bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Successful Rigless Water Shut Off and Reperforation Operations - A Case Study in NPDC Operated Field
Authors: Adio Jaiyeola T , Ajah Gerald E , Akeremale Ayodeji T , Chee Kin Khong 
Published: July 2017

Abstract
As oil fields mature, more wells produce at higher water cut and consequently hydrocarbon production decline. These wells cease to flow overtime due to increased water encroachment. The declining wells and associated facilities are valuable assets that need to be effectively and optimally utilized throughout the producing life of the fields. Remedial actions through water shut-off techniques have been successful in reviving these wells and this has helped immensely in increasing oil production and revenue by reducing OPEX incurred in managing high water production.
At this period of low oil prices, operators are devising strategies of increasing production while saving cost through the use of old (existing) wells to target new reservoirs and optimizing existing perforation intervals as against drilling new wells.
Adoption of the above strategies in some NPDC operated fields has remarkably increased revenue and saved cost.
This paper presents a case scenario of a well in one of the fields operated by NPDC where a rigless intervention operation using coil tubing was carried out to shut-off water production from a zone with cement plug. Subsequently, an oriented re-perforation operation was performed on more prolific shallower (New) zones using electric line unit.
The success of the job was attributed to proper problem diagnosis, job design and execution using reliable and state-of-the-art technologies.
Adjoint-Based Assisted History Matching: A Niger Delta Field Case Study
Authors: Onwuchekwa Chukwuma , Dennar Linda , Ahmed Suleiman , Bakare Olatunji , Emelle Chima 
Published: July 2017

Abstract
Reservoir models are calibrated with production and pressure data to provide some confidence in the prediction of future reservoir production using the models. The last two decades have witnessed the proposal of numerous computer-assisted history matching techniques to ease the laborious task of reservoir model history matching and the related task of uncertainty analysis. Although many of these proposals have proved not to be viable when tried on real (i.e field) cases, some, such as experimental design, are now routinely used in the petroleum industry for history matching and uncertainty analysis. One notable, but largely under-utilised, technique that has generated a lot of interest for application to history matching is adjoint-based optimization.
This paper discusses a field example of the application of the adjoint technique with experimental design to match the historical production and pressure data of a Niger Delta oil rim reservoir with a huge gas cap – the "SWX" reservoir in the "Beska" Field. The "SWX" reservoir, which is one of the few oil reservoirs in the gas-dominated "Beska" field, has been on production since 1992. A decision was to be made on the best time to commence gas cap blow down without jeopardising the life cycle hydrocarbon recovery from the reservoir. A properly history matched model of the reservoir was required for this decision.
Adjoint technique was deployed to assist with the history matching of the "SWX" reservoir which had previously proved difficult to history match. The technique was applied both in the model-maturation stage for improved understanding of the reservoir and the final stages of the history matching exercise to fine tune the history matches of some difficult-to-match wells. The exercise provided an opportunity to test the merits and limitations of the adjoint technique. The result of these tests will be discussed in this paper.
Incorporating the Principles of Decline Curve Analysis in Solving Issues With Paucity of Production Data While Carrying Out Material Balance Modeling
Authors: Okechukwu Sedoo , Oluwajuyigbe David , Unukogbon Obaro , Egwim Stella 
Published: July 2017

Abstract
Material balance analysis is a proven technique for quantifying reservoir performance. Reliable material balance analysis requires accurate pressure and production data amongst other things. In cases where complete production data is not readily available, estimating reservoir performance properties such as pressure and fluid contacts which is needed to support further field development can be a serious challenge. This paper shows how the issue of scarcity of production data can be managed to enable proper reservoir analysis to support further field development.
The paper focuses on a case study on the Ibaba reservoir where paucity of production data is a key uncertainty. The Ibaba reservoir is a Niger Delta reservoir with two parts, Part A and Part B. Both parts have been produced simultaneously from the field for over 40 years. There is a need to carry out material balance analysis on the reservoir to estimate the current fluid contacts to support Short Term Oil Generation activities (STOG). This exercise required production data from inception to the current year 2016. However, for the wells produced in Part B of the reservoir, complete production data was not readily available. To solve this problem, complete production data was generated by performing decline curve analysis on the available production data. A robustness check was carried out and this gives confidence in the results obtained.
How to Drive Contractor Performance and Save Millions
Authors: Okenyi Kingsley , Apena Abayomi , Mba Ognane Edgar F 
Published: July 2017

