bluuebunny/crossref_metadata_2025_split huggingface dataset:
Re-orienting crop improvement for the changing climatic conditions of the 21st century
Authors: Mba Chikelu , Guimaraes Elcio P , Ghosh Kakoli 
Published: June 2012

Abstract
A 70% increase in food production is required over the next four decades to feed an ever-increasing population. The inherent difficulties in achieving this unprecedented increase are exacerbated by the yield-depressing consequences of climate change and variations and by the pressures on food supply by other competing demographic and socioeconomic demands. With the dwindling or stagnant agricultural land and water resources, the sought-after increases will therefore be attained mainly through the enhancement of crop productivity under eco-efficient crop production systems. ‘Smart’ crop varieties that yield more with fewer inputs will be pivotal to success. Plant breeding must be re-oriented in order to generate these ‘smart’ crop varieties. This paper highlights some of the scientific and technological tools that ought to be the staple of all breeding programs. We also make the case that plant breeding must be enabled by adequate policies, including those that spur innovation and investments. To arrest and reverse the worrisome trend of declining capacities for crop improvement, a new generation of plant breeders must also be trained. Equally important, winning partnerships, including public-private sector synergies, are needed for 21st century plant breeding to bear fruits. We also urge the adoption of the continuum approach to the management of plant genetic resources for food and agriculture as means to improved cohesion of the components of its value chain. Compellingly also, the National Agricultural Research and Extension System of developing countries require comprehensive overhauling and strengthening as crop improvement and other interventions require a sustained platform to be effective. The development of a suite of actionable policy interventions to be packaged for assisting countries in developing result-oriented breeding programs is also called for.
Effects of Pore Structure to Conventional Well Log Evaluation in Low Permeability Sandstones
Authors: Zhang F. , Liu Xiao-peng , Hu Xiao-xin 
Published: June 2012

Abstract
The conventional well log evaluation is a challenge for geologists and well log analysts in low permeability sandstones at present due to the effect of the complicated pore structure. In this paper, based on the analysis of the laboratory NMR measurements, core experimental mercury injection capillary pressure data, the casting thin-section and the drill stem testing data, the effects of the pore structure to low permeability sandstones can be conclude to form three different types of low contrast hydrocarbon bearing formations, they are low resistivity contrast of gas bearing formations with water saturated layers, the low porosity and permeanility contrast for effective formation with dry layer and the low porosity and resistivity contrast of formations with high productivity layer and low productivity zone. To evaluate low permeability reservoirs responsibly, the information of pore structure should be first obtained.
Risk Minimization when Perforating with Automatic Gun Release Systems
Authors: Baumann Carlos , Dutertre Antoine , Khaira Kuljit , Williams Harvey , Mohamed Hassan N. 
Published: June 2012

Abstract
Each month thousands of perforating jobs are executed without problems; however, certain wells are susceptible to gunshock damage if they are perforated with inappropriate gun systems. This paper presents the application of a simulation program that predicts perforating gunshock loads reliably. This simulation program enables us to evaluate gunshock loads for any perforating job, including gunshock loads sensitivities to changes in gun type, charge type, shot density, tubing or cable size and length, rathole length, use of shock absorbers, and placement of packers, among others.
This simulation program helps engineers to identify perforating jobs that have a risk of gunshock related damage, such as bent tubing, unintentional weak-point pull outs, failures in gun release systems, and unset packers. When predicted gunshock loads are large, changes to the perforating equipment or job execution parameters are sought to reduce gunshock loads and the associated risks. For example, in this paper we present a typical case where a simple change to the guns charge loading transforms a high-risk perforating operation into a very safe one.
A large number of comparisons between predicted wellbore pressure and field fast-gauge pressure data are available in related SPE articles. These comparisons show that predicted wellbore pressure transients are very good, and in most cases where shock absorbers were used, residual deformation of crushable elements correlate well with the peak loads predicted by this simulation program. Additionally, this program is able to simulate perforating job designs in a short time, allowing engineers to optimize perforating jobs in a timely manner.
The ability to predict gunshock-induced damage in deepwater perforating operations is very important because of the high cost of typical wells and rig time. With the gunshock simulation capabilities presented in this paper, engineers can optimize perforating jobs by reducing gunshock loads, thereby the risk of gunshock-related damage and non-productive time.
Application of Bacterial Mat for Optimized Gas Hydrate Recovery at the Sea Surface
Authors: Dubey A. , Saxena A. 
Published: June 2012

