bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method to Determine the Slip Factor of Centrifugal Pumps through Experiment
Authors: Zhang Yu-Liang , Zhu Zu-Chao , Dou Hua-Shu , Cui Bao-Ling , Li Yi , Xiao Jun-Jian 
Published: July 2014

AbstractIn this paper, a method to determine the slip factor of centrifugal impellers is proposed based on the experimental result of the external performance of centrifugal pumps. This proposed method is superior to the conventional experimental method, which needs not to measure the flow parameters at impeller outlet. The results show that the present method can be used to obtain the slip factor at offdesign condition in a wide range of flow rate besides at the design point.
Heat shock factor 2 is a stress‐responsive mediator of neuronal migration defects in models of fetal alcohol syndrome
Authors: El Fatimy Rachid , Miozzo Federico , Le Mouël Anne , Abane Ryma , Schwendimann Leslie , Sabéran‐Djoneidi Délara , de Thonel Aurélie , Massaoudi Illiasse , Paslaru Liliana , Hashimoto‐Torii Kazue , Christians Elisabeth , Rakic Pasko , Gressens Pierre , Mezger Valérie 
Published: July 2014

AbstractFetal alcohol spectrum disorder (FASD) is a frequent cause of mental retardation. However, the molecular mechanisms underlying brain development defects induced by maternal alcohol consumption during pregnancy are unclear. We used normal and Hsf2‐deficient mice and cell systems to uncover a pivotal role for heat shock factor 2 (HSF2) in radial neuronal migration defects in the cortex, a hallmark of fetal alcohol exposure. Upon fetal alcohol exposure, HSF2 is essential for the triggering of HSF1 activation, which is accompanied by distinctive post‐translational modifications, and HSF2 steers the formation of atypical alcohol‐specific HSF1–HSF2 heterocomplexes. This perturbs the in vivo binding of HSF2 to heat shock elements (HSEs) in genes that control neuronal migration in normal conditions, such as p35 or the MAPs (microtubule‐associated proteins, such as Dclk1 and Dcx), and alters their expression. In the absence of HSF2, migration defects as well as alterations in gene expression are reduced. Thus, HSF2, as a sensor for alcohol stress in the fetal brain, acts as a mediator of the neuronal migration defects associated with FASD.
A system‐level model for the microbial regulatory genome
Authors: Brooks Aaron N , Reiss David J , Allard Antoine , Wu Wei‐Ju , Salvanha Diego M , Plaisier Christopher L , Chandrasekaran Sriram , Pan Min , Kaur Amardeep , Baliga Nitin S 
Published: July 2014

AbstractMicrobes can tailor transcriptional responses to diverse environmental challenges despite having streamlined genomes and a limited number of regulators. Here, we present data‐driven models that capture the dynamic interplay of the environment and genome‐encoded regulatory programs of two types of prokaryotes: Escherichia coli (a bacterium) and Halobacterium salinarum (an archaeon). The models reveal how the genome‐wide distributions of cis‐acting gene regulatory elements and the conditional influences of transcription factors at each of those elements encode programs for eliciting a wide array of environment‐specific responses. We demonstrate how these programs partition transcriptional regulation of genes within regulons and operons to re‐organize gene–gene functional associations in each environment. The models capture fitness‐relevant co‐regulation by different transcriptional control mechanisms acting across the entire genome, to define a generalized, system‐level organizing principle for prokaryotic gene regulatory networks that goes well beyond existing paradigms of gene regulation. An online resource (http://egrin2.systemsbiology.net) has been developed to facilitate multiscale exploration of conditional gene regulation in the two prokaryotes.
Rheological Characterisation of Pseudo Oil Base Mud from Local Materials
Authors: Ekeinde Evelyn , Dosunmu Adewale , Anyanwu Chimaroke , Esop Banny Banny , Odagme Baridon 
Published: July 2014

