bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Optimization of Catalytic Process In-Situ for Heavy Oil and Bitumen Upgrading
Authors: Shah A. , Fishwick R. P. , Leeke G. A. , Wood J. , Rigby S. P. , Greaves M. 
Published: February 2011

Abstract
The worldwide conventional crude oil demand is on the rise and because of the rising prices, unconventional oils are becoming more economically attractive to extract and refine. However, technological innovation is needed, if heavier oil supplies are to be further exploited. Toe-to-heel air injection (THAI), and its catalytic add-on (CAPRI) processes combine in-situ combustion with catalytic upgrading using an annular catalyst packed around the horizontal producer well. These techniques offer potentially higher recovery levels and lower environmental impact than alternative technologies, such as steam-based techniques. An experimental study is reported concerning the optimization of catalyst type and operating conditions for use in the THAI-CAPRI process. Experiments were carried out using microreactors containing 10 g catalyst, with oil flow of 1 ml.min−1 and gas flow of 0.51.min−1, under different temperatures, pressures and gas environments. Catalysts tested included alumina supported CoMo, NiMo and ZnO/CuO. It was found that there was a trade off in operation temperature between upgrading performance and catalyst lifetime. At a pressure of 20 bar, operation at 500 °C led to an average of 6.1 °API upgrading of THAI oil to 18.9 °API, but catalyst lifetime was limited to 1.5 hours. Operation at 420 °C was found to be a suitable compromise, with upgrading by an average of 1.6 °API, and sometimes up to 3 °API, with catalyst lifetime extended to 77.5 hours. Coke deposition occurred within the first few hours of the reaction, such that the catalyst pore space became blocked. However, upgrading continued, suggesting that thermal reactions or reactions catalysed by hydrogen transfer from the coke itself play a part in the upgrading reaction mechanism. The CAPRI process was relatively insensitive to changes in reaction gas medium, gas flow rate and pressure, suggesting that the dissolution of hydrogen or methane from the gas phase does not play a key role in the upgrading reactions. By careful control of the temperature and oil flow rate in the in-situ CAPRI process, additional upgrading compared with the THAI process alone may be effected, resulting in a more valuable produced oil, which is easier to transport.
Evaluation of Stimulation Techniques Using Microseismic Mapping in the Eagle Ford Shale
Authors: Inamdar A. , Malpani R. , Atwood K. , Brook K. , Erwemi A. , Ogundare T. , Purcell D. 
Published: February 2011

Abstract
The main goal in stimulating shale formations is to maximize the reservoir contact with the hydraulic fracture face. In order to achieve this goal current practices include pumping low-viscosity fluids at high rates with small mesh proppant cycles. A novel approach was used in a well in the Eagle Ford shale to enhance the stimulated area. This technique, called “relax-a-frac”, was developed by an operator/service company alliance during the exploration phase. Real-time microseismic hydraulic fracture monitoring (RT HFM) indicated that the conventional slickwater treatments were not providing adequate lateral coverage across the planned stage. To address this issue, controlled changes were made to the pumping schedule, and the effects were evaluated using RT HFM. The results indicated that relax-a-frac proved to be highly successful in increasing the estimated stimulated volume (ESV) in this formation and area.
In relax-a-frac, a part of the stimulation treatment was pumped (usually pad plus proppant slugs), followed by an extended shutdown to relax the formation. Once the surface pressure reached a predetermined value, the treatment was resumed, as per program, with monitoring for microseismic activity. The microseismic activity observed during the second part of the treatment showed a significant increase compared to that of the first part, with improved lateral coverage. The resultant ESV increased significantly from this technique as compared to any other specific changes tried on these wells. Production log results from Well 1 showed a definitive correlation between production contribution and the ESV derived from HFM analysis. This paper documents that this novel approach more effectively stimulates the Eagle Ford shale when compared to the typical treatment designs. Conclusions from a detailed comparison of the well performance and its relation to the treatment design are included.
Continual Bit Design Evolution Improves Performance in the Skinner Ridge Field - Piceance Basin
Authors: Garza Travis , Wimberg James , Kopp Kevin , Cheatheam David , Hettinger Gary , Pantuso Chaunsey 
Published: February 2011

