bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Temperature on Nigeria Tar Sand Bitumen Viscosity
Authors: Ohenhen I. , Ikiesikimama S. S. , Olafuyi O. A. 
Published: July 2016

Abstract
Production of bitumen from tar sands requires heating the reservoir to several degrees of magnitude to reduce the viscosity of the bitumen. Proper characterization of viscosity property of this fluid is necessary for the designing and optimization of recovery methods. In this work, tar sand samples were collected from different locations in the Ore axis of Ondo state. Bitumen were extracted from the tar sands. The effect of temperature on the viscosity of each sample were measured using an NDJ-8S digital viscometer at temperature ranging from 122-374°F. Viscosity behaviour were different from location to location and they typically reduced as temperature increased. Viscosity measurement varied from 876,000cp – 5,200cp as temperature increased from 122-374°F. Some samples showed higher viscosity profile than other sample. Therefore, higher temperature and energy requirement is needed for the recovery process of these Nigeria Reservoirs.
Comparative Studies of the Performance of ASP Flooding on Core Plugs and Beadspacks
Authors: Taiwo Oluwaseun Ayodele , Mamudu Abbas , Olafuyi Olalekan , Mohammed Ismaila 
Published: July 2016

Abstract
In this work, we present extensive study of Alkaline-Surfactant-Polymer (ASP) flooding in reduction of residual oil saturation in both core plugs and heterogeneous beads-packs. During the ASP flooding of the core plugs, the effectiveness of the ASP flooding EOR technique on a typical Niger Delta reservoir core and other model cores and the determination of the rock properties that most affect the displacement efficiencies of the processes were analyzed. And in the beads-pack flood test, the potential of the ASP slug for oil recovery, the effect of heterogeneity on the oil recovery efficiency of the process and the investigation of the displacement efficiency of Hengfloc in ASP slug for recovery of Niger Delta oil were all analyzed. Finally, the performance in both was comparatively examined. In the ASP Flooding for beadspack, four different beadspack labeled as W, X, Y and Z were used in the experiment. For core flood test, four different core samples termed A1, B1 T1 and R1 used. For each type of porous media, Brine saturation, oil saturation, water flooding and SP flooding were all carried out on different core samples.
The results show that the oil recovery by the imbibition process does not follow a regular pattern. It reveals some complexities in the oil mobilization process and an uneven pattern in the oil recovery due the simulated reservoir heterogeneity. It shows that it's not only the grain size of the reservoir rock but also the arrangement of the grains in the core affect the oil recovery. Water flooding can recover about 70% while ASP flooding can recover between 16 to 19% of the original oil in place from the synthesized heterogeneous beads pack. Bernheimer core gives the best results for ASP EOR flooding operations.
Gas Sales and Aggregation Agreements: Key Risks and Value Drivers
Authors: Adedamola Adegun , Isaac Oluwadiya 
Published: July 2016

Abstract
The domestic natural gas market in Nigeria has undergone significant changes in the past decade. Domestic demand has substantially increased, supply projects are been accelerated and the old amorphous market framework is been gradually organized. The strategic aggregator, the Gas Aggregator Company of Nigeria (GACN) is authorized by government policy to administer the domestic gas supply obligations (DSO) issued for operating exploration and production companies.
GACN matches gas suppliers and potential buyers and also negotiates as part of a tripartite party the Gas Sale Aggregation Agreements (GSAAs). The GSAA template was developed to achieve uniform commercial terms in gas sale transactions across strategic offtake industries. The template has provisions that are protected to achieve uniformity and prevent distortion of the price aggregation process while other provisions are bilateral that allow parties ample room for negotiation. The agreement allocates rights and obligations, risks and roles, rewards and penalties to the parties (gas seller and buyer). GSAAs are long term, multi-million dollar commitments and parties are at the risk of exposure to significant economic losses if they are not aware of the key value drivers. Furthermore, outcome of recent negotiations have necessitated redrafting of hitherto sacrosanct provisions in line with reality.
This paper therefore seeks to highlight the key value drivers, bilateral gaps and contractual provisions that can guarantee proper risk allocation and management amongst parties in the GSAA. The paper further explores generic solution to GSAA activation bottlenecks, outlines operability of certain clauses in the GSAA, provides simple mathematical illustrations of the various interdependent gas supply terms and notes potential areas of conflicts during and after negotiations. An insight into other ancillary agreements to the GSAA is also included. Increased education and understanding of the GSAA framework would minimize commercial disputes, support the growth of the domestic gas market and help mitigate the Nigerian energy challenge.
Experimental Evaluation of Particle Sizing in Drilling Fluid to Minimize Filtrate Losses and Formation Damage
Authors: Anyanwu Chimaroke , Mustapha Unubi Momoh 
Published: July 2016

