bluuebunny/crossref_metadata_2025 huggingface dataset:
Lessons Learnt from Well Intervention Operations on Well AA, and The Impact of Detailed Recipe Design on Performance of a Niger Delta Well
Authors: Oladunni Oluwatobiloba , Aihevba Leste , Dokubo Richard , Kudayisi Ayopo , Obadaki Muaz , Eze Celestine , Eze Modestus , Ibama Chika
Published: July 2019

Well Intervention operations are carried out to improve production performance of a declining well, restore production to a well that quit, or improve well integrity, among other reasons. Well bore clean out and stimulation are two of the common well intervention operations done on producing oil and gas wells to improve performance. Well AA, a major oil and gas producer started to decline after three years of production, therefore a well bore clean out and stimulation exercise was designed to improve performance of the well. The first Intervention operation was planned after various crude sample and precipitate analysis reports showed organic deposits (wax and asphaltenes) in the well. Slickline drift also indicated a restriction in the tubing. The treatment recipe for the well intervention was designed based on laboratory test carried out on the crude and precipitate sample that showed an 85% dissolution of the organic deposits in Xylene and 55% dissolution in Solution Z (a mixture of Xylene and HCL). The 85% dissolution was considered adequate to ensure a complete wellbore clean out, with Solution Z planned as the contingent treatment recipe for any solid deposits not dissolved by Xylene. Contingent on the successful wellbore clean out, a matrix stimulation was to be done using an Acid preflush and Regular clay acid as the main treatment. But this operation failed because instead of resulting in an increase in production, the well couldn't produce to surface and had to be shut-in. This paper will review the problems encountered from the unsuccessful intervention of well AA because of the lack of a detailed recipe design to find the best treatment to dissolve organic deposits in the well and precipitates, as well as residues formed from the reaction between organic solids and inorganic acids. In addition, this paper will present the detailed work that went into designing the right treatment recipe for well AA that resulted in successfully reviving the well after the initial failed intervention operation to become a prolific producer of over 1500 stock tank barrels of oil per day.
Production Optimization Strategies for Unlocking Resource Potential in A Heavy-Oil Brown Field - The OML26 Success Story
Authors: Ajao Wale , Isiba Ezinwanneakolam , Okoh Eddy , Okoruwa Immaculate , Omenai Stanley , Abu Nicholas , Babalola Olusegun , Oke Oluwatobi
Published: July 2019

Oil Mining Lease 26 (OML 26) is held by NNPC and First Hydrocarbon Nigeria Limited (FHN) in a Joint Venture relationship and operated by an Asset Management Team (AMT). The license consists of several oil and gas discoveries including the Ogini, Isoko, and Ozoro fields on the western part, Ovo in the central area and Aboh to the east.

Oil Production is mainly from the Ogini and Isoko fields with the Ogini field contributing the largest volume. The Ogini oil is relatively heavy, with in-situ oil viscosity ranging from 3 to 59cp, and an oil gravity ranging from 15°API to 19°API. Field development and production from the Ogini field has been very challenging with the characteristic low GOR, low rate and high watercut. Oil production peaked at 8,900 stb/d shortly after field start-up in the 80s and has been declining since then.

In 2018 however, the field witnessed breakthrough performance stemming from production optimization initiatives and strategies which unlocked resource potential of the field. A peak production of ca 17,000 bopd was recorded during Q4 of 2018 without drilling new wells. A number of production enhancement activities carefully designed, planned, and executed coupled with change in operations philosophy released more volumes transforming the production levels and production profile of the field from a mere 3,000bopd to ca 17,000 bopd peak production. This paper highlights the strategies, optimization techniques and the paradigm shift in operational culture that resulted in the significant change and ramp up of production in the field.
Improving the Thermodynamic Properties of Export Gas Through Condensate Spiking
Authors: Oviawele P. E. , Onwukwe S. I , Nwachukwu N. A. , Onyejekwe I.
Published: July 2019

Disposal of condensate produced from stranded gas field have been a major concern to producing companies due to unavailability of nearby oil flow stations to receive the condensate, which have resulted to abandonment of such fields. This work seek to improve the thermodynamic properties (Heat Capacity, Heating Value, Specific Heat capacity, Heat of Vaporization and Enthalpy) of the export gas through condensate spiking. This was carried out by simulating a natural gas plant, consisting of condensate line and spiking mixer. The simulation was done using Aspen HYSYS, to include the point at which the condensate stream was spiked into the high-pressure dry natural gas stream. Phase envelope and hydrate formation curve for the streams (dry natural gas and the mixture after spiking) were obtained. Case study in HYSYS was used to carry out Sensitivity analysis, to determine the effect of temperature, pressure and flow rate of the condensate on the mixture (export gas). Economic analysis of the project was carried out. Results obtained from the thermodynamic analysis shows that the thermodynamic properties of the export gas after spiking improves, such that the heating value and enthalpy of the export gas increases. The phase envelops shows that hydrate will not form in the export gas streams. Through the sensitivity analyses, the effect of variation in the parameters of the condensate shows that the vapour fraction of the export gas increases as the temperature increase and decrease as the pressure increases. The maximum condensate flow rate was obtained to be 12,500 bbl/day, at a dry gas flow rate of 382.2 MMScfd, for a maximum vapour fraction of 0.953, with this operating parameters, flow assurance problem of hydrate formation, liquid holdup and high pressure drops along the pipeline with be eliminated. Hydrocarbon dew point of −13.41°C was obtained showing that liquid hydrocarbon will not condense out of the gas during transportation. Economic analysis shows that the NPV and IRR are $432.778 million and 33%, indicating that the project is viable for investment. Therefore, it is possible to spike condensate into treated export gas without causing flow assurance problems, and helps mitigate against risk associated with environmental pollution.
A Systematic Approach to Resolving Wellbores Stability Issues While Drilling through Depleted Sandstone Reservoirs, Case Study-GAB Field, Niger Delta
Authors: Onyeji J. A. , Mboto J. S. , Stafford T. W. , Ekun O. A. , Adamo G. , Oladimeji O. E.
Published: July 2019

