bluuebunny/crossref_metadata_2025_split huggingface dataset:
Problems of Smart Contracts Application in Transactions in Virtual Property
Authors: Bogdanova E. E. 
Published: July 2019

The author examines the features of the use of smart contracts in transactions in virtual property, taking into account the fact that the smart contract is a way of fulfilling those obligations in which the transfer of property provision takes place in the virtual world with the help of appropriate technical means. It should be recognized that the list of virtual property is open, at the moment it includes, for example, cryptocurrency, domain names, «game property», virtual tokens.The question of the legal nature of objects related to virtual property is relevant: are they a new independent type of property requiring special legal regimes, or are they a form of known property rights? The paper also notes that smart contracts differ in both vulnerabilities in computer code and insufficiently effective legal regulation. Smart contract, in the opinion of the author, is a kind of written (electronic) form of a contract, the peculiarity of which is that the will of the subject is expressed by means of special technical means in the form of program code. In this case, the will to conclude the contract simultaneously means the will to its execution upon the occurrence of certain conditions of the contract circumstances.In conclusion, the author shows that the automation of performance of obligations in particular and the digitization of contract law in general should not create obstacles to the implementation of the fundamental principles of good faith and contractual justice, to assess the proportionality of the distribution of rights and obligations of the parties, the equivalence of their property.
O ensino primário no Portugal de Oitocentos (1820-1880). Génese e estructuração político-administrativa
Authors: Marques Alves Luís Alberto 
Published: July 2019

Resenha do livro. Áurea Adão (2018), O ensino primário no Portugal de Oitocentos (1820-1880). Génese e estructuração político-administrativa.
KUALITAS BATUBARA FORMASI TANJUNG DI DAERAH SEKAKO, KALIMANTAN TENGAH
Authors: Wiranata Beny , Amijaya Hendra , Anggara Ferian , Tanggara Deddy N.S.P. 
Published: July 2019

Formasi Tanjung yang berumur Eosen merupakan salah satu formasi pembawa batubara di Cekungan Barito, Kalimantan Tengah. Kualitas batubara merupakan suatu parameter penting khususnya dalam proses pemanfaatanya. Penelitian ini bertujuan untuk mengetahui kualitas batubara Formasi Tanjung di Daerah Sekako, Kalimantan Tengah. Sampel batubara diambil dengan menggunakan channel sampling ply by ply dan kemudian dilakukan analisis laboratorium meliputi analisis proksimat, ultimat dan nilai kalori. Batubara seam A dan B Formasi Tanjung di Daerah Sekako memiliki kandungan lengas total 1,98 – 4,33 (wt%, ar), kandungan abu 2,79 – 9,05 (wt%, adb), zat terbang 35,14 – 39,50 (wt%, adb), karbon tertambat 53,47 – 59,41 (wt%, adb), nitrogen 1,51 – 1,86 (wt%, adb), total sulfur 0,29 – 1,54 (wt%, adb), nilai kalori 15.889,93 – 17.235,44 (Btu/lb mmmf) dan fuel ratio 1,35 - 1,66. Batubara tersebut secara umum merupakan batubara high volatile A bituminous. Batubara tersebut berpotensi dimanfaatkan baik sebagai thermal coal maupun sebagai batubara coking. Kata kunci : kualitas batubara, Formasi Tanjung, Cekungan Barito
Minimum Sand Transport Conditions in Gas-Solid-Liquid Three-Phase Stratified Flow in Horizontal Pipelines
Authors: Fajemidupe Olawale T. , Aliyu Aliyu M. , Baba Yahaya D. , Archibong Archibong E. , Okeke Nonso E. , Ehinmowo Adegboyega B. , Yeung Hoi 
Published: July 2019

