bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the Effects of Cesium/Potassium Formate Fluid on Well Log Response—A Case Study of the Kristin and Kvitebjorn Fields, Offshore Norway
Authors: Pedersen B. K. , Pedersen E. S. , Morriss S. , Constable M. V. , Vissapragada B. , Sibbit A. , Stoller C. , Almaguer J. , Evans M. , Shray F. , Grau J. , Fordham E. , Minh C. C. , Scott H. , McKeon D. 
Published: December 2007

Abstract
Kristin is a high-pressure, (90 MPa), high-temperature (exceeding 160°C) gas condensate field operated by Statoil ASA. Kvitebjorn is another gas condensate field with slightly lower pressure and temperature around 78MPa and 150°C respectively. In some of the production wells in these fields, a blend of cesium and potassium (CsK) formate was selected as the drilling fluid, to ensure a stable mud density for well control and in order to reduce formation damage.
Formate muds present a serious challenge to well-log interpretation because both the mud and the filtrate have properties significantly different from conventional oil-and water-based muds. The nuclear log properties of CsK formate that are particularly challenging include high density, high photo electric factor (Pe), low hydrogen index (HI), and high thermal neutron capture cross-section (Sigma). To quantify the borehole and invasion effects on logs acquired in this environment, extensive laboratory experiments and mathematical modeling were carried out for relevant wireline (WL) and logging -while- drilling (LWD) tools.
The laboratory measurements confirmed dramatic effects on nuclear tools. These effects increase with increasing formate fluid density and depth of invasion of the formate fluid. The effects of fluid invasion were so severe that porosity estimation from nuclear logs appeared to be unattainable, unless invasion is shallow and precisely known. LWD data acquired in the first well confirmed these large effects and showed significant changes with time. It was observed that the effect of CsK formate is relatively less on wireline density logs when compared to that of LWD density logs. The proposed explanation is that a significant quantity of gas was present in the invaded zone at the time of WL logging. Nuclear modeling demonstrated that such an explanation is plausible. The basic design differences between WL and LWD tools may also be contributing to the effect.
This case study demonstrates that a reasonable log interpretation is possible in wells drilled with heavy formate muds, albeit with reduced accuracy and precision.
Prediction of Injection-Fluid Distributions for Multiple Zones—Intelligent Injection System
Authors: Sun K. , Konopczynski M. R. 
Published: December 2007

Abstract
Injection fluid distributions present a challenge for the applications of multi-zones intelligent well injection systems. This paper presents two approaches to fulfill this need. The first approach is to apply the available downhole real-time data to calculate fluid distribution based on the existing single phase flow modeling and flow coefficient (Cv) test data of down-hole Interval Control Valve (ICV). For this method, a fluid distribution model for a multi-zone intelligent injection system is derived, and an example of the application of the first method is presented. For the second approach method, zonal reservoir pressure/temperature and injectivity data are considered in the fluid distribution calculation. This method is based on a balanced pressure-system approach. In this paper, each of these fluid distribution prediction methods considers the choke setting of the multi-position ICV, the completion string's geometric sizes, injection fluid characteristics, available wellhead pressure/temperature data, and the reservoir pressure/injectivity data (or measured down-hole real-time data) to do the fluid distribution prediction.
To demonstrate these methods, a hypothetical example of a two-zone intelligent water injection case is illustrated in this paper. The example shows how to use the wellhead pressure/temperature data, zonal reservoir pressure/injectivity data (or measured down-hole real-time pressure/temperature data), with completion string's geometry sizes and ICV positions to predict injection fluid distributions through each zonal ICV. An intelligent injection system operation analysis has been presented based the theoretical models and illustrated example.
The technical contributions of this paper include: Present mathematical models which apply the available downhole real-time data to calculate fluid distribution.Propose a balanced pressure-system search method which applies the zonal reservoir pressure and injectivity to calculate fluid distribution.Present an intelligent injection system operation analysis, which reveals the key roles of changing ICV position and wellhead pressure in the controlling of injection fluid distributions.Present an effective way to handle down-hole realtime data for intelligent injection system.
Rehabilitation of Complex, Massive, and Aged Pipeline Infrastructure in the Gulf of Suez
Authors: Zekry M. M. , Abd El Latif Waleed , Emam A. 
Published: December 2007

