bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Oil Gravity Drainage and Reinfiltration in Naturally Fractured Reservoirs
Authors: Udoh Francis D. , Igbafe Anselem I. , Okon Anietie N.
Published: August 2015

The prediction of production performance in naturally fractured reservoirs is dependent on reinfiltration and capillary continuity phenomena. In fractured reservoirs, reinfiltration and capillary continuity phenomena have been the major setback during gas-oil gravity drainage. The oil contained within the matrix of the gas invaded zone begins to drain down into the fracture system and into the lower matrix blocks, due to the force of gravity. Some of the oil that is drained out of the upper matrix blocks can reinfiltrate into the lower matrix blocks from the top or side surfaces and can flow down through the areas of contact between blocks. To evaluate the effect of reinfiltration in gravity drainage mechanism and fractured reservoir parameters: fracture width (bf) and storativity capacity (ω) on reinfiltration process, a fractured porous media was modeled with ECLIPSE-100 Simulator. The base-case simulation runs (SIM-1 and SIM-2) showed that 55.14% and 53.40% of the oil in-place in the modeled fractured porous media were recovered by gas-oil gravity drainage mechanism without reinfiltration and with reinfiltration, respectively. Furthermore, the sensitivity study of the aforementioned fractured reservoir properties on gas-oil gravity drainage and reinfiltration with simulation runs (SIM-3 through SIM-10) indicate that fracture porosity as well as storativity capacity influence the ultimate oil recovery in naturally fractured reservoirs. Additionally, the fracture width has no influence on gas-oil gravity drainage and reinfiltration in the modeled fractured reservoir. Therefore, gravity drainage recovery mechanism proliferation is affected by oil reinfiltration within the matrix blocks that resulted in 3.173% production reduction. Hence, fracture porosity and storativity capacity are considerable factors in reinfiltration mechanism in naturally fractured reservoirs.
Integrated Reservoir Modeling and Uncertainty Assessment of a Reservoir Complex in the Niger Delta
Authors: Anyanwu Chinedu , Afekhume Daniel , Onobrakpeya Collins , Sonde Adenike , Kakayor Omagbemi
Published: August 2015

Critical decision making with limited information and associated uncertainties is a challenge at every level of the hydrocarbon value chain. This is even more so at early stages of field development projects when geosciences and engineering data are sparse and the understanding of the geological complexities is still limited. Thus, the need for building multiple realizations of representative reservoir models that captures the full range of subsurface uncertainties is crucial to ensure a robust decision-making process.

From previous studies, the Reservoir Complex, X is highlighted as a stack of two gas-bearing reservoirs that merge to form a doublet as observed on seismic and share a common contact towards the flank of the structure. This interpretation informed the modelling of both reservoirs as a single mega unit. An Integrated Reservoir Modeling approach rather than a discipline-focused one was adopted to evaluate the range of uncertainties in the reservoirs. For this study, a multidisciplinary subsurface team built a scenario-based model and performed Sensitivity analysis to identify key uncertainties on input parameters that are most impactful on in-place volumes and recoverables.

This paper discusses techniques employed in building the static/dynamic models, generating estimates for the various uncertainties and how these were analyzed to identify the ‘heavy hitters’. Results from this study identified Structure, Net-to-Gross and Porosity as the top three uncertainties with most impact on static volumes while Structure, PVT and Aquifer size have most impact on recoveries.

Deterministic low, base and high case In-place volumes computed are 509, 627 and 769 BScf while recoveries were 182, 339 and 643BScf respectively. Probabilistically, the in-place volumes were 336, 480 and 634 Bscf while the recoverables were 205, 348 and 550 Bscf respectively.
Modeling Petrophysical Property Variations in Reservoir Sand Bodies Using Artificial Neural Network and Object Based Techniques
Authors: Osarogiagbon Augustine Uhunoma , Udeze Chima Cyril , Imorame Imonitie Jude
Published: August 2015

This study aims at reducing uncertainty in the prediction of petrophysical properties (porosity, water saturation and net to gross) of a field at locations that do not have well data by employing geostatistical simulations, artificial neural network and object facies modeling techniques in modeling the petrophysical property variations across a field. The project has an objective of establishing standard workflows that can be adopted in modeling petrophysical property variation in a field. Four classes of model were developed which are: the pure artificial neural network model, the pure variogram model, the collocated cokriging model and the bivariate cross plot model. The Gullfaks 3D seismic data, Checkshot data and Well log was used in implementing the project using the Petrel 2013 Software.

Stratigraphic modeling, seismic interpretation, Depth conversion and 3D Grid Construction were done to provide an appropriate 3D Grid Structure for Petrophysical modeling. Facies and Petrophysical properties were interpreted at well locations inorder to provide data for modeling facies and petrophysical properties in 3D. The Truncated Gaussian Simulation was used in modeling the Gross Depositional Environment in order to provide an appropriate framework for 3D Facies modeling using Object based techniques.