Abstract
Management of chemical instability in troublesome shales has intensified the need for operators to formulate less reactive muds to safely drill to target depths. While Oil Based Muds (OBMs) mitigate chemically induced drilling problems, they pose constraining issues including disposal and government regulations. Synthetic based drilling fluids (SBF) are a relatively new class of drilling muds that are useful particularly for deepwater and deviated hole drilling. While maintaining chemical stability in drilling operations disposal and biodegradability problems are taken care of. Nevertheless, the base oil for formulating SOBMs is imported at high costs. This work proposes the approach of using local materials such as palm kernel oil, soya beans oil, groundnut oil and palm oil as a base fluid in formulating synthetic base mud. The rheological properties of the locally produced pseudo oil based mud systems were characterized and compared with imported POBM based on API specification. After running chemical analysis, testing the rheological properties and stability of the mud, the palm kernel oil, soya beans oil and ground oil showed comparative results. Developing a local SBM is in line with the local content drive of the federal government and will open new opportunities in the oil and gas industry in Nigeria. SOBMs are biodegradable and thus environmental concerns are ruled out. It will also help us earn foreign exchange for the country by exporting surplus in Gulf of Guinea region. Product substitution from local materials will reduce foreign exchange expenditure and job exportation.
Hydrochloric Acid Applications to Improve Particle Gel Conformance Control Treatment
Authors: Imqam Abdulmohsin , Elue Hilary , Muhammed Farag A. , Bai Baojun 
Published: July 2014

Abstract
Millimeter-sized (10 μm~mm) particle gels have been used widely to control water flow through super-high-permeability zones and fracture zones in mature oil fields. During particle gel extrusion into target zones, the gel can form a cake on the surface of low-permeability, unswept formations. This cake reduces the effectiveness of conformance control as well as the amount of oil that can be recovered from unswept oil formations. Thus, we evaluated the effectiveness of using hydrochloric acid (HCL) to remove gel cakes induced during conformance-control treatments.
The interactions between HCL and particle gels were evaluated to understand the swelling, deswelling, and the gel strength after adding acid. A Hassler core holder was then used to determine the core permeability after gel and acid treatments. Gels swollen in brine concentrations of 0.05%, 1%, and 10% were injected into a sandstone core having a variety of permeabilities. Brine was then injected in cycles through the gel into the core. The core permeability was measured after gel particle injection and after the core surface with the gel cake was soaked in the acid solution for 12 hr. The results indicate that particles swollen in brine concentrations of 0.05% caused more damage than those swollen in higher concentrations of brine. The damage increased as the core permeability increased for all the swollen gels. The results also show that HCL removed the gel cake effectively, and varying HCL concentrations did not exhibit a significant difference in the gel cake-removal efficiency. The gel was found to swell much less in HCL solutions than in brine. After it was deswollen in acid, the gel strengths were measured and found to be higher than those swollen in brine. This work concludes that HCL can be used effectively to mitigate the damage induced by particle gels.
Combination of CJ-DSWP and HWU for Accomplishing Efficient Well Abandonment in Nigeria
Authors: Okwu Alaekwe Ewelike , Ikuenobe John 
Published: July 2014

Abstract
A major global oil and gas producer1 has recently embarked on decommissioning of temporarily abandoned wells onshore, Nigeria. This was largely informed by a drive to ensure commitment to safeguarding of people and the environment and to ensure industry regulatory compliance/best practice. In addition in some cases human habitation has since encroached around these wells; most of which were drilled over 30years ago and have since outlived their useful life. 1
The decommissioning entailed total removal of both surface and sub-surface well equipment, installing permanent barriers to effectively isolate fresh water reservoirs from hydrocarbon bearing reservoirs in an environmentally safe manner, and subsequently restore the surface location, as close as possible, to its original state. Therefore, traditionally a conventional work-over rig would have been required.
However, after an in-depth analysis –technical, economic and safety- the producer chose a combination of the Hydraulic Workover Unit (HWU) and the Casing Jack Dual Stage Work Platform (CJ-DSWP) over the conventional workover rig. The HWU3 and CJ-DSWP4 was provided by Tecon Oil Services, an indigenous services company. The HWU and CJ-DSWP are compact hydraulic units with very small foot print; HWU rigged up directly on the wellhead2, is used to POOH (pull out of hole) the tubing strings and to secure/plug the well, CJ-DSWP deploys internal pressure pipe cutter to cut the casing, safely pull the casing to surface and cut them to shorter lengths for easy handling.
The combination of the HWU and CJ-DSWP has safely decommissioned over 4wells as at December 2013 and also brings a huge cost saving compared to conventional workover rig. This paper is a review of how the HWU and CJ-DSWP duo have been able to accomplish this. It highlights the advantages HWU-CJDSWP offered and as well as the challenges that were encountered.
Limiting Water Production Using Linear Darcy's Flow Concept in an Open Hole Gravel Pack Completion in Deepwater West Africa
Authors: Martin F. , Atebe J. , Tueje M. 
Published: July 2014

