bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Development of Reliability-Based Design Rules for Casing Collapse
Authors: Adams A. J. , Warren A. V. R. , Masson P. C. 
Published: December 2007

Abstract
The API design rules for casing collapse1 give widely varying predicted failure probabilities over the D/t range for well tubulars. For low D/t, they give unconservative designs (excessive risk); and for moderate D/t, over-conservative designs (excessive safety).
This paper describes the development of improved design equations, calibrated using structural reliability methods to obtain a uniform predicted failure probability. The new design rules are simpler to use than the existing API equations, and give either safer or more economic design, depending on D/t ratio.
Predicting the Effect of Continued Gas Enrichment Above the MME on Oil Recovery in Enriched Hydrocarbon Gas Floods
Authors: Stalkup Fred 
Published: December 2007

Abstract
Gas enrichment can be an important optimization variable in hydrocarbon enriched gas drive floods. Slimtube experiments often show that oil recovery increases sharply up to the minimum miscibility enrichment (MME) and thereafter increases very little with further enrichment. However, there are physical reasons why oil recovery might continue to improve with increasing gas enrichment above the MME in a reservoir flood:the gas becomes more viscous and more dense from mixing with oil, which improves sweepout,a smaller lean-gas bank develops, which also may improve sweepout, andricher gases may mix less deeply with oil into the multiphase region leaving less miscible flood residual oil behind.
All of these mechanisms are influenced by the physical gas-oil mixing that occurs in a reservoir flood. Unfortunately, a concern with commercial simulators is that numerical mixing or dispersion, which is artificial and non-physical, may dwarf the mixing from physical mechanisms and cause an unrealistic prediction of the effect of continued gas enrichment on additional recovery even if physical mechanisms such as molecular diffusion and dispersion are accounted for in the formulation of the simulator.
This paper investigates the effect of realistic levels of physical dispersion on any increase in recovery resulting from continued enrichment of hydrocarbon gas above the MME. It does this in simplified reservoir-scale cross sections by 1) minimizing numerical dispersion relative to the input physical dispersion by using two-point upstream weighting and a large number of grid blocks, and 2) by approximating longitudinal physical dispersion with numerical dispersion in single-point weighting simulations by making the grid blocks small enough to mimic the physical dispersivity that might prevail in a reservoir. It also attempts to provide insight into the error large grid blocks may cause when gas enrichment is studied with reservoir models.
The results of this study suggest that recovery may continue to improve significantly with enrichment above the MME and that this effect should not be overlooked when optimizing the enrichment of an enriched gas-drive flood. The results also suggest that extremely small grid blocks in the lateral direction may not be required to realistically assess the improvement in recovery with continued gas enrichment if the mixing from the viscous crossflow caused by alternate water and gas (WAG) cycles dominates the numerical mixing caused by moderate-size grid blocks.
P. 51
Application of Reservoir Strength Characterization and Formation Failure Modeling to Analyze Sand Production Potential and Formulate Sand Control Strategies for a Series of North Sea Gas Reservoirs
Authors: Burton R.C. , Davis E.R. , Morita N. 
Published: December 2007

Abstract
A sand control study was conducted for a series of North Sea gas reservoirs. The purpose of the study was to analyze the formation's sand production potential, formulate a sand control strategy and optimize field operations.
This paper discusses field data and documents the methodology used to characterize formation strength from core measurements, conduct formation failure modeling and history match model results with field sand production data. The study was conducted on the Rotliegendes sandstone formation. However, the methodology presented can be applied to any sandstone reservoir requiring formation failure analysis.
The methodology comprises:
Formation Strength Characterization
Measurement of Formation Compressive Strength Correlation of Strength with Petrophysical Data Triaxial Testing
Formation Stress Characterization
Formation Failure Analysis
Formation Failure Modeling History Matching Model Output to Field Failure Data
Development of Sand Control Strategies
Each of these subjects will be discussed with field data presented to support the discussion and subsequent conclusions/recommendations.
P. 159
The Mounds Drill Cuttings Experiment: Determining Placement of Drill Cuttings By Hydraulic Fracturing Injection
Authors: Moschovidis Zissis A. , Steiger Ronald P. , Weng Xiaowei , Abou-Sayed Ahmed S. 
Published: December 2007