The Pure artificial neural network petrophysical models were generated using 3D Seismic data and petrophysical interpretations at well locations, the pure variogram models were developed using the Object facies model and petrophysical interpretations at well locations, the collocated cokriging models were generated by combining the variogram approach and the pure artificial neural network models using collocated cokriging and the bivariate cross plot models were generated by combining the variogram approach and the artificial neural network models using back propagation from their bivariate cross plot.

The pure artificial neural network models gave the best prediction for porosity, net to gross and water saturation closely followed by the bivariate crossplot model for porosity and net to gross, the collocated cokriging model came second for water saturation prediction accuracy however, the pure artificial neural network model lacked geological patterns of facies which should naturally be present for porosity and net to gross, The pure variogram and collocated cokriging showed the region of oil water seperation more clearly than the artificial neural network method. Appropriate combination of these methods is therefore required for optimal Petrophysical property modeling.
Fracture Optimization for Multi-stage Fractured Horizontal Well with Time & stress-sensitive Parameters
Authors: Dou Xiangji , Liao Xinwei , Hou Tengfei , Zhao Tianyi , Zhiming Chen , Ren Weiyan , Zhang Rui
Published: August 2015

It is widely acknowledged that the conductivity of fracture is influenced by both effective stress and producing time. As a result of dynamic conductivity, the permeability-dependent non-Darcy flow in fracture is also time&stress-sensitive. In this paper, the variations of conductivity and non-Darcy flow velocity coefficient on both time and stress are taken into account to contribute to hydraulic fracture optimization.

The relationship between core permeability and effective stress is first investigated with laboratory experiment, which is modified by taking overburden stress into consideration and conducting core aging treatment to eliminate interspaces. Then, both stress-sensitive and time-sensitive of fracture conductivity is discussed with relative experiments. A new production data analysis method is also proposed to assist in time&stress-sensitivity determination. Afterwards, numerical simulation method together with a simplified economic evaluation procedure is presented to evaluate the impact of unfixed fracture conductivity and non-Darcy flow on fracture optimization.

With laboratory experiment, we find that after taking overburden stress into consideration and conducting core aging treatment, the stress-sensitive of core permeability is weaker than traditional expected result. Besides, the fracture conductivity change exponentially with stress while logarithmically with producing time. However, the combine effect of stress and time should be determined with the modified production data analysis method. Based on numerical simulation and economic evaluation, we come to the conclusion that due to the unfixed fracture conductivity and non-Darcy flow, the fracture conductivity designed should be higher than the value obtained with conventional methods.

Technical contributions in this paper including (a) investigating relationships between stress and reservoir/fracture permeability with modified experiment procedures; (b) discussing the combine effect of stress and time on fracture conductivity; (c) unfolding the impact of time&stress-sensitive conductivity and non-Darcy flow on well performance and fracture parameters optimization.
Work Flow for Reservoir Study and Challenges
Authors: Sylvester Okotie , Buduka Stanley , Bibobra Ikporo
Published: August 2015

The management of oil and gas reservoirs is a dynamic process that require the cooperation of technical, operating, and management groups for the success of petroleum assets. It is a team that consists of robust seismic, geophysics, geology, petrophysical analysis, drilling, logging, geochemistry, reservoir engineering and reservoir management groups to mitigate the effects of uncertainties in reservoir characterization and flow processes via collection and analyses of key geologic, reservoir, and performance data through a logical application of multidisciplinary technologies. Thus, this paper presents a concise reservoir study workflow and challenges to assist new reservoir simulator users and a check for experts in this field with a detailed description of the activities involved in a complete reservoir simulation process from initialization, history matching to predictions. This was achieved by carefully considering the step by step process involved and the data required at each stage of the reservoir model building.
Decline Curve Analysis using Combined Linear and Nonlinear Regression
Authors: Ukwu Austin K. , Onyekonwu Mike O. , Ikiensikimama Sunday S.
Published: August 2015

The varieties of methods for predicting oil well performance are material balance analysis, decline curve analysis and numerical reservoir simulation. Among the techniques, the decline curves have been found quite simple and accurate to forecast oil well performance in the absence of known reservoir parameters. The basic concept of the Arps' hyperbolic decline curve analysis is nonlinear curve fitting. However, the difficulty of finding a proper nonlinear algorithm to tune the Arps' hyperbolic decline equation to match historical oil production has forced analysts to use the exponential and harmonic declines, which are adjudged the approximate limiting cases of the Arps' hyperbolic decline. So, this study advocates a shift in paradigm; that is the use of nonlinear regression algorithm to tune the Arps hyperbolic decline equation initialized from linear curve fitting. The hyperbolic equation was expressed as a linear relationship in terms of the first derivative of production rate with respect to time. The first derivative was obtained from natural spline interpolation which greatly improved the quality of the initialized decline parameters and the accuracy of the decline curve analysis.
Gas well Test Interpretation: Niger Delta Field Experience
Authors: Obeahon P. P. , Daodu O. , Sedgwick A.
Published: August 2015

This work details how production data, well test analysis and PVT data analysis can be used to evaluate the effects of near wellbore condensate accumulation on well productivity for a green field in the Niger Delta. The field, comprising shore-face deposits that were later cut by channels in a high-energy deltaic setting. Prior to this study, six wells had been drilled. Wells -1 and -2 had exploration and appraisal objectives while wells -3, -4, -5 and -6 had development objective. After drilling wells -3, -4, -5 and -6, MRT were conducted on these wells with the key objective of verifying analogue based well deliverability.

