bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Additives on the Acid Dissolution Rates of Calcium and Magnesium Carbonates
Authors: Taylor K. C. , Al-Ghamdi A. H. , Nasr-El-Din H. A. 
Published: December 2007

Summary
A rotating-disk instrument was used to measure the dissolution rates of both calcite and dolomite rock samples in HCl solutions. The results of more than 60 experiments are reported in this paper. The effect of common acidizing additives on the rock dissolution rate is measured for different acids containing quaternary amines, polymer, surfactant, mutual solvent, iron-chelating additive, and dissolved iron. Measurements are made at 23 and 50°C for calcite and dolomite marble samples.
Marble samples from Turkey, Greece, and Italy were analyzed to find suitable reference materials. Marble composed of 100% calcite (calcite marble) as well as 91% dolomite (dolomite marble) was used and compared very well with previously published results. Results of rock dissolution rates with common acidizing additives showed significant differences.
1.5 vol% cationic acrylamide copolymer decreased the calcite and dolomite dissolution rates significantly. At 1,000 rpm, the calcite dissolution rate with 1.5 vol% polymer and 0.1 M (0.36 wt%) HCl had a value that was 11.4% of the value measured with 0.1 M of HCl alone. Polymer changed the acid/rock reaction from mass-transfer-limited to surface-reaction-limited with both calcite and dolomite. This surface effect is possibly caused by polymer adsorption. 10 vol% mutual solvent increased the acid dissolution rate by 9% for calcite and by up to 29% for dolomite. 5000 mg/L iron (III) resulted in surface deposition of iron (III) hydroxide for both calcite and dolomite. At low rotational speeds, this surface layer had an inhibiting effect on the dissolution rate. 2 vol% corrosion inhibitor decreased the calcite dissolution rate by approximately 9%. Citric acid at 12 g/L decreased the calcite dissolution rate by an average of 9%, possibly because of the formation of calcium citrate at the surface. 0.2 vol% nonionic surfactant had no significant effect on the acid dissolution rate of calcite.
Flow Patterns and Minimum Suspension Velocity for Efficient Cuttings Transport in Horizontal and Deviated Wells in Coiled-Tubing Drilling
Authors: Kelessidis V. C. , Bandelis G. E. 
Published: December 2007

SummaryCoiled-tubing drilling (CTD), which has grown significantly in recent years, is normally associated with high-angle to horizontal and extended-reach wells. In these applications, however, hole problems become more troublesome because of inefficient cuttings removal. Among the many parameters affecting efficient cuttings transport in CTD are pump rates, well dimensions, fluid properties, solid sizes, solid loading, and hole inclination. Several attempts have been made to determine the optimum operating range of these parameters, but complete and satisfactory models have yet to be developed.The purpose of this paper is as follows:To provide a critical review of the state-of-the-art modeling for efficient cuttings transport during CTD. To present the critical parameters involved. To establish their range according to what is observed in practice. To propose a different approach for predicting the minimum suspension velocity. To describe the laboratory system that has been set up. The primary purpose of the flow system is to enable the gathering and publication of good-quality data that, together with previously published data, could further enhance our understanding of the flow of solid/liquid mixtures in annuli.
Study of the Effects of Pressure and Temperature on the Viscosity of Drilling Foams and Frictional Pressure Losses
Authors: Lourenço Affonso M. F. , Miska Stefan Z. , Reed Troy D. , Pickell Mark B. , Takach Nicholas E. 
Published: December 2007

Summary
A discussion about horizontal foam-flow behavior in pipes and annular geometry under elevated pressures and temperatures is presented. The study is empirically based and covers the effects of foam quality, foam texture, pressure, temperature, and geometry of the conduit on the rheological response of foams.
Automatic History Matching of Geologic Facies
Authors: Liu Ning , Oliver Dean S. 
Published: December 2007

SummaryThe truncated pluri-Gaussian method for modeling geologic facies is appealing not only for the wide variety of textures and shapes that can be generated, but also because of the internal consistency of the stochastic model. This method has not, however, been widely applied in simulating distributions of reservoir facies or in automatic history matching. One reason seems to be that it is fairly difficult to estimate the parameters of the stochastic model that could be used to generate geological facies maps with the desired properties. The second is that because "facies type" is a discrete variable, it is not straightforward to apply the efficient gradient-based minimization method to generate reservoir facies models that honor production data. Nongradient methods, however, are too slow for large field-scale problems.In this paper, the nondifferentiable history-matching problem was replaced with a differentiable problem so that an automatic history-matching technique could be applied to the problem of conditional simulation of facies boundaries generated from the truncated pluri-Gaussian method. The resulting realizations are consistent with both the geostatistical model of the observed facies and the historic production. Application of the method requires efficient computation of the gradient of the objective function with respect to model variables. We present an example five-spot water-injection problem with more than 73,000 model variables conditioned to pressure data at wells. The gradient was computed using the adjoint method, and the minimization routine used a quasiNewton algorithm. The objective function decreased more than 98% in 13 iterations.
Evidence and Implications for Significant Late and Post-Fold Fracturing on Detachment Folds in the Lisburne Group of the Northeastern Brooks Range
Authors: Bui T. D. , Brinton J. , Karpov A. V. , Hanks C. L. , Jensen J. L. 
Published: December 2007

