bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving LWD Image and Formation Evaluation by Using Dynamically Corrected Drilling-Derived LWD Depth and Continuous Inclination and Azimuth Measurements
Authors: Bordakov G. A. , Kostin A. V. , Rasmus J. , Heliot D. , Laastad H. , Stockhausen E. J. 
Published: March 2009

Summary
The paper illustrates the improvements in logging while drilling (LWD) images and subsequent formation evaluation by using a new methodology for depth and survey measurements corrections.
LWD depth measurements are often considered inaccurate and, therefore, not as reliable for well-to-well correlations, correlations with data acquired with wireline measurements and formation layer thickness determinations. The reasons for these inaccuracies generally originate from the traditional practice that LWD depth is purposely made equal to the driller's depth, which is a static pipe length measurement made by tape at the surface.
There is almost always a difference between the actual measured depth (MD) of the LWD sensor downhole and this static pipe measurement, because downhole the drillpipe is subject to an environment that is not representative of the derrick (e.g., varying drilling mechanical conditions and temperature changes). Here, we demonstrate the applications of the method, which allows dynamic driller's depth correction for the effects of drillstring weight, downhole friction, weight on bit, thermal expansion, residual rig heave, and tide.
Another significant inaccuracy source is a standard practice of calculating borehole position from stationary survey points typically taken every 90 feet (ft) using the minimum curvature method. Neglecting the complex borehole shape between survey stations can lead to a systematic error in determining the borehole position. We consider using continuous inclination and azimuth measurements along with stationary surveys to correct these errors.
We provide comparisons of LWD images before and after the depth and survey corrections to illustrate how the measurement errors affect formation dips interpreted from the images. We demonstrate how improved accuracy allows filtering out the artifacts and provides more decisive and accurate identification of geologic features. We show how using the corrected 3D position improves accuracy of the formation thicknesses calculations and therefore improves the reservoir summation results.
As a result, we propose a borehole 3D position measurement that is accurate, consistent between wells (regardless of rig type or bottomhole assembly [BHA] configuration), and independent of the drilling mode. Using this new measurement significantly improves the quality of the formation evaluation.
Case Studies Illustrating the Use of Reservoir Simulation Results in the Reserves Estimation Process
Authors: Rietz Dean , Usmani Adnan 
Published: March 2009

Summary
Continuous improvements in reservoir simulation software and the availability of high performance computing equipment are making the use of simulation models commonplace for field development and planning purposes. Naturally, this trend has also increased interest in the use of reservoir simulation model results in the oil and gas reserves estimation process.
As simulation specialists who work in a primarily reserves-evaluation company, the authors are routinely asked to evaluate, and in many cases incorporate, simulation results in the reserves estimation process. In addition, the authors are required to opine on the approach and tactics used by clients while they incorporate numerical models in their reserves bookings. Because limited published discussion exists on this topic, the purpose of this paper is to provide some examples of the approach used by the authors. We believe this approach to be appropriate and within the spirit of reserves interpretation as used by typical reserves regulatory bodies such as the U.S. Securities and Exchange Commission (SEC).
Papers previously published have discussed the use of models in the reserves process, including the evaluation of the models themselves (Palke and Rietz 2001; Rietz and Usmani 2005). In contrast, this paper provides three case studies that illustrate how results from various models have been used to assist in quantifying reserves. Two of the examples are based on history-matched models, while the third focuses on a pre-production reservoir where no adequate history is available and probabilistic methods were incorporated to help understand the uncertainty in the forecasts.
While there is no "cookbook" or step-by-step procedure for using simulation results to estimate reserves, the case studies presented in this paper are intended to both show some examples and also spark some debate and discussion. Undoubtedly there will be some disagreement with our techniques, but an open discussion should prove to be beneficial for both reserves evaluators and simulation specialists.
Long-Term Field Development Opportunity Assessment using Horizontal Wells in a Thin, Carbonate Reservoir of the Greater Burgan Field, Kuwait
Authors: Ambastha Anil K. , Matar Al Dawood , Ma Eddie 
Published: March 2009