Abstract
The paper describes the Rehabilitation program developed by GUPCO to ensure that its offshore production facilities retain in safe operating condition through a monitoring and preventive approach. During last five years significant increase in the amounts of acid gases (H2S & CO2) was noticed as some reservoirs have soured under the action of substantial water flood operations and the new high H2S wells.
Moreover water cut in produced fluids has steadily increased over the years andnow averages about 60 %, with some fields as high as 90 %. These problems are further aggravated by activity of Sulphate Reducing Bacteria (SRB) in some producing reservoirs. The aging of oil production reservoirs and associated facilities has resulted in significant corrosion problems and repeated failures throughout offshore facilities.
An extensive range of corrosion mechanisms have been observed, various equipment failures described, including those from offshore, pipeline and onshore process equipment. However, some have been particularly troublesome either in terms of their economic loss potential, their tenacity or the threats posed to personnel safety and the environment. These are briefly surveyed in the paper. Also we discuss the re-qualification programs of the existing offshore platforms and define our criteria to evaluate the adequacy and acceptability of the rehabilitation programs including design, construction, operation, inspection and maintenance of pipelines operations.
Furthermore, we describes a successful case history for early detection and evolution of reservoir souring due to microbial activity at one of the highest producing reservoirs at GOS fields (Badri field) based on our experience and a set of improved laboratory evaluation tests.
Moreover, paper shows in a systematic way the latest research results for Corrosion inhibition of carbon steel in acidic medium using some natural products and heterocyclic compounds containing nitrogen or sulphur.
Portable Multiphase Production Tester for High-Water-Cut Wells
Authors: Oglesby K. D. , Mehdizadeh P. , Rodger G. J. 
Published: December 2007

Abstract
Accurate well testing is required for making intelligent decisions on oil and gas production wells. This paper reports on an effort to assess the application of multiphase metering technology to high water-cut (75+% water) and high volume production wells, as found in many North American Mid-Continent brown fields. A portable multiphase oil, water and gas production well tester was designed and field tested for these wells. Key components of the trailer mounted and battery operated tester are: a compact gas-liquid cylindrical cyclonic (GLCC) separator with control valves, GLCC bypass valving, coriolis liquid meter, infrared water-cut meter, vortex shedding gas meter and a data acquisition unit. One key finding is that separation is not needed in many such applications, thereby significantly reducing the size, weight and cost of future testers. This is due to the inherent downhole well separation and annulus venting used in most such well configurations along with specific coriolis/water-cut meter combinations allowing accurate measurements with gas content up to 10 to 20% GVF.
Efficient Parallel Computing Using Multiscale Multimesh Reservoir Simulation
Authors: Atan S. , Kazemi H. , Caldwell D. H. 
Published: December 2007

Abstract
The multiscale, multimesh flow simulators have been designed for the sole purpose of running very large, heterogeneous reservoir, flow problems on massively parallel computers. This paper shows the flow simulation results and the corresponding CPU times. The multiscale flow simulator is written in Fortran 90/95 with OpenMP directives and compiled on high-performance SMP computers. The simulations were performed for several highly heterogeneous, channelized, reservoir cases with realistic rock-fluid interaction (viscous, capillarity, gravity, and compressibility) to evaluate the efficacy of the multiscale, multimesh simulation in parallel computing. It is shown that the aforementioned multiscale technique reduces computing time by several orders of magnitude, while maintaining the same accuracy as the conventional fine scale simulation.
Determining Anisotropic Formation Resistivity at Any Relative Dip Using a Multiarray Triaxial Induction Tool
Authors: Wang H. , Barber T. , Morriss C. , Rosthal R. , Hayden R. , Markley M. 
Published: December 2007

Abstract
Thin-bedded sand-shale sequences frequently exhibit resistivity anisotropy. That is, resistivity measured perpendicular to the bedding (Rv) is significantly higher than the resistivity measured parallel to the bedding (Rh). It is difficult to determine water saturation in these sequences using standard induction logs that respond primarily to Rh, regardless of relative dip angle. If conductive shale laminations are present, the water saturation is over estimated; equivalently, hydrocarbon in place is underestimated.
A recently introduced triaxial induction tool provides several 3×3 tensor measurements that are sensitive to Rh, Rv and formation dip. A fast and rigorous inversion of triaxial induction data provides logs of Rh, and Rv without shoulder bed effect, and also provides logs of formation dip. The robustness of the inversion algorithm has been validated with synthetic log data.
A petrophysical model has been developed that computes both sand resistivity (Rsand) and shale resistivity (Rshale) from Rh and Rv logs. Fraction of shale, determined using established log interpretation techniques, is an input to the model. Since the induction measurement is relatively deep, the uncertainty in water saturation using the model is greatly reduced compared to interpretation models that use microresistivity logs.
Case studies from oilfields around the world demonstrate the utility of triaxial induction measurements for formation evaluation. Data were acquired in a wide variety of borehole and formation environments. These include oil-based mud, waterbase mud, dipping formations, vertical wells, deviated wells, and a wide-range of borehole sizes. Low resistivity pay zones were identified that might otherwise be missed with standard induction logs. Microresistivity images confirmed the presence of thin laminations and confirmed the dip measurements from the triaxial induction.
Experimental Development of Adsorption and Desorption Kinetics of a CO2-Foaming Surfactant Onto Berea Sandstone
Authors: Zeng Z. , Grigg R. B. , Bai B. 
Published: December 2007

