bluuebunny/crossref_metadata_2025_split huggingface dataset:
Piperacillin/Tazobactam–Induced Paresthesiae
Authors: Lambourne Jonathan , Kitchen Joanne , Hughes Claudine , Merry Concepta 
Published: April 2006

Objective: To describe a case of a delayed-type hypersensitivity (DTH) reaction to piperacillin/tazobactam in which painful paresthesiae were a predominant feature. Case Summary: A 27-year-old man with a history of intravenous drug abuse was admitted for treatment of a pulmonary parenchymal abscess in the setting of lower-limb deep-venous thrombosis and methicillin-sensitive Staphylococcus aureus bacteremia. He was treated with intravenous piperacillin/tazobactam 4.5 g 3 times daily; however, after 2 weeks of therapy, he developed symptoms (eg, fever, chills) and laboratory abnormalities (eg, white blood cell count 2.1 × 103/mm3, erythrocyte sedimentation rate 63 mm/h) suggestive of a DTH reaction. This was accompanied by infusion-related painful paresthesiae. The symptoms and laboratory abnormalities resolved within 48 hours of treatment being switched to flucloxacillin. Discussion: Due to the close temporal association and the absence of any other obvious explanation, we believe these paresthesiae represent an additional feature of the DTH reaction to piperacillin/tazobactam in this patient. Use of the Naranjo probability scale indicated a probable relationship between the paresthesiae and administration of piperacillin/tazobactam. Conclusions: To our knowledge, as of March 24, 2006, this is the first case in which a DTH reaction to piperacillin/tazobactam manifesting as fever, neutropenia, and thrombocytopenia has been associated with paresthesiae.
Simplified Method for Calculation of Minimum Miscibility Pressure or Enrichment
Authors: Yuan Hua , Johns Russell T. 
Published: April 2006

SummaryLocal displacement efficiency from gas injection is highly dependent on the minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME). Analytical methods, which are inexpensive and quick to use, have been developed to estimate MMPs for complex fluid characterizations. Published methods,1–3 however, often require estimation of numerous parameters and little has been written with regard to method robustness. This paper presents a simplified and robust method for MMP or MME calculation.The approach relies on finding key crossover tie lines for a dispersion-free displacement using the method of characteristic theory (MOC). The new method, however, differs from published methods by significantly reducing the number of equations and unknown parameters, and by providing a fast and robust method that can avoid trivial and false solutions. We demonstrate the improvements by calculation of the MMP and MME for a variety of gas/oil systems and also give new analytical solutions for constant K-value systems that give insight into the nature of false solutions. The number of potential false solutions increases greatly with the number of components in the fluid characterization. Thus, any proposed method must ensure convergence to the physical MMP/MME.
Directional Drilling with Casing
Authors: Warren Tommy , Houtchens Bruce , Madell Garret 
Published: April 2006

SummaryCasing while drilling (CwD) has proven to be an effective method of reducing drilling costs and solving drilling problems. Most of the current CwD activity focuses on drilling vertical wells, but interest in directional wells is increasing as CwD benefits in straight holes are demonstrated.A directional CwD system has been run sufficiently to prove that directional drilling with casing is practical with casing sizes from 7 to 133/8 in. The system uses a wireline-retrievable-directional-drilling assembly (positioned atthe lower end of the casing) to replace the conventional directional tools used when drilling with drillpipe. These tools have been used to drill to inclinations greater than 90° and have been retrieved and rerun at inclinations ranging from vertical to horizontal.Directional CwD can be used for a broad range of directional applications to capture proven advantages demonstrated in vertical wells.
Underbalanced Drilling with Casing Evolution in the South Texas Vicksburg
Authors: Gordon D. , Billa R. , Weissman M. , Hou F. 
Published: April 2006

Summary
Underbalanced drilling with casing (UBDWC) is improving drilling performance dramatically in south Texas fields. This approach allows drilling of depleted and high-pressure sands intermingled within one hole section, resulting in significantly less-expensive well plans. Drilling costreductions of 30% have been realized. Smaller-reserves targets areviable—a key advantage in the mature south Texas Vicksburg play.
A Compendium of Directional Calculations Based on the Minimum Curvature Method
Authors: Sawaryn S. J. , Thorogood J. L. 
Published: April 2006

