual forces influence the total transfer. Complex, higher order, non-linear differential equations are able to capture the combined influence of the forces, however their formulation and implementation are extremely challenging.
To investigate whether the total matrix – fracture transfers can be expressed as the sum of the individual forces multiplied with appropriate coefficients, two dimensional models were created using ECLIPSE 100 Black Oil simulator and Eclipse 300 for the study compositional effect.
The results showed that the models can realistically capture the effect of capillary-, gravity- and viscous forces individually. These scenarios can serve as a solid basis for further quantitative analysis regarding the extent, to which the individual forces influence matrix – fracture transfers.
In this study we determined the Minimum Miscibility Pressure (MMP) of CO2 using slim-tube test, we also carried out sensitivity studies of important operational CO2-EOR parameters to determine how they will affect oil recovery factor and displacement efficiency in a single matrix block surrounded by fractures. To ensure miscibility CO2 was injected at a pressure above minimum miscibility pressure.
A significant improvement in CO2 EOR processes and CO2 storage can be achieved by applying the findings of this research in dual porosity – dual permeability models in fracture-matrix systems. These findings not only result in a technical advancement, but could be of high significance from an economical point of view as well.
A slim tube model was set up and used to determine the Minimum Miscibility Pressure (MMP). Seven components (CO2; N2-CH4; C2-NC4; IC5-C7; C8-C12; C13-C19; C20-C30) were presented in the model to compare the rate of dissolution and displacement efficiency. Understanding the process and applying this knowledge to enhance recovery of hydrocarbons, CO2 Capture and Storage can have a significant economic and environmental effect.
Integrated Planning IP in TEPNG - JV District: The Transformation Process
Authors: Akande O. , Iwegbu M. , Dike O. 
Published: August 2020

Abstract
The use of different fragments of planning's existed across entities in Total E & P - JV District but these planning were neither integrated nor centrally coordinated which resulted in: poor visibility of inter-relationship with other entities, making it time consuming to identify clashes and concurrent activity issues; inability to optimize/align activities with production shortfalls; use of different planning tools/templates which resulted in duplication of data/activities & planners spending much time in data entry and generating reports; and difficulty with linking Integrated Planning (IP) to organizational business model/budget which gives a poor overview of the operational cost/efficiency and resources optimization.
These prompted the IP transformation project, where a review of the situation along with its limitation were discussed during workshops organized with entity schedulers and their management. Return on experience from other affiliates on Implementation of IP were also reviewed and data gathered/feedbacks from entities were used to develop the new IP deliverables. A central enterprise planning software was adopted, schedulers were selected, trained and processes, rules were equally defined and developed.
We now have a single centrally coordinated IP database that now enables the identification of anticipate clashes and Synergies, proper POB management, enhancement of Contracts and Procurement to better anticipate required resources (materials), follow progress, Improved communication and transverse approach across the Total E & P JV-District, arbitration and report when required and incorporation of IP in established JV business processes.
The scope of the transformation project includes HSE, Production, Maintenance, Drilling and Completion/Well Services, General Services, Events, Inspection, Engineering/Construction and Projects, Contracts and Procurement, Shutdown, Campaign of Works, Technical Logistics and General Activities. These entities can now extract planned activities with varied time scales with deliverables ranging from weekly, 4monthly, 1 yearly (work program) and 24 monthly.
Wringing Value from a Mature Reservoir: An Offshore Niger Delta Case Study
Authors: Ogbuagu Frank , Okani Nnamdi , Silpngarmlers Lynn , Strebelle Sebastien 
Published: August 2020

Abstract
The objective of this paper is to share lessons from an intensive study of a mature reservoir and highlight its results. This study also aims to demonstrate the value that can be obtained from a mature conventional oil reservoir when the appropriate assessment processes are utilized.
The case study is an offshore oil reservoir with over 50 years of production with waterflooding for almost a decade. The dynamic simulation model from an earlier assessment of the reservoir showed significant deviation following years of waterflooding, as it became more challenging to understand the water front movement, predict water cut changes and deliver more reliable liquid production forecasts. The reservoir had historical challenges with water production and matching the water-cut from producing wells emphasizing the deviation of the existing simulation model from actual data. As a result, a cold-eye review of all available data without anchoring on prior interpretations was required.
An updated reservoir characterization and earth modelling methodology was applied during the study with attendant improvements in structural and stratigraphic representation of the reservoir. A full-field assessment methodology was employed in the study both for the fault framework and model building, ensuring the inter-reservoir connections and dependencies were captured. Additional scrutiny was applied to initial fluid contacts, leading to the resolution of longstanding uncertainties.
This resulted in the delivery of a new dynamic simulation model with a much better water cut history match compared to the previous study. Fluid contact tracking over time was also better matched using the new model. The new model indicated an increase in original oil in place of 38% leading to the identification of 2 new infill producer opportunities with total estimated ultimate recovery of several millions of oil barrels.
Screening Criteria for Waterflood Projects in Matured Reservoirs: Case Study of a Niger Delta Reservoir
Authors: Imuokhuede Peter Ibiezugbe , Ohenhen Ikponmwosa , Olafuyi Olalekan Adisa 
Published: August 2020