Abstract
Well A from a deepwater development project in West Africa was designed to produce oil from a sandstone reservoir buried approximately 2200m below seabed. To maximize reservoir exposure, the trajectory was designed to have a sub horizontal drain (70°) over a 430m long open hole. Sand control was also required so that sand free production will be ensured. The Open hole gravel pack technique was selected to achieve these objectives.
While drilling the reservoir section, a 43m long unexpected water bearing layer was found below the production casing shoe, 100m away from the main oil reservoir objective. With no specific equipment available to provide a perfect isolation of the unexpected water bearing sands encountered, alternative plans had to be considered for completion of the well on a short timeframe. Being an open hole completion, it was considered too risky to suspend the well in order to procure specialized equipment for water shut-off. The Drilling and Completion team made the decision to apply the physics of linear Darcy's flow to mitigate the potential water production.
This paper aims at describing how the challenges brought by this water zone were successfully overcome leading to the delivery of a $90M well showing positive initial results i.e. good PI, good skin, no sand production and no noticeable water production.
Influence of Aquifer Support on Gas Condensate Reservoir Performance
Authors: Izuwa Nkemakolam Chinedu , Nwosu Chimezie Nnanedum 
Published: July 2014

ABSTRACT
Reservoir gas can condense to liquid when reservoir pressure declines below dew point pressure. This liquid will remain in the formation and then reduce productivity and deliverability of wells due to blockage problem. A method of improving the recovery is allowing for aquifer water influx/water injection and gas injection to maintain reservoir pressure and prevent it from falling rapidly.
This paper investigates the influence of aquifer support on gas-condensate reservoir. A zero-dimensional (material balance) approach was used for the reservoir model and prediction. Optimal hydrocarbon production and effect of aquifer influx were studied using different aquifer sizes. Results of gas volumes, condensate and total fluid recovery in percentage were analyzed for the case study reservoir without aquifer influx as the first scenario and with aquifer influx as the second scenario. The results show that aquifer influx reduces condensate accumulation in the reservoir by driving them to the surface.
Modeling Crude Oil Production Outlook: A Case Study of the Oil and Gas Industry in Nigeria
Authors: Kingsley-Akpara Chiamaka , Iledare Omowunmi O. 
Published: July 2014

Abstract
In the past four decades, Nigeria has made impact on the global oil and gas exploration and production industry. As one of the lead exporters of crude oil and natural gas in Africa, an oil production model which tracks oil exploitation process is imperative to facilitate good national economic planning and industry strategy. The impact of technological advancement, policy incentives and economics can be estimated from such petroleum production model.
This paper reviews historical crude oil production in Nigeria; develops an empirical model to describe and explain the competing factors underlying its production patterns. The production model equations are formulated; with a non-linear curve fitting method to estimate the Hubbert's model parameters for Nigeria. The model is used to forecast future production outlook for Nigeria.
At the currently estimated reserves of 37.2 billion barrels, the model results suggest that production rate should have peaked at 2.70 MMSTB/D in year 2010, and forecasted that the estimated ultimate recovery, at year end 2050, will be 65 billion barrels (~ cumulative production of 31.25 billion barrels up till 2012 plus current proven reserves of 37.2 billion barrels). It suggests that the nation had just produced 50% of its currently estimated proved reserves. The Hubbert model was accurate for forecasting US crude oil production, but its strict symmetry has received criticism from experts (Lynch, 2002) (Cavallow, 2004) (Iledare, 2000) who believe that the model underestimates future production which our experiences also confirm. We specified the nature of the errors which resulted in considerable deviations of production trends from the Hubbert model.
We suggest however, alternative model for analysing the exploitation process in Nigeria in the form of successive curve re-fitting of Hubbert model to new production data from time to time to check the effect of new technology, economics or policy implementation on Nigeria's crude oil production.
Maximizing Recovery in a Lobate Mature Water-flooded Reservoir
Authors: Jeboda Olatunji , Ambastha Anil , Eme Vincent , Ogugua Emeka 
Published: July 2014