The study area is characterized by sequences of sandstone and shale formations. Hydrocarbon production depletes the pore pressures within the sandstone reservoirs while the shale formations retain their original pressures. This leads to the narrowing of the safe mud weight window while drilling and increases the probability of the occurrence of wellbore stability issues such as loss circulation, tight spots, stuck pipe and hole collapse during drilling and casing run activities. Depleted reservoirs were traversed while drilling through the intermediate (12-1/4") hole section in GAB-7H. It was drilled with 9.0ppg equivalent mud weight (EMW) and an equivalent circulating density (ECD) of 9.6ppg EMW to the target depth. While running the 9 5/8" casing, it was observed that the wellbore had collapsed, thereby preventing the casing from getting to bottom of the hole which led to the abandonment of the hole section and a consequent side-track. This paper presents the lesson learnt and best practice that were adopted for GAB-7Hst and subsequent wells in the GAB field.

Prior to the drilling of the sidetrack, a one-dimensional mechanical earth model (MEM) was constructed using petrophysical logs and formation tests of GAB-7H and other offset wells. Shale pore pressure was derived from gamma-ray, resistivity and sonic logs using the Eaton's and Bower's methods while sand pressures were measured/ estimated from modular dynamic testers (MDTs) and depletion models. The fracture gradient was derived using Matthew's and Kelly equation. Shear failure gradient was calculated using Modified Lade equations and log derived mechanical rock properties. The post-drill analysis of the offset wells was then calibrated with the drilling events and mud weights used. This revealed that the mud weight used to drill the 12-1/4" in GAB-7H was inadequate. An optimum mud weight program coupled with close monitoring of ECD is a key requirement to successful well construction in the GAB field, where several reservoirs at various states of depletion, sandwiched by shale formations are traversed. These has led to several successful drilling operations in the field.
Application of the Combined Analytical Methods & Time Lapse Seismic 4D as a Veritable Tool for Water Shut Off WSO Operations – Deepwater Akpo Field
Authors: Usman Musa , Biu Victor , Oukmal Jed , Adeyemi Adeoye
Published: July 2019

The prohibitive costs & risks associated with performing PLT and potentially the isolation of the water producing zone through WSO in deepwater fields such as Akpo renders these operations economically unattractive.

This paper addresses the application of analytical method including the use of 4D monitor results to replace conventional PLT to identify, screen and select viable successful water shut off candidates.

Prior to executing water shut-off treatment programs, a combination of 4D seismic interpretation, production history review as well as the collection of completion and reservoir information were thoroughly performed to ensure that the wells are properly selected.

Well's diagnostic plot (WOR and WOR′) must be consistent with the type of water coning or channeling problem identified from the 4D time lapse seismic and also the depth of possible mechanical plug must be around or above estimated current oil-water contact (COWC).

Two candidate wells having 6-5/8″ SAS Slot 10 in 8.5″ open hole, at approximately 4,000 meter TD, and 82 deg C reservoir temperature were selected. The water cut values were 55% in one well and 60% in the other.

This paper presents below the significant upside for WSO attributed to the use of analytical method and integration of 4D seismic data by eliminating the need to run a traditional PLT. The operation was technically & economically successful on one well with a decrease of watercut from 55% to 16% resulting in the well incremental oil production of ~3kbopd. Operation is planned mid 2019 for the second well
Formulation and Evaluation of Slow-Release Fertilizer from Agricultural and Industrial Wastes for Remediation of Crude Oil-Polluted Soils
Authors: Obieze Chinedu Christopher , Chikere Chioma Blaise , Adeleke Rasheed , Akaranta Onyewuchi
Published: July 2019