Abstract
Producing sand during oil and gas production is unavoidable. Sand is produced along with oil and gas and its deposition in pipelines is a significant risk as it can cause pipe corrosion and flow assurance difficulties. It is therefore key that flow conditions are sustained to guarantee lack of deposition of sand particles. The minimum combination of mixture velocities that guarantee continuous sand motion is known as the minimum transport condition (MTC). Here, we investigate the effect both of sand concentration and particle diameter on MTC in a horizontal pipeline in the stratified flow regime. Non-intrusive conductivity probes were utilised for the detection of sand. These sensors are commonly used for the measurement of film thickness in gas and liquid flows, but we demonstrate their use here for sand detection after suitable calibration. It was observed that at the ultra-low sand concentrations of our experiments, MTC increases with both sand particle diameter and concentration. We developed a new correlation based on Thomas's lower model but included a sand concentration correction term that also applies at low particle concentrations. The correlation's predictions compared favourably with our measurements at MTC as well as data obtained from the open literature at medium concentrations.
Improvements to the Dynamic Material-Balance Method of Reservoir Surveillance
Authors: Lawal Kazeem A. , Okoh Oluchukwu M. , Yadua Asekhame , Ovuru Mathilda I. , Eyitayo Stella I. , Ramaswamy Sunil 
Published: July 2019

Abstract
Given sufficient performance and other data, material balance (MB) is a common method of determining the hydrocarbons initially in-place (HCIIP) in a reservoir. The application of this method requires, as a minimum, historic cumulative production (including injection) and average reservoir pressure. However, determination of historic average reservoir pressures would require shut-in of wells, hence production deferments. As an improvement to the classical MB, the dynamic material balance (DMB) method was developed by Mattar and Anderson (2005). Unlike the MB method, direct measurements of average reservoir pressure are not critical to DMB. In its basic form, the implementation of DMB requires historic production rates, flowing bottomhole pressures and cumulative production, thereby eliminating associated deferments. Although DMB has performed satisfactorily in some applications, its overall robustness remains to be fully explored.
This paper conducts rigorous sensitivity checks on selected DMB models. Based on insights gained, their relative strengths and weaknesses are highlighted. To keep the problem tractable, detailed simulations are performed on different three-dimensional (3D) multiphase homogenous reservoir models of known HCIIP. Different cases are simulated, generating relevant performance datasets to evaluate DMB. The parametric tests conducted on this undersaturated compressible oil reservoir include (i) constant vs. variable production rates; (ii) rate hysteresis; (iii) vertical vs. horizontal well; (iv) single vs. multiple wells; (v) healthy vs. damaged well; and (vi) variable skin factors, with hysteresis.
Within the parameter space examined, simulation results show that DMB performance (e.g. HCIIP) is sensitive to some of the parameters and subsurface realisations investigated. Against this background, some improvements and guidelines are proposed to enhance the capability and performance of DMB as a technique for reservoir surveillance.
Injectivity Monitoring & Evolution for Water Injectors in a Deepwater Turbidite Field
Authors: Onwuchekwa Vincente , Usman Musa , Wantong Paterne , Biu Victor , Oukmal Jed 
Published: July 2019

Abstract
Water injection is one of the key improved recovery techniques used for pressure maintenance and sweeping. Throughout the life of a field, changes in injectivity can have an effect on reservoir pressure management and sweep efficiency which both have a direct impact on production.
This study aims to present an original methodology to analyse the performance of water injectors in a deepwater turbidite field and evaluate the evolution of their injectivity over time.
An injectivity monitoring tool was developed by incorporating injection flowrate and pressure data with the following analytical techniques: (i) Instantaneous Injectivity Index, (ii) Hearn Plot or Reciprocal Injectivity Index, (iii) Hall Plot, (iv) Derivative Hall Plot and (v) Pressure Transient Analysis.
The injectivity monitoring tool was able to capture subtle changes in injectivity and demonstrate the long term trend of stable injectivity in this field, even in situations where only wellhead pressure and injection flowrate were available.
The resulting analysis showed that there is very good injectivity for all water injectors in this field with little or no degradation over time. One of the key drivers for the good injectivity is the water injection process philosophy in this field. This process consists of injecting deaerated seawater with biocides in order to prevent bacterial growth which causes near wellbore plugging. Another contributing factor to the good injection performance is the presence of injection valves which enable each injector to perform downhole shut-ins to stop migration of fines and curtail any possible water hammer effect when intermittent injection shut-ins required.
It was furthermore found that there was no significant difference in injectivity that could be associated to deviation angle or completion type (Stand Alone Screens (SAS) or Expandable Sand Screens (ESS)). Injectors completed with SAS however appeared to exhibit increased injectivity with increasing screen length but no such correlation was apparent between screen length and injectivity for injectors with ESS.
Rotary Steerable Directional Jetting Service Successfully Delivering Step Change in Directional Well Design for Soft Sediment Formation in Deepwater Nigeria
Authors: Osita Humphrey , Foekema Nico , Oredolapo Olawale , Ozioko Raphael , Chapoulie Antoine , Omojowolo Kehinde , Okoroafor John 
Published: July 2019

