bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Commercial Installation of MazeFlo™ Technology for Remedial Sand Control Application in Ubit Field
Authors: Okoroh K. , Hommema J. , Igwebike C. , Oguamanam U. 
Published: July 2013

Abstract
This paper describes the successful installation of the first commercial MazeFlo™ in a remedial sand control application and post job well performance. MazeFlo technology is an enhanced reliability sand screen with applications for remedial sand control and new completions. The reliability enhancement is achieved through a secondary sand screen in combination with a set of compartments to self-mitigate sand breakthrough from primary screen damage. The candidate well is located offshore West Africa with a high angle reservoir interval length of 1500 ft measured depth. It was originally completed with a 4-1/2" pre-perforated liner across the open hole interval without sand control and historically became a sand producer post initial completion. Though a high rate producer, the well was subsequently shut-in for sand production and a MazeFlo screen was installed to restore production.
This paper will share installation results and learnings from the rig-based intervention that was required to install the 2-3/8" MazeFlo screen inside the existing 4-1/2" pre-perforated liner. Handling and running of the MazeFlo screens was flawless due to front-end engineering, planning, and collaboration with key service providers. Post job well performance will also be discussed.
Design Of A Microreactor For Biodiesel Production From Algae
Authors: Ajilo V. I. , Falode O. A. 
Published: July 2013

Abstract
There is a growing interest in the production of biofuels mainly because of environmental protection and energy supply reasons. Currently, most research into efficient biofuel production is being carried out and predictions from small-scale production experiments bear out that using algae (microalgae, among other biofuels) to produce biodiesel may be the only viable method by which enough automotive fuel can be produced to replace current world conventional diesel usage. Also, studies show that some species of algae can produce up to 60% – 80% of their dry weight in the form of oil. Because the cells grow in aqueous suspension where they have more efficient access to water, CO2 and dissolved nutrients, microalgae are capable of producing large amounts of biomass and usable oil in either high rate algal ponds or photo-bioreactors. This oil can then be turned into biodiesel which could be sold for use in automobiles. Economic wise, regional production of microalgae and processing into biofuels will provide great benefits to rural communities. Hence, there is need for optimal, efficient and safe production of biodiesel from microalgae.
In this work, we propose a project for the design and construction of a biodiesel microreactor. It is drawn using the PDMS software. The design of the reactor requires the modelling of the complex series of reversible reactions which are known to take place; process characterization of the biodiesel production system by dividing it into unit processes; design of a process model; derivation of thermodynamic equations that govern the whole system; and algorithm using FORTRAN 95 to enhance the estimation and proper management of the productivity of any quantity (mass) of algal biomass to be converted to useful volume of biodiesel. Finally, a test of the use of this biodiesel in vehicles is presented.
Compilation of Instantaneous Source Functions for Varying Architecture of a Layered Reservoir with Mixed Boundaries, Horizontal and Vertical Well Completions; Part V: Letter ‘H’ Architecture
Authors: Adewole E. S. 
Published: July 2013

Abstract
If a reservoir is layered and the layering precipitates an architecture in the form of letter ‘H’, then modeling pressure distribution or understanding the character of the influencing external boundaries can be achieved through a study of instantaneous source functions for a horizontal and vertical wells completed in the layers of the reservoir. This is the main objective of this compilation. In this paper, both crossflow and no-crossflow layers are considered, and the external boundaries are varied as sealed and constant-pressured. Only the vertically top layer has a vertical well in all the models considered.
The study shows that a two-layered reservoir of latter ‘H’ architecture has no inverted form in terms of external boundary variation, no matter the axis of symmetry considered for inversion. The reservoir architecture presents one (1) mandatory infinite-acting boundary each at the bottom and at the top of the composite, vertically-stacked reservoir. There are a maximum of two (2) opposite external boundaries in each layer that may be considered sealed or subject to external fluid drive (constant-pressure). In all, sixteen (16) different external fluid and sealed boundary combinations are possible assuming crossflow interface. Fifteen (15) different combinations of edged fluid drive are also possible assuming crossflow interface. No bottom or top external fluid drive is possible for this architecture. For crossflow interface, only one (1) architecture may be subject to double edged external fluid drive in both layers, while six (6) architectures may have double edged external fluid drive possibility for no-crossflow interface reservoir architecture. Therefore, every well enjoys an infinite-acting source strength of the kind I(z), whether the interface is sealed or permits crossflow.
Analysis Of Wellbore Stability In Multilateral Well Design And Construction
Authors: Anyanwu Chimaroke , Dosunmu Adewale , Fekete Paul , Ekeinde Evelyn , Odagme Baridon 
Published: July 2013

