bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Rheological Model for pH-Sensitive Ionic Polymer Solutions for Optimal Mobility-Control Applications
Authors: Huh C. , Choi S. K. , Sharma M. M. 
Published: December 2007

Abstract
Polyelectrolytes are water-soluble polymers that form molecular networks by association in solution. The properties of such polymers are very sensitive to the pH and ionic content of the solution. Polyelectrolytes such as poly(acrylic acid) can swell up to ∼1,000 times of its own volume by retaining a huge volume of water, or they may reversibly deswell to their original volume. Their solution viscosity can accordingly be changed by several orders of magnitude in a controlled manner by adjusting the solution pH. This remarkable property of pH-sensitive polymers can be exploited for a number of improved oil recovery (IOR) applications, as proposed by Al-Anazi and Sharma (2002). A key advantage for polyelectrolytes such as poly(acrylic acid) is their very low cost, because immense quantities are manufactured annually for consumer and industrial applications. For IOR processes, such as surfactant flooding, CO2 flooding and alkaline flooding, a major technical challenge is to bring the injected chemicals into contact with the oil and to properly herd the mobilized oil to producers, minimizing the undesirable influence of reservoir heterogeneity. Placement of the mobility control polymer in desired locations in the reservoir for controlled viscosification can significantly alleviate the problem of volumetric sweep. For the optimal control of the polymer viscosity at the desired locations, the dependence of the polymer rheology on pH, salinity, polymer concentration and molecular structure needs to be known accurately. The rheology correlation can then be employed for IOR process simulations for optimal design of mobility-control bank placement and viscosification, and for evaluation of its effectiveness.
A comprehensive rheology model is developed by combining the ionic hydrogel swelling theory of Brannon-Peppas and Peppas (1988) with the Mark-Houwink equation that relates the polymer intrinsic viscosity with polymer molecular size; the Martin equation that relates the characteristic Newtonian viscosity with polymer concentration and intrinsic viscosity; and the Carreau equation that relates polymer viscosity with shear rate. The ionic swelling theory had been independently validated with laboratory swelling experiments earlier, and the Mark-Houwink, Martin, and Carreau equations have been employed to characterize aqueous polymer solution rheology. The polymer solution viscosity can, therefore, be reliably predicted as a function of pH, salinity, polymer concentration, and shear rate. The model predictions match the laboratory-measured viscosity data reasonably well, for a range of pH, salinity, polymer concentration, and shear rate. The model is presented in a form that can be implemented in an IOR process simulator for optimal mobility control applications, as described above.
Evaluating Barnett Shale Production Performance Using an Integrated Approach
Authors: Frantz J. H. , Williamson J. R. , Sawyer W. K. , Johnston D. , Waters G. , Moore L. P. , MacDonald R. J. , Pearcy M. , Ganpule S. V. , March K. S. 
Published: December 2007

Abstract
This paper presents the results of using a shale-specific, finite-difference reservoir simulation model to history match and forecast production data from the Barnett Shale reservoir. The paper will illustrate the many uses of the model for vertical and horizontal wells including determining gas in place, recovery factors, optimal well spacing, drainage areas and drainage shapes, optimal fracture half-lengths and conductivities, infill evaluations, horizontal well modeling and optimal number of stimulation treatments, analysis of microseismic data, and compression evaluations. The model was developed in the early 1990s to incorporate all of the production mechanisms inherent in shales including matrix gas porosity, gas desorption isotherm, single-or two-phase flow of gas and water in the natural fractures, layers, complex hydraulic fractures, and variable flowing bottomhole pressures. The paper will discuss the methodology to incorporate all field data into the simulator including core, logs, well test, completion, stimulation, microseismic, and production data. Examples will be given using public datasets. We also show production comparisons between vertical and horizontal wells since this is of topical interest in the play's development history. Furthermore, we discuss the various types of data to collect, their importance to proper stimulation design, and the integration methodology to evaluate and complete shale reservoirs.
Why Don't We Pump More Type I/II Lightweight Slurries?
Authors: Myers R. R. 
Published: December 2007