Abstract
With increasing energy demand, the oil and gas industry requires new technological developments in the field of unconventional resources along with sustainable development. In this paper we put forward the concept of Bacterial Mat for optimised recovery from marine gas hydrates. Along the India’s 7,500 km of coast line we have vast reserves of gas hydrates which can meet our needs for several centuries. Gas hydrate is a solid compound in which methane is trapped within a crystal lattice of water under high pressure and low temperature condition. The carbon content present in the form of gas hydrates is twice the carbon present in all known fossil fuels of the earth. One litre of gas hydrate contains on an average 168 litres of methane gas at STP.
The primary condition for the stability of gas hydrate is high pressure and low temperature i.e. a minimum depth of 300m and a temperature lesser than 2°C. Several technologies have been experimented for the extraction but the main problem faced was uncontrolled liberation of methane which is a powerful green house gas.
Our suggestion is to use Bacterial Mat for the optimised recovery of gas hydrates. This bacterial mat contains Archae bacteria. These bacteria can survive in extreme environment and can produce methane from CO2 & H2O. This process is exothermic and can raise the temperature to 140°C leading to escape of methane from gas hydrates. These bacteria will breed on an artificial animal intestine mat from which they will get nutrients for growth. The bacterial mat will be sent to the seabed and fixed to the bed with its arms on the edges where gas hydrates are deposited. After achieving the desired saturation of gas, it is produced from the sea surface installation.
The above suggested methodology is an optimised and economical way to recover gas hydrates. Firstly it will help to change the focus of extracting resources from conventional to unconventional resources. Secondly, it will lead to sustainable development and reduce the hazard of global warming to a large extent. Thirdly, this technology has huge potential in the petroleum industry.
Modeling the Effect of Pipe Rotation on Pressure Loss through Tool Joint
Authors: Bui B. 
Published: June 2012

Abstract
Drilling engineers frequently make expensive misjudgment due to improper prediction and control of pressure along the wellbore. The flow of fluid in the wellbore is complicated not only by contraction and expansion through tool joints, but also by the effect of pipe rotation.
Field data has proved the excessive pressure drop through tool joint. Extensive experimental and theoretical studies have been conducted to study the effects of tool joint and pipe rotation on pressure loss along the drillstring. However, there is a discrepancy between published studies about the effect of pipe rotation on pressure drop in pipe and annular flow. For Newtonian fluids, it is well known that pipe rotation does not affect the pressure drop. Nevertheless, for non-Newtonian drilling fluids, several experimental works reported the reduction of pressure loss; while other works reported the increase in pressure loss.
In this study, the flow of drilling fluid through contraction and divergence across the tool joint is investigated using Computational Fluid Dynamics (CFD) software package. Different pipe rotation speeds are used to simulate the flow of an incompressible Yield Power Law fluid in both pipe and concentric and eccentric annuli. The velocity and pressure profiles are analyzed and compared to emphasize the effect of tool joint and pipe rotation on pressure loss. The results show that pressure drop through tool joints is significant. Pipe rotation has small effect on pressure drop at low velocity, and different effects on pressure drop at higher velocity. Positive and negative effects depend strongly on flow geometry and flow velocity.
The results of this study provide valuable information about the flow of drilling fluids through tool joints and along the wellbore. These give useful insight into the effect of pipe rotation and tool joint on pressure drop. Accurate calculation of pressure drop along the wellbore with pipe rotation is highly important in hydraulic program, optimization and well control, especially for deepwater wells.
Influence of Resin/Asphaltene Ration on Paraffin Wax Deposition in Crude Oils from Barrackpore Oilfield in Trinidad
Authors: Garcia-James C. , Pino F. , Marín T. , Maharaj U. 
Published: June 2012

Abstract
The precipitation and deposition of paraffin wax during production, transportation and storage of crude oil are common problems encountered by the majority of oil producers around the world. During the last decade, the Barrackpore oilfield in Trinidad has reported wax deposition on nineteen (19) of its wells. This condition has been exacerbated due to the reduction of temperature, pressures and losses of gas which have allowed wax to separate from the crude oil, precipitate and deposit in the walls of tubings, thereby reducing their diameter and restricting the flow of oil through the system. The situation represented a serious problem for Petroleum Company of Trinidad & Tobago (Petrotrin), because it caused a reduction in the production levels and significant economic losses. This study was based on the necessity to find feasible solutions to minimize this problem. The research was focused to determine if there was influence of the resin/asphaltene ratio on wax deposition under laboratory conditions, to start an understanding process of the causative factors of these depositions. In addition, the influence of two (2) different wax inhibitors were studied for comparison, since it is understood they may behave as resins peptizing the asphaltene particles and keeping them in solution. To ensure the validity of this investigation, extensive bibliographical reviews were undertaken, followed by numerous laboratory tests such as SARA analysis, Cloud Point Tests and Wax Content Tests as methods to evaluate the crude oil and its behaviour under various conditions. The results showed that wax and asphaltene content are the controlling factors in the precipitation and depositions processes respectively.
How Advances in Technology Can Help Safely Abandon Offshore Exploratory Wells in and Around the Caribbean Sea Region
Authors: Segura Richard , Haq Mohammed A. , Durrant Steve 
Published: June 2012