Abstract
The number of multilateral wells drilled in the Niger Delta all geared towards increasing recovery as well as other field development objectives. However, a major challenge facing the successful drilling of these special trajectory wells is hole instability. The cost of instability according to some operators can be as high as $ 600MM per Year. Wellbore instability poses a unique threat in multilateral wells such that the tendency for collapse or fracture increases at the bore hole junctions. Casing deformation, difficulty in through-put of drilling tools and equipments, to mention but a few, are among the major problems associated with this instability.
This research revisits the issue of wellbore stability with emphasis on multilateral wells. A modified failure model is developed by including a stress concentration factor based on the junction configurations. The Mogi criterion was applied to account for intermediate stress and predict the minimum mud pressure below which shear failure will occur. A risk and uncertainty factor is attached to this model for sensitive model parameters including stress concentration factors, and lateral bore entry angle.
Results from two case studies presented in this work showed that collapse gradient prediction by Mogi based model were more reliable than those of Mohr based model. In case 1, a minimum mud weight of 0.52 psi/ft was predicted to be sufficient to maintain stability. A mud weight of 0.53 was used to drill the lateral section and hole pack offs were encountered at build angle of 30°. However, the Mogi prediction was 0.57 and sufficiently prevented hole collapse. In case 2, the Mogi predictions are all well above the actual mud weight used as against the underestimation with Mohr's.
An Improved Predictive Tool for Liquid Loading in a Gas Well
Authors: Fadairo Adesina , Femi-Oyewole Damilola , Falode Olugbenga 
Published: July 2013

Abstract
As the search for natural gas becomes increasingly high due to its high demand worldwide, the oil and gas industry is faced with the challenge of liquid loading in gas or condensate wells. It is imperative to properly design and predict the operational parameters necessary for handling flow assurance challenges due to simultaneous flow of gas with liquid. The model of Guo et al is the most recent systematic approach for predicting liquid loading in gas well. However, it did not account for the accumulation and kinetic terms in the momentum energy equation used to estimate bottom-hole pressure in a gas/oil/water/solid four phase flowing well. The two neglected terms in Guo et al formulation have significant effects on the gas well operational parameters such as the minimum gas flow rate for preventing liquid loading.
This paper presents an improved model that describes a systematic approach for estimating liquid loading in a gas well without neglecting any term in the fundamental momentum equation. The results obtained showed that at the early production time where initial transience at the onset of flow is experienced, the critical gas flow rate obtained from the new model is lower than that predicted from Guo et al model due to inclusion of accumulation term while at the later production time, the critical gas flow rate obtained becomes higher than that predicted from Guo et al model and increases as the transient period elapses. Results further show that at some point during production, the minimum energy required to lift liquids out of the wellbore is more than that required at the earlier stage of production. The new model is reasonable, reliable and better when compare with Turner et al and Guo et al models. It is useful for operators to refine their procedures and better manage the risk of liquid loading during natural gas production.
Enhancing Reservoir Surveillance and Management in Mature Depleted Reservoirs Using Reservoir Operating Envelopes: The Sofad Field Case-study
Authors: Sonde Adenike , Osho Rotimi , Ayeni Kayode 
Published: July 2013