The following conclusions arise from the interpretation of the test data. Well-3 will deliver at a lower rate of 50MMscf/day as opposed to the pre-test estimate of 100MMscf/day. This is due to higher Darcy and non-Darcy coefficients. Furthermore, flowing bottom hole pressure recorded during testing and from the first four months of production indicates that the reservoir was been depleted below the dew-point pressure of 4724 psi by about 100 psi. These observations, in combination with declining productivity index and producing condensate-gas ratio suggest that condensate dropout is most likely responsible for the high skin, hence well-3 potential was revised from MRT interpreted estimate of 89MMscf/day to 50MMscf/day. This decrease in well potential from 100MMscf/day to 50MMscf/day decelerated gas recovery by about 3 years.

Well-4 data interpretation indicated low non-Darcy skin and Darcy coefficient. Single pressure build-up (PBU) interpretation indicated pressure leaks into the casing-tubing annulus, an inference substantiated by the observation of consistent high casing-head pressure in the well. Possible causes of high casing-head pressure were investigated and attributed to poor tubing connection.

Both wells 5 and -6 penetrate the same sand. A four-point test was performed on Well-6 while performing PBU on Well-5 hence no pressure stabilization on these well due to Interference effect. Interpreted results indicates that Well-5 has a higher Darcy skin and lower non-Darcy coefficient compared to Well-6, with both wells expected to deliver the planned offtake rates of 100MMscf/day within acceptable drawdown limits.

This work identifies dew point pressure as an extremely important factor to consider when designing gas well test, generating deliverability envelopes and optimizing condensate recovery as productivities can be reduced by 50% when condensate banking begins.
Formulation of Local Alkaline- Surfactant-Polymer (Asp) For Enhanced Oil Recovery in Niger Delta: A Review
Authors: Uzoho C. U. , Onyekonwu M. , adnAkaranta O.
Published: August 2015

The Niger Delta basin has being producingfor over 50years using primary recovery method. It is gradually advancing into secondary oil recovery stage after which the tertiary oil recovery techniques will be exploited. The primary and secondary recovery methods are only able to recover about 30–35% of oil from the reservoir leaving the 65–70% trapped. As the demand for energy and the cost of drilling increases globally, there arises the need to squeeze the bottom of the barrel. Chemical processes is one of the tertiary recovery techniques which involves the use of chemicals (Alkaline, Surfactant, and Polymer) for enhance oil recovery but these synthesized chemicals are imported and expensive. Several researchers have shown that Alkaline-Surfactant-Polymer (ASP) blends have high potentials to enhance oil recovery through a combination of the positive effects of these three types of Enhanced Oil Recovery (EOR) agents. Research had also shown that local materials in our environment can enhance oil recovery. This review paper outlines local materials that have being in use in the formulation of ASP for EOR. Challenges involved in using these local materials are also outlined. One of such challenges is that most of thesematerials are also used as food. The use of agro-wastesfrom plants that have similar characteristics as the consumable local materials for the formulation of local ASP is proposed. These agro-wastes provide salinity tolerance and are stable at high temperature when compared with synthesized chemicals. Their utilization will minimize production cost as their cost will be theoretically independent of oil price, maximize profit, convert waste to wealth and create job opportunities for Nigerians.
Gas Flaring: Proposed Hydrate Solution as a Feasible Option for the Niger Delta
Authors: Ogolo Naomi A. , Onyekonwu Mike O.
Published: August 2015

Gas flaring in the Niger Delta region of Nigeria is a critical issue and several futile attempts over the years to phase out the ugly practice propagates no imminent solution to the problem. Owing to this fact, there is a need to sort an alternative measure in the interim to halt the practice pending when the issue will be properly addressed and considering the challenges that hinder gas flare abatement using current available methods in the region. The proposed solution in this work entails converting flared gas to solid natural gas hydrate (NGH) at flare sites, store and transport the solid mass to its final destination where re-gasification will take place by heating to recover the trapped gas. The water produced during re-gasification from the solid mass will be sent back to the hydrate plant for re-use. Three benefits of this proposal include saving the environment from pollution, monetizing flared gas and job creation for the masses. However, the major challenges that will face the proposal are easy access routes to flare sites, insecurity at flare stations as sites for gas hydrate plants due to their remoteness and the need for further research to enhance and tailor the available NGH technology to suit the flared gas composition of the Niger Delta.