Abstract
This paper describes the successful technique to start a kickoff below the 36-in. conductor casing with much higher dogleg severity (DLS) capability than a conventional motor directional drilling method in a soft sediment formation by using a rotary steerable system (RSS) equipped with directional jetting. This technique uses a rotary steerable system (RSS) equipped with directional jetting to provide the operator with a step change in directional well design for reaching shallow reservoirs with inclinations close to horizontal.
The challenging aspect of the well design was that only 650m (2133ft) of TVD was available to perform the directional work. This section consisted of weak and soft sediment formations that did not support conventional directional drilling methods.
To address the operator's challenge, it was determined that a RSS configured for directional jetting could deliver the higher DLS for the optimal well trajectory. This system combines two techniques, rotary steerable and directional jetting, to achieve the directional objective. This field-proven application was successfully used by several operators, as described in SPE-173057-MS, and applied in this deepwater low-UCS environment. The extensive engineering evaluation, using finite-element analysis and torque-and-drag calculations, confirmed the bottom hole assembly (BHA) design was technically feasible without compromising safety and drilling efficiency.
Three wells successfully delivered all directional objectives with this technique. The highest inclination was recorded in the top hole as planned; the sailing angle was lower compared to other wells drilled with conventional directional drilling methods, and the target sands reached at an angle close to horizontal. Completions ran without issues. This technique delivered above 3°/30m DLS in the deepwater soft formation and all future wells for this operator will use this technique for the tophole drilling.
A Mechanistic Approach to Subsea Gas Pipeline Capacity Utilization – Case Study
Authors: Umuteme Ogenethoja , Umeh Ebuka 
Published: July 2019

Abstract
One of the biggest challenges after the initial gas field discovery lies in the transportation. The natural gas supply is constructed in such a way that transportation remains an integral part of the gas utilization system. This is because the operator has to understand the mechanism behind transporting from the well to the wellhead; from the wellhead to the topside while efficiently avoiding hydrate formation; from the topside to the processing facilities and from the processing facilities to the delivery point for the final consumers.
This paper was structured to address subsea gas pipeline flow assurance issues relating to the initiation of hydrate and internal corrosion. Through experience and extensive literature studies, an Optimization Systematic Model was developed. This model is procedural in nature, incorporating both risk analysis and predictive models. The model was further used to investigate the susceptibility of the case study, Inter-western African Gas Pan Pipeline (IAGPP), to hydrate and internal corrosion. The results of the case study confirmed that the model is helpful in that it can bring flow assurance issues to management focus. This research suggested a new derived equation – the Thermo-Mechanistic Model (T-MM), used to explain PIPESIM simulation results and the optimization options. The T-MM can be used to understand the behavior of gas enthalpy to variations in gas pipeline flowrate. In general, there is a need to keep gas pipeline capacity optimization in focus; to proactively avert cases of hydrate and internal corrosion by using the model developed. Learning from the IAGPP case study also shows that there is the need to accurately assess gas availability for transmission.
Rigless Recompletion Using Cement Packer – EROTON E & P Experience
Authors: Emeka Onyeka , Adeeyo Yisa , Etim Augusta , Oluwalade Opeyemi , Ohabuike Onyema , Okene Uzoamaka , Bakor Leziga , Ukauku Ikwan , Afolabi Niyi , Esimaje Jolomi 
Published: July 2019