Abstract
Operating envelopes are used in many industries, including the oil industry, to define appropriate operating boundaries and limits for production systems. In the oil industry, the boundaries generally include minimum and maximum operating rates, as well as minimum and maximum operating pressures and temperatures for the different components of the production system. Today, the use of operating envelopes has been extended to the subsurface (specifically hydrocarbon-bearing reservoirs) with the aim of identifying optimum limits for production rates and reservoir pressure depletion.
The Sofad field is one of the biggest and most structurally complex oil fields in the Western Niger Delta straddling land, swamp and shallow offshore. The high offtake rates from the reservoirs, coupled with the high fault density, have inhibited the response of the otherwise active aquifer especially in the key producing reservoirs. As a result, the key reservoirs have suffered severe pressure depletion over the years.
Analyses of the historical production/pressure trends of these reservoirs clearly indicate that the reservoir pressures are generally sensitive to the rates of production from the reservoirs. Thus, it became essential to evaluate the maximum production rates for these reservoirs in order to manage the reservoir pressure depletion and consequently maximise oil recovery (pending the execution of the water injection project for pressure maintenance).
This paper presents how the operating envelopes for the reservoirs were designed. It also showcases how the operating envelopes are being used in ensuring the maintenance of reservoir pressures, which has led to an improvement in the recovery from these reservoirs over the last 3 years (2010 – 2012).
Application of Injection Fall-Off for Reservoir Characterisation and Production Optimisation: Cases from a Deepwater Field
Authors: Ojeke Akpoebi N. , Lawal Kazeem A. , Ibianga Deri 
Published: July 2013

Abstract
In producing assets, the drive to reduce production deferments is increasing the interests in injection fall-off (IFO), as against pressure build-up, tests for reservoir characterisation. The IFO, which entails the measurement and analysis of pressure transients due to the shut-in of an injector after a period of continuous injection, provides estimates of important subsurface parameters such as static pressure, transmissibility and, where applicable, induced-fracture characteristics. This paper documents the application of IFO in selected cases from an oil-producing deepwater field.
The pressure fall-off curves obtained for two water injectors in the subject deepwater field are analysed. Particular attention is paid to the analysis of the fall-off curves and the identification of the various flow regimes. The estimation of key subsurface parameters such as skin factor, transmissibility, and boundary characteristics is detailed.
To reduce interpretation uncertainties, an integrated application of geoscience data has been employed to constrain the possible range of IFO interpretations. In addition, the IFO results have been used to rationalise the declining injectivity indices observed in the subject injectors, while providing clues for these observations at the pore scale. In essence, this work reechoes the credentials of IFO, as a credible and cheaper alternative to pressure build-up tests, for the characterisation of subsurface systems.
Integrated Production System Modeling (IPSM) as an Opportunity Realization and Optimization Tool for Improved Asset Management
Authors: Eli Awan , Aboaja Ugochukwu , Ajayi Ayo 
Published: July 2013

Abstract
This paper presents the Mede & Mafe field Integrated Production System Modeling (IPSM) strategy, synopsis of work done and benefits derived from the model. The IPSM provided a simple fit-for-purpose tool for understanding, diagnosing and tracking the fields’ performance as well as optimizing well production and facility throughput.
The main areas which the IPSM was used are:
Opportunity identification and validation Optimization and Prediction of field performance.
The IPSM enabled the integration of flow assurance with subsurface deliverability using well and reservoir operating conditions as boundary conditions & separators static pressures as topside constraints. The IPSM modeling strategy was aligned to meet the requirements of Well and Reservoir Management (WRM) minimum standard.
Opportunity realization and optimization from the existing wells were achieved after calibrating the model to match actual field performance within ±5% error margin. Additionally, the opportunities generated from the Integrated Drainage Point Reviews (IDPR) were ranked and validated with the IPSM model to quantify Short Term Oil Gains (STOG) within calculated well and reservoir operating envelopes.
The model is also used as a standard tool for quarterly Production System Optimization meeting with continual update made to enhance well and reservoir management of these fields.
The IPSM has been used in four PSO reviews with seven (7) bean-up opportunities identified/validated delivering oil gain of 1500bopd. An opportunity to improve flow assurance and de-bottleneck the Mafe bulklines with a potential to deliver 1700bopd was also identified.
Seismically Driven Reservoir Characterization
Authors: Fehintola Tope , Umeh Emeka , Obieke Chris 
Published: July 2013