The process involved in making NGH mainly requires natural gas, water, low temperature (2 to 10°C), high pressure (50 to 120bars) and catalysts (such as Sodium dodecyle sulphate) for increase in rate of formation and stability. The formed hydrates can be preserved at atmospheric pressure under a temperature range of −10°C to −40°C for about two weeks or more. Reported economic analysis shows that transporting natural gas in form of hydrate especially when the volume of gas involved is relatively small from many scattered locations separated by long distances like in the Niger delta case is cheaper than transporting the same volume of gas as LNG. Several challenges that have hindered gas flaring abatement in the Niger Delta will be resolved by this proposed solution.
The Effect of Reservoir Pressure Drawdown on Well Completion/Performance Efficiency
Authors: Joseph A. , Ajienka J. A. , Onyeizugbe S. O.
Published: August 2015

Using a database from Niger Delta, this study developed correlation of well completion/production efficiency as functions of pressure drawdown and sand control type to quantitatively evaluate the effect of pressure drawdown on well performance.

Generally, Completion/performance efficiency declines exponentially with reservoir pressure drawdown. Critical pressure drawdown for various sand control types beyond which significant formation damage will occur are recommended. Apart from external gravel-pack (EGP) and milled casing under-reamed gravel-pack (MCUGP) wells which can tolerate drawdown of ±400 psi, the critical drawdown for other sand control types is ±250psi. With these correlations, drawdown for tubing conveyed perforation can be carefully designed and well completions evaluated. More so, real time prediction of production performance efficiency can be evaluated given the pressure drawdown.
Downhole Electrical Heating techniques in the Orinoco Oil Belt, are they always reliable? Appraisal analysis to Petrocedeño's Pilot Project
Authors: Randy Alvarez
Published: August 2015

This paper gives a brief description about the appraisal analysis conducted for the Down Hole Electrical Heating Petrocedeño's Pilot Project, which has revealed several issues of concern during the evaluation of the oil recovery techniques, focused in the Orinoco Oil Belt (OOB) Field features and the need to have optimized production.

OOB is one of the most prospective assets of Venezuela natural resources. Since its discovery, it has shown a very concerning mobility challenge, which once was considered too high to be produced commercially, also it drove to catalog that oil as tar and sell it as coal. With the development of several technologies and techniques, and the increment of the oil price through the time, the exploitation of the Orinoco Oil Belt Fields has become feasible.

Despite the experience gathered in analog reservoirs in Canada and United States, thermal applications of EOR and IOR, such as SAGD, HASD, CSS, VAPEX, Etc., cannot be implemented in most of the mature fields in the OOB, because their development plans just considered primary recovery, plus thermal materials were not used in producer well completions. Then, it was necessary to choose a technique with low thermal impact to the completion configuration, in order to increase oil production in those developed fields, helping to reach the final recovery factor estimated to primary production.

Since Petrocedeño Field is one example of that scenario and as other fields in the OOB, Downhole Electrical Heating was seen as a possible solution to accomplish with the production requirements. Considering that Petrocedeño has experience with non-thermal techniques aimed to increase oil rate, it was possible to compare and to identify several features that helps to decide which case is best suited to use rather DHEH or the others techniques according to each wells characteristics.

Finally a comparison will be provided and the key issues that helps to decide which scenario is better to use the Downhole Electrical Heating Technique. As a general conclusion, it was pointed that, since the reservoirs are not homogeneous, hence the fields can have more than two reservoirs contained in the same area and may be in the same structure, plus each well has its own challenges according its dimensions, there is not a single solution to have an improvement in the production, and the increment of recovery factor, which has to be finally defined to each well individually.
Developing a Framework for Maximizing Marginal Oil and Gas Field Economics
Authors: Adeogun Oyebimpe
Published: August 2015

The notion to develop marginal oilfields as a means of increasing oil and perhaps marginal natural gas reserves in Nigeria has not been well defined since inception. Many have argued that oilfields regarded as marginal have often times been allocated discretionally because the Federal Government of Nigeria has the sole prerogative to classify fields as marginal. In Egypt for instance, fields with recoverable reserves of less than five million barrels of oil are regarded as marginal. To this end, this paper seeks to redefine the concept of marginal oilfields in terms of concrete and measurable terms, keeping in perspective the recoverable reserves, prevailing fiscal terms and available technology and economic conditions.

Considering the nature of marginal oilfields, a review of the contractual agreement for operators was examined with new fiscal terms recommended. This was necessitated to determine at what point these fields become unattractive to investors with existing technology. A comprehensive economic analysis was carried out showing that these fields are actually a worthwhile investment if adequate incentives are granted by the government. A downward review of signature bonus by 50% had little or no impact on rate on return of investment. A reduction in royalties and petroleum taxes as proposed in the yet to be approved Petroleum Industry Bill 2012, will make the investment in marginal field more rewarding for investors than ly established fiscal terms. Further reduction of oil price below the proposed benchmark of $50 in this work also has adverse effect on the development of marginal oil fields. Financing projects of a high degree of uncertainty poses a challenge to the development of marginal oilfields and various options were suggested including equity financing, technical partnerships, sourcing of loans from local and foreign banks.
Substantiation of Reservoir Lateral Hydraulic Connectivity Based on Integrated subsurface and Production test result - Niger Delta Field Experience
Authors: Adepoju Yaqub , Anyaehie James , Ogbuli Andrew , Balogun Olalekan , Awa Chukwunweike , Mora-Glukstad Miguel , Kakayor Omagbemi
Published: August 2015