Abstract
To achieve superb performance in drilling, one should look at the major causes of failure and tackle them head on. That was exactly what was done in Nigeria. In collaboration with directional drilling contractor, the Shell Nigeria Exploration and Production Company (SNEPCo) Wells (Drilling and Completion) team brought losses due to non-productive time (NPT) from millions of dollars down to zero in only a little more than three years.
SNEPCO's non-productive time (NPT) values was considerably high which resulted in the drilling and completions of only three wells. This performance was not sustainable and something had to be done.
The strategy used to turn things around and as reported in this paper was to Define and accurately measure NPT and inefficiencyHave a pre-defined performance metrics or KPIRoot Cause Analysis Investigation, Implementation of Learning and Continuous Improvement.Effective Collaboration and People Management
A General Approach to Production Forecasting of Long-Term Reservoir Performance
Authors: Mohammed S. 
Published: July 2017

Abstract
Arps’ empirical equations have gained widespread acceptance due to their explicit nature and the ease of applicaton of the equations to field data. The major challenge, however, is that the analyst needs to have a prior knowledge of the type of decline (whether exponential, hyperbolic or harmonic). This has long been a major concern because not only is the Arps’ decline exponent difficult to estimate, but also an erroneous estimate of the decline exponent does have a significant adverse effect on the predicted rates and estimated reserves. The traditional efforts to solving this problem encompass type curves analysis with several values of Arps’ decline exponents; a trial-and-error technique; rate derivative plots and assumption of a minimum decline rate. Unfortunately, type curve analysis is subjective and non-unique, trial-and-error method is time-consuming, and rate derivative data are almost always noisy.
This paper proposes a general approach that can be used to forecast long-term reservoir performance without a prior knowledge of the type of decline. The proposed approach couples the rate-material balance time relation, which was previously developed by Palacio and Blasingame, and the rate-time exponential equation. In particular, the rate-material balance time relation is used to estimate the input parameters of the rate-time exponential equation. The theoretical basis for coupling the rate-material balance time relation and the rate-time exponential equation is presented. Models for estimating the ultimate recovery and productive life of the reservoir are also presented. The validity of the rate-material balance time relation for any types of rate decline renders the proposed approach general in its applicability; consequently, the proposed approach will enable engineers to apply a single unique method to predict long-term reservoir performance regardless of the type of decline. Simulated and field data are presented to demonstrate the utility of the proposed approach.
Analysis of Post-Drill Pore Pressure and Fracture Gradient Model of G-Field, Offshore, Niger Delta
Authors: George C. O. , Thomas S. W. , John M. , Gani A. , Emmanuel A. K. , Norbert A. E. 
Published: July 2017