Abstract
Integration of well and seismic data is a key component of optimal reservoir characterization for field development. In a green, partially appraised ultra deepwater field with few wells, the proper use of well data as calibration points for the seismic data becomes more important. The workflow can be complicated in instances of multi loop reservoirs with differing AVA signatures. An alternative to existing workflows is required for such reservoirs.
The current integrated workflow involves carrying out seismic inversion for reservoir properties; this is typically done for each reservoir model because of rock property differences between reservoirs. Reservoir properties are estimated from inverted PImpedance and S-Impedance through the use of rock property models. The rock models describe how the reservoir PImpedance and S-Impedance changes with variations in a particular reservoir property, such as net:gross or porosity.
With reservoirs of differing Amplitude Variation with Angle (AVA) signatures, different rock models must be applied to the inverted P and S-Impedance to generate varying versions of the same reservoir property, e.g. the rock model of an acoustically hard low porosity sand will vary from an acoustically soft high porosity sand. The varying version of the reservoir property will then be applied to different portions of the reservoir model.
While seismic inversion gives a non-unique solution, the integration of well data allows for derivation of a technically best fit solution, as well as an estimate of the associated uncertainty. The resulting inversion aids in the building of a reservoir model that honours geophysical, petrophysical and geologic data. This paper will present how the integration of well and seismic data was used to optimally characterize an offshore green field development and create a fit-for-purpose reservoir model.
A Holistic Approach to Defining Well Operating Envelopes
Authors: Hamzat Kassim , Adenike Sonde , Olukayode Ayeni , Juliet Njoku , Ayotunde Ajayi , Adebisi Akande 
Published: July 2013

Abstract
Well performance management is a critical aspect of production system optimisation in an oil and gas field. Accurately defining the well operating envelope will not only ensure asset integrity, but will also ensure realistic production performance expectations (forecasts) from available well resource. This paper discusses an approach to defining well operating envelopes that incorporates the technical limits and constraints of the various components of the producing well (i.e. reservoirs, sand face completions, tubing erosion and surface production facility, etc.). The methodology employs a visualization tool to graphically represent the operating envelope for the wells based on these constraints.
This approach has been implemented in several fields and wells in Shell Nigeria with varying completion types and field-wide constraints. It has also been proven to be flexible enough to accommodate the possible variations between well types and field peculiarities. The case study of five fields in SPDC Swamp West Asset presented in this paper will demonstrate this flexibility. Some of the benefits realized include improved reservoir management and water cut control. Furthermore, the visualization tool has been used to carry out exception based well surveillance that has proven to improve our response time to well deviations for better deferment management.
Case Histories of Drilling Challenges and Prediction of Equivalent Static Density of HPHT Wells in Niger-Delta
Authors: Madu S. O. , Akinfolarin A. A. 
Published: July 2013

Abstract
Instability of drilling fluid density downhole in the high pressure, high temperature hole section of a HPHT well has been posing many drilling challenges like well control (kick/blowout) or high ECD that could lead to the fracturing of formation especially where the operational window between the pore pressure and fracture gradient is very narrow which is often the case for HPHT wells. Accurate prediction of dominant effect of temperature or pressure on the change in the equivalent static density of drilling mud prior to drilling is important to benchmark with the real time pressure measurement.
This study uses Kutasov empirical model and subsurface data to predict the behavior of equivalent static density (ESD) of the anticipated drilling fluid in Niger Delta.
Furthermore, the equivalent static density of drilling fluids of some HPHT wells are modeled to investigate some drilling issues that were experienced during the drilling of these wells. Finally some HPHT case histories and their specific drilling challenges are discussed as part of this study.
Modeling Gas Water Contact Effects in Pressure Transient Behavior using Analytical Aquifer modeling and Numerical Simulation
Authors: Kehinde Dare , Ikwan Ukauku , Oghene Nkonyeasua , Afolayan Olatunbosun , Awa Chukwunweike 
Published: July 2013