Field X is one of SPDC's major gas fields located onshore of Nigeria with six well penetrations and two key reservoirs, A1000X and B4000X,. The field is covered by a 1992 3D seismic reprocessed PSDM with relatively poor imaging quality. This caused uncertainties with respect to the interpretation of possible intra-reservoir fault compartmentilization. These intra-reservoir faults are on the footwall of two major southern and eastern boundary faults. To optimally develop these reservoirs, it was proposed to drill an appraisal well in the eastern fault block, modelled as a reservoir compartment, and subsequently carry out an interference test to establish the lateral hydraulic connectivity of the reservoirs.

A new seismic data was acquired and processed to resolve the uncertainties associated with the poor imaging quality of the 1992 seismic. The interpretation of the new seismic showed similar structural trend, albeit with better clarity of the subsurface images in the fault shadow zones.  It also showed continuous seismic reflection loops suggesting a more better lateral reservoir connectivity To better understand the reservoir lateral hydraulic continuity, a multidisciplinary integrated study was conducted using all available data (production tests, Seismic and Petrophysical data).

This paper covers the multi- disciplinary work carried out to establish the lateral connectivity of the reservoirs and its significant cost reduction to the total project cost.
Detection of Water Encroachment into a Marginal Field Oil Reservoir for Ultimate Recovery
Authors: Bisong Anthony Oso
Published: August 2015

One key element of effective well and reservoir management is the application of numerical simulators to solving complex and challenging reservoir issues like aquifer water encroachment into an oil reservoir. Hydrocarbon reservoirs are often in contact with an aquifer that provides pressure support through water encroachment. It is common to speak of edge-water and bottom-water while discussing water encroachment into a reservoir. Bottom-water occurs directly beneath the oil zone while edge-water occurs off the flanks of the structure at the edge of the oil zone. Thus, the prediction of reservoir performance and behaviour usually requires an accurate model. A single-well numerical simulation model was developed using Eclipse® software to detect aquifer water encroachment into an oil reservoir, predict the performance, behaviour and ultimate recovery of the reservoir. Five scenarios of a marginal field reservoir were modeled: no water influx, bottom-water influx, edge-water influx and combined edge- and bottom-water influx. Results obtained from the numerical simulation model were validated with an analytical model MBAL. The results shows that the reservoir depletion without water influx gave the lowest oil recovery and fastest rate of pressure decline, bottom-water influx and combined edge- and bottom-water influx gave the same oil recovery factor while edge-water influx gave the highest oil recovery factor and low rate of pressure decline. The fifth scenario investigated why edge-water influx gave the highest oil recovery factor than the combined edge- and bottom-water influx.
Slug Flow and it's Mitigation Techniques in the Oil and Gas Industry
Authors: Enilari B. T , Kara F.
Published: August 2015

As multiphase production moves to environments of greater water depth and lower temperatures, there poses a huge setback in the assurance of continuous flow from the reservoir through the pipelines to the topside. Slug flow which is a common occurrence encountered in the oil industry is characterized by an alternating flow of liquid and gas resulting in an unsteady behavior of the fluid. In this paper a hypothetical case model exhibiting slugging characteristics is being developed using OLGA. The paper investigates the effect of current slug mitigation techniques such as topside choking, implementation of gas injection and a combination of the two used in the industry. The aim of this paper is to discuss on the results produced from each technique and decide on the most effective approach. From the generated results and research, it was observed a combination of both gas injection and topside choking simultaneously provides the most effective approach in eliminating slugging and increase production.
Subsidence Prediction Using Analytical Approach
Authors: Awasthi Amit , Williams Omolara
Published: August 2015

Geomechanical screening of the A-B fields revealed the reservoir compaction of reservoirs as one of the risks. As a design input for the two offshore wellhead platforms in field A and field B, information on seabed subsidence due to reservoir compaction/subsidence was computed. In order to determine the amount of subsidence an analytical approach utilising the nucleus of strain method from Geertsma was adopted in this study.
An Integrated Multi-Disciplinary Approach to Predict Fluid Contacts in a Partially Appraised Field - A Case Study of Yoko Field in Niger Delta
Authors: Adedoyin Orekoya , Eteobong Etokakpan , Suleiman Ahmed , Basak Prahlad , Ekwealor Jude , Ejiuwa Nworie , Remmy Ugboaja , George Kakayor , Onyeagoro Kachi
Published: August 2015

The need for the estimation or evaluation Original Oil Water Contact (OOWC) prior to reservoir development is very pertinent to appropriate well placement within a reservoir. Oil and gas water contacts are determined via various sources including but not limited to Petrophysical logs, RCI data, Reservoir Simulation, Fault Seal Analysis (FSA), Quantitative Interpretation and Hydrocarbon Column Analogues. This paper focuses on an integrated approach of predicting OOWC using some of the methodologies highlighted above.