Fertilizers are used to enhance the degradation and sequestration of oil-polluted environments, but a decrease in fertilizer efficiency can lead to severe environmental consequences. The aim of this study was, therefore, to formulate a slow release fertilizer using nutrient-rich, ecofriendly and readily available agricultural and industrial wastes. The formulated fertilizer was coated with a renewable, nontoxic and biodegradable material which was then tested against commercial NPK fertilizer for its effect on hydrocarbon degradation rate. Crude oil polluted soil from an artisanal refining site was used to evaluate the efficiency of the fertilizers. Next-generation sequencing technique was used to determine the microbiome of the oil-polluted soil. Metabolic fingerprints were also determined as remediation progressed. Other parameters monitored were pH, extractable total petroleum hydrocarbons (ETPH), NO3- -N, total phosphate and total potassium. Initial ETPH of the polluted soil was 16,388 mg/kg which reduced to 2,250.21 mg/kg after 56 days of remediation. The formulated fertilizer gradually led to an increase in soil pH from being slightly acidic (5.6) to near neutral (6.9), while the commercial NPK fertilizer led to a further decrease in soil pH. Both fertilizers enhanced degradation without significant differences, however, the formulated fertilizer greatly improved microbial diversity. Proteobacteria, Chloroflexi and Acidobacteria dominated the soil microbiome with Acidocella being the leading bacterial genus. Signature metabolites identified included benzenamine, cyclobutanone, octadecane and hexadecane which were all related to hydrocarbon biodegradation. The study revealed that the formulated fertilizer effectively enhanced the restoration of oil-polluted soils as well as microbial diversity and soil fertility. It also shows that acid-loving bacteria are important in the bioremediation of acidic oil-polluted soils.
3D Numerical Modeling of Linear Flow of Non-Newtonian Fluid in Porous Media: Application to Non-Newtonian Draw-Down Pressure Transient Analysis
Authors: Adenuga Kazeem , Achumba Gabriel , Ezenworo Ebuka
Published: July 2019

In this study, a 3-Dimensional non-linear partial differential equation (PDE) describing flow of non-Newtonian fluid in porous media was developed for a no-flow boundary reservoir. Non-Newtonian fluid flow in porous media has direct applications in polymer flooding for secondary oil recovery operations and flow of heavy crude in the reservoir. This novel work presents the pressure behavior of horizontal wells with non-Newtonian fluid flow in porous media as well as the methodology for analyzing pressure transient data from non-Newtonian reservoirs.

The main assumptions in the mathematical modeling of the differential equation are; permeability anisotropy with directional permeabilities kx, ky and kz horizontal well is in the y-direction perpendicular to direction of maximum permeability kx effects of gravity, skin and wellbore storage were neglected and the reservoir fluid was considered to be a non-Newtonian pseudo plastic fluid that obeys power law model in an isothermal condition.

The derived equation was discretized using finite difference approach; A 3D numerical simulator was developed with the aid of MATLAB to solve the system of linear equations obtained from the discretization of a 15 X15 × 15 grid system to obtain pressure transient data. Type curves in terms of PwD and tD were generated for different power law flow index n ranging from 0.1 to 1 for horizontal well length of 600ft, 1000ft and 1200ft.

The developed type curves in this study were validated with a Newtonian case using Tiab Direct synthesis (TDS) technique to analyze the radial flow regime for the determination of average permeability as well as the early linear flow for determining kx The results obtained from the Newtonian fluid case were very close to the actual property been determined.
Integrated Static/Dynamic Modeling of Reservoir Stack Helps to Resolve History Match Challenge and Identify New Drill Opportunities
Authors: Yusuf Nurudeen Oluwatosin , Bovet Paul , Silpngarmlers Lynn
Published: July 2019

Simulation studies are often conducted on single-reservoir levels even though hydrocarbon accumulations hardly occur in isolation. However, it is sometimes beneficial to conduct studies on multiple reservoirs to evaluate opportunities in the sequence simultaneously. This can help to optimize the development plan by enabling the combination of opportunities with multiple strings and providing an avenue to evaluate interactions among reservoirs. Where these interactions exist, they can be critical parameters in the simulation history matching process1.

This approach was used in the simulation studies of five reservoirs across two fields (Field_A & Field_B). Collaboration among an interdisciplinary team helped to overcome challenges in the history matching process, especially regarding a recent observation that one reservoir was exhibiting an increasing reservoir pressure while on production with no water injection. The learnings/insights from the study were used to improve field management of reservoirs with water injection, optimize base production, and identify five development opportunities with a proposed incremental recovery of 15 MMBO.
Resolution of a Perennial Water-Cut History Match Challenge Helps to Optimize Drilling Program
Authors: Yusuf Nurudeen Oluwatosin , Andrew Parrish , Silpngarmlers Lynn
Published: July 2019

Reservoir_B7 is one of the top reservoirs in Adobe field and was considered for further development in a multi-year drilling campaign. The initial opportunity identification and new drill forecasts for this reservoir were done using an old simulation model. Over the years, the challenge with this model had been the prediction water production from existing producers which necessitated the introduction of local permeability barriers in the model. However, to validate this opportunity and ensure reliability of production forecasts, a new simulation study was commissioned.