Abstract
Post-drill pore pressure and fracture gradient analyses were carried out in an offshore hydrocarbon field, of Niger DeltaBasin, the G-field, using petrophysical logs, drilling parameters and pressure data. Four wells were analyzed and the results from the analysis will serve as a look back in building a Pre-Spud pore pressure and fracture gradient model for future drilling of exploration and production wells. The overburden gradient and normal compaction trend were generated based on an empirical formula. The pore pressure gradients were computed using the Eaton’s and Miller’s method respectively. Mud weights, drilling parameters and drilling events were used to calibrate the pore pressure gradients. Fracture gradient was computed using Mathews and Kelly’s method with pore pressure definitive, overburden gradient and effective stress ratio as the inputs. Based on the empirical methods, pressure transition zones were detected across the four wells with three (3) pressure ramps of magnitude of 1.23 ppg (Pound Per Gallon), 2.55ppg and 1.52ppg respectively. Pore pressure gradient model generated from the study revealed normally pressured zones at the shallower part of the unconfined section in all the wells within the range of 870 and 6273 feet TVD (True Vertical Depth) with an average shale pore pressure of 8.4ppg for Well 1,4715 and 9145 feet TVD with an average shale pore pressure of 8.5ppg for Well 2, 2614 and 7736 feet TVD with an average shale pore pressure of 8.39ppg for Well 3 and 4227 and 7972 feet TVD with an average shale pore pressure of 8.4ppg for Well 4. The top of the overpressured zones (&gt;0.47 Psi/ft) (9ppg) were established across the four wells. The analysis of pore pressure of the field shows that the depth to the overpressured zones ranges from 7498 to 8859 feet TVD for Well 1,9825 and 13582 feet TVD for Well2, 7741 and 12264 TVD for Well 3 and 8307 and 12220 feet TVD for Well 4.
Fast Tracking Field Development Optimisation With Nature Inspired Heuristics
Authors: Ilamah Osho , Ebere Maurice 
Published: July 2017

Abstract
Wells are a crucial element in any field development optimisation effort. A field development will not be optimal unless we drill optimum types and number of wells, at optimum locations in the reservoir. Traditionally, a manual trial-and-error approach is taken for field development optimisation. The manual approach allows the engineer to exercise full control over the process, which can be beneficial when the engineer is very knowledgeable, but this approach is very inefficient and unreliable. Increasingly, stochastic optimisation algorithms are being applied to identify optimal or near optimal well configurations. For typical field development optimisation problems, these stochastic algorithms require many thousand objective function evaluations, in the form of reservoir simulations, and this is a major issue.
In this paper, we demonstrate an alternative approach to field development optimisation. It starts with one or more sets of candidate wells, with associated type, location and trajectory information. Iteratively, elimination of wells is performed based on a simulation derived well valuation metric. The elimination of wells corresponds to a modification of the development well configuration (well count, locations and well types). Therefore, by comparing the field level valuation metrics obtained across iterations, we can determine the optimal development well configuration. Our approach focuses the optimisation search only on the promising areas of the solution space, represented by the initial candidate well sets, or starting well configuration. Determination of locations and trajectories of the initial candidate wells is therefore key. In our work, we determine the locations and trajectories of initial candidate wells using patterns, potential estimates and an Ant System.
Two examples are used to illustrate the effectiveness of our approach. The results show that the approach significantly speeds up field development optimization, allowing simultaneous optimisation of well locations, well count and well types.
Use of Petro-Elastic Analysis to Evaluate Potential for Sand Production in Petroleum Reservoirs
Authors: Ukaonu Cyril , Odubanjo Teleola , Lawal Kazeem A. , Eyitayo Stella I. , Ovuru Mathilda I. , Anyadike Emeka , Matemilola Saka 
Published: July 2017

Abstract
Sandstone formations that have potential to produce sand during the life of the well account for a significant fraction of global recoverable volumes of oil and gas resources. The economics, environmental and safety implications of sand problems are critical enough to justify good knowledge of the potential for sand failure and production. Reliable evaluation of potential sand production is required to identify the needs for and the specification of sand-exclusion equipment during the project execution phase.
To address these challenges, this paper presents a simple workflow that is premised on the petro-elasticity of the formation. Specifically, the proposed workflow uses cross plots of compressional sonic logs and density logs on reservoir-by-reservoir and well-by-well basis. From a petro-elastic standpoint, compressional sonic logs contain information on travel time required for sound waves to travel through the subject formation. The fundamental relationship between formation compaction (strength) and porosity has been explored to establish the trend of compaction, hence vulnerability of a sandstone formation to failure.
In illustrating the applicability of the proposed concepts and workflow, some field examples from the Niger Delta are presented. Using wells with known history of sand failure and production, the workflow has been applied retroactively. The methodology presented is very useful for establishment of a quick screening sand control requirement. From a qualitative standpoint, it is found that the performances of the proposed workflow are in reasonable agreement with the history of sand failure and production in the example wells.
Smart Well Completion Design using Feed-Through Swell Packers in a Gas Well: A Case Study
Authors: Adejoke Adebayo , Hamzat Kassim , Laoye Abiodun , Cosmas Nwankwo , Iyengumwena Ricky , Nnadi Magnus 
Published: July 2017