Abstract
All oil and gas wells inevitably shifts from asset to liability, whether the result of reaching its economic limit or sustaining irreparable damage. At the end of its life cycle, a subsea well and its supporting infrastructure must be carefully dismantled to ensure they pose no safety or environmental threats and to salvage useable components. In addition to creating significant safety and environmental hazards, failure to properly abandon a subsea well can lead to a noncompliant status with regulatory agencies and undermine an operator’s image. Despite its multiple liabilities, abandonment offers no real return on investment, underscoring the importance of minimizing cost. The challenge is to retrieve the wellhead without damage so it can be used again, minimizing or eliminating damage not only to the wellhead but also to personnel and environment.
This paper will describe the technological tool system available to retrieve subsea wellheads in a single trip. This technology serves as an alternative to equipment that poses environmental and safety hazards, such as mobile offshore drilling units and explosive severance devices. By latching on to the external profile there is no damage to the internal seals. Also the external latch procedure allows more clearance to allow the cuttings to flow out of the ports and away from the working mechanism. The wellheads retrieved have a much greater chance of being re-used with minimal damage. The external latch design allow for more strength and less chance of tool failure. This paper will also discuss some global case histories.
Frac-packing Shallow Unconsolidated Reservoirs – Onshore Trinidad
Authors: Batohie G. , Maharaj G. 
Published: June 2012

Abstract
This paper presents the results from frac-packing of wells in shallow, unconsolidated reservoirs onshore Trinidad. The objectives of this type of treatment were to improve the initial production rate and consequently the net present value of the wells, as well as mitigate the productivity impairment associated with conventionally gravel packed wells.
Most of Trinidad’s onshore crude oil production is considered to be mature in that the oil reserves are still being produced by primary means with tertiary recovery methods accounting for roughly one third of total production. With declining oil production, there exists the need for higher production rates; frac packing is considered to be one suitable intervention to achieve this goal. In addition, lower skin from frac pack completions in comparison to gravel packs and the ability of the frac pack to maintain this low skin during the life of the well accrues recoverable reserves.
Treatment results show an increase in the average production rate of 200% compared to the pre-fracture rates. There is also a projected increase in recoverable reserves of 8-35% per well due an extended producing life prior to the eventual abandonment rate. The data presented in this paper provides encouraging results for future frac packing on land.
Simulation Study for Optimizing Injected Surfactant Volume in a Miscible Carbon Dioxide Flood
Authors: Afonja Gbolahan , Hughes Richard G. , Nagineni Venu , Jin Lu 
Published: June 2012

Abstract
The viability of any Enhanced Oil Recovery (EOR) method lies with its ability to increase oil recovery in an economically efficient manner. The practicality of carrying out a CO2/surfactant enhanced oil recovery operation is affected by the high cost and large volume of surfactant needed in the field.
This paper presents the results of a numerical simulation study that was carried out to analyze and establish critical parameters that can be used to obtain the minimum but most effective volume of surfactant needed for generation of foam in a porous medium which will in turn yield optimum oil production. The results obtained from laboratory experiments, which were based on the comparison of a low and high injected surfactant concentration, serve as inputs to a reservoir simulator for modeling and estimating surfactant requirements.
Numerical models were designed to simulate the co-injection of carbon dioxide and surfactant solution into a Berea sandstone core that was saturated with brine and oil after a waterflood process. Some of the values of parameters used include surfactant concentrations of 0.1 wt % and 0.5 wt %, average back pressure of 2350 psi and total flowrate of 0.4 cm3/min, with CO2 injected at 0.3 cm3/min and surfactant solution at 0.1 cm3/min, which gives a volumetric flow ratio of 3:1 and foam quality of 75%.
Results indicate that injecting a solution with a larger surfactant concentration increased foam strength with a corresponding increase in pressure drop. A decrease in CO2 relative permeability is also observed as more gas is trapped within the rock due to foam blocking. Carbon dioxide is thereby able to contact more of the oil contained within the reservoir.
Operational Challenges and Lessons Learned From Drilling an Ultradeepwater Wildcat Well in a Logistically Challenging Frontier Environment Offshore French Guiana
Authors: Peters A. , Priestley J. 
Published: June 2012

Abstract
Exploration for hydrocarbons continues to expand into frontier environments. The project management, logistical and supply chain challenges of drilling in these areas is increased due to their remoteness. This paper presents the operational challenges and lessons learned from drilling a successful ultradeepwater wild cat exploration well in a logistically challenging frontier environment offshore French Guiana.
The Role of the Oil and Gas Industry in the Transition Toward a Sustainable World
Authors: Strauss Nicolás 
Published: June 2012