Abstract
Filtrate losses from drilling mud is a serious issue because it gives rise to several problems during the drilling phase and the production phase of the well. Such problems range from pipe sticking, formation damage to loss of productivity due to phase trapping. Several methods have been proposed and applied to manage this problem but most have been ineffective. Some researchers in the past sought to reduce filtrate invasion by formulating muds capable of forming a seal over the formation pores using bridging agents with properly distributed particle sizes. Others tried to leverage the mud cake permeability by ensuring a high proportion of coarse particles in the mud but only succeeded in controlling invasion to a small extent. The main objective of this work is to reduce filtrate losses and formation damage through investigation of the effect of particle sizing of mica and alumina nano particles on filtrate loss. Four muds were prepared—mud #1: base mud; mud #2: base mud + 60microns mica; mud #3: base fluid + 40microns mica; mud #4: base fluid + alumina nano particles. The names 40 mics mica and 60 mics were derived from the d50s of the 20-200microns mica and 20-325microns mica respectively. Results from the API filtration experiment showed that muds containing large percentage of fine particles, produce filter cakes that have very effective sealing ability. This was evidenced in the respective 30mins fluid loss values obtained for the different muds: base mud (23ml), mud #2 (20ml), mud #3 (17ml), mud #4 (13ml). The alumina nano mud offered the least mud cake permeability, hence the very low amount of filtrate. Field application of this discovery in mud formulation will reduce costs of treating damage and optimize hydrocarbon recovery as phase trapping will become a non issue.
Success Factors for Reservoir Navigation in the Niger Delta Sedimentary Basin: A Case Study of Well-X
Authors: Ndokwu Chidi , Imomoh Victor , Okowi Victor , Onuchukwu Amaka , Idris Maaji 
Published: July 2016

Abstract
The Niger delta sedimentary basin is a depositional complex of Cenozoic-aged sand and shales that extend from an approximate of longitude 3˚ to 9˚ east and latitude 4˚ 30' to 5˚ 20' north. This delta is characterized by progradation, rapid sedimentation, continual loading of sediments and gravity-driven syn-depositional deformations. Hydrocarbon exploration in the Niger delta started in 1937, mainly onshore. Exploration and production now extends offshore.
Given the enormous resources that go into drilling a well, the objective is to get it right the first time (especially when drilling high-angle and horizontal wells with their associated problems of true vertical depth uncertainty and resolution of surface seismic). In drainhole sections, geological uncertainty and production technology pushes geo-steering to the limits. Sometimes, these challenges put forward questions such as: is the reservoir faulted, compartmentalized, thin, undulating or show vertical lithological changes; how far from the roof must the trajectory be; what is the minimum required drain length; and how much dogleg is acceptable?
To achieve success in the reservoir navigation of any well, some success factors must be considered: the drilling strategy, available downhole tool (drilling system and formation evaluation), surface software, personnel and communication protocol. This paper examines these success factors using the example of Well-X. The goal is to bring more understanding to the procedures involved in reservoir navigation, the challenges posed by geology, the factors to consider when planning a modern geo-steering job, the importance of teamwork, the benefits of integrated interpretation and the value communication brings to the entire process.
An Investigation of Dehydration Inefficiencies and Associated Design Challenges in a Gas Dehydration Unit-A Case Study of X Gas Plant
Authors: Ibeh S. U , Chibueze S. E , Abonyi C. L 
Published: July 2016

Abstract
The value and contribution of natural gas in both domestic and economic terrains are extensive. However, its contaminants limits direct application and hence must be treated. Water vapour existing in equilibrium with dry gas is the principal among contaminants. Most corrosion both with acid gases and carbonate salts are traceable to the presence of water. Also the formation of solid icy structures called hydrates constitutes a threat to flow assurance. Removal of water by TEG dehydration trains is not uncommon.
Dehydration inefficiencies such as high water content of the outlet gas and glycol losses could impair operations and considerably reduce profit. Inefficiency in GDU was identified to be due to design factors and operational conditions/scenarios. In the case studied, laboratory analysis of TEG was combined with process simulation results to resolve inconsistencies in design and operational phases. Recommendations for further improvements were also presented.
Challenges, Opportunities and Learnings of Brown Field Re-Entry; A Case Study of XYZ Field in Niger Delta
Authors: Oso Bisong Anthony , Oludewa Awani , Favour Otite , Ebby Ajayi 
Published: July 2016