Summary
The minimum curvature method has emerged as the accepted industry standard for the calculation of 3D directional surveys. Using this model, the well' strajectory is represented by a series of circular arcs and straight lines. Collections of other points, lines, and planes can be used to represent features such as adjacent wells, lease lines, geological targets, and faults. The relationships between these objects have simple geometrical interpretations, making them am enable to mathematical treatment. The calculations are now used extensively in 3D imaging and directional collision scans, making them critical for both business and safety. However, references for the calculations are incomplete, scattered in the literature, and have no systematic mathematical treatment. These features make programming a consistent and reliable set of algorithms more difficult. Increased standardization is needed.
Investigation shows that iterative schemes have been used in situations in which explicit solutions are possible. Explicit calculations are preferred because they confer numerical predictability and stability. Though vector methods were frequently adopted in the early stages of the published derivations, opportunities for simplification were missed because of premature translation to Cartesian coordinates.
This paper contains a compendium of algorithms based on the minimum curvature method (includes coordinate reference frames, toolface, interpolation, intersection with a target plane, minimum and maximum true vertical depth (TVD) in a horizontal section, point closest to a circular arc, survey station to a target position with and without the direction defined, nudges, and steering runs). Consistent vector methods have been used throughout with improvements in mathematical efficiency, stability, and predictability of behavior. The resulting algorithms are also simpler and more cost effective to code and test. This paper describes the practical context in which each of the algorithms is applied and enumerates some key tests that need to be performed.
Analysis of Interference Tests With Horizontal Wells
Authors: Al-Khamis M. , Ozkan E. , Raghavan R. 
Published: April 2006

SummaryOne of the common assumptions in horizontal-well interference-test analysis is to ignore fluid flow in and out of the horizontal observation well and represent it by a point. In some cases, the active well is also approximated by a vertical line source. Using a semianalytical model, this paper answers three fundamental questions:What is the critical distance between the wells to represent the horizontal observation well by an observation point? Where should the observation point be placed along the horizontal well? Under what conditions may the active well be approximated by a vertical line source and the exponential integral solution be used to analyze observation-well responses?Two correlations are presented to simplify the analysis of horizontal-well interference tests. Example applications are presented, and error bounds are documented.
Improved Microseismic Fracture Mapping Using Perforation Timing Measurements for Velocity Calibration
Authors: Warpinski N. R. , Sullivan R. B. , Uhl J. E. , Waltman C. K. , Machovoe S. R. 
Published: April 2006

SummaryA method is decribed wherein microseismic mapping of hydraulic fractures is improved by using crosswell data to calibrate and/or verify dipole-sonic-velocity data. In the perforation-timing procedure, crosswell-velocity data are obtained by monitoring the firing pulse from the receiver-orientation perforations and recording the timing pulse along with the arrivaldata. From these results, a simple one-dimensional model of velocities canbe extracted and used to validate, refine, or correct the detailed dipole-sonic data or provide a warning of discrepancies
High-Temperature Wells With Lost-Circulation Demands and Reverse-Circulation Techniques Using Foamed-Cement Systems: Two Case Histories
Authors: Moore Robert , Bour Daniel , Reed Shawn , Hernandez Rafael 
Published: April 2006

SummaryDrilling activities in diverse areas can pose significant challenges for conventional cement systems and circulation methods. To overcome these challenges, a unique cementing system and a circulation method have been tested in the field with great success. This paper details how these technologies and techniques were successfully used in the cementation process of one casing string in a relatively shallow geothermal well in central California and a relatively deep string in central Wyoming.Globally, many wells experience lost-circulation problems that require the reduction of circulation pressures to allow proper placement of cement to provide annular coverage. To help minimize these circulation pressures, cement was directly pumped into the annulus, significantly reducing placement pressures and allowing placement of the cement with no apparent losses—a process referred to as the reverse-circulation placement technique (RCPT). In the deep and shallow applications discussed, the placement technique and the individual slurry designs address temperature issues.
An Innovative Approach To Integrate Fracture, Well-Test, and Production Data Into Reservoir Models
Authors: Bahar Asnul , Ates Harun , Al-Deeb Maged H. , Salem Salem E. , Badaam Hussein , Linthorst Steef , Kelkar Mohan 
Published: April 2006

SummaryThis paper presents an innovative approach to integrate fracture, well-test, and production data into the static description of a reservoir model as an input to the flow simulation. The approach has been implemented successfully in a field study of a giant naturally fractured carbonate reservoir in the Middle East. This study was part of a full-field integrated reservoir-characterization and flow-simulation project.The main input available for this work includes matrix properties and fracture-network, well-test, and production data. Stochastic models of matrix properties were generated using a geo-statistical methodology based on well logs, core, seismic data, and geological interpretation. The fracture network was described in the reservoir as lineaments (fracture swarms) showing two major fracture trends. The network and its properties (i.e., fracture porosities and permeabilities) were generated by reconciling seismic, well-log, and dynamic data (Well Test and Production Log Tool, PLT).**The challenge of the study is to integrate all the input in an efficient and practical way to produce a consistent model between static and dynamic data. As a result, it is expected to reduce the history-matching effort. This challenge was solved by an innovative iterative procedure between the static and dynamic models.The static part consists of the calibration of model permeability to match the well-test permeability. It is done by comparing their flow potentials, kh. In this analysis, the dominant factor in controlling production at each well, either matrix or fracture, was determined. Based on the dominant factor, matrix or fracture permeability was modified accordingly. This way, the changes in permeability are consistent with the geological understanding of the field.The dynamic part was carried out through a full-field flow simulation to integrate production data. The flow simulation at this stage was used to match production capacity, [i.e., to determine whether the given permeability (matrix and fracture) distribution is enough to produce the fluid at the specified pressure during the producing period of the well]. The iteration is stopped once a reasonable production-capacity match is obtained. In general, a good match was achieved within three to four iterations. The generated reservoir description is expected to substantially reduce the effort required to obtain a good history match.
Near-Wellbore Formation Damage Effects on Well Performance: A Comparison Between Underbalanced and Overbalanced Drilling
Authors: Ding Y. , Herzhaft B. , Renard G. 
Published: April 2006