Abstract
Results of eight series of adsorption and seven series of desorption experiments of CO2 foaming surfactant CD1045 onto and from Berea sandstone, each with a different initial concentration, are presented in this paper. Non-linear pseudo first and second order kinetic models for adsorption and desorption processes were derived. A simplex optimization method was adapted for the calculation of kinetic parameters of these models. This method can be used for calculating not only the kinetic model parameters, but also the absolute errors between the model and the measurements, and thus the fitness of the model. Using this simplex method and the experimental results, the adsorption and desorption processes of CD1045 onto and from Berea sandstone were found to follow pseudo second order adsorption model and pseudo first order desorption model, respectively.
Electrical Impedance Tomography (EIT) Technique for Real-Time Saturation Monitoring
Authors: Stacey R. W. , Li K. , Horne R. N. 
Published: December 2007

Abstract
Three-dimensional Electrical Impedance Tomography (EIT) is a technique that has the potential to provide estimates of reservoir saturation at multiple scales by determining the resistivity distribution within the subsurface. In theory EIT is well suited for researching oil and brine systems due to the large contrast in resistivity between the two phases. Here in our initial laboratory investigation we have applied the EIT technique to measure the saturation distribution of water within a core.
The initial EIT experiment presented here used a Berea sandstone core with 48 electrodes attached in three rings of 16. The core was open to the atmosphere with saturation occurring by natural imbibition and desaturation by evaporation. The voltage potential field was measured by applying a direct current pulse across the core and measuring the voltage potential at all electrodes, essentially applying the 4-wire resistance technique over all electrodes in turn. The result was a data set that embodies the resistivity distribution within the core, and by inversion the resistivity distribution was reconstructed, which allowed for the inference of the saturation.
The data processing was accomplished by utilizing the EIDORS toolkit which was developed for application to this nonlinear and ill-posed inverse problem. The procedure utilizes a finite-element model for forward calculation and a regularized nonlinear inverse solver to obtain a unique and stable inverse solution1.
Experiments have indicated EIT is a viable technique for studying the displacement characteristics of fluids with contrasting resistivity, and is capable of detecting displacement fronts in near real-time. The current system is also a quantitative technique able to measure saturation distributions accurately between 20% &lt; Sw &lt; 65%. These limitations were imposed due to connate water connections to the electrodes and ion mobility effects caused by the DC voltage source. It is anticipated that the applicability of EIT will increase with the implementation of an AC voltage source.
Factors Controlling the Proper Design of Effective Insulation Fluids for Oilfield Applications
Authors: Wang X. , Qu Q. , Stevens R. , Javora P. 
Published: December 2007

Abstract
Flow assurance has been a major consideration in deep water completions where undesired heat loss from production tubing to outer annuli can lead to the deposition of sludge, paraffin and asphaltene materials, the formation of gas hydrates, and cause severe flow assurance problems and loss of productivity. In recent years, thermal insulation fluids have been successfully applied in wellbore and deepwater risers to prevent undesired heat loss. Case histories have demonstrated that installation of insulation fluids is an effective alternative to conventional insulation options such as an external insulation or nitrogen gas for deepwater risers. These successes have made this insulation technology the preferred method in many GOM Deepwater projects.
Field practices and flow assurance simulations have shown that the ideal thermal insulation fluid design relies on effectively confining thermal convection and minimizing effective thermal conductivity of the fluid. How do fluid compositions affect these factors? What is required for an insulation fluid to be effective in an oilfield installation? These questions will be addressed.
This paper will discuss the proper testing methods that are relevant to oilfield flow assurance reality and are required to qualify thermal insulation fluids fit-for-use. Fluid rheology and intrinsic thermal conductivity have been assumed by some as two controlling factors for an effective thermal insulation fluid, especially in typical flow assurance simulations. Utilizing proven testing methods, these assumptions will be re-examined and discussed in terms of oilfield thermal insulation reality. Relationship between fluid chemical composition, fluid rheology and effective thermal insulation will be explored. Findings on how to optimize the fluid compositions to achieve the desired insulating potential and make the application of such fluid economical and practical in the field will be presented. Selected field cases will be discussed in reference to these recent findings.
Screening for Potential Asphaltene Problems
Authors: Wang J. X. , Creek J. L. , Buckley J. S. 
Published: December 2007