The study explores the feasibility of further oil development in the Yoko field to grow production and increase reservoir ultimate recovery. Three wells have been drilled so far in the field and none encountered OOWC. Three (3) key reservoirs account for about 69% of the total field hydrocarbon resource but with significant uncertainty in fluid contacts column (about 132ft) and wide static and recoverable volume range.

An effective and commercially viable field development plan is premised on the reduction of contact uncertainty. Inorder to narrow the contact uncertianty, a multidisciplinary approach has been used and they include (a) Petrophysical Logs (b) Analogue oil column studies from adjacent fields (c) Fault Seal Analysis (FSA) to determine maximum column in the reservoir (d) Quantitative Interpretation (QI) and (e) Dynamic simulation.

The analogue oil column from neighbouring field was used to benchmark the possible oil column for Yoko field. FSA which relies on the sealing capacity of the faults due to the amount of mechanical mixing from fault throws was also considered. The upper and lower limits of the fluid contacts were estimated from acoustic impedance amplitude plotted against depth. The reservoir dynamic models was also history-matched (7 years of production history) to calibrate and ascertain the limits of the possible contacts for the reservoirs.

The result of the evaluation is a significantly reduced volumetric uncertainty range. In one of the reservoir, there was a progressive reduction in fluid column uncertainty from 132 ft to 11 ft. In general 55 – 92% reduction of the initial uncertainty was achieved. This reduced range enabled a commercially viable Development Plan for the field.
Effective Monitoring of Green House Gas Emission - A Laboratory Approach
Authors: Ibemere Uche , Mmata Bella , Onyekonwu Mike
Published: August 2015

The continuous emission of Green House Gases (GHGs) constitutes a threat to both human life and the ecosystem. Carbon dioxide (CO2), Methane (C1), Nitrous oxide (NO2), Hydro-fluorocarbons (HFCs), Per-fluorocarbons (PFCs), and Sulphur hexafluoride (SF6) are usually classified as Green House Gases. The release of these gas molecules into the atmosphere tends to deplete the ozone layer which ordinarily serves as a protective shield from harmful ultra violet rays. The consequent effect of this is global warming, besides the danger of exposure to harmful ultra-violet rays. Though the release of GHGs can occur during combustion of sundry wastes, fossil fuels, agricultural materials, the activities of the oil and gas industry is the major culprit.

To successfully monitor the release of these gases from facilities and specific operations, reliable independent laboratory experimental data is highly needed to assess trends, measure the efficiency of mitigation strategies and initiatives. Accurate measurements of all GHGs emissions are critical for establishing emission baseline and improved accountability.

In this work, flare gas samples were collected from five different flow stations in the Niger Delta region. Gas chromatographic technique was used to determine the bulk molecular composition of the flare gas, using ASTM D1945. Analytical results indicate flow stations A & B flared more GHGs components, C & D flared less while E had inconsistent trend in amount of GHGs flared. All results were quantified and calculated at 95% confidence level. The outcome of this work will aid both the operators of production facilities and regulatory bodies in tracking and controlling the emission of GHGs.
Reduction of Uncertainty in Material Balance derived Original Hydrocarbon in Place Estimate by the inclusion of Fluid Contact History Matching
Authors: Olu Okpani , Hammed Shittu , Idogun Iroro , Anil Ambastha
Published: August 2015

The classical Material Balance equation (F = N*Et + We) is a zero-dimensional reservoir modeling methodology that is used to estimate original oil-in-place volume (N), gas cap size, and aquifer influx (We). The material balance equation is a single equation with many unknowns (e.g. N, m, We); thus the solution to the equation is inherently non-unique. In other words a range of original oil in place (STOOIP) gives good match of the material balance equation. The range of STOOIP solutions of the material balance equation is often too high. In this paper a methodology is suggested for reducing the uncertainty in the material balance derived STOOIP values. In the proposed methodology, the material balance equation is further constrained by history matching the average fluid contacts in the reservoir.

Three case studies were used to illustrate the application of material balance and fluid contact match in STOOIP estimation. The first case study is a synthetic reservoir with a STOOIP of 100 MMBO, initial gas cap and aquifer influx. The result shows that solving only the material balance equation gives a very wide range of STOOIP of 80 - 300 MMBO, while including the fluid contact match reduced the STOOIP range to 80 – 125 MMBO. The second case study is a real reservoir with initial gas cap and aquifer influx. Using material balance alone the STOOIP range was 80 – 800 MMBO whereas including the fluid contact match gave a lower STOOIP range of 100 – 120 MMBO. The last case study also shows a reduction in the range of STOOIP estimation from 50 - 500 MMBO for solving the material balance equation alone to 90 - 120 MMBO when the fluid contacts are history matched. These case studies show that uncertainty in the material balance STOOIP estimates are greatly reduced by matching fluid contacts.
Petrophysical Properties of Nigeria Tarsand Revisited
Authors: Ohenhen I. , Olafuyi O. A. , Ikiensikimama S. S.
Published: August 2015

Heavy oil and Bitumen from tar sands are important energy assets, and have the potential to significantly contribute to the overall energy supply in Nigeria. Nigeria tar sand deposits are found in large accumulations, notably, in huge outcrops in the South-Western region. The initial survey in the early 1980 indicated existence of tar sands in commercial quantity. Petrophysical parameters of these tar sands were measured. However, little information was provided under which conditions these parameters were obtained. Key issues of concerns are the state of technology at that time and how well are the petrophysical characteristics of these sands defined.