Summary
The Mauddud reservoir in the Greater Burgan field is a thin, carbonate reservoir containing light oil in a 10 to 20-feet (ft) target zone with "good" porosity. Matrix permeability is low, and natural fracture density can be variable in this reservoir. Thus, this reservoir must be exploited using horizontal wells. In the early 1990s, 16 horizontal wells were drilled in this reservoir. Five more horizontal wells have been drilled in 2005 and 2006 in an effort to scope out the long-term potential of this reservoir. However, only three of these five new wells had a production history of a few months that could be used in our history-matching effort. Thus, the history-matching effort concentrated on 19 wells (16 old plus 3 new wells).
In conjunction with the drilling of recent horizontal wells, a comprehensive reservoir characterization program culminating into a full-field reservoir simulation model has been completed. The 24-million cell geological model was scaled up to a 9-million cell model at a 164-ft by 164-ft areal grid level to properly incorporate flow characteristics of horizontal wells into the simulation model. Matrix permeability of the scaled-up model was enhanced by using a unique process based on analytical solutions for short fractures and fracture density/orientation mapping for the entire field. This reservoir simulation model has been history-matched for the 13-year production history of 16 1990s horizontal wells along with a production history of a few months for 3 new wells using only a global-permeability multiplier and water relative-permeability curve shape modification. This model has been used in the forecast mode to assess long-term field development opportunity for the Mauddud reservoir. Primary depletion results show that horizontal wells drilled in an intelligent manner in this difficult reservoir hold the key to economic development of this reservoir.
Modeling Conformance as Dispersion
Authors: Coats K. H. , Whitson C. H. , Thomas L. K. 
Published: March 2009

Summary
For decades the effect of physical dispersion (in-situ mixing) in porous media has been of interest in reservoir engineering and groundwater hydrology. Dispersion can affect the development of multicontact miscibility and bank breakdown in enriched-gas drives and miscible solvent floods of any mobility ratio.
The magnitude or extent of dispersion is quantified by the rock property physical dispersivity, α, which is on the order of 0.01 ft for consolidated rocks and several times smaller for sandpacks, as found in many laboratory measurements.
Numerical studies of the effect of dispersion on enriched-gas drives and field tracer tests often use input values of a scale-dependent dispersivity 100 to 1,000 or more times larger than ≈0.01 ft. These large scale-dependent dispersivity values stem from large apparent dispersivities (αa) determined by matching the 1D convection/diffusion (C/D) equation to production-well-effluent tracer-concentration profiles observed in field tracer tests.
A scale-dependent dispersivity can be used only as a fitting factor to match or explain the effluent profile of a single producer at a fixed distance from an injector. It cannot represent physical dispersion to justify the conclusions reached by its use in simulations of enriched-gas-drive, field-tracer-test, or other reservoir displacement processes. It has no predictive value in any numerical simulation.
The scale-dependent apparent dispersivities reflect conformance or other behavior not governed by the 1D C/D equation and should not be used to justify large dispersivities as input to numerical studies. This paper shows that large apparent dispersivities observed in field tests can result with physical dispersivity no larger than the ≈0.01-ft laboratory-measured value.
Heterogeneity alone (no physical dispersivity or molecular diffusion) causes no in-situ mixing and cannot explain observed large apparent echo-test dispersivities. Large apparent dispersivities for two reported echo (single-well inject/produce) tracer tests are shown to result from a model with drift alone and no dispersion.
The widely reported scale dependence of apparent dispersivity is a simple and necessary consequence of mis-applying the 1D C/D equation, with its single parameter of Peclet number, L/α, to conformance it does not describe. The conformance portion, aac, of apparent dispersivity, αa, is scale-dependent, but physical dispersivity is a rock property independent of scale and time. The value of αa approximately obeys an additive dispersivity principle, αa≈α + αac, where αac is dispersivity representing conformance and αaG&gt;&gt;α in field displacements.
Discussion of Interrelationship of Temperature and Wettability on the Relative Permeability of Heavy Oil in Diatomaceous Rocks
Authors: Dietrich J. K. 
Published: March 2009

