bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Ultrasonic Waves on Immiscible and Miscible Displacement in Porous Media
Authors: Hamida T. , Babadagli T. 
Published: December 2007

AbstractInsight into the physical principles governing the mobilization of oil by ultrasonic waves is vital for developing novel techniques of oil extraction. Various mechanisms such as peristaltic transport due to mechanical deformation of the pore walls, reduction of capillary forces due to the destruction of surface films, coalescence of oil drops due to the Bjerknes forces, oscillation and excitation of capillary trapped oil drops, forces generated by cavitating bubbles, and sonocapillary effects may be responsible for enhancing the flow of oil through porous media in the presence of an acoustic field.This paper aims at analyzing the influence of high-frequency, high-intensity ultrasonic radiation on the immiscible and miscible displacement in porous media. Capillary imbibition (co- and counter current) and viscous displacement (Hele-Shaw) experiments were performed with and without ultrasonic waves.We observed that the increase in ultimate recovery is more pronounced than the increase in recovery rate when ultrasonic waves were applied in capillary imbibition experiments. The cases yielding enhancements on displacement efficiency (higher recovery rate and lower residual oil saturation) due to ultrasonic effects were identified.To analyze the viscous displacement under ultrasonic waves, experiments were performed on Hele-Shaw models. Immiscible (for mineral oil-brine and mineral oil-surfactant pairs) and miscible (for mineral oil-pentane, mineral oil-kerosene and mineral oil – 2-Propanol pairs) displacement experiments were performed. Changes on the displacement fronts and patterns were observed under ultrasound. Fractal techniques were used to analyze the changes and correlate them to the intensity of ultrasonic waves.
High CGR Facilities Optimization Using a TMFS
Authors: Al-Taweel A. B. , Alvarez-Cohecha C. J. 
Published: December 2007

Abstract
This paper discusses a method for selecting pipeline sizes and receiving facilities suitable to wet gas wells for new field development. It involves the use of a modern Transient Multiphase Flow Simulator (TMFS) for building detailed network models, and its results have been validated by measurements. Gas wells considered in the study cover a wide range of Condensate Gas Ratio (CGR) 20-294 bbl/MMSCF, 8"-30" pipeline sizes, and 4 km-130 km pipeline lengths. Most previously published data on gas-condensate networks were for pipeline length less than 100 Km and liquid content range of 1-130 bbl/MMSCF compared to the subject fields.
A minimum gas velocity of 15-18 ft/sec is required for continuously sweeping liquid and preventing load-up in the studied pipelines to prevent slugging. The gas-liquid ratio does not appear to significantly influence the minimum sweep velocity in the studied range of liquid content, consistent with previous industry published data in a 1-130 bbl/MMSCF range. Variables that have been analyzed include pressure drops, pipeline liquid inventories, hydrocarbon liquid holdups, and slugs generated by rate changes and scraping operations.
Use of modern transient multiphase flow technology provided accurate predictions of gas-well pipeline design. These can be used to select optimum pipeline sizes, which will result in increased gas production and operational flexibility. At high flow rates, the high gas velocity provides an effective liquid transport, allowing a low pipeline liquid content. At low flow rates, the liquid phases, and in particular the aqueous phase will start accumulating in the pipeline increasing pipeline corrosion risk.
Using a Transient Multiphase Flow Simulators eliminated the need for field separation and aided in selecting pipeline sizes based on cost effectiveness analysis. Smooth operation of receiving facilities was also achieved via stable delivery of gas and liquids to process.
Gas-System Safety Evaluation Using a TMFS
Authors: Al-Taweel A. B. , Currie R. D. 
Published: December 2007

Abstract
Transient Multiphase Flow Simulators (TMFS) can be valuable tools in defining operational strategies for multiphase flow systems. The consequences of changes in operating conditions are difficult to predict, but they can be accurately represented using accurate TMFS models. Safety analysis and the ability to describe propagation of pressure fronts are important applications of a TMFS. A TMFS may be useful for safety analysis in the design phase of pipeline project, such as the positioning of valves, regulation equipment and measuring devices. Critical ranges in pipe monitoring equipment may be estimated and emergency procedures investigated.
This paper presents two case studies for applications of a TMFS. The first is development of a well tubing phase envelopes to determine operating parameters for gas wells, and the second is evaluation of the safety design aspects of a high volume, high pressure gas gathering system based on modelling of the system with a TMFS.
Tubing phase diagrams for high pressure gas wells provide a method of selecting operating conditions to prevent corrosive water condensation in tubing strings. A three-phase envelope was created that represented the flow regime in well tubing. Flow analysis, using a TMFS, allowed for selection of the proper operating range for the well for the given tubing.
Building a network dynamic model for a two-phase, high pressure gas gathering system aided in selection of Wellhead Emergency Shutdown system (WSD) and production manifold relief settings. The model allowed evaluation of the gathering system safety devices and consequences of failures for events such as Emergency Shutdown (ESD) valve closures and pipeline ruptures. A secondary benefit of the model development was verification of the design MAOP and sizing of the gas gathering system.
Step Change Towards a Zero Incident Work Environment— Managing the Human Factor
Authors: Grant P. J. , Senior L. M. , Lake J. H. 
Published: December 2007