Summary
In exposed detachment-folded Lisburne Group carbonates, field evidence and statistical analysis suggest that a significant population of fractures postdate folding. Both prefold fractures and penetrative strain associated with peak folding are overprinted by late-folding and post-folding fractures. Late-folding fractures strike east/west, parallel to the fold axes. These, and the earlier structures, are consistently overprinted by pervasive late north/south extension fractures. Both east/west and north/south fracture sets have similar average and median spacings.
Statistical analysis of fold angle and fracture spacing indicates that, as the folds tighten, both the east/west and north/south fracture spacings increase by a factor of two or three and become slightly more variable. This behavior is opposite from that expected if the fractures were closely related to folding. It suggests that the two sets are similar to each other and are only weakly affected by the folding.
This weak genetic relationship between folding and formation of the most obvious fractures serves as an important example with major consequences for reservoir modeling. Complex genetic and timing relationships between fractures and folds may result in several fracture sets, each having different characteristics (e.g., size, amount of fill, and termination type). Unless recognized, this could result in inappropriate wellbore placement or inaccurate productivity and recovery estimates. Modeling of this fractured system, for example, showed permeability changes greater than 80%, depending on fracture fill, timing, and flow direction.
Operational Experience by Applying Direct Electrical Heating for Hydrate Prevention
Authors: Urdahl Olav , Børnes Atle Harald , Kinnari Keijo J. , Holme Ragnhild 
Published: December 2007

Summary
The novel technique of applying electrical heat to prevent hydrate formation in multiphase pipelines has been applied successfully on the Norwegian continental shelf. The first pipelines in which direct electrical heating (DEH) was applied have recently been put into operation. DEH is based on applying electrical current through the steel wall of the pipeline, generating heat through wall resistance. By applying DEH, the fluid temperature can be maintained at greater than the hydrate equilibrium temperature (HET). Operational experience has proven that the concept is successful with regard to temperature control. It has been shown that the DEH system is capable of heating the pipeline inventory from the seabed temperature to one greater than the HET.
The DEH system installed on the Huldra-Veslefrikk condensate pipeline is described in detail here. This is an 8-in. pipeline with a length of 16 km. The application of the DEH system with respect to hydrate prevention and possible hydrate remediation is also discussed in detail.
Development and Applications of the Sustaining Integrated-Asset-Modeling Tool
Authors: Liao T. T. , Lazaro G. E. , Vergari A. M. , Schmohr D. R. , Waligura N. J. , Stein M. H. 
Published: December 2007

Summary
Integrated Asset Modeling (IAM) is a process that combines reservoir, well, and surface-facility models to create a complete system for reservoir and well optimization. This methodology ensures that the interactions among all components are correctly simulated. To realize the full benefit of IAM models, it is critical that changing reservoir and well conditions are entered to keep the models up to date and valid. If an IAM model is not frequently and properly maintained to reflect new conditions, it will rapidly lose its value as it ceases to accurately predict well production rates and pressure drops in the system.
An application tool was developed to provide easy updating and maintenance of IAM models for production optimization, surface-network debottlenecking, and production allocation. This tool automates the routine tasks required to update and maintain large-scale IAM models. The unique feature of this tool is its ability to calculate well production rates in almost real time by feeding well operating parameters obtained from the SCADA system into updated well-performance models. These production rates can be used to allocate total volumes measured at gathering centers back to individual wells. In addition, engineers can keep track of well matching parameters, such as productivity indices or skins, in the process of automatically maintaining IAM models using the sustaining integrated asset modeling (SIAM) tool. Trends in these parameters can then be analyzed to diagnose potential well problems and select workover candidates. Application of this tool in business units (BUs) has consistently resulted in a 90% reduction in model maintenance and management time, a streamlined process to maintain and update IAM models, and an improvement in production-allocation accuracy. These improvements have constituted a step change in IAM model application effectiveness across asset teams within BP.
Physicochemical Interactions During Surfactant Flooding of Fractured Carbonate Reservoirs
Authors: Seethepalli Anita , Adibhatla Bhargaw , Mohanty Kishore K. 
Published: December 2007