A systematic approach was employed during the new study which involved continuous engagement between Earth Modeler and Simulation Engineer. This led to identification of a low-quality facies which had not been properly characterized. Recharacterization of these facies led to an improvement in history match with an overall good pressure and saturation matches on both well-by-well and reservoir levels. The latest history matched model was used to validate the proposed opportunity and indicated a sub-economic incremental recovery. This led to elimination of hitherto top opportunity from the drilling program and preventing a bad investment by the company.
Experimental Investigation of Nanoskin Formation Threshold for Nano-Enhanced Oil Recovery Nano-EOR
Authors: Omotosho Yetunde A. , Falode Olugbenga A. , Ojo Temilola I.
Published: July 2019

Enhanced Oil Recovery (EOR) methods continue to be dominant in improving world’s oil reserves as producing fields mature. Global growth of 18% was recorded in proved reserves between 2007 and 2017 (BP Statistical Review, 2018), with North America, which has invested in several EOR techniques, contributing about 14% to this growth. This proves that EOR stands as a long-term solution to the menace of dwindling reserves. Recently, nanotechnology has been gaining attention for application in the petroleum industry. It has been established that nanoparticles dispersed in base fluids such as water, brine or certain organic solvents (nanofluid) exhibit some special properties proved to be advantageous for EOR purposes. Additional recovery of about 30% has been recorded. However, permeability damage, which has been widely reported, is yet to be critically studied and analysed.

The objective of this research was to investigate how two important properties; concentration and injection rate of the nanofluid, affect oil recovery, and as well establish the thresholds of conditions which lead to permeability impairment and injection fluid loss during nanoflooding with silica nanoparticles. The permeability impairment layer which is gradually formed at the rock pore surface is termed nanoskin (a concept introduced by the author).

Four core samples were flooded with brine followed by silica nanofluid of four different concentrations viz; 0.01, 0.5, 2.0 amd 3.0% wt/wt respectively. The flooding process was accompanied with changing injection rates viz; 0.5, 1.0, 2.0, 3.0 cm3/min.

The result indicated that concentration of 2.0% wt/wt and injection rate of 2.0 cm3/min were threshold levels that guaranteed optimal oil recovery from the Niger Delta core samples. The overall result demonstrates that nanoflooding is a viable EOR technique and establishes a combination of parameters that will minimize nanoskin formation during nano-EOR process.
Using Deep Learning and Computer Vision Techniques to Improve Facility Corrosion Risk Management Systems 2.0
Authors: Ejimuda Chijioke , Ejimuda Chukwumaijem
Published: July 2019

During fit for service or corrosion risk assessments of oil and gas facility systems, a key parameter required to design and implement an effective risk management strategy is visual inspection. This paper explains how using state of the art computer vision and deep learning techniques could address such challenges. We used majorly the python programming language, Tensorflow Application Programming Interface, Resnet deep learning architecture, GPU machines and cloud computing technologies to achieve this. Beyond the challenges of obtaining sufficient corrosion defects data, our final solution is a systematic method that would assist field personnel, facility engineers, service companies and management more accurately detect corrosion defect types and failure modes unbiasedly. This leads to more cost effective and quicker recommendation of preventive or corrective measures.
Continuous Circulation Technology to Reduce Drilling Days in Offshore West Africa: Case Study
Authors: Johnson Rachel , Zerari Djamel , Salicante Piervittorio , Midolo Paolo
Published: July 2019

Continuous circulation technology is a form of managed pressure drilling (MPD) where the constant circulation of drilling fluid is maintained by allowing the rig pumps to remain on while adding and removing stands of drillpipe. Using continuous circulation, many drilling challenges are solved through continuous hole cleaning and solids transport, including maintaining constant bottomhole pressure (BHP), reducing the loading of solids and cuttings bed formation resulting from a pumps-off state, mitigating stuck pipe incidents, reducing ballooning effects, providing continuous cooling of bottomhole assembly (BHA) components, and improving formation integrity. Continuous circulation technology was used extensively for its hole-cleaning benefits during a 17-month development, gas drilling, and oil drilling campaign on a deepwater drillship in offshore West Africa from 2015-2016. Operations restarted in 2018 and are ongoing in 2019.

Deepwater drilling using continuous circulation in this field provided a solution for significantly helping improve the rate of penetration (ROP) through continuous hole cleaning when drilling one stand per hour or faster. With constant circulation during the drillpipe connection process, the operator was able to significantly decrease the amount of time spent on hole-cleaning activities after a stand was drilled down in both oil-based mud (OBM) and water-based mud (WBM) applications. The enhanced hole cleaning provided by continuous circulation also helped improve cuttings transport efficiency, mitigate stuck pipe incidents, and enhanced the ability to drill a clean hole.

This continuous circulation system was used on a deepwater drillship in offshore West Africa on 16 wells from 2015-2016, following two wells drilled without this technology, and four wells after the restart in 2018. Overall, more than 535 operating days and more than 1230 successful continuous circulation drillpipe connections were performed during both drilling and tripping operations. Because of the increased ROP provided by continuous hole cleaning with the system, approximately five drilling days were saved per well, totaling to an approximate 85 drilling day reduction over the planned drilling campaign from 2015-2016, resulting in a significant cost savings to the operator and to obtain first production much sooner than anticipated.