Abstract
We present a rapid screening technique that uses a minimal amount of measured data. Only in cases where asphaltene precipitation is predicted by the screening test would further experimental evidence, such as the measurement of onset pressure, be required. Currently the criteria introduced by de Boer et al.1 are widely used for screening purposes. In general, these criteria yield predictions that are somewhat pessimistic, in part because they fail to account for differences in stability between specific oils and their asphaltenes.
In this paper we propose a practical screening method that is easily applied, yet can dramatically improve the accuracy of stability predictions. The method is a modification of the ASphaltene InStability Trend (ASIST) technique2 for predicting the onset pressure during depressurization. The information required in the simplified screening method includes routine PVT data, compositional analyses, and a single onset titration using stock-tank oil and a light n-alkane precipitant such as n-heptane. The predicted onset solubility parameter at the bubble point is compared with the calculated solubility parameter of crude oil at that pressure to determine whether asphaltene would become unstable and precipitate. Twenty-seven crude oil samples from many different locations have been used to develop and test this method. Results are in agreement with the more detailed ASIST predictions and clearly identify specific cases where de Boer predictions are overly pessimistic.
Effect of Water Depth on Bridging Tendencies in Ultradeepwater Blowouts in Gulf of Mexico
Authors: Nesheli B. A. , Schubert J. J. 
Published: December 2007

Abstract
A blowout is an uncontrolled flow of reservoir fluids into the wellbore to the surface, causing serious, sometimes catastrophic, problems in different types of petroleum engineering operations. If the formation's strength is low and the pore pressure is high, bridging can be a very effective method for blowout containment. In this method, the formation caves into the open hole or onto the casing and stops the flow of the formation's fluid, either naturally or intentionally. This method can be effective in deepwater blowouts where the formation has high pore pressure and considerable shale intervals with low strength.
In this paper, wellbore stability and fluid flow performance subroutines have been developed with Visual Basic for Applications (VBA) programming. By integrating the subroutines together, we made a simulation tool to predict wellbore stability during blowouts and, consequently, predict wellbore bridging during normal and blowout situations. Then we used a real case in the country of Brunei to investigate a field case of a bridged wellbore to validate the simulator.
Based on this simulation tool we are able to determine the potential location of bridging during the blowout situation and compared the model with real data and field observations during normal and blowout situations. The difference between our simulator and existing models is that existing simulators only determine breakouts in static situations not during the blowout.
In the final part of this paper we studied the effect of water depth on bridging tendency during a blowout for the deepwater Gulf of Mexico (GOM). Since we could not find much real data in this area, we used general trends and correlations related to the GOM for parts of our study. The results of our study showed that water depth delays the occurrences of breakout in the wellbore during blowouts (i.e. for greater depth of water, wellbore collapse occurs farther below the mudline). However, the depth in which collapse occurs is different for different maximum horizontal stress amounts.
Exact Solutions in a Model of Vertical Gas Migration
Authors: Silin Dmitriy B. , Patzek Tad W. , Benson Sally M. 
Published: December 2007

Abstract
This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding atmospheric emissions of carbon dioxide and consequent global warming. One of the key questions regarding the feasibility of this technology is the potential rate of leakage out of the primary storage formation.
We seek exact solutions in a model of gas flow driven by a combination of buoyancy, viscous and capillary forces. Different combinations of these forces and characteristic length scales of the processes lead to different time scaling and different types of solutions. In the case of a thin tight seal, where the impact of gravity is negligible relative to capillary and viscous forces, a Ryzhik-type solution implies square-root of time scaling of plume propagation velocity. In the general case, a gas plume has two stable zones, which can be described by travelling-wave solutions. The theoretical maximum of the velocity of plume migration provides a conservative estimate for the time of vertical migration. Although the top of the plume has low gas saturation, it propagates with a velocity close to the theoretical maximum. The bottom of the plume flows significantly more slowly at a higher gas saturation. Due to local heterogeneities, the plume can break into parts. Individual plumes also can coalesce and from larger plumes.
The analytical results are applied to studying carbon dioxide flow caused by leaks from deep geological formations used for CO2 storage. The results are also applicable for modeling flow of natural gas leaking from seasonal gas storage, or for modeling of secondary hydrocarbon migration.
Remotely Operated Platforms: Fact, Fiction, or Future
Authors: Levett B. A. 
Published: December 2007

Abstract
Remote operations technology is currently being successfully applied to the finance and transportation industries as well as the military. Closer to home in the oil and gas industry, remote operations have been applied to unmanned platforms, subsea equipment and satellite wells. The potential for remote operations is significant for offshore platforms, but it is imperative to separate fact from fiction. It is a common misconception to believe that all human interactions at offshore platforms can be eliminated. The potential is bigger than can be imagined today but not to that absolute degree. A pilot study was performed to determine what the risks and rewards were for implementing remote operations on several platforms in the Norwegian sector of the North Sea. Activities such as remote equipment monitoring, use of a centralized control room, specialists serving multiple platforms and campaign maintenance planning were assessed for impact on operating expenses (OPEX), functionality, reliability and safety. Reward potentials included reduction in OPEX, reduction in offshore personnel, less lost production and improved safety.