Abstract
With global Oil prices still recovering from the down cycle and coupled with high cost of drilling new wells, EROTON E & P has devised strategies to manage declining oil production, increase oil production from her existing assets and add new reserves through team integration and improved subsurface data management by using fit-for-purpose technology (cement packer) and other collaborative tools.
Cement packer technology is a relatively fast-to-deploy and cost-effective rig-less intervention technique that allows easy access to hydrocarbon reserves behind pipe which are located above and between production packers in wells where the existing completion intervals have reached their economic limit. This technology can be used to separate a new zone earmarked for completion from other intervals including non-hydrocarbon zones. The cement plug is pumped into the allocated space to serve as an effective production packer. This becomes viable and economic option when the interval is above an existing parker. Cement packer activity can be carried out using a rigless unit with the benefit of significant cost savings while achieving seamless isolation of the production intervals.
One example from the strings of successful cement parker operation, among a few others, is the CAAK-040 well in CAAK field. The well was drilled in 1988 and completed on X3050B and Y4050B reservoirs. Both intervals quit in 2001 at BSW above 80%. After the integrated subsurface evaluation using all available data including CO logging acquired across the existing and proposed completion intervals, CAAK-040 was proposed for a zone change. A rigless workover intervention of the well was executed and the production interval switched from Y4050B to C8000B reservoir on the new short string using cement packer technology to isolate Y4050B completion and recomplete in the new target sand. CAAK-040 did not flow after the cement packer and perforation operations were successfully executed and the well had to be lifted to production using a temporary gaslift system.
Currently, the well is performing above the planned potential of 1500bopd from C8000B reservoir. This paper will discuss the lessons learnt and best practices from the cement packer and re-perforation of CAAK-040 using a rigless workover unit.
There is continuous monitoring to ensure all approved company procedures and minimum standards are strictly adhered to.
To date, we have a total of five (5) wells that have been recompleted and reserve added using cement packer. This activity has accelerated the production system unlocking of short-term oil generation (STOG) production of over 5,000 b/d of oil in one-year target. The average total cost of this operation is about 20-30% of a conventional workover. Thereby saving the company over $20m with added rewards of reactivating shut-in wells and producing reserves that were previously sub-economical and inaccessible.
Ecological Remediation of Heavy Metals in Crude Oil Polluted Waters Using Duckweed
Authors: Ekperusi Abraham O. , Sikoki Francis D. , Nwachukwu Eunice O. 
Published: July 2019

Abstract
Heavy metals are present in crude oil produced worldwide in varying concentration as impurities. Such metals are also exposed to the environment when oil spill occur. In this study, we applied the duckweed, Lemna paucicostata as an ecological based treatment method for the phytoremediation of heavy metals present in crude oil polluted waters. Duckweed was applied in an artificial constructed wetland mesocosm contaminated with crude oil to simulate a spill site. Heavy metals were analyzed following established guidelines using AAS for a 60-day period. The results showed that heavy metals reported in this study were above permissible limit. Initial cadmium, chromium, lead and vanadium decreased by 4.36, 7.06, 17.95 and 2.47% after 15 days respectively and then decreased further by 11.21, 19.94 and 32.4% for Cd; 13.15, 16.9 and 13.76% for Cr; 20.51, 30.77 and 41.03% for Pb; and 4.12, 15.66 and 26.37% for V after 30, 45 and 60 days respectively. There was no significant difference between the mean values of the metals across the duration. The result of this study showed that duckweed moderately removed heavy metals from crude oil polluted waters. Extending the duration of the study could increase the potentials of the plant to remove a higher amount of metals from the contaminated media. This result could be translated to real life application as an ecological base tool for the sustainable remediation of metals in crude oil polluted environment.
Evaluation of the Inhibition Efficiency of Plant Extract PE as Gas Hydrate Inhibitor in a Simulated Offshore Environment
Authors: Elechi Virtue Urunwo , Ikiensikimama Sunday Sunday , Ajienka Joseph Atubokiki , Akaranta Onyewuchi , Onyekonwu Mike Obi , Okon Okon Efiong 
Published: July 2019