Summary
Prediction of formation damage that occurs while drilling horizontal wells is a critical point for optimizing an oil field's development. The economic impact of near-wellbore drilling-induced damage and cleanup efficiency has led to significant progress being made in both experimental and numerical studies to assess wellbore flow properties during oil production. As a result, a numerical model has been developed to study the impact of various parameters related to the properties of drilling fluids on well inflow performance.
This paper describes a numerical approach developed in this model to simulate near-wellbore formation damage caused by underbalanced drilling (UBD). It is generally expected that UBD will be of benefit by preventing formation damage. However, this benefit can be lost for various reasons. For instance, an overbalanced pressure can be applied on the formation during short periods of time for various operational reasons and can cause severe formation damage because of the absence of external cake protection and huge filtrate invasion. Another possible cause of formation damage in UBD is related to spontaneous imbibition, which induces water-blocking, which was observed while drilling tight gas reservoirs.
A methodology for the modeling of possible formation damage during UBD is presented. Crossflow phenomena caused by spontaneous imbibition is taken into account to model the filtrate invasion from the well to the porous media, as the well is in production.
Injection of Aquifer Water and Gas/Oil Separation Plant Disposal Water Into Tight Carbonate Reservoirs
Authors: Raju K. U. , Nasr-El-Din H. A. , Hilab V. V. , Siddiqui S. , Mehta S. 
Published: April 2006

Summary
Disposal of produced water from oil fields is a major concern for environmental and economic reasons. One way to dispose of this water is to mix it with aquifer water and inject it back into the formation. One of the carbonate reservoirs in Saudi Arabia produces wet oil where the total dissolved solids (TDS) of the produced water is high (up to 238,000 mg/L). The produced water also contains dissolved gasses (H2S and CO2) and suspended material (oil and corrosion products). Thus, disposal water from a gas/oil separation plant (GOSP) not only has CaCO3 scaling potential, but can also precipitate sulfides because it contains nearly 750 mg/L of H2S. In contrast, the aquifer waters from the area contain approximately 2 mg/L of total iron. Therefore, if these two waters were to be mixed, the possibility of damaging the formation from iron sulfide precipitation could be signficant. The objective of this study is to assess potential formation damage that can result when the two waters are mixed and injected into the tight carbonate reservoir.
The current study included a detailed analysis of field waters, determination of scaling potential of various waters, and extensive coreflood testing using reservoir cores. A unique feature of this study was that the cores were examined after the injection of the mixed waters by computerized tomography (CT) and scanning electron microscopy (SEM) to determine both macro and porelevel effects on core properties.
The study revealed that the injection of mixed water into reservoir cores created wormholes, which increased core permeability. This new finding indicates that disposal water is not always damaging. On the other hand, the precipitated iron sulfide particles seem to damage the cores, but the damage was constrained by the core initial permeability. For example, the iron sulfide particles (0.25 μm) caused damage to cores with permeability of less than 20 md after injecting 1,000 pore volumes (PV) of the mixed waters. However, no damage was observed in cores with permeability greater than 60 md, even after injecting 600 PV of the same mixed water.
The study identified various types of scale resulting from mixing produced and aquifer waters, and determined conditions under which these waters could be injected. Also, the study highlights an unexpected benefit of injecting H2S-containing waters, which is to create wormholes and thus significantly increase permeability of tight carbonate reservoirs.
Reservoir Simulation of CO2 Storage in Deep Saline Aquifers
Authors: Kumar A. , Ozah R. , Noh M. , Pope G. A. , Bryant S. , Sepehrnoori K. , Lake L. W. 
Published: April 2006