Abstract
Throughout the decades to come world’s population is expected to rise as well as the energetic, food and water demand. All that, together with the everyday more rigid international environmental regulations alongside with the ongoing vertiginous technological advancement, will induce to a restructuration of global economy on the inter-governmental and institutional level in order to reinforce the fundamental pillars of sustainability: the environmental, social and economical. New energy systems will be implemented and scarcity of resources will be more severe, leading the economy not only to shift but to adapt to unconventional energy carriers and commodities. This combined with the targeted impact of these policies, concerning living standard improvements, social inclusion and carbon mitigation among others, will raise new and demanding challenges to face.
This paper intends to present an overview of the energetic playing field throughout the transition towards a more sustainable world and the role of the Oil & Gas industry within this period. This article will identify and explain the challenges and constraints to be faced as well as the opportunities of undertaking ventures in this shifting environment. Also, the paper will broaden the concept of Green Economy, main theme of the 2012 UN’s Conference on Sustainable Development, and present strategies to develop an energy system to function and sustainably endure in time within the mentioned framework and explain why the O&G industry is a fundamental participant and a major "game changer" in this process.
Petroleum holds a key role in this transition as being the most widespread energy carrier and the most competitive element of the current energy system. Therefore, the O&G industry has the opportunity to become the main "driver of change" and to impulse a more prosper and sustainable energy network for the world.
It’s imperative that the O&G sector keeps a long-term perspective in order to remain in force and profitable. This paper proposes some guidelines to do so and intends to raise awareness on the fact that sustainability is not only changing the way we analyze a project but moreover the way we do business in the O&G industry.
A New Generation of Well Surveillance for Early Detection of Gains and Losses When Drilling Very High Profile Ultradeepwater Wells, Improving Safety, and Optimizing Operating Procedures
Authors: Le Blay F. , Villard E. , Hilliard S. , Grønås T. 
Published: June 2012

Abstract
As the industry continues to expand into ultradeepwater plays, an increasing number of tight tolerance wells warrant the use of an efficient system for determining early influxes or losses during drilling, tripping, and cementing operations. The narrow mud weight window for the majority of these wells requires an advanced solution in order to operate in all such conditions without compromising on safety. This paper describes a new early detection flow monitoring system and setup for floating rigs, and presents its application via a case study of a very high-profile ultra deepwater well.
Good well surveillance for floating rigs requires precise measurements combined with an efficient smart process adapted to deepwater conditions in order to raise a reliable alarm in any condition, while minimizing the risk of false alarms. Careful sensor selection and sizing, together with particular attention to installation is required in order to achieve this degree of accuracy for all the drilling phases. The solution described in this case study provides drilling surveillance for all hole sizes, with flow up to 2000 gpm for accurate and early detection, and significantly increased safety during drilling, tripping, and cementing operations.
This case study describes how kicks can be detected with a high degree of reliability much earlier than with the standard pit volume and flow paddle monitoring. In addition to this, it has shown its value by characterizing, in real time, the consequences following a packoff event and also by differentiating between a wash out and pump failure.
Crew confidence in this detection system rapidly led to modifications of the operational procedures. For instance, flow checks were previously done for every pipe connection, taking up expensive rig time. Due to results obtained in the previous hole sections, the drilling procedures were updated in order to significantly reduce time spent flow-checking, while still maintaining maximum safety during the operations.
Understanding Trinidad Gas Reservoir Performance: Mango, Mahogany, and Immortelle Field Water Drive Reservoir Anomalies
Authors: Roopa I. , Khan Z. , Baksh K. 
Published: June 2012

Abstract
The Mango, Mahogany and Immortelle Field gas and condensate fields are located in the Columbus basin, 35-40 miles off the southeast coast of Trinidad in water depths of between 200 to 300 feet. All reservoirs are comprised of highly faulted stacked sandstone reservoir units of varying ages between Quaternary to Pleistocene. Most reservoir units are less than 0.5 tcf and are usually produced by one or two wells.
The permeability of these reservoirs varies from 10 – 2000 mD and due to the presence of both edge and bottom aquifer, water drive and subsequent water breakthrough prediction is key to understanding reservoir performance and reserves estimation. Some of the reservoirs in the Mango, Mahogany and Immortelle Field gas fields have tendencies toward pressure maintenance by natural water drive. The resultant effect of this phenomenon is not often readily apparent in the early stages of gas production.
This paper examines methods used in recognizing and evaluating this type of reservoir. The methodology here is to apply simple classical techniques before complex reservoir characterization and time consuming reservoir simulation models are built since it is not often necessary. The results of the comparison indicate the presence or absence of water drive. Results are illustrated using actual field data. It shows the "text book" Mango Field case compared to water drive anomalies from the Mahogany and Immortelle Fields; where the drive mechanism have historically been misunderstood. The earliest possible detection of water drive allows strategies to be formulated to achieve optimum conservation and economic benefits.