Continuous circulation technology has proven to reduce overall nonproductive time (NPT) and total drilling days. During a long-term drilling campaign, additional improvements were recognized with superior prewell planning and front-end engineering design to minimize interference with rig operations and equipment and improve understanding and communication between the service company and operator. A newer generation, dual-activity rig helped prevent downtime by providing a platform for continuous repair and maintenance activities while drilling.
Implication of Structural Analysis in the Development and Management of a Maturing Field – The Akpo Case Study
Authors: Nosike Livinus , Uwerikowe Gabriel , Biu Victor , Adeyemi Adeoye , Usman Musa
Published: July 2019

Regional studies are known to show major compartmentalization in an oil field, while observations during development and production often highlight local structural connectivity issues that require fault characterization at field-scale to mitigate uncertainty in reserve or stakes. The Akpo field, located in the deep offshore Niger Delta, exemplifies a maturing field where these structural connectivity issues are dominant and play significant roles in field development. Structural discrepancies in the crest and flanks of the anticline result in varying water contacts and overpressure differences, affecting connected volumes and sweep efficiency.

Qualitative fault throw analysis, aided by 4-D monitoring results, show that same faults may be sealing and communicating at difference areas, across reservoir fairways in the deep offshore turbiditic channel complexes, delineated as architectural elements. Shale Gouge Ratio (SGR) helps in further constraining the sealing/leaking impact of fault gouge at a log-scale, such that adjacent well data can be used quantitatively to assess preferential flow paths across and within faults zones. This revealed an along-fault, up-fault and across-fault connectivity anisotropy.

This work addresses how the fault characterization was used to assess the following: Reservoir compartmentalization, leading to panel separated as fault blocks.Communication across fault, shown by throw map and SGR.The varying water contacts, which tend to result from upwelling of fluid within panel.Sweep across panels, from injectors to producers.The well in real-time operational situation, where well trajectory traverses a fault.

The study resulted in an improved infill well planning and placement, targeting unswept hydrocarbon, where well trajectories were determined by knowledge of fault compartmentalization, initial static connectivity shown by virgin pressures and present dynamic communication across injector-producer pairs. Post-mortem analysis of these infill wells was helpful in understanding the dynamic role of the crestal-collapse faults offsetting the reservoirs in the Akpo anticline, leading to optimization and increased productivity.
Well Control: Hard or Soft Shut-In, The Onshore Experience
Authors: Ogunyemi Ephraim O. , Oghenewoakpo Supreme
Published: July 2019

This paper investigates the effect of pressure surge referred to as "water hammer" on the formation as a result of shut - in procedure. Two methods are generally used to shut – in the well when kick is experienced: a soft shut – in or a hard shut – in. It is generally believed that when a well is hard shut – in, the additional surge pressure is capable of fracturing the formation creating a big issue in well pressure control. Hence, most operators advise against the use of this procedure. Drill sim 50 was used to simulate various kick sizes ranging from 2bbls to 20bbls and the resultant pressure surge due to water hammer was calculated and added. The result obtained indicated that soft shut – in procedure allows additional influx that increases the pressure on the formation while hard shut – in reduces the additional influx thereby reduces the possibility of formation breakdown. For all the kick sizes considered, the BHP for hard shut – in with additional pressure surge due to water hammer effect was not up to formation fracture pressure of the various depths considered.

The paper concludes that more time will be saved to prevent additional influx if hard shut – in procedure is adopted especially in an onshore location of Niger Delta on which the simulation studies was carried out.
Lessons Learnt During Hydraulic Workover for ESP Replacement
Authors: Othman Mohammed , Ojanomare Choja
Published: July 2019

The Well A14 was drilled in 2004 with dual completion and flowed for about 7 years. The well was shut-in due to high water cut and sand production. In December 2011, the well was re-completed single with 7’’ Cased Hole Gravel Pack and ESP + YTool. The well was later sidetracked and deviated to a tie-in point in order to encounter the target at optimal structural positions and provide additional drainage points on the target level to optimize hydrocarbon recovery from the field. The flowed for a period of 2 ½ years and stopped flowing as a result of electric fault on the ESP. Following this and the unfavorable price of crude oil at the time, there was need for an optimized means of intervention; several factors were considered and a HWO intervention using HWPU was selected. This paper addresses the contingent challenges faced and how these were overcome in the course of this 2nd W/O to recover the existing completion and run-in with a new design of ESP and accessories. During POOH the old completion after laying down the D-ESP packer on surface, the well kicked as a result of poor circulation during the killing operation. This resulted in a loss of control and fluid influx spilling to the environment. This challenge was addressed in compliance with the best standards. The W/O was resumed and the entire completion string and ESP assembly + Ytool retrieved. Subsequently during the final installation of the new ESP, the string parted at the threaded connection and the entire ESP completion assembly was lost in hole. This second incident was carefully reviewed by the team involved prior mobilization of fishing equipment and eventual recovery of the lost-in-hole in a single attempt. The entire completion containing the lost-in- hole, on about 2000m of 3 ½" Tubing completion was recovered; the new assemblies were prepared and RIH successfully. The well was eventually completed and currently flowing (≈2000bopd). The responsible team reviewed the incidents, identified lapses and proposed future procedures in order to forestall reoccurrence.
Impact of Well Production Tubing Diameter on Multiphase Flow Regime Profile in Oredo Fields, Niger Delta, Nigeria
Authors: Dala Joshua , Akanji Lateef T. , Olalekan Olafuyi , Bello Kelani , Jadhawar Prashant
Published: July 2019