Summary
Recovery from fractured, oil-wet/mixed-wet, carbonate reservoirs by waterflooding is poor. Dilute surfactant methods are being developed to improve oil recovery from fractured carbonates. This paper investigates the interactions of dilute alkaline anionic surfactant solutions with crude oil on carbonate mineral surfaces. Wettability, phase behavior, interfacial tension, and adsorption experiments have been conducted. Anionic surfactants have been identified that can change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant dodecyl trimethyl ammonium bromide (DTAB) with a west Texas crude oil. All the carbonate surfaces (lithographic limestone, marble, dolomite, and calcite) show similar behavior with respect to wettability alteration with an anionic surfactant. Anionic surfactants, which lower the interfacial tension with the crude oil to very low values (&lt;10−2 mN/m), have also been identified. The adsorption of the sulphonate surfactants can be suppressed significantly by the addition of Na2CO3, because the addition of carbonate can change the zeta potential of calcite to a negative value. Greater than 50% OOIP can be recovered from oil-wet carbonate cores by spontaneous imbibition of 0.05 wt% anionic surfactant solutions in the laboratory scale.
Three-Phase Imbibition Relative Permeability
Authors: Naar J. , Wygal R.J. 
Published: December 2007

Abstract
An equation for three-phase (water, oil, gas) imbibition oil permeability is developed, assuming the water to be the dominant wetting fluid. Oil isoperms are obtained for consolidated sandstones characterized by. The evolution of an oil-gas system imbibing water from is shown to proceed along a line of constant oil saturation with increasing oil permeability and decreasing gas saturations. When the gas saturation cannot be reduced further, the system evolves along a line of constant with decreasing oil saturation and permeability. The initial gas saturation is shown to reduce markedly the effect of complete wetting by either oil or water on flow performance.

Introduction
Imbibition oil isoperms are required for performance prediction when a well is producing water, oil and gas. This situation occurs in multiphase displacements such as underground combustion, steam injection and the water flooding of highly depleted reservoirs. In a recent paper, a model was presented for the prediction of two-phase imbibition characteristics. This paper extends the imbibition model to the case of three phases by assuming that the water is the dominant wetting fluid. The following results were obtained from the model:an analytical expression of oil isoperms;oil isoperms as functions of reduced water, oil and gas saturations, valid for all sandstones having a capillary pressure curve which can be approximated by; andevaluation of the three-phase flow performance as dictated by complete wetting by either oil or water.
The agreement between predicted and observed oil recovery in the presence of a gas phase, reported in Ref. 1, is a partial support for the present development. However, experimental data are not available at this time to check fully the model predictions. Perhaps this paper will stimulate the collection of such data.

THEORETICAL
The imbibition model of a porous medium has been described previously, and the reader is referred to the paper of Naar and Henderson for details. In brief, the model is formed by the random interconnection of straight capillaries, with a provision for the blocking of the non-wetting phase by the invading wetting fluid.
Real Time Optimization: Classification and Assessment
Authors: Mochizuki Satoshi , Saputelli Luigi A. , Kabir C. Shah , Cramer Ron , Lochmann Mark , Reese Richard , Harms Larry , Sisk Carl , Hite J. Roger , Escorcia Alvaro 
Published: December 2007

Summary
The Real-Time Optimization (RTO) Technical Interest Group (TIG) has endeavored to clarify the value of real-time optimization projects. RTO projects involve three critical components: People, Process, and Technology. Understanding these components will help establish a framework for determining the value of RTO projects. In this paper, the Technology component is closely examined and categorized.
Levels within each Technology category are illustrated by use of spider diagrams, which help decision makers understand the current status of operations and the future RTO status. The perception of uncertain value has been one of the critical issues in adopting RTO systems in our industry. Therefore, case histories are reviewed to demonstrate the impact of RTO projects.
To assist RTO project promotion further, we list lessons learned, suggest a justification process, and present a simple example of an economic-evaluation process.

