bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unified Model for Steady-State Foam Behavior at High and Low Foam Qualities
Authors: Alvarez J. M. , Rivas H. J. , Rossen W. R. 
Published: December 2007

Abstract
Foams are used routinely worldwide to divert acid in well-stimulation treatments and on a pilot basis to divert gas flow in improved-oil-recovery projects. The complexity of foam behavior and apparent contradictions between foam studies has bedeviled attempts to understand foams and design effective field treatments.
In 1992 Osterloh and Jante[1] identified two distinct foam-flow regimes: a high-quality (dry) regime in which steady-state pressure gradient is independent of gas flow rate, and a low-quality (wet) regime, in which pressure gradient is independent of liquid flow rate. New data for foam with a variety of porous media and surfactant formulations, over a range of flow rates, show this behavior to be general. In each regime foam behavior is dominated by a single mechanism: at high qualities by capillary pressure and coalescence, and at low qualities by bubble trapping and mobilization. A new, unified model based on these insights unites foam behavior in acid well stimulation and gas-diversion IOR and reconciles apparently contradictory data. This model correlates the effects of parameters like rock permeability and surfactant formulation on foam behavior in the two flow regimes and on the transition between the two regimes. A variety of laboratory data, including bubble sizes, support the model assumptions.
Implications of these results for design of foam processes for IOR and acid diversion are discussed. These insights can guide the selection of foam formulation and injection quality for foam applications.
Effect of Gas Enrichment above the MME on Oil Recovery in Enriched-Gas Floods
Authors: Johns R. T. , Sah P. , Subramanian S. 
Published: December 2007

Abstract
The interaction of phase behavior and flow, in the presence of dispersive mixing, is examined for 1-D four-component enriched-gas displacements. Numerical and analytical solutions demonstrate that oil recovery may be substantially increased by gas enrichment above the minimum enrichment for miscibility (MME). The level of increase is dependent on the level of dispersive mixing and the size and shape of the two-phase region.
A critical gas enrichment (CGE) above the MME is defined that separates the multi-contact miscibility region into two regions: MCM1, when the gas lies within the region of tie-line extensions, and MCM2, when the gas lies outside. For enrichments below the CGE (in MCM1), oil recovery can increase significantly with enrichment. Above the CGE (in MCM2), oil recovery is not as sensitive to enrichment for the cases studied. Displacements in the MCM1 region exhibit a combined condensing and vaporizing mechanism, whereas displacements in the MCM2 region are purely condensing.
Project of Increasing Oil Recovery from UAE Reservoirs Using Bacteria Flooding
Authors: Zekri Abdulrazag Y. , Almehaideb Reyadh A. , Chaalal Omar 
Published: December 2007

Abstract
Due to the recent decline in oil prices, most of the enhanced oil recovery (EOR) processes, and especially the ones typically recommended for light crude such as micelles, polymer, or miscible gas injection processes have become economically unattractive. The oil industry currently is in dire need of a reasonable cost process that can both technically and economically be successful. For this reason, a tremendous amount of research effort was directed at UAE University to investigate the possibility of using bacteria, which is a minor cost material, to improve the oil recovery in UAE oil reservoirs.
This project focused initially on the study of the interfacial tension (IFT) between crudes from four different UAE reservoirs (BH, UZ, St, and UAD) and a thermophilic bacteria solution. The bacteria were obtained from local water tanks. The system temperature was varied between 30°-100°C and salinity ranged from 0 to 100,000 ppm. Tertiary bacteria solution core flooding experiments were then performed using carbonate rocks at reservoir conditions without injection of nutrient with the bacteria during the core flooding experiments. A good amount of effort was directed, throughout the work, to characterize the bacteria used and identify the mechanism by which bacteria works to improve the oil recovery.
Results of these laboratory studies show an abrupt reduction in IFT at high salinity and high temperature (i.e. reservoir condition) for all studied systems except for the St crude, which was sulfur rich. The IFT decreased from 40 dynes/cm to 0.07 dynes/cm for most of the studied systems. Also, tertiary bacteria flooding at reservoir conditions, on average, resulted in an incremental oil recovery of 15 to 20 % of the pore volume.
Cryo-SEM and ESEM: New techniques to Investigate Phase Interactions within Reservoir Rocks
Authors: Robin M. , Combes R. , Rosenberg E. 
Published: December 2007