Schembre et al. (2006) interpret the effects of temperature on diatomite wettability and relative permeability for a specific set of laboratory conditions. These researchers imply that countercurrent imbibition (CCI) of hot water and oil–driven by capillary-pressure forces–is the dominant mechanism in the thermal recovery of heavy oil from diatomite. While their results are appreciated and of theoretical interest, additional experimental work would seem to be necessary before conclusions can be drawn about fieldscale key mechanisms and achievable-oil-displacement efficiencies.
Several features of the testing procedures used by Schembre et al. (2006) prevent scaling their results from the laboratory to the field: extracted rather than preserved core material was used, deadoil rather than live-oil was used, and the cores were not stressed during testing. Bennion et al. (1985) demonstrated the importance of measuring relative permeabilities using preserved core material, overburden stress conditions, and live crude oil. These types of relative permeability functions–rather than those measured using dead-oil and extracted cores that were unstressed–were very similar to those developed empirically by Coats et al. (1977) and Dietrich (1981) to reproduce cyclic-steam field performance. Bennion et al. (1985) found that laboratory-measured relative permeability curves from preserved core, when performed at reservoir conditions, do not need to be adjusted downward to match low water production typical of cyclic-steam response.
Regarding the effects of stress, heating amorphous Opal-A diatomite has been shown to be capable of causing a sample compression of 25% or more and a severe reduction in permeability (Dietrich and Scott 2007). Heating in the absence of a change in effective stress from the initial equilibrium condition causes compaction; heating at elevated effective-stress levels causes much more compaction (Fig. D-1). Sample compression of 25% or more is expected to severely alter the primary pore structure and, hence, the relative-permeability and capillary-pressure characteristics of the diatomite. Wilson (1956) showed that an overburden stress causing only a 5% reduction in porosity of a sandstone core can produce a sufficiently large change in pore size distribution to affect the relative permeability of the core.
Authors' Reply to Discussion of Interrelationship of Temperature and Wettability on the Relative Permeability of Heavy Oil in Diatomaceous Rocks
Authors: Kovscek A. R. , Schembre J. M. , Tang G. -Q. 
Published: March 2009

Summary
Dietrich's discussion is wide ranging. We agree that oil recovery from diatomite rocks is influenced by a variety of mechanisms, that compaction plays a role, and that more work in the area of recovery mechanisms and their representation within a reservoir simulator is warranted. His critique of our work, however, incorrectly summarizes our experimental procedures and it misrepresents the importance that we attribute to hot-water imbibition in relation to the other mechanisms that contribute to thermal oil recovery. His discussion of the simulation of field-scale recovery processes does not appear to acknowledge the need for upscaling or the inherent nonuniqueness present in history-match results. Our work highlights the role of fines detachment as well as silica and mineral dissolution combined with compressive stress (Schembre et al. 2006; Ikeda et al. 2007; Ross et al. 2008). We have found that rock wettability evolves favorably to a more water-wet state with elevated temperature. This change in wettability contributes positively to recovery.
CT Study of Liquid Diversion With Foam
Authors: Nguyen Q. P. , Zitha P. L. J. , Currie P. K. , Rossen W. R. 
Published: March 2009