Abstract
For nearly two decades in the Appalachian Basin many hundreds of Type I/II lightweight cement slurries with reduced compressive strengths, and increased elasticity have been successfully applied to Devonian Shale wells. More recently, hundreds of reduced density slurries have been successfully pumped on surface and intermediate casing jobs. Despite this success, the majority of new cement bid requests in the Northeast Region and perhaps across the U.S. for that matter still specify API monogrammed cement. The reality for the Northeast U.S. is that no cement plant within 450 miles manufactures to the API specification, except LaFarge at their Joppa facility. Plants manufacturing to API specification turn out a product that may vary more greatly batch to batch than the Type I/II cements. So much for uniformity and consistency, the most valued advantages of API cement.
The situation begs the question: Why are drilling engineers so reluctant to pump more cost saving Type I/II lightweight slurries if they meet the technical criteria and are clearly more cost effective? One reason may be regulatory; state oil & gas code books were written years ago specifying API cement and compressive strength requirements for many applications. Another is awareness, many State Oil & Gas Regulatory Agencies may not know about the recent advances in oilwell cements, nor the fact that API cement is not available in their area of responsibility.
This paper will lay out the case for Type I/II lightweight cement slurries, how they have superior mechanical properties for long term zonal isolation, and some example applications best suited to them. Supporting technical data includes cost savings and case histories of some applications. Efforts to educate the state regulatory agencies along with an example of successful requests for variances will be presented.
Comprehensive Performance Design Criteria for Hydraulic Fracturing
Authors: Manrique J. F. , Poe B. D. 
Published: December 2007

Abstract
Several works have tried to address hydraulic fracturing treatments using a unified theory approach based on the dimensionless productivity index concept. The observations and recommendations from these works are based on numerical simulation, resulting from single phase liquid and simplifications such as steady state or pseudo steady state conditions. However, the behavior in the reservoir is not a simplified one and the assumptions made previously by other authors limit the application of the technique.
In this paper we present the correct and rigorous mathematical solution of the dimensionless productivity index. The application of a General Expression for Dimensionless Productivity in Bounded Reservoirs is presented and applied to multiwell systems
Field examples and results are presented, where production analysis suggested changes and optimization of fracturing fluids, breakers, job sizes, designs, types and mass of proppant, etc. Guidelines for performance optimization and practical standards are obtained from field production results and are also presented.
Liquid Lifting From Natural Gas Wells: Tubing-Casing Junction
Authors: Christiansen R. L. , Girija E. , Riggins L. , Elsener G. , Sutton R. P. , Smeenk R. 
Published: December 2007

Abstract
Effective removal of water and hydrocarbon liquids from gas wells can maintain and increase gas production. In this paper, results of flow loop tests on transport of liquid from casing to tubing is reported for flow rates ranging from 50% below to 50% above the critical gas flow rate for the tubing. The results show that liquid transport is severely constrained at the tubing-casing junction because the gas flow rate is usually much below the casing critical flow rate. To resolve the tubing-casing bottleneck, six approaches were tested: constrictions in the tubing, a vortex-generating device in the tubing, an assembly of baffles in the casing, a ball pack in the casing, a closed-end pipe in the casing, and foam-generating surfactants. The first two approaches provided no benefit. The last four approaches enhanced liquid lifting, in some cases by a factor of 10 or more. All approaches that increase liquid transport from the casing to the tubing also increase pressure gradient. Approaches that boost liquid transport rate with a small increase in pressure gradient are most desirable.
Streamline Tracing on Unstructured Grids
Authors: Sun S. , Gai X. , Wheeler M. F. 
Published: December 2007