Abstract
Recent advances in scanning electron microscopy allow the observation of liquid samples, either under a frozen state in the case of Cryo-SEM (Cryo Scanning Electron Microscopy) or directly with ESEM (Environmental Scanning Electron Microscopy).
In the case of sandstones, cryo-SEM studies have pointed out the special affinity between kaolinite and oil after aging, and shown the importance of both amount and distribution of kaolinite on wettability behavior at the core scale. Good correlations were found between observations at the pore scale and wettability indices. Wettability alterations were shown to be very sensitive to thermodynamic conditions (pH, salinity, etc.).
It has also been used to study the impact of the spreading coefficient on oil recovery by gas injection. It has been experimentally shown that both wettability and spreading could affect gas injection efficiency by controlling the distribution of the three phases at the pore level. It proved to be efficient in other studies such as emulsion characterization or asphaltene deposition.
The main advantage of ESEM is to operate under reduced pressure and to allow the observation of liquid-containing samples without any special preparation. Combined with Energy Dispersive X-ray Spectroscopy (EDS), it also allows elemental analysis.
It has successfully been used to investigate the sensitivity of different clays to freshwater, to characterize oil base muds, to analyze formation damage mechanisms and to improve acid stimulation.
Dynamic experiments are also possible such as drying, freezing or even capillary flows.
ESEM allows wettability estimation by direct visualization of both oil and brine in their liquid state; it has confirmed the results obtained by Cryo-SEM and the correlation between fluid distribution with either pore structure (carbonate) or mineralogy (sandstone).
Defining Reservoir-Rock Properties, Deep-water Depositional Facies of the Qua Iboe member, Pliocene, Offshore Nigeria
Authors: Joiner S. D. , Kreisa R. D. , Bloch R. B. , Paul J. B. 
Published: December 2007

Abstract
Reservoir facies provide the critical interrelationships among (1) basic reservoir lithologies, (2) reservoir properties, and (3) wire-line log measurements. In addition, each reservoir facies is linked to its depositional environment, thus providing the basis for understanding its three-dimensional geometry and interconnection. A reservoir-facies classification has been designed for the deep-water deposits of the Pliocene Qua Iboe Member of the Agbada Formation as they occur in Mobil Producing Nigeria's (MPN) Joint Venture Acreage. The facies are based on lithology and registered to laboratory-measured reservoir properties. Grain-size characteristics such as size, sorting, and terrigenous mud content are the principal factors that control reservoir properties. All reservoir facies have been precisely quantified in terms of routine and special core analysis and their compatibility with completions fluids has been tested. Furthermore, quantitative wire-line log criteria have been developed, allowing recognition of the reservoir facies in uncored wells with considerable accuracy. Log and reservoir properties associated with the facies are tailored to burial depth for each field, and even different reservoirs within a single field. Using these standardized classification schemes for all MPN reservoirs allows for better communication among reservoir technologists and the transfer of insights gained from one field to other fields.
Exploring Mature Areas: The Role of Technology
Authors: Krol D. E. , Noual V. , van Maren P. J. T. 
Published: December 2007