The impact of production tubing diameter on multiphase flow regime profile is investigated. For a given isolated section of the production tubing in selected wells drilled and completed in Oredo fields, velocity profile and fluid flow characteristics at the production tubing centreline and along the pipe wall were evaluated. Complex flow behaviour is characterised by tubing diameter and asymptotic flow pattern at the tubing surface where no-slip boundary condition was imposed. Future inflow production performance relationship (IPR) and influence on vertical lift performance are determinable from the multiphase flow regime profiles. Furthermore, we investigate the impact of production tubing diameter on multiphase flow regime profile in Oredo oil field Nigeria. Mechanisms responsible for complex fluid flow behaviour and transition in different tubing configuration with implication on production optimisation and performance analysis are also included in the model design and analysis. From the results obtained in this study, it is evident that higher volume of oil is producible from bigger production tubing. However, implications on vertical lift performance and production optimisation require a more critical analyses.
RESEARCH IN THE RETIREMENT VILLAGE COMMUNITY – DOES THE RECRUITED SAMPLE REFLECT THE RESIDENT POPULATION?
Authors: Connolly Martin Joseph , Hikaka Joanna , Bloomfield Katherine , Broad Joanna , Wu Zhenqiang , Boyd Michal , Peri Kathy , Calvert Cheryl , Tatton Annie , Higgins Ann-Marie , Bramley Dale
Published: July 2019

Background

Retirement Villages (RVs) for older people represent a burgeoning industry. However, we know little about residents’ demographics and health/disability issues - information which could inform health planning, facilitate independence and reduce service demand. RVs are semi-closed communities: access for researchers is most conveniently gained via RV managers. We are studying RV residents in Auckland, New Zealand (NZ) to acquire demographic, health, disability and social data, with a randomized-controlled-trial of a multidisciplinary intervention aimed to reduce adverse outcomes. We here describe recruitment problems we encountered.

Methods

We planned to approach all RVs in Auckland/Waitemata Districts, with random sampling of residents in each village using unit/apartment lists as the sampling frame. Exclusions: Refusal of/inability to consent (complying with NZ legislation; ACER<65, or person clinicians felt lacked capacity). We planned access via RV managers and contact residents by ‘letter-drop’ then ‘door-knocks’. In ‘small’ RVs (n<60 units), we planned to contact all residents, with random selection in ‘larger’ RVs.

Results

We approached managers of 53 of the 65 RVs. 38 initially replied positively, of which 34 permitted us to recruit residents, 6 did not reply. Another 9 declined our first approach, of which eight were ‘small’, seven independently-owned. Some managers prohibited ‘letter-drops’ or ‘door-knocks’ at all or without prior residents’ meetings to assess acceptance of this methodology. Hence, we had to recruit volunteers (in 23 villages) via residents’ meetings, posters/newsletters and word-of-mouth. We recruited 578 residents from 33 villages (one village had no volunteers) (median age=82yrs; 420 female; 217 sampled, 361 volunteers).

Conclusions

Due to organizational/managers’ policy, and the fact that NZ legislation did not allow recruitment of residents without legal capacity to consent, our sample does not fully represent our RV population. Future RV research should consider alternative recruitment strategies e.g. random sampling from national census, electoral roll, or via residents’ organizations.
Hematological Reference Ranges for Apparently Healthy Blood Donors in Debre Markos, North West Ethiopia, 2016
Authors: Birhan Mekuriaw Mesfin , Tadele Tigist , Haile Diresbachew , Demeke Dessalegn , Getahun Biruk , Assefa Sefialem
Published: July 2019

Objective

The aim of this study was to determine hematological reference ranges for apparently healthy blood donors in Debre Markos, North West Ethiopia.

Result

A total of 250 adults with the median age of 20 (range 18 to 48) years were recruited. The mean ± standard deviation of hematological values were white blood cells (WBC) count 6.34±1.82×103/µl (males) and 6.96±1.89×103/µl (females); absolute neutrophil count 3.57±1.47×103/µl (male) and 3.99±1.38×103/µl (females); absolute lymphocyte count, 2.09±0.64×103/µl (males) and 2.27±0.68×103/µl (females); absolute mid-sized cell count 0.68±0.36× 103/µl (males) and 0.70±0.37×103/µl (females); red blood cell (RBC) count 5.13±0.49×106/µL (males) and 4.57±0.36×106/µL (females) platelets, 255.86±65.96 × 103/µl (male) and 280.67±65.71× 103/µl (female).
Effects of electroacupuncture therapy for depression: study protocol for a multi-centered, randomized controlled trial
Authors: Cai Wa , Ma Wen , Chen Ai-Wen , Shen Wei-Dong
Published: July 2019

Background

As a major public health problem, depression has a negative impact on individuals and society. The aim of this well-designed trial is to evaluate the efficacy and safety of electroacupuncture (EA) treatment for depression.