In the present work, outcrops samples were taken from seven (7) different locations in the Nigeria tar sand reservoirs. Their petrophysical properties such as porosity, permeability, and water saturation were estimated at surface conditions. Laboratory results obtained showed good agreement when compared with data from existing literature.
Assessment of Injection Pressure Margin in Deep Water Injection Well Design
Authors: Poon Becky B. , Wodu Ebimobowei K. , Ekebafe Abraham O. , Ognane Edgar Mba , Itua Osazua J. , Otoh George A.
Published: August 2015

Waterflooding is a proven secondary recovery mechanism for hydrocarbon production while maintaining reservoir pressures. To achieve the desired voidage replacement ratio, each injector well is designed to inject at a certain rate to support its paired producer. From a safety perspective, it is essential to avoid 1) injection above shale fracture pressure that could result in top seal failure and 2) injection above fault propagation pressure that could result in fault reactivation/propagation. The potential consequences of these hazards are out of zone injection or loss of containment. Following recent major oil spill incidents around the world (e.g. Macondo disaster in the Gulf of Mexico), regulations have become more stringent on well designs pertaining to wellbore stability and reservoir geomechanics.

This paper will showcase an integrated effort at assessing the injection pressure margin and the impact on the detailed injector well designs for a deepwater turbidite field development in the Gulf of Guinea (Nigeria). The technique applied requires a good understanding of the fracture pressures, rock strength, failure mechanism and good drilling and completion practices. To test different scenarios, one well injecting to a deep reservoir and another well injecting to a shallow reservoir were selected for this assessment. Pore pressure, fracture pressure, and injection pressure along the wellbore were analyzed to ascertain the margin between the downhole injection pressure and fracture pressures above and at the proposed casing shoe setting depths.  The results of this study provided basis for injector well designs, justification for full field geomechanics modeling, and recommendations for data acquisition while drilling and well reservoir monitoring throughout the injection/production period.
Towards Sustainable Community Development: A Case Study of SPDC Community Transformation and Development Index (SCOTDI)
Authors: Ite Uwem , Osayande Nedo , Onaolapo Bolarinwa
Published: August 2015

Many business organisations face the challenge of determining the success or failure of their corporate social responsibility (CSR) initiatives, particularly with respect to the impacts and effect on community development and corporate-community relations. Indeed, this can be partly attributed to the fact that CSR as a discipline lacks a well-developed and elaborate methodology to measure, capture and report its impact. Yet, a business case and justification for continued support for CSR initiatives requires at a minimum, some evidence that demonstrates the return on corporate social Investment for both the company and its external stakeholders. The limited nature of such available evidence has meant that the debate over the relationship between CSR and development in the Niger Delta remains contested, and the policy challenge confronting community relations managers, remains poorly understood. This paper seeks to address the gaps in knowledge by examining the SPDC Community Transformation and Development Index (SCOTDI) launched in 2013. SCOTDI represents an innovative effort to systematically integrate and adapt a number of international standards into a composite index to assess, rank and recognised the performance and development outcomes of SPDC's Global Memorandum of Understanding (GMoU) with its host communities. The model provides a means for assessing the extent to which GMoUs are able to contribute to community development, provides an incentive for positive inter-cluster competition, thus ensuring their long–term sustainability, and facilitating the effective and efficient allocation of scare resources for community development.
Surgical Management of Abnormal Uterine Bleeding in Fertile Age Women
Authors: Finco Andrea , Centini Gabriele , Lazzeri Lucia , Zupi Errico
Published: August 2015

Abnormal uterine bleeding is a common gynecological disease and represents one of the most frequent reasons for hospital admission to a specialist unit, often requiring further surgical treatment. Following the so-called PALM-COEIN system we will attempt to further clarify the surgical treatments available today. The first group (PALM) is characterized by structural lesions, which may be more appropriately treated by means of surgical management. Although hysterectomy remains the definitive and decisive choice, there are many alternative techniques available. These minimally invasive procedures offer the opportunity for a more conservative approach. Precise and accurate counseling facilitates better patient selection, based on the patient's desires, age and disease type, allowing treatment to be individually tailored to each woman.
Defecating Disorders: A Common Cause of Constipation in Women
Authors: Dimitriou Nikoletta , Shah Vikas , Stark Diane , Mathew Ronnie , Miller Andrew S , Yeung Justin MC
Published: August 2015