Abstract
Traditional methods for streamline tracing are mainly based on the Pollock Cartesian scheme and its extensions, which require dual grids to treat general tensor fields on unstructured meshes. The complexity and inflexibility of dual grids impose substantial limitations on the application of streamlines.
In this paper, we propose a computationally efficient method to construct streamlines on the original grid, taking flow fields from arbitrary schemes including Galerkin finite element methods. An essential component of the proposed streamline construction is fast processing of non-conservative velocity fields to recover or maintain local mass conservation and normal flux continuity simultaneously. Our construction involves balancing conservation residuals on each pair of adjacent elements using a Gauss-Seidel type iteration. Locally conservative velocities are extended from element faces to interiors using a local single element mixed finite element method. Streamline and travel time are then obtained using standard methods of integration based on the Pollock algorithm.
The proposed approach is shown to possess several advantages: it treats general tensor fields on unstructured and even nonmatching grids, maintains the optimal order of accuracy for high order elements, and avoids the difficulties imposed by nonphysical sinks and sources due to numerical inaccuracy. Several computational examples on structured and unstructured meshes are presented to demonstrate the effectiveness of the proposed method.
Reservoir Characterization of Fractured Cambrian Reservoirs, Algeria
Authors: Guehria F. M. , Yawanarajah S. , Touami M. 
Published: December 2007

Abstract
It has long been recognized that the faults in the Hassi Messaoud field are necessary for the successful production from the Cambrian sandstone reservoirs. What is less understood is the dual nature of these faults in that they can both control transmissibility through permeability enhancing fractures, and control trapping (sealing) through permeability reducing diagenesis. The key to optimally exploiting this or any fractured reservoir is the ability to predict the existence and properties of both. Without these faults and fractures, the Cambrian reservoirs would be classified as being tight with matrix permeabilities that are less than 40 mD, usually less than 3 mD, and porosities of between 3-8 %. In addition, the production history of the wells indicate variability in matrix versus fracture contribution, which suggests that the field was composed of more than one type of storativity-based, fractured reservoir.
An integrated reservoir characterization study was conducted in Zones 1A and 1C to confirm the above premises. Reservoir quality and compartmentalization of the Cambro-Ordovician Ra and Ri reservoirs are believed to be related to stratigraphic, diagenetic, and structural variability. There is much evidence for reservoir heterogeneity especially around faults i.e. variation in reservoir thickness, rapid changes in porosity and permeability, variable production performance, variable water production. There is also evidence that fracture intensity varied from north to south and that this affected well performance. A number of wells were picked for detailed evaluation based on their production history and proximity to faults.
Continuous Model Update of Natural Fractures Characterization in Sinan Field To Optimize Production
Authors: Solís R. , Cabrera C. , Liévano R. , Monroy F. , Cruz G. , Saputelli L. 
Published: December 2007

Abstract
In this paper, we show the case history for the characterization of the naturally-fractured light oil reservoir, Sinan, which is located in the Gulf of Mexico continental shelf, at 40 km north of Frontera port, state of Tabasco, Mexico.
Historic production test data from preciously drilled wells showed tremendous well productivity variation as function of well location, and trajectory design.
We built a complex 3D structural framework with the use of static and dynamic information. Up-to-date well drilling data was used to continuously calibrate the model as well as 33 km2 processed seismic information. The resulted framework was derived from the integration of two seismic cubes (time and depth post-migrated), resistive image logs, sonic logs, dipolar logs, core information (petrophysical data), well testing, and geological information. This model provides a quantitative framework for the spatial distribution of subsurface properties of the Sinan Field.
As a result of the applied methodology, drilling trajectory and target of proposed development wells were reconsidered. Recommended proposals as a result of this study allow better reservoir fluid contribution which increase and optimize production. The resulted model will be continuously updated to support the drilling of approximately 5 wells per year to fulfill field development requirements.
PS Reflections in Seismic Data
Authors: de Bruin J. A. , Chahine A. A. , Wijnands F. M. 
Published: December 2007