Abstract
Safety results within the oil & gas industry have shown continuous improvement in the last decade, with particular focus placed on the equipment and process elements. The challenges faced in reaching and maintaining a zero incident work environment will now hinge around managing the "human factor" whilst also maintaining the equipment and process standards achieved to date. To influence the results we will have to influence the people.
In 1999, we presented a paper in the Aberdeen SPE conference based upon a proactive observation and feedback process – people were the focus. In 2004, at the SPE Calgary SPE conference we presented a paper on Performance Leadership Coaching, again focusing on the potential of fully appreciating the human factor.
Now, after extensive research and testing involving over 2000 workers, the ability to better manage the "human factor" has been uncovered, and a method for practical application established using the "e- colours process". We have developed and refined a process for using personality traits, not only as a communication tool but also as a risk management tool. This methodology is being tried and tested offshore today.
It has always been stated that there is no "silver bullet" when it comes to safety. Yet we all seek the next step change in safety excellence and the results that goal implies. If indeed we are to make the paradigm shift required then it will only come through taking the time and effort to understand human being's actions and reactions, in a context that any roustabout, roughneck or supervisor, can appreciate while working on the job at hand.
What has become evident through our extensive research in the field, offshore, is a clear picture of an element that has eluded us in the past.
People of the same personality traits and tendencies (identified by us using the e-colours) do in fact, have the same approach to safety and their perception of risk tolerance, even to a point of predicting, when asked, how they could get hurt.
This process very much supports the ethos of the SPE conference which is founded upon "Living and Working in Harmony". This can only be achieved by understanding the people with whom we work.
We have some clear examples of how this process works and indeed how lives could have been saved if utilised.
Modeling of Initial Saturation Distributions in Oil/Water Reservoirs in Imbibition Equilibrium
Authors: Bech N. , Frykman P. , Vejbæk O. V. 
Published: December 2007

AbstractA new technique is presented for the modeling of initial saturations in water wet oil/water reservoirs with large transition zones that have been exposed to imbibition as a result of structural tilting, hydrodynamic effects, gas cap leakage or compaction, or water influx during production. The method quantifies the extent of imbibition that the reservoir has undergone and determines the locations of the existing and the original, paleo free water levels. This is done by matching calculated and log derived water saturations utilizing existing empirical correlations for drainage and imbibition capillary pressure curves. From this information, the saturation in reservoir regions without well control may be computed.In addition, a method is proposed for the identification of imbibition conditions. It is based upon an estimation of the capillary pressure from logged saturations. If a plot of the capillary pressure vs. depth deviates from a linear trend it is an indication of imbibition.The new method has been tested by field data from the North Sea. It is shown that the method can capture a large residual oil zone and a free water level far above the oil-water contact and that it is able to establish a good approximation to the saturation distribution resulting from the imbibition. It is also shown that a considerable error in the initial saturation distribution, and hence in the oil-in-place estimate, may be introduced if imbibition is not taken into account.
Marine Biodiversity—Exploring the Deeps
Authors: Walls A. , Clarke J. 
Published: December 2007

Abstract
As exploration and production move into ever deeper waters, the tools and techniques for assessing the environmental impacts of deepwater projects are being developed.
This paper outlines the various complimentary techniques that BP Angola is using to describe biodiversity and to monitor the environment in water depths ranging from 1200m to over 2000m. These include: wide ranging, snap-shot in time benthic surveys, which are targeted based on the geophysical information we have in the area mainly looking at seabed microfauna, using a variety of physical and photographic sampling techniques, including the deployment of BP Angola's deepwater short term environmental platform.Short range, extended timescale monitoring with Remotely Operated Vehicles of opportunity mainly photographic looking at larger animals, with trials of traps to gather microfauna. The ROV also photographs animals within the water column as it travels between the rig and the well.Observations of marine mammals, turtles, birds and surface visible fish from seismic and survey vessels.Long term (25 years) monitoring of deep ocean environmental processes with the deployment of deep sea environmental platforms; a cooperative project involving Scripps Institution of Oceanography, Aberdeen University, Texas A&M University at Galveston and Southampton Oceanographic Centre. These platforms should help us understand the linkages between deepwater biodiversity and climate change.
The data gathered is used in managing the environmental impacts from our operations and also in our Environmental Impact Assessments. In addition,the data is shared with the wider scientific community and used in local capacity building to ensure added value.
The described techniques represent a major step forward in the characterisation of deepwater environments and are applicable in other deepwater areas.
Case Study: Detailed Hydraulic Fracture Analysis Leads to a Better Understanding of a Complex Reservoir
Authors: Rovira A. M. , Jacot R. H. 
Published: December 2007