Abstract
One important process for revitalization and optimisation of mature reservoirs is secondary recovery by waterflood. However, some engineers do not understand the science and, consequently, without proper plan lose millions of dollars of investment because they target reservoirs for waterflood secondary process which do not possess appropriate characters.
This paper presents screening criteria for waterflood projects in a matured field in the Niger Delta region of Nigeria. Data set for a field X in the Niger delata was simulated. Sensitivity analysis was carried using different scenario and their results were reported.
Six parameters which can be used to screen reservoirs for water flood potential were proposed in this paper.The result of the evaluation showed that waterflood are best applicable for reservoirs with residual oil saturation of less that 33%,gas saturation of greater than 15% and API gravity of less than 30cP.
Delivering Best in Class Wells: A Case Study
Authors: Okoli Ugo’ , Numbere Otokini , Ntiwunka Greg , Ifediora Emmanuel , Nwagu Chike , Aigbedion Prince , Okubor Eleanor , Salami Hassannah 
Published: August 2020

Abstract
It is possible to conduct a drilling and completion operation, sustaining a high operational performance and ensuring low Non-Productive Time (NPT) throughout a well drilling and completion campaign. The results from a recent onshore drilling campaign proves that with the right people, planning and process, a hitch free drilling and completions campaign can be achieved. In this case a perfect campaign was defined as;
Delivering the planned work-scope (5 wells) within the approved Authority for Expenditure (AFE) cost and duration. Drill to the specified Total depth, penetrating all the subsurface targets within the stated tolerances specified. Achieve less than 15% overall non-productive time. Deliver the planned work-scope without Fatalities (FAT), Loss Time Injuries (LTI), Restricted Workday Cases (RWC), or uncontrolled discharges to the environment. Deliver wells without well control issues, Stuck-pipe incidents or any train wrecks. Deliver wells with minimal formation damage. Maintain technical and operational integrity by complying with statutory regulations and company governance documents always.
In order to avoid previous problems encountered while drilling the appraisal wells, critical sections of the Well delivery process were thoroughly reviewed and optimized as required. These include: The Well Design, Rig selection/certification and acceptance, Safety, and drilling operations and logistics. The optimization methods are extensively discussed in this paper. The improvement and close optimization of the mentioned facets of the project helped to save circa $14MM from the project. When compared with other land projects in the same terrain (Niger Delta), the campaign was observed to be a top performer in the P-10 region of the performance percentile.
Parameterization of Fault Seal Analysis as Input to In-Place Volume Assessment
Authors: Adenaiye Olaniyi 
Published: August 2020

Abstract
This paper presents an integrated approach for addressing uncertainty in hydrocarbon column based on fault seal analysis and column-height prediction for a target reservoir ‘F’ in a field in the Niger Delta area.
The target field is in the shallow offshore of the Nigerian delta, about 20km south of the present-day coastline. The field was discovered in the sixties by an exploration well; Further appraisal wells confirmed hydrocarbon in a footwall block, but with uncertainty in fluid contact.
‘F’ reservoir is a highly faulted collapsed crest structure sandwiched between regional and counter regional faults. Numerous antithetic and synthetic faults dissect the reservoir to form several compartments. Seismic data covering the area was shot in the late nineties and is deemed to be of relatively low quality leading to suboptimal imaging of the faults.
To address structural framework uncertainty, two structural model realizations were built for ‘F’ reservoir, focusing on the trapping mechanism, namely, a fault assisted 3-way dip closure (i.e. closure is bound by a major antithetic fault). This trapping mechanism has major impact on the hydrocarbon column height that can be held by the fault.
The column heights for the model realization was estimated from two different fault seal analysis methods: – i.) Bretan et al., 2003; and ii.) Yielding et al., 2010. The results viz., column heights from each of the two methods for the structural model realization were presented as one of the input parameters for the volumetric uncertainty assessment carried out to determine an optimal development plan for the reservoir.
Investigation On the Effect of Change in Relative Permeability On Oil Recovery
Authors: Ezeaneche Obinna , Wobo Monica , Uzoho Chidinma , Onyekonwu Mike 
Published: August 2020

Abstract
The knowledge of relative permeability is key in oil production mechanism as it affects multiphase flow which is vital to producible reserves in petroleum reservoirs. In this study, the impact of altering end point saturation on relative permeability curve and how it influences oil recovery was investigated on field X in Niger Delta, Nigeria. The saturation end points obtained after a simulation study was used as a start point to predict oil production. These end points saturation of water and oil were altered and varied according to facies. The eclipse simulation tool was used in conducting the prediction runs. The result obtained showed wide variation from actual production forecast (i.e. ≥ 25%) when end points were varied with no guided limit from experimental data. This study reveals the need for an accurate determination of residual oil saturation as it was seen to have an impact on forecast and history match.
Quantifying the Risks of Wellbore Failure During Drilling Operations Using Bayesian Algorithm
Authors: Adeyemi Emmanuel A. , Ogbe David O. , Wu Xingru 
Published: August 2020

Abstract
The wellbore integrity plays an important role in petroleum operations like drilling, well completion and production. Caliper, Electrical image logs, Acoustic televiewers (ATV) and Optical televiewers (OTV) are some of the devices currently used in the industries to identify breakouts. However, these techniques are restricted in applications. For instance, caliper sometimes indicates the effect of drill spiral grooves as borehole enlargement zones; poor resolution and complicated processing procedure limit the application of the electrical image logs. The ATV and OTV which give better outputs are not often used due to the high cost of installation and operation. These limitations necessitated a new approach to quantifying the wellbore instability. This research work focuses on data analytics and the development of the Bayesian Algorithm (with code in Python) to predict the wellbore failure probability using real-time pore pressure and fracture gradients data obtained from the wellbore using modified d-exponent.