Abstract
The UK North Sea is mature after 30 years of exploration. The application of new technology to continue the discovery and development of smaller reserve base fields is essential. Advances in 3D seismic acquisition have enabled improved subsurface imaging. Ocean Bottom Cable (OBC) seismic can improve imaging of fields overlain by gas chimneys. PreStack Time and Depth Migration have contributed to better definition of steeply dipping prospects underlying diapirs. Amplitude Variation with Offset (AVO) can reduce exploration risk in a proven play. Quantitative interpretation techniques (e.g. seismic inversion) can be used to image reservoir units in mature areas. High resolution geochemistry can also assist intra-reservoir characterisation. New drilling techniques (e.g. multilateral wells) can unlock fault blocks, layered reservoirs or small outstep accumulations. Extended reach drilling from platforms is also effective in mature areas. Long distance subsea tiebacks, for both high pressure/ high temperature and low energy fluids, can make the development of small and remote hydrocarbon accumulations feasible. The Shell Expro multi-discipline organisation has identified new practices for exploration/keeper well design and equipment procurement which reduce the time between field discovery and first production. Innovative engineering designs are unlocking small field development. New commercial practices are also required to facilitate application of technology in mature areas.
The Other Millennium Dome
Authors: Hodges Sean , Line Charles , Evans Bob 
Published: December 2007

Abstract
A large (&gt; 300 km2) dome-shaped structure (Ben Nevis dome) lies beneath a thin basalt layer in the far north of the UK continental shelf. A large gravity and magnetic anomaly (known confusingly as Brendan's Dome) lies only 20 km to its north-west. Shell/BPA⁎ modelled these features using high-resolution gravity and magnetic datasets and concluded that, whereas the anomaly is generated by an igneous intrusion, the Ben Nevis dome is composed of sedimentary material. A 3D seismic survey was subsequently acquired over Ben Nevis, greatly improving imaging of the sub-basalt dome, and also showing fine details of the intra-basalt structure. After considering several models for the formation of the Ben Nevis dome, Shell/BPA's preferred model is that it was probably formed by localised inversion of a Cretacous graben-fill when the adjacent Brendan's Dome gabbroic pluton was intruded.
The Search for Mountains of Oil: Exploration Activity in the Atlantic Margin, West Of Shetland
Authors: Parr R. S. , Cowper D. , Mitchener B. C. 
Published: December 2007

Abstract
BP Amoco and Shell have been major participants in the exploration activity in the deep water, West of Shetland, U.K.C.S. which has led to two new oil fields producing less than 6 years after discovery. The discovery of Foinaven and Schiehallion, both named after Scottish mountains, not only involved detailed technical understanding of the seismic response and rock properties, but also commitment by the participants to the vision of opening a new basin.
This paper reviews the historical exploration effort West of Shetland (W.o.S.) and then focuses on BP's discovery of both the producing fields. It describes the critical role of integrating careful seismic processing/analysis with the rock and fluid properties to exploit the Direct Hydrocarbon Indicators (D.H.I.'s). These were applied to reduce exploration risk and build the drilling strategy.
The discoveries also fundamentally changed the oil industry's perception of the basin. This led to a large investment in new acreage, widespread 3-D seismic surveys and a flurry of deepwater drilling activity. However, to date, no commercial discoveries have been announced outwith the main Foinaven-Schiehallion fairway. This paper concludes with an overview of the type of future opportunities that may exist within the basin.
Digital Imaging for Subsea Operations: Innovative ROV Tooling and Image Analysis Combinations for Mooring Chain Assessments Yield Cost Savings and Operational Confidence for Offshore Operators
Authors: Hall Anthony D. , Lethbridge Gail M. 
Published: December 2007

Abstract
Welaptega Marine Limited with the support of Shell UK Exploration and Production Limited and Total Oil Marine UK has developed and commissioned a system for the in situ measurement of offshore mooring chains. The chain measurement system (CMS) is deployed by ROV and functions as an optical caliper. After a series of trials and operational programs the system has proven itself to be a cost-effective and powerful analytical addition to the IRM tool arsenal for floating installations. It provides operators with opportunities to track the wear of chain moorings overtime, and to use the information to both anticipate and thereby avoid the failure of mooring systems, and to optimise logistic and cost planning related to the replacement of offshore mooring chains.
FPSOs Lessons Learned
Authors: Knowles N. , Selwa J. R. , Bankes G. J. 
Published: December 2007