Abstract
Reservoir E is an offshore saturated black-oil reservoir with three lobes, initially thought of as independent reservoirs, but later seen as lobes of same reservoir with acquisition of more pressure data. It started production in 1968, but was shut-in in 1985 due to declining pressure. After the onset of waterflood in 1992, pressure data showed the reservoir behaving like two pressure tanks aerially (Main and Horn Area).
The main area showed good pressure response from water-flooding but limited response was observed in the horn area. The challenge has been how to improve the current reservoir performance given the availability of reserves especially in the horn area which is pressure challenged.
This paper describes a three-dimensional, three-phase, black-oil simulation of Reservoir E. The purpose of this study was to investigate and identify the optimal operating scheme for maximizing recovery in this reservoir.
Improving the Accuracy of Gas Measurements/ Gas Accounting in the Oil and Gas Industry – Pitfalls and Remedies A Case Study of an Onshore Field in Nigeria
Authors: Ibeh Stanley , Obah Boniface , Nnakaihe Stephen , Umeh Valentine E. 
Published: July 2014

Abstract
Determining the accurate amount of natural gas produced, consumed and distributed poses a significant challenge in the oil and gas industry. Thus, arise the need for proper confirmatory analysis of the produced gas volumes against the utilized volumes.
Operating companies often desire that the amount of gas produced (measured and recorded) to be properly utilized for accountability and economic reasons. The primary essence of accurate gas measurements is to ensure that accurate gas production reports are submitted to the government and to confirm that accurate gas volumes are handled by the production facilities. However, in some cases, optimum accuracy is never attained thereby generating erroneous gas measurements and also hampering right economic decisions.
This paper tends to address some of the impediments to accurate gas measurements and possible solutions of these problems. It also elaborates on the effects of various flow meters (i.e. orifice meters, ultrasonic meters) on the gas measurement readings and provides the frequency for proving and calibration of meter types and its corresponding effects on gas measurements. An onshore field (F3Y-field) was used as case study and was instrumental to providing a new procedure for computing the reported flare volume with greater accuracy with the help of gas balance equations.
Effect of Viscosity of Heavy Oil Class-A on Oil Recovery in SP Flooding Using Lauryl Sulphate and Gum Arabic
Authors: Atsenuwa Julie , Taiwo Oluwaseun , Dala Joshua , Mohammed Ismail , Olafuyi Olalekan 
Published: July 2014

Abstract
Chemical flooding methods are used to recover residual oil left after water flooding. Several chemical flooding processes have been used to improve recovery. Alkaline-free surfactant polymer combination flooding (SP flooding) can avoid side-effects encountered in alkali-surfactant-polymer (ASP flooding) combination flooding. As part of the ongoing research on the use of Gum Arabic as a polymer in chemical flooding in Nigeria, this paper investigates the effect of heavy oil viscosity on oil recovery during SP flooding.
Improved oil recovery through SP flooding was studied by conducting linear displacement experiments using engineering grade class IV glass beads. The glass beads were treated to be strongly water wet. The viscosity of oil samples used for the different experiments ranged from 3 to 140 cp. Lauryl Sulphate and Gum Arabic were used as the surfactant and polymer respectively.
Result shows that oil recovery by water flooding ranges from 15% – 25% and for SP 15% – 35% keeping the polymer concentration constant. Thus, increasing oil recovery can be achieved as the viscosities of oil increases. The result from this study will help develop effective methods for implementing SP flooding using Gum Arabic that is vastly available in Nigeria in heavy oil fields. It will give the oil industry a new option for improving oil recovery from heavy oil reservoirs.
SP flooding will be handy to improve oil recoveries from many marginal oil fields in Nigeria or those that face shut-down due to uneconomic operating cost, but still contain significant amount of oil.
Application of Seismic Inversion in the Identification of Common Hydrocarbon Fluid Contacts between Reservoirs
Authors: Jegede Temitope , Engel Stephan , Austin Anaevune , Mbah Reggy 
Published: July 2014