Abstract
A brown field is an oil or gas asset that has matured to a production plateau or even progressed to a stage of declining production, where significant oil or gas reserves have been produced. Acquisition of brown fields all over the world was on the increase prior to the current volatility of crude oil price in the international market. On acquisition of brown fields, the new investors are always eager to revive the field, explore for more reserves and increase production to maximize profit by seeking to extend the economic producing life of the field using cost-effective, low risk, adaptable technologies. Brown fields' re-entry are usually associated with enormous challenges and opportunities that requires proper solutions to unlock such opportunities to maximize production, break even and maximize profit. This paper focuses on re-entry/re-opening challenges, opportunities, solutions and learnings of XYZ field in Niger delta. Areas to be discussed include; wells selection, estimated vs actual start-up rates, well reactivation, wellheads and facility refurbishment.
Hydrocarbon Utilization Optimization for Sustainable Development in Nigeria: Economic Growth Potential
Authors: Echendu Joseph C. , Iledare Omowunmi O. , Onwuka Emmanuel O. , Ikiensikimama Sunday S. 
Published: July 2016

Abstract
The risks and uncertainties associated with oil price volatility and its global economic impact recently is creating a new thinking in terms of hydrocarbon utilization and energy security. Petroleum rent seeking nations are re-evaluating their micro/macroeconomic policies towards budgeting and producers are restrategizing on the most efficient cost of extraction means for sustained development and production. Ensuing oil geopolitics and regional conflicts are also driving a new energy supply and demand route in meeting global energy demand.
Consequently, this work proffers an energy model that helps to answer the microeconomic implications of oil price volatility on resource based economies. The model incorporates empirical data and estimated aggregate domestic utilization needs to proffer solution on appropriate energy security and sustenance policy to adopt given forecasts of domestic oil and gas production and imports.
The research aim is to analyze the nexus of oil price and economic potentials, especially in Nigeria, with respect to the petroleum value chain. Analysis of the challenges and prospects of hydrocarbon utilization towards economic growth and understanding of the resource base, energy demand and supply mix including development strategy towards energy sustenance are portrayed.
Empirical results reveals that increased domestic utilization of resources gives comparative economic advantage in the balance of trade; eliminate opaque subsidy product loss margin; increase transparent downstream refining; and enormous revenune recapture opportunites approximately 25%, ceteris paribus. Result also shows that Nigeria and Africa at large compete favourably in terms of resource base among the committee of nations. As a result, value creation, economic and pragmatic policy and strategy are plausible imperatives toward energy security and stability.
Comparison of Permeability Plugging Characteristics of Locally Sourced Wellbore Strengthning Materials for Mature Fields Drilling
Authors: Dosunmu Adewale , Anyanwu Chimaroke 
Published: July 2016

Abstract
There is a lot of room for improvement in oil and gas technology among the complex processes in exploration and production. However, the need to prolong the value of mature assets and provide better access to their reserves focuses considerable investment on drilling programs. Pore pressure depletion and its consequent loss circulation problems make up the wellbore instability concerns in mature fields as they translate to cost overruns, Non-Productive Time, Equipment damages. Although loss circulation problems are not new to the industry, repeatedly the need arises to design optimally plugging system to isolate thief zones from the well, while drilling. Wellbore Strengthening materials available to the industry put significant weights on mud costs and usually availability as when needed is not guaranteed. In this work, the performance of a locally sourced Wellbore strengthening material, palm kernel shell (a waste product) is compared with materials used in field operations. The Particle sizing and size distribution as well as permeability filtration tests were conducted to assess and compare the performance of these materials with regards to loss circulation control. Results from these tests showed that permeability plugging characteristics of these local materials compared favorably with those used in field operations.
Managing Subsurface Uncertainty Through Effective Well and Reservoir Management in a Gas Reservoir_X1000YM Reservoir Case Study
Authors: Korubo Waazor , Magnus Nnadi , Suleiman Ahmed , Tunji Bakare , Chima Emelle 
Published: July 2016

Abstract
Understanding the dynamics of a reservoir based on performance and acquired data is key to optimal field development. This is the case for a matured gas reservoir with more than 2Tscf of gas in-place in the Niger Delta.
Based on initial data acquisition during the field development planning, the reservoir was interpreted to be compartmentalized by series of intra-reservoir shales. After four years production, acquired performance data analysis suggests increased communication between reservoir units and lower range of in-place volumes. This is believed to be driven by high mobility of gas and presence of intra reservoir faults that breached the intra-reservoir shales. This updated understanding forms the basis of the re-evaluation of the reservoir.
The depth uncertainty used to generate the low and high case top reservoir structure was revised from 60ft to 33ft (based on residual analysis). The dynamic model was re-calibrated with the updated static model using the Experimental Design (ED) workflow. Performance data from the producing wells were used to calibrate the simulation model to ensure consistent ultimate recoveries estimation. The estimated developed ultimate recovery from the reservoir simulation is comparable with the results from a P/Z analysis and material balance model.
The novelty of this approach is the ability to manage subsurface uncertainty through effective use of well and reservoir data to improve reservoir understanding. Overall, the subsurface uncertainty management strategy ensured collaboration within the sub-surface team, effective use of the installed permanent downhole gauges, and integration of surface and sub-surface data in the update of the simulation model.
Achieving Cost Effective 4D Monitoring in Deep Water Fields
Authors: Effiom Oghogho 
Published: July 2016