Defecating disorders are a common and complex problem. There are a range of anatomical and functional bowel abnormalities that can lead to this condition. Treatment is difficult and needs a multidisciplinary approach. First line treatment for defecating disorders is conservative. For those that fail conservative treatment, some may respond to surgical therapy but with variable results. The aim of this review is to offer an overview of defecating disorders as well as provide an algorithm on how to diagnose and treat them with the help of a multidisciplinary and multimodal approach.
Increased BMI During Pregnancy: How do Midwife Lead Maternity Carers Respond?
Authors: Pan Sze Yin , Dixon Lesley , Paterson Helen , Campbell Norma
Published: August 2015

Aim: To determine the knowledge base of midwife lead maternity carers (LMCs) and explore their adjustments in practice for obese women. Materials & methods: A nationwide cohort study of LMC midwives in New Zealand concerning obesity in pregnancy using an electronic survey. Results: A total of 428 LMCs responded. Most respondents were aware of the risks of obesity during pregnancy. Midwives felt it was important to provide customized care. Various barriers to accessing support for obese women within the health system were identified. Discussing weight and obesity was acknowledged as a sensitive issue for both the woman and the midwife. Conclusion: This study highlights the need to improve access to and availability of supportive maternity services and resources for pregnant women with increased BMI.
Quality or Sacrifice? The Influence of Decision Task and Product Characteristics on the Dual Role of Price
Authors: Chang Shin-Shin , Chang Chung-Chau , Su Wei-Gan
Published: August 2015

People perceive price as a cue of monetary sacrifice, a quality signal, or both. However, this research proposed that the relative salience of these two roles varies with different decision tasks (i.e., selection and rejection). Furthermore, the effect of decision task type on price perception differs by product type (i.e., tangible goods or services). Two experiments show that (1) the price–quality perception under the selection task is higher than that of a rejection task for tangible goods but not for services; and (2) for goods and services, the sacrifice perception is greater in the rejection task than that in a selection task. These findings have important implications for formulating product assortment and marketing communications strategies.
Effects of L2 Learning Orientations and Implementation Intentions on Self-Regulation
Authors: Tseng Wen-Ta , Chang Yu-Jen , Cheng Hsing-Fu
Published: August 2015

In this study, a classic L2 learning orientation framework and a multi-faceted implementation intention construct were used to predict self-regulation. Attention was particularly paid to the way in which different types of implementation intentions predicted the self-regulatory capacity. A two-phase research design was executed. A pilot was conducted to ensure the reliability and validity of the scales. In the main study, a series of regression analyses examined the links among the variables of interest. The modeling results indicated that the effects of the integrative and instrumental orientations were substantially diminished after the implementation intentions were incorporated into the orientation structure. The empirical findings strongly suggest the need for L2 learners to utilize strategic planning in response to situational and temporal cues in the process of goal pursuit. Further discussions focused on the effects of both orientations and implementation intentions on the self-regulatory capacity in language learning.
Exploring the Relations between Student Cynicism and Student Burnout
Authors: Wei Xueyan , Wang Rongrong , MacDonald Elizabeth
Published: August 2015

Research on the negative effects of student cynicism has been limited, especially regarding its relation to student burnout. This study examined the relations among student cynicism (policy cynicism, academic cynicism, social cynicism, and institutional cynicism) and student burnout, as evidenced by emotional exhaustion, depersonalization, and reduced personal accomplishment, in a sample of 276 Chinese undergraduates. Hierarchical multiple regressions showed that four aspects of student cynicism together explained substantial variance in student burnout. Policy cynicism was the strongest contributor to emotional exhaustion. Social cynicism was the primary contributor to depersonalization, and also to reduced personal accomplishment. Student cynicism overall had the strongest relationship with reduced sense of personal achievement. The findings outline the negative functional relations between student cynicism and student burnout.
J. M. Synge's Playboy:A Necessary Reassessment
Authors: Salmon Eric
Published: August 2015

IT IS A CURIOUS FACT THAT The Playboy of the Western World., a play which mightily offended its first audiences, still does not-in spite of its, by now, obvious stature and importance-gain easy or ready acceptance from the ordinary reader or theater-goer. Most people, on first becoming acquainted with the play, seem not to like it. Perhaps in the light of this there is room for reassessment. It is a play about which a good deal has already been written, but not all that has been written has served to illuminate the play, more especially from the point of view of the playas a piece of theater-in-performance. There seem to me to be elements in this play that have never been noted at all and even where several of these elements have been noted, they have not been sufficiently related to each other as parts of a unique whole, so the total sense of the play has been missed.
The Logic of Illogic: Ionesco's Victims Of Duty
Authors: Mast Gerald
Published: August 2015

Ionesco condemns "detective thrillers" and then, immediately afterwards, apparently begins to write one himself. But Ionesco's thriller is different; his riddle is never solved. Who is Mallot? What has he done? How did Choubert know him (if Choubert did in fact know him)? What difference does it make if his name ends in a "d" or a "t"? These riddles remain riddles. "You seek, and then you find." Choubert does a lot of seeking. But he never finds. Ionesco sets up the theoretical rules of the game, and then, under the pretense of observing them (enter the detective), he breaks them all.