Abstract
Interpretation of reservoir boundary conditions and well drainage areas have been historically done conventionally; using analytical and numerical simulation approaches with constant pressure, no flow, leaky and conductive boundaries. This paper investigated the effect of Gas Water Contact (GWC) boundary on the pressure transient behavior.
The novel approach adopted involves building numerical simulation well test models that investigate the effect of using Carter Tracy analytical aquifer model to simulate the response at the aquifer interface of a gas reservoir using SAPHIRE software. Bourdarot1 and Kuchuk2 stated that the effect of an aquifer can be modeled with a constant pressure boundary model. This model assumes that the pressure at the boundary of the reservoir consistently remains at the initial reservoir pressure during the drawdown and build up phases of the well test. Hence, it suggests that the pressure support from gas cap is very strong due to expansion and that the multi phase flow effects can be neglected. These assumptions work well for gas cap depletion systems. However, in the case of a water drive system, they may be incorrect.
The result of this investigation indicates that pressure transient at Gas Water Contact boundary behaves like a constant pressure boundary for gas reservoir with small sized aquifer or a radial composite system for gas reservoir with large or infinite aquifer respectively. The former is due to the change in fluid diffusivity and very high mobility contrast. (Khμ)1→(Khμ)2 (with 2&gt;&gt;1) coupled with expansion of active gas cap while the later is due to mobility contrast coupled with expansion from the active water influx. The result of this investigation was compared with the conventional analytical method of using a constant pressure boundary assumption.
It is recommended to apply the results of this investigation in: (i) estimating the Gas Water Contact in a down-dip reservoir and therefore help in the quantification of reservoir volumes to support existing reliable technology for determining the Lowest Known Hydrocarbon (LKH) in a Gas Down To (GDT) scenario by applying shrinking box technique to a recognized onset of constant pressure or radial composite effect in a DST or multi rate test in a down dip gas well (ii) Analytical Aquifer boundary modeling in well test designs as it affects drainage area and volume.
Comparative Study Of Different Salts On Hydration Of Bentonite
Authors: Uti L. O , Joel O. F 
Published: July 2013

Abstract
The make up water is one of the main building blocks of the drilling mud. The pH, hardness, and salt content of the make up water determine the yield and performance of the bentonite clay. hydration and dispersion of dry clay are greatly affected if the makeup water contains salt or various metallic ions. Many drilling muds are prepared with seawater for economy and convenience. This research study therefore details a comparative study of different salts namely sodium chloride, potassium chloride and calcium chloride on the hydration of bentonite. The rheological values were determined using FANN viscometer with different concentrations of NaCl, KCl and CaCl2((0%,0.5%, 1.0%,1.5%,2.0%, 2.5%, 3.0%, 4.0%, 4.5% and 5.0%) respectively by weight of bentonite. Test results indicated that plastic viscosity for NaCl, KCl and CaCh ranged from 11 to 5 cP, 9 to 8 cP and 9 to 4 cP respectively. Also the yield point ranged from 13 to 2 lb/100ft2,17 to 8 lb/100ft2 and 17 to 1lb/100ft2 respectively. The fluid loss also ranged from 15 to 20ml/30mins for NaCl, 12 to 16ml/30mins for KCl and 18 to 30ml/30mins for CaCh respectively. Test results indicated that increase in the concentration of the salts resulted to decrease in rheological properties and increase in fluid loss respectively. The effect was more pronounced with CaCl2 than the other two salts. It is imperative to introduce fluid loss and viscosifying additives when using mix water with high salt concentrations.