Abstract
During times of cost constraints, expensive seismic data acquisition is an activity that is often seen as expendable in a bid to reduce the cost of reservoir management in deepwater offshore fields where such activities can easily add hundreds of millions of dollars to the capital expenditure. It becomes imperative for a field management team to devise innovative ways to aerially monitor their field to manage the subsurface uncertainties that limit the effectiveness of injector wells that support production through water flooding.
One method involves the use of a borehole recording system (DAS-VSP) that can be used to acquire well bore seismic in wells that have fibre optic cables installed. The seismic around the wellbore can be acquired without the use of a rig or a receiver installation on the sea floor. Field studies in Gulf of Mexico indicate that 4D acquired by DAS-VSP are comparable in signal quality to other acquisition methods. Additional advantage is that this system has a low acquisition footprint; hence the surveys can be acquired prior to injection start up in new wells and more frequently in order to determine the efficacy of injection in the short term.
A second method involves the use of i4D, which leverages ocean bottom node technology. It is an intelligent way of acquiring 4D signals in short time stamps (weeks) to get dynamic information with fewer nodes around problem wells. i4D identifies changes due to pressure and water flooding while it is taking place. The cost implication of i4D is an order of magnitude less than full field OBN acquisition because fewer nodes are used in a smaller shot box.
These methods will not totally replace the value of a full field 4D survey, but they can be used to provide the necessary information in-between full field surveys.
Individually, these methods are limited in scope but by combining them, 4D monitoring is achieved cost effectively to close knowledge gaps over time.
Stability of dronabinol capsules when stored frozen, refrigerated, or at room temperature
Authors: Wempe Michael F. , Oldland Alan , Stolpman Nancy , Kiser Tyree H. 
Published: July 2016

Abstract

Purpose
Results of a study to determine the 90-day stability of dronabinol capsules stored under various temperature conditions are reported.

Methods
High-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was used to assess the stability of dronabinol capsules (synthetic delta-9-tetrahydrocannabinol [Δ9-THC] mixed with high-grade sesame oil and other inactive ingredients and encapsulated as soft gelatin capsules) that were frozen, refrigerated, or kept at room temperature for three months. The dronabinol capsules remained in the original foil-sealed blister packs until preparation for HPLC–UV assessment. The primary endpoint was the percentage of the initial Δ9-THC concentration remaining at multiple designated time points. The secondary aim was to perform forced-degradation studies under acidic conditions to demonstrate that the HPLC–UV method used was stability indicating.

Results
The appearance of the dronabinol capsules remained unaltered during frozen, cold, or room-temperature storage. Regardless of storage condition, the percentage of the initial Δ9-THC content remaining was greater than 97% for all evaluated samples at all time points over the three-month study. These experimental data indicate that the product packaging and the sesame oil used to formulate dronabinol capsules efficiently protect Δ9-THC from oxidative degradation to cannabinol; this suggests that pharmacies can store dronabinol capsules in nonrefrigerated automated dispensing systems, with a capsule expiration date of 90 days after removal from the refrigerator.

Conclusion
Dronabinol capsules may be stored at room temperature in their original packaging for up to three months without compromising capsule appearance and with minimal reduction in Δ9-THC concentration.
Effect of comprehensive rehabilitation on the upper limb function in patients after mastectomy
Authors: Zwolińska Jolanta , Homenda Małgorzata , Kwolek Andrzej , Misior Anna 
Published: July 2016

AbstractIntroduction: Breast cancer is the most common cancer in Poland, in Europe and the US. Women after breast cancer treatment suffer from various motor dysfunctions. The most frequent is upper limb dysfunction on the operated side caused by lymphedema and limitations in the shoulder complex mobility. Physical therapy and psychotherapy have a significant beneficial effect on the quality of life of these women. The aim of the study was to assess the effect of comprehensive rehabilitation on the upper limb function and incidence of lymphedema, sensory dysfunctions and pain on the operated side.Material and methods: The experimental group included 19 patients with diagnosed breast cancer. All of them underwent a standard surgical intervention - radical mastectomy according to Patey’s method followed up by outpatient rehabilitation according to a designed plan. The control group consisted of 16 women who underwent the same treatment but did not take part in the designed rehabilitation program. During the examinations the following parameters were measured: motion range of the shoulder complex, hand-grip strength and occurrence of lymphedema, pain and sensory dysfunctions.Results: Women in the experimental group improved the upper limb mobility on the operated side and hand-grip strength, and rated lower their level of pain intensity.Conclusions: The outcomes confirmed the necessity to implement early rehabilitation program as a follow-up treatment for patients after mastectomy. Comprehensive rehabilitation leads to reduced pain intensity and improved upper limb function on the operated side and has a beneficial effect on the general physical fitness of women.