Summary
The mobility and flow distribution of liquid injected after foam control the effectiveness of foam/acid matrix well-stimulation treatments and the injectivity of liquid in many foam improved-oil-recovery processes. We present a computed-topography (CT) study of liquid injection following foam, in which both mobility and the sweep of liquid are determined directly, the latter by CT imaging. Earlier experimental work is extended in that the effects of foam quality, foam-injection rate, post-foam liquid-injection rate, and core heterogeneity on liquid mobility and displacement pattern are observed directly. CT images show that liquid fingers through foam rather than displacing it evenly. As a result, 1D models for the displacement cannot represent the process accurately. The formation of the finger is at least partly stochastic: In different experiments in the same core, with similar initial foam states, the liquid finger took markedly different paths through the core. Liquid injected after foam does not follow simply the path of mobile gas in the foam. In these experiments, post-foam brine injection was not qualitatively less effective than post-foam surfactant injection, though there were differences in both post-foam mobility and fingering pattern. Implications of field application of foam-acid diversion in matrix-stimulation treatments are discussed.
Predicting Horizontal-Openhole-Completion Success on the North Slope of Alaska
Authors: Erwin Michael D. , Ogbe David O. 
Published: March 2009

Summary
The Colville River field represents the first widespread and successful application of horizontal openhole completions on the North Slope of Alaska, and one of the first in the world. The purposes of this paper are to examine why this completion technique was selected and identify key parameters that favored its successful application in the Colville River field. The optimal completion technique for a candidate well is determined by reservoir properties, geologic setting, rock mechanics, development plan, and completion design. In this paper, we will review the unique advantages and disadvantages of horizontal openhole completions in the Colville River field.
Three key parameters were critical to the success of horizontal openhole completions and could be applied broadly in other situations. Using these three criteria, other major North Slope reservoirs were evaluated to determine their potential for horizontalopenhole-completion applications. Focus areas in this evaluation include in-situ reservoir parameters, development plans, fluid contacts, and wellbore geometries. The results show that only one other major field on the North Slope could have benefited from horizontal openhole completions.
The results of this paper are meant to provide guidelines for future application of horizontal openhole completions on the North Slope of Alaska and elsewhere.
A Hybrid Approach To Improve Reserves Estimates in Waterdrive Gas Reservoirs
Authors: Yildiz Turhan 
Published: March 2009

Summary
The conventional reserves estimate methods for waterdrive reservoirs are well established. Typically, the techniques proposed by Havlena and Odeh (1963 and 1964) and McEwen (1962) are used. In general, the reserves estimated from these procedures are not unique since the recorded historical production data are simultaneously solved for aquifer parameters and reserves. Normally, multiple combinations of reserves and aquifer parameters match the field data equally well. Hence, a range of reserves—rather than a unique value—is found. The upper and lower limits of the reserves range may vary several-fold.
In this paper, a hybrid approach that makes use of available methods is used to narrow the reserves range estimates in water-drive gas reservoirs. The hybrid approach combines the McEwen method, apparent gas-in-place (GIP) vs. time, the modified Roach (1981) method, and the modified Havlena and Odeh method for partial waterdrive.
Effect of Dual Cure Composite as Dentin Substitute on Marginal Integrity of Class II Open-Sandwich Restorations
Authors: Koubi S. , Raskin A. , Dejou J. , About I. , Tassery H. , Camps J. , Proust J-P. 
Published: March 2009

Clinical Relevance
Dual-curing composites may present a good alternative to RMGIC in open-sandwich restorations and they act as a dentin substitute. However, this study showed that RMGIC remains the best intermediate material when open-sandwich restorations are indicated.
The Effect of Preoperative Ibuprofen on Tooth Sensitivity Caused by In-office Bleaching
Authors: Charakorn P. , Cabanilla L. L. , Wagner W. C. , Foong W-C. , Shaheen J. , Pregitzer R. , Schneider D. 
Published: March 2009

Clinical Relevance
The use of an analgesic may help to reduce tooth sensitivity during in-office bleaching. Within the limitations of this study, Ibuprofen (600 mg, PO single dose) reduced tooth sensitivity during, but not after the treatment period.
Effect of 2% Chlorhexidine Digluconate on the Bond Strength to Normal Versus Caries-affected Dentin
Authors: Komori P. C. P. , Pashley D. H. , Tjäderhane L. , Breschi L. , Mazzoni A. , de Goes M. F. , Wang L. , Carrilho M. R. 
Published: March 2009