Abstract
This present study emphasizes the inhibition capacity of a local inhibitor, Plant Extract (PE) on structure I (sI) gas hydrate. The Plant Extract (PE) was screened using a mini flow loop made of 316 stainless steel of internal diameter of 0.5-inch encased in a 4-inch PVC pipe skid mounted on a metal frame work fitted with pressure and temperature gauges, mixer vessel, pumps and control switches. Pressure and Temperature readings were recorded for 120 minutes. Plots of Pressure and Temperature versus Time for 1, 2 and 3wt% of the local inhibitor alongside Pressure versus Time plot of PE and MEG were done as a way of comparison. Calculations for Inhibition Efficiency (IE) for local inhibitor PE and MEG was also done. 1wt% of the plant extract (PE) had a high inhibition efficiency of 84.21% while 2 and 3wt% had inhibition efficiency of 60.53% and 73.68% respectively. The overall inhibition efficiency of Plant Extract (PE) was higher than that of MEG for 1wt% (60.53%) and 2wt% (55.26%) but had the same efficiency at 3wt% (73.68%). The optimum weight percentage for PE is 1wt% because of its high efficiency. It is clearly shown that Plant Extract (PE) is a better gas hydrate inhibitor which is gotten from nature and is environmentally friendly unlike Mono Ethylene Glycol (MEG) which is synthetic and toxic to both human and aquatic life. It is therefore recommended for field trial.
Production and Characterization of Tyrosinase Enzyme for Enhanced Treatment of Organic Pollutants in Petroleum Refinery Effluent
Authors: Osuoha Justice Obinna , Abbey Bene Willie , Egwim Evans Chidi , Nwaichi Eucharia Oluchi 
Published: July 2019

Abstract
One of the cruel environmental quagmires confronting the Petroleum industry is the high organic pollutant levels in the bio-treatment unit of its refinery wastewater treatment plants which is not in line with the design specification. High level of organic pollutants in discharged non-compliant effluents from petroleum refineries leads to varied environmental hazards. Wastewaters discharged from petroleum refineries are characterized by the presence of toxic pollutants like phenols, polycyclic aromatic hydrocarbons (PAHs), metal derivatives, etc. Numerous enzymes from plants, fungi and bacteria have been reported to be involved in the degradation of toxic organic pollutants but with limited field trials. The present study focuses on production and characterization of enzyme, tyrosinase expressed by native microorganisms in refinery wastewater and its application in the removal of organic pollutants from petroleum refinery effluents. A total of 10 microbial strains were identified and isolated from refinery wastewater and screened for expression of tyrosinase using standard microbiological methods. Among 10 isolates, 4 isolates; Bacilus subtilis, Verticillium sp., Penicillium sp. and Aspergillus flavus were selected for enzyme characterization and production based on the magnitude of the zone of clearance they produced. Tyrosinase was produced in broth and partially purified by ammonium sulfate precipitation, dialysis and Sephadex G-75. The purified enzyme was immobilized in sodium alginate and was used for the treatment of petroleum refinery wastewater. Results revealed that the immobilized enzyme significantly removed phenol and PAHs present in the wastewater by 95 %, and 89 % respectively. These findings highlight the viability of enzyme, tyrosinase, for the degradation of organic pollutants in petroleum-derived effluents.
Gains of an Effective Community Management Framework: The OML26 Experience
Authors: Okpowo Blessyn , Ageh Ebenezer , Agodo Peter , Okon Akpan , Mfon Bassey , Emmanuel Tata 
Published: July 2019

Abstract
The Oil Mining License (OML) 26 Asset is in Isoko North Local Government Area, about 60km east of Warri in Delta State, an onshore asset in the northern Niger Delta. NPDC and FHN are partners for a joint operation of the mining lease and currently executes its function through an Asset Management Team (AMT), comprising employees of NPDC and FHN.
The company (OML 26 JV) entered into a Global Memorandum of Understanding (GMOU) with OML 26 host communities to create an understanding and guide its relationship with the communities. The GMOU did not produced the desired result as OML 26 operations have often been interrupted by Community related issues. There is a lack of mutual trust on both sides and the Community and its agents tend to hold the company to ransom at the slightest opportunity. In a bid to reverse the trend, the AMT took the initiative to step back and assess the root cause of the acrimony, thoroughly engage the right elements within the Community to gauge their perspectives, and then developed a series of initiatives aimed at regaining the trust of the host communities. A framework is being developed that has engendered collaboration with the host communities (within its operating area) to build a mutually beneficial and symbiotic relationship that enables each party to achieve their goals and aspirations albeit in a peaceful, hitch free atmosphere. The AMT in line with the vision of the JV Partners is committed to sustainable community development, human capital development and capacity building, economic empowerment, and infrastructural growth. This paper highlights the key elements of the framework and the engagement strategies that has enabled the AMT to enjoy relative peace and operational stability while ramping up production and executing developmental projects in the communities.