Abstract
Smart well technology allows production acceleration from multiple completions and value realization from otherwise marginal reservoirs. Critical to the success of a smart well completion targeting more than one reservoir is the proper design selection and reservoir isolation to prevent cross flow.
This case study describes the selection of a suitable gas well design from different available options, the considerations made in the design selection which incorporated the different completion components, one of the components being the feed-through swell packers which is its first use in the company, to achieve reservoir isolation. The paper also describes the execution of the selected completion design in one of the cases, as well as the testing of the well to verify reservoir isolation, and confirm the effectiveness of the feed-through swell packer.
The selected completion design was cost effective, reduced operational / deployment risks (compared to other isolation options) and had no adverse impact on well productivity of the wells. It also achieved the objective of accelerating the recovery of a combined volume of 221 Bscf of gas from marginal gas reservoirs in a field.
Standard Operating Procedure for Analysis of Oil Rim Occurrence & Viability in Gas-Down-To Reservoirs
Authors: Ikpera Cordelia , Ekong Inem 
Published: July 2017

Abstract
Nigeria has over 180 Tscf of gas resource volumes to support its export and domestic gas demand. Significant quantity of these resource volumes are associated with reservoirs encountered in down dip oilrim with varying oilrim thicknesses or in Gas-Down-To (GDT) situation requiring appraisal and justification prior to gas development which may lead to restriction on gas readiness.
Unlocking these gas volumes is key to maintaining gas supply and meeting contractual obligations. Therefore, this paper presents a Standard Operating Procedure (SOP) which provides a structured approach and workflow for analyzing and managing the uncertainty of potential oilrim below known GDT reservoirs and evaluating the technical producibility and viability of the oilrim reservoirs. It also discusses the different methods currently being used in the industry, applications and boundary conditions in estimating hydrocarbon fill below know GDT and highlights results of blind test analysis carried out for five wells drilled in the Niger Delta. The application of this SOP provides a quick assessment guide to aid timely decision on gas field development without necessarily drilling an appraisal well thereby saving huge cost especially in this era of low oil price and funding challenges.
The SOP adopts an integrated approach and involves the use of available geoscience and engineering data to estimate fluid contact below known GDT. It takes into account the environment of deposition, reservoir depth, historical knowledge and production data to estimate contact and oilrm viability. Minimum data required for each analysis is detailed in the SOP workflow and methodology outlined for ease of adaptation.
These methods are reliable techniques and should not be used in isolation but to compliment the other. Results from blind test analysis for five wells selected for this study demonstrates a potential savings of $60 MMUSD from drilling a minimum of two appraisals wells and enabled a timely decision to be taken for the development of the gas reservoirs leading to maximimzation of cash flow and NPV.
Grain Size Effect on Permeabilty and Pressure Drop in Alkali-Surfactant-Polymer Flooding
Authors: Onuoha Sean O. , Olafuyi Olalekan , Taiwo Oluwaseun 
Published: July 2017