Abstract
Offset VSP data in the Deir Ez Zor area contains significant mode-converted shear wave energy. This allows us to obtain two results: a P-wave and an S-wave OVSP image. The additional information contained in the shear wave image can significantly aid interpretation. There are however differences in character, amplitude and polarity. Interpreted in conjunction with Zoeppritz equation modeling, these can provide information about lithology and fluid content that cannot be extracted from P waves alone.
We now believe, based mainly on evidence from offset VSP data, that part of the noise in our surface seismic consists of mode converted shear waves, rather than P-wave multiples. NMO velocities and AVO anomalies in prestack surface seismic data corresponded with modeled PS responses. Such modeling thus provides a method of identifying suspected PS reflections in the vicinity of wells with OVSP data or full waveform sonic and density logs. Depending on the importance of a particular event, if there is a suspicion that it may be a PS reflection, it will often be justified to obtain OVSP data and to re-evaluate pre-stack surface seismic data.
Advances in Integrated Horizontal Production Logging in Openhole Completions
Authors: Al-Ismail M. S. , Zeybek M. , Kelder O. , Al-Muthana A. S. , Mubarak S. , Abdulrahman A. 
Published: December 2007

Abstract
Production logging, especially in highly deviated, horizontal wells still exhibits challenges due to multi-phase, complicated flow regimes in undulating long well bores in open hole completions. Because of the advances in measurement technology and interpretation techniques, production logging objectives can be achieved in more challenging conditions; the improved confidence in the result is crucial to associated decisions and well interventions.
In this paper, we present four field examples that used the latest technological advances and the best practices in integrated production logging in horizontal wells with openhole completions using either coiled tubing or tractor conveyance. The first example detected a super-permeability zone and a changing water salinity profile in the wellbore. The second example identified crossflow in a shut-in multilateral well; subsequent workover revived the oil production to initial production levels. The third example provides a discussion of the effective design of tractor-conveyed horizontal production logging to identify water entry and define the flow profile. The last example relates the first use of a new, compact, integrated production logging tool that pinpointed water entries in a horizontal openhole completion. This compact production logging system provides comprehensive, continuous data for the analysis of complex horizontal flow behavior.
The results of these field examples show how the application of the latest advances in horizontal production logging operations can significantly improve our understanding of well behavior and reservoir characterization. Combining these advantages with effective remedial action and workover operations can increase production and extend the life of horizontal openhole producing wells.
Accelerated Well Delivery through High Performance Directional Drilling Systems—A Middle East Case History
Authors: Vestvik J. , Andersen T. , Istad N. , Rattray E. , Sutcliffe B. , Craig C. 
Published: December 2007

Abstract
An integrated drilling system, custom designed to optimize drilling performance on the World's largest proven offshore gas field, has produced a step change in drilling performance resulting in reducing the overall planned spud to total-depth drilling by half.
This paper will focus on how this exceptional performance was achieved with specific focus on the new-generation positive displacement motor (PDM) and PDC bit combination and the "performance directional drilling" techniques employed.
Physio-Chemical Characterisation of Vegetable Oils and Preliminary Test Results of Vegetable-Oil-Based Muds
Authors: Amanullah Md. 
Published: December 2007