Clinical Relevance
Attempts to use CHX adjunctively with conventional etch-and-rinse adhesives may play a clinically relevant role in the preservation of resin-dentin bonds.
Deproteinization Effects of NaOCl on Acid-etched Dentin in Clinically-relevant vs Prolonged Periods of Application. A Confocal and Environmental Scanning Electron Microscopy Study
Authors: Sauro S. , Mannocci F. , Tay F. R. , Pashley D. H. , Cook R. , Carpenter G. H. , Watson T. F. 
Published: March 2009

Clinical Relevance
Complete removal of the collagen matrix prior to dentin bonding procedures has been proposed as a strategy to prevent later degradation, which may jeopardize the longevity of resin-dentin bonds. This study demonstrates that a complete removal of the exposed collagen matrix from the etched dentin surface can be achieved by applying a 12 w/v% NaOCl solution, but at this concentration, it requires a far longer reaction time than is clinically acceptable.
A Clinical Evaluation of Two In-office Bleaching Regimens With and Without Tray Bleaching
Authors: Matis B. A. , Cochran M. A. , Wang G. , Eckert G. J. 
Published: March 2009

Clinical Relevance
In-office tooth bleaching, followed by at-home bleaching with trays, was shown to be more effective than in-office bleaching without at-home bleaching. Three 15-minute applications of an in-office bleaching agent were more effective than one 40-minute application.
Influence of Power Density on Polymerization Behavior and Bond Strengths of Dual-cured Resin Direct Core Foundation Systems
Authors: Oto T. , Yasuda G. , Tsubota K. , Kurokawa H. , Miyazaki M. , Platt J. A. 
Published: March 2009

Clinical Relevance
The dentin bond strength and polymerization behavior of the dual-cured core foundation resins tested in this study were affected by the power densities of the curing unit. When using dual-cured core foundation systems, practitioners should consider power densities for getting optimal bond strength.
Effect of Operator-specific Handling on Tooth-composite Interface and Microleakage Formation
Authors: Schneider H. , Busch I. , Busch M. , Jentsch H. , Häfer M. 
Published: March 2009

Clinical Relevance
After calibration of the restoration procedure, three operators experienced differences in tooth-composite interface morphology and microleakage formation. These differences reflect technique-sensitivity of the etch-and-rinse adhesive. The lowest microleakage on dentin was related to an enhanced interface integrity. After additional application of an adhesive component, sealing of the enamel and dentin was partially enhanced, but microleakage formation did not decrease. These results are helpful in the comparative evaluation of other bonding systems.
Computational Investigations on the Dynamics of Tires Rolling on Rough Roads
Authors: Brinkmeier M. , Nackenhorst U. 
Published: March 2009

Abstract
Finite element methods are well established for the mechanical analysis of tires in industry. For stationary rolling contact analysis a relative kinematics description based on a mixed spatial–material description provides a suitable framework for efficient computations of quite detailed tire models. Despite these advantages, special effort is necessary for the reliable treatment of tractive rolling with friction, or even when inelastic material properties have to be considered. An additional challenge is the simulation of high-frequency response for comfort analysis, for example.
This paper focuses mainly on the latter aspect, namely, the transient dynamics response with respect to rolling noise prediction. The theoretical basics have been outlined in prior publications; this presentation concentrates on a systematic analysis of the transient dynamic behavior of rolling tires based on a modal analysis first. Based on computed eigenvectors, a partial modal energy criterion is introduced to judge the influence of different assembly parts on the dynamics of rolling tires. The capability of the suggested approach will be outlined in a second part, where the transient dynamic response due to the excitation from different road surface textures and bridge connection constructions are discussed. The sensitivity of these computations with regard to the excitation mechanism will be shown, from which a much higher potential in road construction regarding traffic noise reduction is concluded.
The presented results are the partial outcome of research project “Leiser Straßenverkehr 2,” funded by the Federal Ministry of Economics and Technology (BMWi) and organized by the Federal Highway Research Institute (BAST). This research was performed in close cooperation between tire manufacturers, road construction companies, and universities.