Abstract
In order to improve the efficiency of the enhanced oil recovery process, researchers have come up with different methods such as mobility control, chemical, miscible, thermal and other processes such as microbial. In chemical flooding for example, alkaline, polymer, surfactant, surfactant polymer (SP) and alkaline surfactant polymer (ASP) have all been employed in the quest for better efficiency. However, grain size effect on the recovery system during these tertiary recovery techniques has received less attention over the years.
This paper presents evaluation of the effects of grain size on residual oil saturation (ROS) from experimental studies of oil recovery potentials of a formulated ASP slug in synthetic porous media. 1% weight of sodium hydroxide (NaOH), 0.15% weight of shell enordet 0242 supplied by shell research centre and 0.02% weight of hengfloc 63020 were used as alkali, surfactant and polymer respectively. Ranges of core grain sizes of 0.063 to 0.090, 0.106 to 0.150, 0.150 to 0.212, 0.212 0.300 and 0.425 to 0.600 micron were considered in five different experiments performed. Each of the experiment was accomplished by a procedural sequence of brine saturation, oil saturation, water flooding and ASP flooding.
The results show that the porosity of the synthesized core increases with decreasing grain size from 37.2% to 43.74% for a range of 0.600 micron to 0.063 micron of sizes. The permeability of the synthetic core decreases from 2309 millidarcy to 669 millidarcy as the grain size decreases from 0.600 micron to 0.063 micron. Pressure drop across the beads pack increases from 0.294 psi to 1.015 psi as the grain size reduces. The oil recovery by an immiscible fluid through the beads pack increases as the pore throat get smaller or the grain size reduces. The volume of ROS after flooding reduces as grain size reduces.
Niveles de empatía y ética profesional en candidatos a sub-especialidad médica
Authors: Jiménez-López José Luis , Arenas-Osuna Jesús , Ángeles-Garay Ulises 
Published: July 2017

La percepción actual de una atención médica deshumanizada y de baja calidad ha cuestionado la capacidad empática y ética de los profesionales de la salud. Las investigaciones en este campo reportan fluctuaciones en estos atributos a lo largo de la formación de los médicos. Objetivo: Explorar los niveles globales de empatía y ética profesional, así como los niveles de cada componente de ambos atributos, en una muestra de candidatos a subespecialidad médica. Metodología: Se incluyeron 65 residentes que solicitaron cursar subespecialidad en una unidad médica de alta especialidad. Como parte del proceso de solicitud, respondieron el Test de Empatía Cognitiva y Afectiva y la Escala de Actitudes Éticas Profesionales. Resultados: Las puntuaciones promedio de la muestra calificaron como media en empatía y como óptimas en ética profesional. La comparación por género, especialidad y competencias mostró menor empatía afectiva y mejor competencia ética en las mujeres; mayor empatía cognitiva en subespecialidades quirúrgicas; y ausencia de correlación entre las dos variables en general, y en particular por competencia. Conclusiones: Se resalta la importancia de medir las competencias particulares de cada atributo dado que la variación en competencias específicas repercute en diferentes aspectos de la formación del médico, como la elección de especialidad, la selección de candidatos, la elaboración de programas académicos y el adecuado aprendizaje sobre la construcción de una efectiva relación médico-paciente. © Revista Colombiana de Ciencias Sociales.
Impacto psicológico del ciberbullying en estudiantes universitarios: un estudio exploratorio
Authors: Redondo Jesús , Luzardo-Briceño Marianela , García-Lizarazo Karol Lizeth , Inglés Cándido J. 
Published: July 2017

Los objetivos de este trabajo fueron determinar la prevalencia del ciberbullying entre los participantes del estudio, así como conocer el impacto psicológico tanto en cibervíctimas como en ciberagresores, analizando además las diferencias de género de dicho impacto. Método: la muestra estuvo constituida por 639 estudiantes de la Universidad Pontificia Bolivariana, seccional Bucaramanga, con una media de edad de 17,6 años (chicos N = 303, chicas N = 334). Para ello se emplearon los siguientes instrumentos: (a) Escala de ciberagresiones; (b) Escala de cibervictimización; y (c) Symptom Assessment-45 Questionnaire (SA-45). Los resultados evidencian que un 27,5% de la muestra ha sido agredida en alguna ocasión, así como que 26,7% ha sido acosador durante el último año. Por otro lado, los resultados demostraron que existe un impacto psicológico (escalas del SA-45) tanto en las cibervíctimas, como en los ciberagresores. Conclusiones: Respecto a las diferencias de género en ciberbullying se evidenciaron solo en algunas escalas (primordialmente depresión, ansiedad, sensibilidad interpersonal y somatización), aunque no fueron significativas entre los síntomas psicológicos reportados en este estudio (salvo en las escalas relacionadas con Somatización y Ansiedad fóbica). © Revista Colombiana de Ciencias Sociales.