Abstract
FPSO Developments have become a popular choice for smaller fields around the world. However, the majority of developments have encountered significant problems with design/operation and/or project overruns. This paper, based on a study carried out by IGL Engineering Ltd., for the Offshore Safety Division of the UK Health & Safety Executive reports on the principal types of problems encountered, discusses the underlying causes and proposes appropriate remedial actions to prevent recurrence on future projects.
The Gullfaks Satellites: New Subsea Technology, Start Up and Operational Experience
Authors: Knudsen Tor Willgohs 
Published: December 2007

Abstract
Norway's Gullfaks South, Rimfaks and Gullveig fields have now been tied back to the Gullfaks A platform. Production began on 10 October 1998. Innovative technology has been adopted from subsea wellhead to platform. Developed faster and more cheaply than any comparable previous project in the North Sea, these satellites will make an important contribution to continued profitable operation of the main field.
A major goal for this Gullfaks satellites project (GFSAT), operated by Statoil, was to reduce the cost of subsea installations by 40 per cent compared with the group's earlier Statfjord satellites project. This objective has been met. All facilities have now been successfully installed, but not all the objectives for quality assurance of design and fabrication were met. This caused some problems for completion and production operations.
Further development is now under way in the Gullfaks area, covering gas reserves in Gullfaks South and Rimfaks for export to continental Europe. This GFSAT Phase 2 project, due to come on stream in October 2001, will use more or less the same subsea technology as Phase 1 but with some improvements. It again involves substantial modifications to the Gullfaks C and A platforms.
Dynamic Underbalanced Drilling Effects are Predicted by Design Model.
Authors: Rommetveit R. , Saevareid O. , Lage A. C. V. M. , Guarneri A. , Georges C. , Nakagawa E. , Bijleveld A. 
Published: December 2007

Abstract
A dynamic model for underbalanced drilling has been developed in a joint industry project. The model is of use for planning an operation, and especially evaluations of dynamic pressure and flow effects. Use of the model can help prevent excessive pressure transients during operations, which will have negative effects on well productivity.
Experiments have been performed in a vertical, extensively instrumented, test well. The experiments focused on dynamic operations; such as kick-off or unloading, changes in liquid and/or gas injection rates and pipe connections as well as "steady state" periods. The tests were performed with either "parasite string" gas injection, or drillstring gas injection.
Simulations with the dynamic model has been performed, using experimental quantities as input (geometries, liquids, rates etc.)
Results show that the model performs very well for "parasite string" gas injection. For drilling gas injection system, the model performs well for low and medium gas rates. For very high gas rates, there is still room for improvements.
Well Construction, Competency, and the Tay Bridge Disaster
Authors: Laing C. M. 
Published: December 2007

Abstract
This paper makes uncomfortable comparisons between the Tay Bridge Disaster and some of today's well construction projects. It relates lessons learned from that disaster to the UK Design and Construction Regulations for wells and explores the importance of competency. It argues for more open access to information related to accidents and dangerous occurrences and for more sophistication in personnel selection.
Radical Solutions Required: Completions Without Packers and Downhole Safety Valves Can Be Safe
Authors: Durham Craig J. , Paveley Craig A. 
Published: December 2007