Methods/Design

A three-arm parallel, non-blinded, randomized controlled trial was performed in four hospitals (centers). 144 participants will be divided into three groups: electroacupuncture (EA) group, hand acupuncture (HA) group and western medicine group. Participants in EA group and HA group received 12 sessions of acupuncture treatment for 4 weeks. Participants allocated to western medicine group will only take 20mg fluoxetine orally per day for 4 weeks. The primary outcome is Hamilton Depression Scale (HAMD). Secondary outcomes are Self-Rating Depression Scale (SDS), Depression Scale of traditional Chinese medicine (Depression Scale of TCM), brain fMRI and blood biomarkers including neurotransmitters 5-HT, DA, NE, inflammatory cytokines IL-1β, TNF-α, IL-6 and neurotrophin BDNF. All the outcomes will be assessed at baseline, 4 weeks after EA treatment onset and 6-month follow-up.

Discussion

The results of this trial will verify the efficacy and safety of EA treatment for depressive patients and provide acupuncturists and clinicians with robust clinical evidence.
The social media intervention for lower back pain education study (SMILE): a protocol for a randomized trial to reduce occupational low back pain in nursing professionals
Authors: Kazemi Seyedeh Somayeh , Tavafian Sedigheh-Sadat , Montazeri Ali
Published: July 2019

Background Low back pain in nursing profession remains an important health issue. This study aims to assess whether a theory based interactive social media intervention could change job-related risk behaviors among nursing personnel. Methods This is a community-randomized controlled trial. Three settings of hospitals will randomly be assigned to the study arms: Intervention setting 1 receiving an in-person educational package; intervention setting 2 receiving the same material a web-based; and a control setting receiving nothing. The intervention would contain materials related to occupational risk behaviors and will try to promote the knowledge, attitude, skill, and self-efficacy of nurses on low back pain preventive behaviors. The primary outcome will be reduction in low back pain. The study also will assess whether the intervention could reduce pain-related disability and improve the quality of life. Discussion Occupational low back pain among nurses could adversely affect both patients and nurses’ health. This study is an attempt to see if social media could play a role to guide the development and implementation of future interventions.
HIV Pre-Exposure Prophylaxis (PrEP) Knowledge, Familiarity, and Attitudes among Healthcare Professional Students
Authors: Przybyla Sarahmona , Fillo Jennifer , Kamper-DeMarco Kimberly , Parks Kathleen , Bleasdale Jacob , Klasko-Foster Lynne , Morse Diane
Published: July 2019

Background

The federal government’s plan to End the HIV Epidemic by 2030 includes a primary goal to reduce new HIV infections by 90 percent. One key contributor to this plan is pre-exposure prophylaxis (PrEP), a medication taken by HIV-uninfected individuals to prevent infection. While knowledge and acceptance of PrEP among clinicians is growing, few studies have assessed knowledge and awareness among future healthcare professionals in academic training programs. Given the limited research on PrEP among healthcare professional students, a better understanding of knowledge and familiarity with PrEP prescription may inform the development of educational interventions targeting this population in an effort to increase implementation. The present study aimed to assess and compare healthcare trainees’ PrEP awareness, knowledge, and familiarity with prescription guidelines with a broad goal to better understand and prevent gaps in academic training regarding PrEP.

Methods

A cross-sectional web-based survey of medical, nurse practitioner, and pharmacy students enrolled at two universities was conducted between October 2017-January 2018. The study assessed participants’ awareness, knowledge, and familiarity with PrEP prescribing guidelines and willingness to prescribe PrEP and refer to another healthcare provider.

Results

The survey was completed by 744 participants (overall response rate = 36.2%). There were significant differences among student groups in all domains. Pharmacy students had the greatest PrEP knowledge, awareness, and familiarity with prescribing guidelines. However, medical students reported the greatest comfort with performing PrEP-related clinical activities and willingness to refer a candidate to another provider. Greater familiarity with PrEP prescription guidelines was associated with willingness to prescribe the medication.

Conclusions

Healthcare professional students’ responses enhance our understanding of the relevant experiences and perspectives of future healthcare providers that influence their knowledge towards the promotion of PrEP through prescription and referral intentions. The gaps in students’ knowledge offer opportunities for the development of educational strategies to support HIV prevention among future healthcare professionals.
Comparative genomics of swine pathogen Chlamydia suis with human- and mouse-adapted Chlamydia spp
Authors: Dimond Zoe E , Hefty P. Scott
Published: July 2019

Background

The phylum, Chlamydiae, contains a unique set of obligately intracellular bacteria with specific host ranges, despite high genomic relatedness between species. Chlamydia suis, a ubiquitous swine pathogen, has the potential for zoonotic transmission to humans and often encodes for resistance to the primary treatment antibiotic, tetracycline. Because of this emerging threat, and to gain a better understanding of the basic biology, comparative genomics for a tetracycline-resistant swine isolate (R19) with inter- and intra-species genomes was performed.