Abstract
A detailed fracture history matching study coupled with initial flowback production data from a five well drilling program led to a better understanding of the Wilcox formation. The purpose of the study was to determine the source of excess water production from the Lower Wilcox. This paper describes a hydraulic fracture study performed on 26 fracture treatments completed in the Middle and Lower Wilcox zones located in South Conroe, Texas.
Treatment data, which included surface treatment pressure, slurry rate, and proppant concentration, were analyzed with a pseudo-3D fracture model1 to determine fracture geometry and conductivity. Minifrac and After Closure Analysis2 (ACA) were performed to provide estimates of fracture fluid efficiency, closure pressure, reservoir transmissibility, and reservoir pressure. Non-ideal leakoff behavior identified in a large percentage of the minifracs complicated the analysis. The limited Repeat Formation Tester (RFT) and core analysis data were used to validate permeabilities estimated through ACA techniques.
The results of the study indicate that the fracture geometries were consistent with the original fracture designs, confirming the fractures were treating the targeted zones. Fractures were slightly more contained in the Middle Wilcox due to lower net to gross sand ratios than seen in the Lower Wilcox. The fracture study influenced a re-interpretation of previous log analysis for the Lower Wilcox, which concluded that the Wilcox in this field contained short gas columns with long transition zones, accounting for the high water production.
This combination of detailed minifrac analysis, ACA, and pseudo-3D fracture modeling led to a better understanding of the complex nature of the formation and an optimized fracture design for any future completions. Learnings and techniques applied in this study can be used to improve and optimize hydraulic fracture treatments in reservoirs in other geographic areas.
A Study of Branched Alcohol Propoxylate Sulfate Surfactants for Improved Oil Recovery
Authors: Wu Y. , Shuler P. , Blanco M. , Tang Y. , Goddard W. A. 
Published: December 2007

Abstract
This investigation considers one class of anionic surfactant, a series of branched alcohol propoxylate sulfate surfactants, as candidates for chemical EOR applications. This experimental results show that these surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (IFT) at dilute concentrations, and without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low IFT at several percent sodium chloride concentrations, and hence may be suitable for use in more saline reservoirs.
Adsorption tests onto kaolinite clay indicate that the loss of these surfactants can be comparable to or greater than other types of anionic surfactants.
Surfactant performance was evaluated in oil recovery core flooding tests. Selected formulations could displace most of the waterflood residual oil in place even with dilute, 0.2 wt% surfactant solutions from Berea sandstone cores.
Case Study: Cased-Hole Density Application, North Slope, Alaska
Authors: Hupp D. , Bennett L. , Campaign W. 
Published: December 2007

Abstract
This paper provides a case study of the techniques used to acquire, process, and interpret cased hole density data combined with logging-while-drilling (LWD) resistivity data for completion decisions in a sidetrack well from the North Slope, Alaska. Density data, acquired through 3.5-in. casing, augmented the openhole LWD resistivity and gamma ray data used to investigate possible water breakthrough and formation water saturation before completing this well. The cased hole density data were critical to this decision because they were not available with LWD, could not be acquired in an open hole because of borehole conditions, and were necessary for porosity determination. Formation lithologic effects precluded the use of alternative through-casing porosity measurements such as neutron log data.
After acquisition, the density data were processed to account for casing and cement effects and were then compared with offset density data for quality-control purposes. A petrophysical analysis was performed using this processed density with the LWD resistivity and gamma ray (GR) information to aid in the completion decisions. The objective of determining if water breakthrough had occurred was met, and this well was perforated and fractured accordingly. Well tests indicated the presence of low water cut and competitive oil rates, which confirmed the petrophysical interpretation.
The ability to acquire accurate formation density data after casing had been set reduced completion decision uncertainty. This added another tool to the completion decision process while this field was developed.
A New Algorithm for Retrieval of Air Quality from Landsat TM7
Authors: San L. H. , Jafri M. Z. M. , Abdullah K. 
Published: December 2007