Summary
We present the results of compositional reservoir simulation of a prototypical CO2 sequestration project in a deep saline aquifer. The objective was to better understand and quantify estimates of the most important CO2 storage mechanisms under realistic physical conditions. Simulations of a few decades of CO2 injection followed by 103 to 105 years of natural gradient flow were performed. The impact of several parameters was studied, including average permeability, the ratio of vertical to horizontal permeability, residual gas saturation, salinity, temperature, aquifer dip angle, and permeability heterogeneity. The storage of CO2 in residual gas emerges as a potentially very significant issue meriting further study. Under some circumstances this form of immobile storage can be larger than storage in brine and minerals. Most importantly, we find that permanent storage is feasible. That is, the storage process can be designed to place large volumes of CO2 in forms that will not escape the aquifer any faster than fluids originally present in the aquifer.
A New Generation Chemical-Flooding Simulator
Authors: John A. , Han C. , Delshad M. , Pope G. A. , Sepehrnoori K. 
Published: April 2006

SummaryCompositional reservoir simulators that are based on equation-of-state (EOS) formulations typically do not handle the modeling of aqueous phase behavior, and those that are designed for modeling chemical processes typically assume simplified hydrocarbon phase behavior. There is a need to have a single reservoir simulator capable of combining both approaches to benefit from the advantages of both aqueous and hydrocarbons models. Developing and implementing fully implicit procedures for modeling both hydrocarbon and aqueous phase behavior simultaneously is a complex process. An approach to integrate a surfactant phase behavior model into an existing fully implicit, parallel, EOS compositional simulator is presented in this paper. Physical property models describing the flow and transport of surfactant and polymer species have been implemented. These properties include surfactant phase behavior, interfacial tension, capillary desaturation, viscosity, adsorption, and relative permeability as a function of trapping number. Polymer properties include viscosity, permeability reduction, inaccessible pore volume, and adsorption. The simulation results were validated by comparison with the explicit chemical-flooding simulator UTCHEM and are shown in this paper. Test runs were performed with high-resolution models in a parallel environment, with results indicating a good scalability of the simulator.
Fast History Matching of Finite-Difference Models Using Streamline-Derived Sensitivities
Authors: Cheng Hao , Kharghoria Arun , He Zhong , Datta-Gupta Akhil 
Published: April 2006

SummaryWe propose a novel approach to history matching finite-difference models that combines the advantages of streamline models with the versatility of finite-difference simulation. Current streamline models are limited in their ability to incorporate complex physical processes and cross-streamline mechanisms in a computationally efficient manner. A unique feature of streamline models is their ability to analytically compute the sensitivity of the production data with respect to reservoir parameters using a single flow simulation. These sensitivities define the relationship between changes in production response because of small changes in reservoir parameters and, thus, form the basis for many history-matching algorithms. In our approach, we use the streamline-derived sensitivities to facilitate history matching during finite-difference simulation. First, the velocity field from the finite-difference model is used to compute streamline trajectories, time of flight, and parameter sensitivities. The sensitivities are then used in an inversion algorithm to update the reservoir model during finite-difference simulation.The use of a finite-difference model allows us to account for detailed process physics and compressibility effects. Although the streamline-derived sensitivities are only approximate, they do not seem to noticeably impact the quality of the match or the efficiency of the approach. For history matching, we use a generalized travel-time inversion (GTTI) that is shown to be robust because of its quasilinear properties and that converges in only a few iterations. The approach is very fast and avoids many of the subjective judgments and time-consuming trial-and-error steps associated with manual history matching. We demonstrate the power and utility of our approach with a synthetic example and two field examples. The first one is from a CO2 pilot area in the Goldsmith San Andreas Unit (GSAU), a dolomite formation in west Texas with more than 20 years of waterflood production history. The second example is from a Middle Eastern reservoir and involves history matching a multimillion-cell geologic model with 16 injectors and 70 producers. The final model preserved all of the prior geologic constraints while matching 30 years of production history.
Science and magic in African technology: traditional iron smelting in Malawi
Authors: van der Merwe Nikolaas J. , Avery Donald H. 
Published: April 2006

Opening ParagraphIron smelting was still widespread in Africa at the beginning of the twentieth century and was recorded in a number of areas by missionaries, administrators, travellers and the like. A wide variety of technical procedures and associated magic was observed in the process. The quality of these early accounts varies depending on the technical expertise of the observers and their interest in (or bias against) the ritual aspects. Reviews of the early literature, both technical and ritual, have been provided by Cline (1937) and others and no attempt in this direction will be made here. It will suffice to say that magic associated with smelting appears to be universal in sub-Saharan Africa, as are certain themes. These include the following:1. For iron smelting to be successful, the smelters must be technically expert and a variety of supernatural forces must be propitiated. This propitiation takes the form of ceremonies and ritual and involves the application of special materials or medicines. The combination of ritual and medicines is referred to here as magic.2. The iron smelters, especially the leaders, command the knowledge to carry out both the technical and magical components of smelting. This makes them more than ordinary craftsmen and gives them special status, usually high; alternatively they may be outcasts.3. Sexual symbolism and taboos accompany smelting, often expressed through the exclusion of women from smelting in progress, compulsory celibacy for the smelters, or female anthropomorphic details added to smelting furnaces.