Results

A 1.094Mb genome was determined through de novo assembly of Illumina high throughput sequencing reads. Annotation and subsystem analyses were conducted using novel bioinformatic platform, PATRIC, revealing 986 putative genes (Chls_###) that are predominantly orthologs to other known Chlamydia genes. Subsequent comparative genomics using C. trachomatis and C. muridarum, human and mouse pathogens, respectively, revealed a high level of genomic synteny and overall sequence identity. Around 857 genes were found to be conserved between these three species while 92 unique C. suis components were annotated. Direct comparison of chlamydia-specific gene families; inclusion membrane proteins, polymorphic membrane proteins and the major outer membrane protein as well as the plasticity zone, demonstrates the high gene content identity with C. trachomatis and C. muridarum as well as highlights putative host-specificity factors.

Conclusions

This study constitutes the first genome-wide comparative analysis for C. suis, generating a fully annotated reference genome using NIAID bioinformatic tool, PATRIC. Overall, these analyses build upon previous C. suis analyses to compare the composition of key genetic components with two closely related Chlamydia species. These studies will enable focused efforts on factors that provide key species specificity and adaptation to cognate hosts that are attributed to chlamydial infections, including humans. Continued analysis of the C. suis genome will facilitate studies into the complexities of the chlamydial proteome and discovery of basic biology.
The effect of a web-push survey on physician survey response rates: a randomized experiment.
Authors: Delnevo Cristine D. , Singh Binu
Published: July 2019

Background: Achieving a high response rate for physicians has been challenging and with response rates declining in recent years, innovative methods are needed to increase rates. An emerging concept in survey methodology has been web-push survey delivery. In this delivery method, contact is made by mail to request a response by web. This study explored the feasibility of a web-push survey on a national sample of physicians.
Methods: 1000 physicians across six specialties were randomly assigned to a mail only or web-push survey delivery. Each mode consisted of four contacts including an initial mailing, reminder postcard, and two additional follow-ups. Response rates were calculated using AAPOR’s response rate 3 calculation. Data collection occurred between Febuary – April 2018 and analyzed March 2019.
Results: Overall reponse rates for the mail only vs. web-push survey delivery were comparable (51.2% vs. 52.8%). Higher response rates across all demographics were seen in the web-push delivery with the exception of pulmonary/critical care and physicians over the age of 65. The web-push survey yielded a greater response after the first mailing requiring fewer follow-up contacts resulting in a more cost-effective delivery.
Conclusions: A web-push mail survey is effective in achieveing a comparable response rate to traditional mail only delivery for physicians. The web-push survey was more efficient in terms of cost and in receiving responses in a more timely manner. Future research should explore the efficiency of a web-push survey delivery across various health care provider populations.
Towards Developing a Model for the Evaluation of Hospital Disaster Resilience: A Systematic Review
Authors: Ostadtaghizadeh Abbas , Aliabadi Saeed Fallah , Ardalan Ali , Fatemi Farin , Khazaei Bijan , Mirjalili Mohammad Reza
Published: July 2019

Background: Hospitals play a vital role in disaster stricken regions. The resilience of hospitals conducts related services without interruption and it can mitigate the risk of the injuries during and after disasters. The aim of this paper was to obtain the indicators required for the evaluation of hospital resilience.
Methods: This systematic review was conducted in 2018. Through this systematic review, the international electronic databases were investigated for the researches published in English. The exclusion and inclusion criteria were determined to extract the effective indicators resilience of the structural and non-structural parts in hospitals in order to develop a model to keep the system performance at an acceptable level.
Results: Out of 1794 researches that were published until September 2018, 89 articles and guidelines with full text were surveyed. 32 articles and guidelines were then selected and analyzed to collect the indicators related to hospital disaster resilience (HDR). Initially, the domains and the indicators were extracted from these selected researches.
Conclusion: As our suggested model, the indicators categorized into three domains including constructive, infrastructural and also administrative resilience. Also, 27 subdomains proposed that the indicators were designed to be the component for each of them. Since diverse indicators affect hospital resilience, therefore, other studies should be conducted to propose some models or tools to quantify the hospital resilience in different countries and scopes with an all hazard approach.
Key words: Disaster; Hospital; Resilience; Structural and non-structural systems; Indicators;
Board of Commissioners in Corporate Governance, Firm Performance, and Ownership Structure
Authors: Utama Cynthia A. , Utama Sidharta
Published: July 2019

The purpose of this study is to investigate: firstly, the two-way causality between firms performance and the size of BOC; secondly, the non-linear effect of board size on the firms’ performance; thirdly, the direct and moderating effects of the ownership structure on the influence of firm performance on board size. Using the ROA as a measure of firm performance, we find that there is a simultaneous relationship between firm performance and the size of BOC: the size of the board has an inverted U-shaped effect on firm performance while firms performance has a negative influence on board size. We find that the size of the board of commissioners increases firm performance up to a certain level, but a very large board reduces firm performance. We find marginal evidence that ownership structure has a moderating effect on the impact of firm performance on board size. We document that the negative effect of performance on board size dissipates as ownership right increases. The negative effect of performance on board size marginally strengthens. Thus, our study contributes to the literature by finding that the negative influence of firm performance and board primarily occurs on firms that are subject to high incentive expropriation by controlling shareholders.