Abstract
An algorithm for remote sensing applications of air quality over land using Landsat TM7 has been developed. The algorithm was developed base on the aerosol characteristics in the atmosphere and the data from visible bands were employed. The surface reflectance values in the visible bands (red and blue), were retrieved using dark targets with reference to the mid-infrared band data at 2.1 micron. This algorithm was tested using a satellite Landsat TM7 data acquired on 6 March 2002. The in situ PM10 measurements were collected simultaneously with the acquisition of the satellite image. The atmospheric component reflectance and apparent temperature values were extracted corresponding to the ground-truth location and later used for algorithm regression analysis of the air quality. The measured and estimated particulates of size less than 10-micron (PM10) were highly correlated with linear correlation coefficient (R) of 0.9. Finally, a PM10 map over Penang was generated using the proposed algorithm. An average filter of window size 3 by 3 was used in this study to remove noise from the image. The image was then colour- coded for visual interpretation. This study indicates that the remote sensing data could be used for air quality mapping.
Production Monitoring Through Openhole Gravel-Pack Completions Using Permanently Installed Fiber-Optic Distributed Temperature Systems in the BP-Operated Azeri Field in Azerbaijan
Authors: Brown G. , Field D. , Davies J. , Collins P. , Garayeva N. 
Published: December 2007

Abstract
This paper describes the use of fiber-optic distributed temperature systems to monitor production from BP's Azeri field in Azerbaijan and highlights the benefits and issues encountered during the start-up of the first production wells.
Production from BP's Azeri field in the Caspian Sea commenced in February 2005. These offshore wells are completed across multiple sand intervals using sand screens with gravel packs. Each fiber-optic monitoring system was installed with the completion in a purpose-built groove in the side of the gravel-pack screen. The screen is connected to the upper completion string via a hydraulic wet-connect enabling fiber passage from surface to total depth.
The primary Azeri reservoir consists of multiple sand bodies in the Pereriv formation. Commingled completions across these sand bodies are providing wells capable of producing more than 40,000bopd. The issues that dictate the requirement for regular distributed temperature (DTS) monitoring are long, high-angle well bores and the need to understand well and reservoir performance by sand body. Additionally, the requirement for minimal production interruptions during the early years of field life does not favor conventional production logging, which would also cause interruptions to the drilling program.
A thermal model is used to analyze the producing well temperature profiles and calculate the flow contribution from each of the producing zones.
The results demonstrate that, once deployed, permanently installed fiber-optic distributed temperature monitoring is a cost-effective and low-risk method of monitoring multiple-pay sand screen completions without having to reduce production rates to allow conventional production logging to be carried out.
Successful Pinpoint Placement of Multiple Fractures in Highly Deviated Wells in Deepwater Offshore Brazil Fields
Authors: Surjaatmadja J. B. , Miranda C. , Rodrigues V. F. , Graças F. C. M. das , Silveira M. A. , Neumann L. F. , Fernandes P. D. 
Published: December 2007

Abstract
The application of hydrajet technique to stimulate highly-deviated and horizontal wells has become a successful method to improve well productivity for different field conditions in the world.
In the past 2 years, an operator company has successfully implemented a relatively new hydrajet stimulation technique in shallow waters off Brazil. In deepwater locations, additional problems had to be overcome, which proved achievable using this new technology.
This paper discusses a reservoir-based methodology to determine the optimum number of transversal fractures for a horizontal deepwater well. The method starts with the review of geology and stratigraphic aspects of the field to better understand the relationship between fracture orientation, geological faults, and regional tectonic effects.
With this preliminary characterization, well-log interpretation of the pilot well and horizontal wellbore is performed to identify porosity and permeability index of the carbonate formation being drilled.
A study using well testing and nodal analysis is conducted to verify reservoir properties based on real production data. Next, a numerical simulator is used to obtain a production forecast varying the number of transverse fractures intersecting the well. Finally an economic evaluation of net present value vs. number of fractures is performed to determine the optimum number of transversal fractures.
Production results are then evaluated and compared to the other stimulation attempts in offshore horizontal completions in the area.
The Impact of Shale Barriers and Injection Strategy on CO2-Flooding and Sequestration Performance
Authors: Janssen P. H. , Bossie-Codreanu D. 
Published: December 2007

Abstract
In this paper the impact of stochastic shale barriers and injection-strategy on recovery-factor and sequestration capacity have been investigated for secondary CO2-floods in horizontal oil reservoirs. Permeability fields, shale size and shale fraction have been varied in several numerical simulations and the calculated oil recovery factors have been correlated to a dimensionless number relating the viscous to gravity forces. The results show that for relatively homogeneous reservoirs the impact of shale barriers can be accounted for using an upscaled vertical permeability and that a unique relationship can be found between recovery factor and ratio of viscous to gravity forces. For layered reservoirs the impact of shales depends very much on the vertical layer permeability arrangement, pressure drop ratio, and optimisation of injection strategy. Based on the best field characterisation (permeability and shale barriers), injection strategies aim at simulating an overall CO2 injection in all layers, followed by an analysis of the flooding mechanisms, and ending with an optimisation of the vertical conformance. This is recommended especially for low to intermediate pressure drop ratio.