Abstract
Mineral oil-based drilling muds are toxic, not readily biodegradable and thus have cumulative impact on terrestrial, coastal and marine habitats. The base fluid for mineral oil-based mud development has limited source of supply. Vegetable oils are renewable, highly biodegradable, can be produced as per industry demand and thus could be a suitable candidate for development of a highly biodegradable oil-based mud with a sustainable source of supply. They have higher flash and fire points, better thermal stability, no detrimental impact on the surrounding environment and are much less hazardous compared to mineral oils. Due to biodegradable nature of vegetable oils, drill cuttings will have no environmental impact if the cuttings are disposed directly to the surrounding environments. Due to non-reactive nature of vegetable oils with clays and shales, their technical performance in maintaining borehole stability is comparable to mineral oil. On the other hand, due to readily biodegradable nature and negligible toxicity effect, vegetable oil-based mud performance should be comparable to water-based mud from environmental point of view. Hence, vegetable oil-based mud could be a potential solution to meet the current as well as future technical and environmental challenges.
An invert emulsion mud was developed using a blend of vegetable oil to study the rheological and filtration properties and evaluate its suitability for oil well drilling. Initial mud formulation indicates that development of a viable OBM is not possible using the conventional approach due to the high inherent viscosity of vegetable oils and significant thermal degradation at high temperature. However, processing and treatment of vegetable oils lead to the formulation of a vegetable oil-based mud with desirable rheological properties and excellent thermal stability. Preliminary test results indicate that the processed vegetable oil-based mud produces suitable low end rheological properties including gelling characteristics. Thermal conditioning of the mud at 150 °C for 16 hours indicates no significant changes in the rheological properties of the mud. The high thermal characteristics of vegetable oils indicate their safe operation for all practical range of temperatures.
A Critical Comparison of Real Option Valuation Methods: Assumptions, Applicability, Mechanics, and Recommendations
Authors: Bratvold R. B. , Laughton D. , Enloe T. , Borison A. , Begg S. 
Published: December 2007

Abstract
More than thirty years after the debut of the famous Black-Scholes option pricing formula, and more that twenty five years after Stewart Myers coined the term, real option valuation has yet to catch on at most companies in the upstream petroleum industry as part of the asset decision-making process.
While there is a great deal of agreement about the appeal of the underlying ideas, a variety of contradictory implementations, many of which are ill founded or poorly constructed, have been suggested for putting real options into practice. The resulting confusion has made an already difficult problem of diffusion of innovation even more difficult.
In this paper, we build on the work done at the SPE workshop on valuation held in Banff in 2003 to create a detailed taxonomy of the various approaches to real options valuation that have been proposed, and use this taxonomy to compare the different methods. The comparison uses, as an example, an offshore production drilling decision that is realistic on a business level both in structure and data.
Taming Complexities of Coupled-Geomechanics in Rock Testing: From Assessing Reservoir Compaction to Analyzing Stability of Expandable Sand Screens and Solid Tubulars
Authors: Kanj M. Y. , Abousleiman Y. N. 
Published: December 2007

Abstract
Well geomechanics and "smart" completion designs in many of Saudi Aramco's fields are essential to support the company's efforts to apply the extended-reach and MRC well technologies. MRC wells are being aggressively targeted to optimize development economics, enhance recovery, maximize production, minimize differential drawdown across the sand face, reduce sanding potential, and defer water coning. In addition, many unconsolidated sandstone reservoirs require positive sand control measures. As such, Expandable Sand Screen (ESS) tubulars have seen a recent surge in applicability for completing conventional and MRC wells in sand prone, troublesome formations. Today, solid expandable tubulars are being tested on a number of wells in a pseudo mono-diameter structure. Though attractive, the long-term performance of these tools in the arabian reservoir environments is yet to be explored.
This paper simulates the impact of reservoir production and depletion on expandable tubulars and sand screen completions when the compacting reservoir behaves as a permeable poroelastic medium. A general poroelastic solution model encompassing a multitude of boundary and initial conditions is discussed in this paper. The model simulates the uniaxial (Ko) testing of solid and hollow ge-omaterial cylinders (Geertsma, 2005). Thus, it helps infer about potential problems that might influence the survivability of "expandables" and disrupt the outflow from the well. The herein presented proof cases on reservoir and cap rocks are supported with numerical application, experimental validation, and physical interpretation of the coupled poromechanical processes that are reflected in the anisotropic, time-dependent rock responses during testing. The manuscript also demonstrates that this enhanced approach to modeling visualization will ultimately ease the tractability of the pertinent physical phenomena as well as support the model's computational credibility to engineers and experimentalists in the oil and gas industry.