Abstract
The paper describes a comprehensive field experiment (the Mounds Drill Cuttings Injection Experiment) to improve our understanding of the mechanics and modeling of the processes involved in the injection of drill cuttings.
Disposal of drill cuttings from offshore, arctic, and other remote or environmentally sensitive locations is of importance from both economic and environmental perspectives. The transportation of such wastes has the potential for accidental spillage of materials in environmentally sensitive locations such as waterways or wetlands. An attractive disposal option (that is coming into more common use) is to inject the cuttings into deep formations where they will not interfere with surface and sub-surface potable water sources. The major issue associated with this technology is to assure that the cuttings are permanently stored and contained and not transported upward to the surface or toward aquifers.
The paper describes the field setting where the experiment is being conducted, the criteria used for formation selection, the technical scope of work, the series of experiments planned and issues which arise when planning and implementing such an experiment.
The test program includes the deployment of fracture imaging diagnostic tools to determine the size, shape and orientation of the created hydraulic fractures and the drill cuttings in the fractures. The diagnostic imaging techniques are microseismic mapping, surface tiltmeters, downhole tiltmeters and surface monitoring of injection fluids, pressures and volumes. Observation of cores from the affected area will provide direct evidence of the fractures to support information inferred rom the microseismic data.
The plan also includes characterization of the mechanical properties of the cores, and laboratory and numerical modeling of the micromechanics of the cuttings injection process.
This experiment is unique in that this is the first time all of these monitoring techniques have been utilized simultaneously at a single location.
The paper will add to the industry's technical knowledge base by providing insight into technical and implementation issues, which arise in planning such a comprehensive experiment. This insight could find applications worldwide for conducting similar field tests.
P. 227
The Development of a New Compact Electrostatic Coalescer Concept
Authors: Urdahl Olav , Berry Pat , Wayth Nick , Williams Trevor , Nordstad Knut , Bailey Adrian , Thew Martin 
Published: December 2007

Abstract
The demand for more cost effective field developments has led to a substantial focus on separation equipment that reduces weight and deck space. Of particular concern are field developments with subsea production templates and multiphase transportation to existing field installations. Additionally, the environmental aspects concerning the use of large amounts of chemical demulsifiers are crucial these days.
In this paper we present a new Compact Electrostatic Coalescer (CEC) that has the capability to reduce both weight and size, and to eliminate the use of chemical demulsifiers, in some cases.
The basic principle of the CEC is the application of a high-voltage A.C. electric field to an emulsion system flowing under turbulent conditions. The influence of both the electric field and the turbulent mixing are utilized in the breaking of the flowing emulsion.
The performance of the laboratory version of the CEC is discussed with respect to emulsion properties, flow rate, applied voltage and residence time in the electric field. Performance is quantified using both a Malvern Particle and Droplet Size Analyzer and a Hamanatsu Image Analysis System.
Some results from a prototype test on live crude are also given.
P. 111
Reducing Emulsion Problems By Controlling Asphaltene Solubility and Precipitation
Authors: Kokal Sunil , Al-Juraid Jamal 
Published: December 2007

Abstract
The precipitation of asphaltenes during crude oil production can cause a number of problems. One problem is the agglomeration of asphaltenes at the water-oil interface and formation of tight emulsions. These asphaltenes can form a thick pad in the dehydration equipment, which can significantly reduce the demulsification rate or increase the demulsifier dosage. Several gas-oil separating plants (GOSPs) in Saudi Aramco have been experiencing such problems.
The paper discusses the emulsion problem in these GOSPs. Several asphaltene dispersants and surfactants were evaluated for their ability to inlubit the precipitation of asphaltenes from crude oils and in reducing demulsifier dosage at the GOSP. Laboratory experiments were conducted to determine the onset and flocculation of asphaltenes from crude oil with and without the dispersants and surfactants. The criteria for asphaltene dispersants/surfactants selection and their application in mitigating emulsions are presented. Certain chemical additives were identified that reduce the agglomeration of asphaltenes at the oil-water interface and enhance the demulsification process when added to regnlar commercial demulsifiers. The mechanism of emulsion stabilization by asphaltenes and other solids is presented.
This paper highlights how a concerted team effort has led to a reduction in demulsifier consumption by 40-50 % in these GOSPs during the past two years. This has resulted in savings of over $500,000 annually. Some of the very tight emulsion producing wells that were shut-in during the winter months are now producing and are expected to do so in the future.
P. 145
Improved Methods for Multivariate Optimization of Field Development Scheduling and Well Placement Design
Authors: Pan Yan , Horne Roland N. 
Published: December 2007

Abstract
Optimization of reservoir development requires many evaluations of the possible combinations of the decision variables, such as well locations and production scheduling parameters, to obtain the best economic strategies. Running a simulator for such a large number of evaluations may be infeasible due to the computation time involved.
This study investigated two multivariate interpolation algorithms, Least Squares and Kriging, to generate new realizations from a limited number of simulations in order to predict the optimal strategies in a field development scheduling project and a waterflood project. The result was a significant reduction in the simulation effort required. The recommended solutions were obtained by searching for the optimal objective function values among the interpolation realizations. Additional simulation runs were performed to refine the search for the final optimal solution in the vicinity of the intermediate optimal region.
The net present value was used as the objective function in both projects. The field development scheduling simulation was achieved by an economic model taking account of all the costs and profits during the time period being studied. In the waterflooding application, movement of the waterfront was tracked and the oil and water production at each production well was calculated, after which the optimum well placement strategy was determined.
The results obtained using the interpolation methods showed that the algorithms are able to reduce the number of simulation runs, to provide a global sketch of the objective function surface, to avoid possible failure at local optima, and to reach the absolute optimum by refining the grids near the intermediate optima. The approaches were shown to be practical, and will be useful in full-scale optimization problems in which simulation costs would be prohibitive for iterative nonlinear optimization methods.
Emulsion Characteristics of High Water-cut Oil Wells
Authors: Janssen P.H. , Harris C.K. 
Published: December 2007