Introduction
Industry case histories demonstrate many types of benefits from RTO such as production-volume increase; better return on investment (ROI); higher decision quality; health, safety, and environment (HSE) improvements; and operational expenditures (OPEX) reduction. However, they have lacked systematic project-evaluation processes for justification.
Today, promoting RTO is, in essence, a competition for capital within a company. The project teams that recognize this fact and then clearly outline the purpose, benefits, costs (direct or indirect), and strategic business alignment of their proposals will be in an advantageous position to secure funding. Because RTO is still an emerging discipline, classifying projects of this nature is still dependent on an individual's point of view. This paper provides classification of RTO to help provide a common vocabulary to address a multitude of issues.
Optimization of Horizontal Well-Completion Design With Cased/Perforated or Slotted Liner Completions
Authors: Furui K. , Zhu D. , Hill A. D. , Davis E. R. , Buck B. R. 
Published: December 2007

Summary
A well completion is a critical interface between the productive formation and the wellbore. An effective completion must maintain the mechanical integrity of the borehole without creating any significant restrictions on the flow capacity of the well. In this paper, a process is outlined to design optimal completions for horizontal wells by applying comprehensive skin-factor models that include damage and turbulence effects for all common types of completions.
Slotted or perforated liner, cased, perforated, or gravel-pack completions have been used in horizontal wells for borehole stability and sand-control purposes. However, these completions may have lower productivity (as characterized by a positive skin) relative to an equivalent openhole completion, because the convergent flow to perforations or slots increases fluid velocity in the near-well vicinity. In addition, any reduced permeability zones (formation damage caused by drilling, completion, or other processes) magnify the convergent flow effects and therefore may result in substantially increased skin factors. Compound effects of formation damage around the well completion, a crushed zone because of perforating, plugging of slots, and turbulent flow, as well as interactions among these effects, are included in the model.
This paper illustrates how to use skin factor models to screen the available completion types for cased/perforated and slotted liner completions. This screening approach considers reservoir permeability, permeability anisotropy, fluid properties, formation damage effects, and rock mechanical characteristics as the key parameters. The types of completion that yield the most productive well performance for this matrix of properties are presented.
A more detailed completion design is then illustrated by showing how the skin-factor models were used to redesign the slot configuration of liner completions for viscous oil reservoirs on the North Slope of Alaska. Application of the slotted or perforated liner models to the readily available liners showed that the completion skin factor can vary by as much as 40%, depending on the detailed characteristics of the slots or perforations in the liner (slot or perforation size, density, and distribution). The example showed that optimizing the performance of the completion can increase well productivity at little or no cost and with no loss in liner mechanical strength.
Innovative, Integrated, and Cost-Effective Chemical Management on the Miller Platform
Authors: Wylde J. J. , Williams G. D. M. , Careil F. 
Published: December 2007

Summary
The BP-operated Miller Field poses a unique chemical challenge as it has, arguably, the harshest oilfield scaling regime in the North Sea, if not the world. Some 3 million litres of chemical are consumed each year and the management, supply, use, and performance of every aliquot of chemical is imperative to see Miller through to its planned cessation of production.
The Miller Field is a mature North Sea asset and produces a potential of 80,000 BWPD with its 16,000 BOPD. The unique challenge posed by Miller is that the produced water contains very high concentrations of scale-forming components combined with a very high corrosivity potential. Chemicals are routinely deployed to control scale, corrosion, emulsions, foam, biological fouling, and hydrates.
Two major step changes have occurred in the past 12 months that have delivered significant improvement to chemical management processes. The first step is the use of a novel, best-in-class, scale-inhibitor chemistry. Two years were spent in an industrywide search as well as developing and extensively testing the chemical in the laboratory. The new chemical is now deployed on more than 75% of the Miller wells. The longevity of scale-prevention treatments has been doubled on some wells when compared to the incumbent products.
The second step change was the application of innovative relative permeability modifier chemistries that not only increase oil production but actually shut off water production. Cross-linked polymer gels are pumped down wells and inflate in the presence of water, effectively blocking the flow path, but deflate in the presence of oil, allowing flow.
By implementing these changes, significant steps have been taken toward ensuring that continuation of production to the proposed cessation of production remains a viable proposition.
The Dimensionless Productivity Index as a General Approach to Well Evaluation
Authors: Diyashev Iskander R. , Economides Michael J. 
Published: December 2007

SummaryPetroleum-well performance and its evaluation are clearly some of the most important functions of modern production engineering. We present a general approach to the issue by employing the field-derived, dimensionless productivity index (JD), which we calculate from measured information including the production rate, reservoir and flowing pressures, and well and reservoir data.The JD is independent of well completion (i.e., it transcends the geometry), whether the well is under radial flow, is hydraulically fractured, or whether it is vertical or horizontal. The determined JDs are then compared against benchmarks we have developed for optimized production, such as the concept of unified-fracture design (UFD) or maximized horizontal well performance. We have developed deterministic methods for this analysis and new means to depict the results graphically.Such evaluations are important in concluding whether the well is underperforming or whether past engineering could have been improved and by how much. Decisions such as refracturing, the redesign and improvement of future treatments, and whether to fracture vertical or drill horizontal wells can be readily made.