Abstract
The Piceance Basin is one of several unconventional gas resources that have been the subject of intense industry activity throughout onshore North America. Due to challenged Rocky Mountain natural gas prices and a recent high cost environment, drilling and completing wells quickly and inexpensively is crucial to managing the economic conditions in Chevron’s Skinner Ridge Field development in western Colorado.
A focused effort on continual improvement has been employed by the Chevron Piceance Drilling Team to maximize drilling efficiency. In terms of drilling performance, an obvious method to reduce drilling time and cost is to physically drill faster by achieving increased drill bit rate of penetration (ROP) without compromising bit reliability.
The following paper summarizes performance improvements achieved through numerous bits trials, dull bit grading analyses and design iterations through a process of application design engineering at the supplier/customer interface. The result has been a step change in drill bit performance exhibited by the continual increase in average 7-7/8 inch bit ROP: from 45 ft/hr during the initial delineation program to 184 ft/hr on the most recent development well pad. Based on this demonstrated performance, the bit designs and cutter technologies have been transferred to other operations, showing that the application of this design approach provides practical means of maximizing efficiency.
Preliminary Assessment of Oil-Rim Reservoirs: A Review of Current Practices and Formulation of New Concepts
Authors: Lawal Kazeem A. , Wells Inewari A. , Adenuga Ademola O. 
Published: February 2011

Abstract
Where oil is the primary target, undesirable production of gas and water complicates the exploitation, management and performance evaluation of thin oil reservoirs. Conventionally, either as a precursor or benchmarking tool for relatively expensive simulation studies, zero-dimensional first-pass models are employed to evaluate performance.
This paper reviews some common models for conducting preliminary assessment of oil-rim reservoirs. The models, diverse in underlying concepts and functional forms, are Osoro et al. (2005), Wyne et al. (2005), Kabir et al. (2004), Vo et al. (2004), and Irrgang (1994). By highlighting their relative strengths and weaknesses, they are shown to be generally inconsistent, inherently limited in scope of applicability, and could yield non-physical results. Consequently, they are not robust as screening and validation tools. The main explanation for the non-robustness of these empirical and simulation-based correlations is that they do not capture the key physics of oil-rim reservoirs. Hence, a different approach is imperative.
In sharp departure from current practices, an integrated energy-balance approach is introduced. In principle, the energy potential of the reservoir establishes the upper bounds of hydrocarbon recovery. For a system under gas-cap drive, an expression for the theoretical limits of reservoir energy is derived, showing that the primary controls of reservoir potential are initial reservoir pressure and volume of gas-cap. Further developments of the proposed concept would focus on deriving expressions for the demand-side of the energy balance.
Solutions to the Down Hole Vibrations During Drilling
Authors: Yaveri Mokhtar , Damani Karan , Kalbhor Harshad 
Published: February 2011

Abstract
The drilling of a well is a dynamic process hence vibrations are inevitable. Drill string vibration induces premature wear and damage to the drilling equipment which results in fatigue failures. Not only will this increase the overall drilling time but also incur huge losses in the form of MWD tools failure and down-hole tools failure affecting the economics of the project. This is neither feasible to the operator nor to the service provider.
It has become necessary for the drilling industry to come up with solutions which can mitigate the problem of drilling dynamics. To understand drilling dynamics in detail we performed a case study on 16 offshore wells. The case study focuses on the vibration problems encountered in the 8.5" section of the 16 wells. We tried to evaluate the reason for the vibrations occurring such as stick slip & lateral vibrations and studied the intensity at which it was occurring. The solutions we have proposed can find tremendous applications in the industry to control and reduce down hole vibrations.
The ability to monitor and correctly interpret dynamic drilling behaviour depends on background knowledge of vibration problems and how they occur. Appropriate corrective action can have a significant impact on MWD tool life, drill-string life, motor life, bit life, drill rates, and drilling efficiency. The work presented here will give solutions which can be used to reduce drill string vibrations and help the economics of the project. Based on our study on the 16 wells, we derived conclusions and have come up with a few actions in the form of a ‘Ten Point Plan’ that can help mitigate vibrations.
Appropriate Gas Price Determination in the Emerging Nigerian Gas Market
Authors: Akinpelu L. O. , Iwayemi A. P. 
Published: February 2011

Abstract
The key challenge of Gas Pricing in the Nigerian Environment is the need to balance three seemingly conflicting objectives: Maintaining the required level of Gas Supplies to support Domestic Economic GrowthProviding Producers with sufficient incentives to continue to invest in Exploration & Development of New Gas Reserves andMaximizing Revenue from Exports
At the current level of development of the Gas Industry in Country, the fundamental question of how to achieve economic pricing as the industry transits from a monopolistic market structure characterized by administered prices to a competitive structure, based on a market determined pricing mechanism will have to be addressed.
We present a simple model to determine the appropriate price of Gas to be paid at the wellhead. The Model focuses the different End Users towards the ultimate price – Opportunity Cost pricing as proxied by the netback Gas Export Price or Export Parity Pricing (EPP). There will be a Transition period to full Market Pricing – determined by how quickly the Market develops.
A Scalar factor is used to achieve the level of support deemed appropriate for the different sectors identified in the Gas Master Plan: Power, Export LNG and Commercial Sectors during the transition period. The Scalar factor will be a fraction during the transition period and reach a value of 1.0 at the end of period (or Sector Pricing will equal Export Parity Price). The magnitude of the Scalar factor and its rate of change will reflect a combination of Policy Objectives and Market Responsiveness thereby ensuring the needed dynamism into the Pricing Model.
Nigerian Gas Masterplan and Policy: Is It a Constrained Energy Policy?
Authors: Onyeukwu Humphrey 
Published: February 2011