Abstract
In most countries the legislation regarding the design and operation of oil and gas producing wells does not specifically prescribe production packers or downhole safety valves. When interpreting the legislation, Operators generally specify a requirement for double barriers in wells that can sustain natural flow. Production packers and downhole safety valves are used commonly in completions to satisfy this requirement. The resulting policies provide a standard for well barriers and define an operational envelope that ensures pressure integrity and environmental protection consistent with safe operating practice. Through detailed risk and hazard analysis it has been possible to demonstrate that the elimination of packers and downhole safety valves from completions can be tolerated while achieving substantial savings through reduced equipment, workover and intervention costs. This paper summarises some of the reasoning and methodology used to justify the elimination of packers and downhole safety valves from completions and encourages the wider use of risk-hazard analysis techniques to develop more radical completion solutions.
Experiences and Learning Points From the Use of Steerable Rotary Drilling Systems on Northern North Sea Platforms.
Authors: Poku Ernest K. 
Published: December 2007

Abstract
KCA Drilling is incentivised under their lead contractor relationship with Shell Northern Business Unit (NBU) to introduce such technology as can be economically justified to improve drilling performance. One of the ways this aim was achieved in 1997 was the investigation and introduction of alternative BHA technology. One technology that has been introduced is Steerable Rotary Drilling (SRD) which was undertaken in late 1997 to improve on the overall ROPs observed with bent subs and mud motors. This technology was perceived by Shell Well Engineering as becoming a high priority due to the increasingly complex wells being drilled in the NBU. The tools were used in the 8 ½" hole section through a combination of Cretaceous shales and Jurassic sandstone formations on two wells. There have been some successes and some important learning points from the initial campaign which involved the drilling of around 15,500 ft of 8 ½" hole with the new technology across two wells. Quantitative information on achieved ROPs, rotary speed requirements, doglegs achieved and the Mean Time Between Failure (MTBF) of the SRD tool are detailed in the text. This paper details the benefits of SRD technologies in low dayrate environments and the prospects of enhancing overall drilling performance thereby reducing the costs of marginal wells. The paper also details a consistent approach for selecting suitable well candidates for the application of rotary steering technology in comparison to oriented steering based on an equation that incorporates technical factors including ROP, rig dayrate and SRD tool economics. The paper also explains ongoing work to improve and enhance the SRD tools further for more demanding applications. It also details the effects the alternative BHA characteristics are having on other technologies in the oil industry e.g. PDC bit design and cementing.
The NeuRobot Project: Advances in Drilling Technology for the New Millenium
Authors: Harris T. W. R. , Vullinghs P. J. J. 
Published: December 2007

Abstract
Coiled Tubing Drilling, and wider reeled systems, is being established within the industry as a highly promising technology development. This has the potential to significantly cut well costs and add value to numerous hydrocarbon field development projects. To realise such benefits, Shell U.K. Exploration and Production (Shell Expro), operator in the U.K. sector of the North Sea for Shell, Esso and other co-venturers, are working on "The NeuRobot™ Project", which can produce an advanced subsea well field development system, made up of three main technology drives
Advanced well-bore construction technology comprised of expandable solid tubulars, which can be used to construct reeled monodiameter wells An intelligent reeled drilling system incorporating advanced geosteering technology Small, highly automated, dynamically positioned, reeled system drilling vessels.
The paper will review the past development, current status and future strategy of the NeuRobot™ Project, highlighting the benefits of the numerous individual technologies that define NeuRobot™.
Solving Sanding Problems using a Sand Production Management System. Case Histories
Authors: Webster Craig McK. , Tovar D Juan J. 
Published: December 2007

Abstract
In this paper three case studies are presented of a Sand Production Management System (SPMS™) used to successfully predict, evaluate, resolve and manage sand production problems. These cover drilling and production problems in Lake Maracaibo, a subsea development in the North Sea and a prediction and management in the Far East. As a primary feature, the SPMS™ integrates the geomechanical characteristics of a reservoir, its deliverability and equipment performance throughout the life of the field. The system is based on a geomechanical model that determines the in-situ rock properties and field stresses then predicts the changes that will occur during reservoir depletion. Critical issues addressed include optimum well deviation and orientation, borehole size effects, critical production conditions, time to abandonment and sand control measures. In each of the cases, both drilling and production performance were improved significantly while minimising or avoiding sanding problems.