Abstract
Field X is located around the south-western part of Port-Harcourt and was discovered in 1965, but came on-stream in 1974. Six wells have been drilled in the field with two existing strings. There are two wells closed in, two wells abandoned and two wells suspended. There were no well repair or completion activities done on the field. There is a 10Mbpd capacity flow-station with a 4" export tie-in into the bulk line system.
The field is a 4-way dip closure consisting of two culminations separated by a saddle. Both structures are highly faulted E-W elongate anticlines and are bounded to the north by a boundary fault and open to the South. Wells 1 & 2 has produced while wells 3 and 5 were abandoned and wells 4 and 6 were suspended. Hydrocarbons were discovered between 7300 and 10000 feet in the C, D and E sands. 17 reservoirs have been identified and oil production has occurred from D5.0W in wells-1 and 2, but there has been no production from the Eastern Block.
Advancement in Material Balance Analysis
Authors: Kanu Austin Ukwu , Obi Onyekonwu Mike 
Published: July 2014

Abstract
The foremost objective of producing reservoir material balance analysis is to determine STOIIP and aquifer properties which ensure that the aquifer influx into the reservoir reliably offsets production. But the different views canvassed on this analysis are hampered by the limitation that the material balance equation is an ill-posed pressure-implicit depletion function. So, this program has adopted a robust and self-adaptive nonlinear regression to advance material balance analysis. The program validated two examples and pointed out the shortcomings of the authors solutions.
Efficient Drilling Time Optimization With Differential Evolution
Authors: Awotunde Abeeb A. , Mutasiem Mohammed A. 
Published: July 2014

Abstract
The drilling of an oil well is a very expensive operation. Consequently, asset teams often seek to minimize drilling costs by optimizing the drilling process. The most important factor in cost consideration is the length of time during which a drilling rig is hired. The fact that the rigs are often hired on a day rate means that the longer the drilling time, the higher the drilling cost. Thus drillers often seek to minimize the total time required to drill a well in order to minimize the drilling cost. However, the drilling time is often made of many components, some controllable and others uncontrollable. While the most common factor drillers seek to minimize is the time spent on the actual mechanical drilling of the well, this is not necessarily the most time consuming part of the drilling operations. Minimizing the time spent on the actual drilling is done by seeking optimum parameters that increase the rate of penetration of the bit. Another factor that may help reduce the total rig time is reducing the frequency at which the bottomhole assembly (BHA) is pulled out of hole to change worn out bits. Thus, it is important to optimize the drilling process to yield the lowest overall drilling time.
In this study, we proposed an optimization scheme that optimizes drilling operations by maximizing the drilling rate (ROP) and the bit life. The scheme optimizes drilling operations by finding the optimum values of drilling parameters that reduce the overall drilling time of any particular section of the formation. The drilling parameters we considered are RPM, WOB and mud flow rate. We used differential evolution as an optimizer to obtain the optimum ROP and optimum bit life that yield the lowest drilling time. We set upper and lower bounds for each of the operational parameters and tested the method on different sections.
Two cases are considered. The first maximizes the drilling rate (ROP) while the second minimizes the total time (i.e. mechanical drilling time and trip time and bit change time at the surface). Findings show that optimizing the ROP yields the lowest time at shallow depths. However, at deeper depths, optimizing the total time yields better the lowest overall time.
Significantly, the approach helps to identify the optimal values of drilling parameters at different hole sections needed to achieve the lowest overall drilling time. Hence, the method can save money that would otherwise have been used to hire the drilling rig for an extended period of time.