Abstract
The Nigerian Gas policy is been aligned to maximise the oil and gas sector value to the economy and transit from an oil industry to an integrated oil and gas industry. These initiatives have been geared towards boosting the domestic market and realize maximum revenue possible from gas. As a result, the gas policy framework in Nigeria has been undergoing series of reforms and new policy initiatives and these have initiated the Gas Master Plan, namely: the Domestic Gas Supply Obligation, the Gas Pricing Framework and the Gas Infrastructure Blueprint.
In the light of the interplay of political and economic factors in Nigeria, the paper examines the strength of the Nigerian Gas Master Plan and Policy to unlock the potentials of a viable Nigerian domestic gas market and discusses to what extent is the Policy constrained. The paper shall identify the magnitude of these constraining factors and would seek to answer the question in view of the stated objective of the Nigerian Government to position the domestic market on a sustainable growth path and leveraging gas for the economic growth of the country.
Modeling of Hydrate Dissociation in Subsea Natural Gas Production Flowlines
Authors: Osokogwu U. , Ajienka J. A. 
Published: February 2011

Abstract
Gas hydrate is one of the major challenges facing production and transportation of natural gas from the remote regions of deep waters, ultra-deep waters and the arctic areas where large reserves have been discovered globally. Gas hydrate is grouped into three types; type I, II and H. Among the aforementioned types, type II is of interest to the oil and gas industry because this is the one that obstructs natural gas flow in production pipelines. In dissociating hydrate in a production pipeline, the following techniques are applied; thermal, chemical, depressurization and mechanical. However, depressurization technique is the most widely used in field of operations where absolute hydrate plugs in production pipelines are experienced. This method has been applied from time past with rule-of-thumb as there are limited models on hydrate dissociation. In this study, a mathematical model was developed based on cubic-degree polynomial using Fourier law. The developed model considered a radial dissociation from a two-sided approach on a fixed boundary which was finally programmed into software called PIPECLEAN using Visual Basic(as shown in Fig 7 and 8) and validated with published experimental data. Results show that dissociation commences from a temperature of 285.7K and above 13hours to dissociate a production flowline that is plugged off by gas hydrate. The study will aid depressurization operations in the field to predict hydrate dissociation real-time, the dissociating temperature to achieve this and the hydrate penetration depth inwardly from the walls of a pipeline. More importantly, the developed model will assist in curbing the problem of guesses when dissociating hydrate in field of operations. One limitation is that the model cannot determine gas evolved during dissociation.
Well and Reservoir Parameters Estimation (K and Skin) Using the Statistical Diagnostic Approach....Part II
Authors: Biu Victor T. , Biu Emmanuel O. , Buduka Stanley , Ajienka Joseph , Onyekonwu Mike 
Published: February 2011

Abstract
In pressure transient analysis, the derivative, typecurve and semi-log pressure curve is used to estimate wellbore and reservoir parameters. How accurate are this figures which solely depend on the extent of the transient period as interpreted by the derivative plot considered for reservoir characterization. Though this approach is universally accepted by welltest analysts, reservoir engineers and the academia in the oil and gas industry but the possibility of over or under estimating wellbore and reservoir parameter is not in doubt, hence there is need to checkmate such interpretation using alternative approach
This paper focus on permeability and skin estimation using the statistical approach to checkmate the quantitative interpretation of the derivative method. Part 1 of this work focus on flow regime identification using the statistical method.
Result from channel sand, low and high permeability reservoir, infinite acting and closed boundary indicates that the estimated permeability for both approach is much closed. Maximum difference of about 13% is notice in closed boundary model while the minimum difference is about 1% in infinite acting reservoir response. Generally, the best match for K and S estimate is seen in channel sand and high K, acidized model. Also in all cases considered, lower slope is obtained from the Statdev approach which is responsible for lower estimated permeability. Invariably the Statdev depict larger extent of transient flow regime as compare with the derivative, making it applicable even where data whose fingerprint for the transient period are insufficient for the analysis.
Optimization of Gas Condensate Reservoir Using Compositional Reservoir Simulator
Authors: Udosen Emmanuel O. , Ahiaba Okpanachi O. , Aderemi Samuel B. 
Published: February 2011

Abstract
In the past years several authors have fielded many questions from companies, both domestic and international concerning gas condensate reservoirs. It appears that gas condensates are becoming more important throughout the world. Also, many international petroleum societies are beginning to have conferences specifically oriented to gas condensate reservoirs and discussing all parameters germane to such systems. Based on this increased interest, we took up the challenge to study gas condensate reservoir, and in this paper we have highlighted the best production method and future exploitation plans for a gas condensate reservoir using a compositional simulator to justify the application of WAG, pressure depletion and gas cycling technique aimed for optimum reservoir and production performance. The results show a remarkable improvement of condensate recovery after an optimization job was done for different scenario. Also, this paper emphasize on a major associated problem with producing gas condensate reservoir, which is the effect of retrograde condensation that results to condensate (blockage) banking, thus causing a reduction in reservoir and well performance.
Bubblepoint Pressure Correlations for Niger Delta Crude Oils
Authors: Okoduwa I. G. , Ikiensikimama S. S. 
Published: February 2011

Abstract
Knowledge of bubble point pressure is very important in reserve estimation and other petroleum engineering calculations such as modeling of fluid flow through porous media and multiphase flow in pipe. When laboratory PVT analysis is not readily available, empirical PVT correlations becomes the best alternative. In this study, correlations for bubble point pressure for Niger Delta crude oils were developed using non-linear multiple regression. This was done by categorizing Niger Delta crude oil into five oil API gravity ranges (API≤21, 21&lt;API ≤ 26, 26&lt;API ≤ 35, 35&lt;API ≤ 45 and API&gt;45). Different correlation models were developed for each oil API gravity range. Different quantitative and qualitative approaches were used to compare the new correlations with other published correlations. The results of all the correlations show that better correlations were obtained when the crude are categorized into oil API gravity ranges. For Niger Delta Crude Oil, the new correlations developed by this study performed better than existing published bubble point pressure correlations.
NMR-Openhole Log Integration: Making the Most of NMR Data Deliverables
Authors: Ehigie S. O. 
Published: February 2011

Abstract
The benefits of NMR data integration as a technique for improving conventional openhole log evaluation are already appreciated by many practitioners. Two pathways for achieving this integration are (1.) using NMR data to refine input parameters for conventional log analysis (sometimes in-lieu of core data) and (2.) using certain NMR-based analyses to constrain the results emanating from openhole log analysis.
However, in practice, a key factor to the slow take-up of NMR-openhole log integration techniques (in addition to a generally limited appreciation of the techniques themselves) remain in the disparate NMR data delivery formats among the service providers. Essentially, it is fair to say that NMR data delivery has yet attained the same level of standardisation that has already been witnessed in conventional openhole logging. For example, the NMR acquisition dataset from the major service providers are not strictly equivalent, and consequently often require different manipulation and interpretation strategies. This state of affairs also means that an integrated NMR-openhole log interpretation procedure may be difficult to transfer, in a consistent way, between acquisition datasets from different service providers.
Furthermore, unless specific data requests are communicated prior to NMR log acquisition, most service providers will deliver only a partial dataset of the acquisition, at best. Bearing in mind that logging contractors do not generally retain their clients' data indefinitely, maximizing the value of originally-delivered NMR log data may often become the only possible objective many years after their acquisition.
The focus of this paper, therefore, is discuss how NMR data are delivered by the different logging companies and to recommend NMR-openhole log integration techniques for making the most of a variety of NMR data, as may have been originally delivered by the different service providers.
Evaluating the Impact of Fiscal Provisions in the Draft Petroleum Industry Bill on Offshore E&P Economics and Take Statistics in Nigeria
Authors: Iledare Omowumi O. 
Published: February 2011

Abstract
The structure and conduct of the global E&P industry have changed significantly over the years; to the extent that the search for and development of petroleum resources have become mostly driven by the attractiveness of fiscal regimes rather than geological prospectivity only. A dynamic and stable fiscal arrangement must now include contract terms and instruments that will willingly give up an appropriate proportion of economic rents to investors to guarantee sustainable capital investment flow for resource development. A high exploration risk and low prospective region must balance government takes with an attractive rate of return on investment. Of course, where exploration risks are low and geological prospects are high, the host government can be expected to want to capture a high economic rent per unit of hydrocarbon production. This paper reviews the economics of offshore petroleum exploration and production (E&P) operations within the context of the ensuing petroleum industry institutional restructuring and reforms in Nigeria. The paper provides a careful review of the fiscal terms and instruments in the draft petroleum industry bill (PIB) and the effects on the economic measures and government take statistics of an archetypal deepwater oil and gas venture in offshore Nigeria.