Abstract
A laboratory study was executed which investigated the characteristics of the oil-water-mixture that is produced by a high water-cut well. By means of core-flow experiments the concurrent flow of oil and water in the near-wellbore region of a high water-cut well was simulated. Production parameters and formation and fluid properties were varied in the experiments. The effluent of the different types of cores produced a mixture of large millimeter-sized drops and micro- droplets which were typically of the order of the pore size. The size distribution of the produced emulsion droplets was measured by a particle size analyzer, based on laser diffraction.
The experimental results revealed that the droplet diameter produced by different sandstone cores was a unique function of pressure gradient and interfacial tension and independent of the type of sandstone.
Furthermore it was observed that wettability has a strong impact on the type of oil-water morphology.
P. 405
Horizontal Well Performance Evaluation and Fluid Entry Mechanisms
Authors: Lenn Chris , Kuchuk Fikri J. , Rounce Justin , Hook Peter 
Published: December 2007

Abstract
In this paper, the use of various measurements is presented for performance evaluation of horizontal wells. The importance of formation evaluation and the challenges of testing in horizontal wells are reviewed. Factors affecting the productivity of horizontal wells are explored. The difficulties in horizontal well productivity estimation due to their long length in the formation compared with vertical wells and inadequacy of measurements during drilling and production are shown. It is also shown that how reservoir heterogeneity affects the reservoir pressure distribution and hence fluid entry profiles and well productivity. Using field examples, we show that the new integrated production logging measurements can be used to assess horizontal well productivity by identifying productive zones, fluid entries, and determining the fluid distribution (oil, gas, and water) in the well- bore. A range of fluid entry mechanisms from over twenty recently logged wells are described and classified. The continuing development of production logging technology for horizontal wells is described. The field examples indicate that horizontal wells have permanent water sumps, regard- less of whether they produce water or not, which leads to reduced oil entry. Performance simulations have shown that for these horizontal wells a 30 to 50 percent productivity (PI) reduction is found when they are compared with their full potential.
P. 365
Multiple Hydraulic Fracturing of Deep Gas-Condensate Wells in Oman
Authors: Jones A.T. , Al Salhi M.S. , Al Shidl S.M. , England M. , Pongratz R. 
Published: December 2007

Abstract
This paper describes the design, execution, and analysis of multiple hydraulic-fracturing treatments in deep gas-condensate wells in Oman. Improved fracture performance is being aggressively targeted to increase well productivity and reduce the number of wells initially required for the contractual production capacity of Oman's LNG plant that is currently under construction. In addition to using conventional fracture processes, engineers optimize fracture design by using both state-of-the-art dynamic gas-condensate reservoir modeling and fracture geometry modeling. They also analyze well-test data and discuss operational experience.
P. 437
Pioneering Subsea Intelligent Completion Installations - Aquila Case History
Authors: Marangoni M. , Giuliani C. , Botto G. , Ferrario G. 
Published: December 2007

Abstract
For those who are not familiar with the concept, intelligent completions are one of the hot topic of today's well completion technology.
The idea is that control of production parameters is done more effectively and efficiently at reservoir level possibly without or with a minimum of direct well intervention. Thus, the design of ‘intelligent’ systems that allows remote manipulation via a control umbilical of devices permanently installed downhole.
The technology is today in its infancy but it is fuelled by great expectations from the oil industry.
This paper provides the case history, from the background of early engineering to the field deployment, of one of the pioneering application: the first intelligent completion in a subsea environment.
New Exact Spherical Flow Solution with Storage and Skin for Early-Time Interpretation with Applications to Wireline Formation and Early-Evaluation Drillstem Testing
Authors: Proett Mark A. , Chin Wilson C. 
Published: December 2007

Abstract
The wireline formation tester, which is frequently operated over short durations, and a new formation testing tool that obtains pressure measurements during the drilling program, have provided the impetus to develop improved pressure transient analysis methods that support formation evaluation during early-to-intermediate test times. Existing methods, for example, apply to late times only, and are approximate in that they do not model the entire timewise pressure response; alternatively, the detailed models that are available for more exact analysis are numerical, chart-oriented, and not amenable to simple physical interpretation.
This paper extends recent work that has solved the spherical flow boundary value problem for storage with an exact analytical solution.1,2 Here, the general spherical flow formulation, including both wellbore storage and skin effects, is solved by inverting the complete Laplace transform to produce an exact, closed form, analytical solution. This new solution reduces to previously published early- and late-time solutions in the respective asymptotic limits. However, the new solution permits convenient pressure response to theory matching over the complete time regime (early-, transitional-, and late-time data), rather than conventional late-time, spherical flow matching; it permits critical pressure-transient interpretation using only early-to-intermediate-time data, thereby reducing required rig time.
The new solution is derived for the full initial-boundary value problem for transient, compressible, spherical flow using Laplace transforms. Closed-form expressions are obtained for pressure, pressure derivative, and sandface flow rate in terms of complex error functions. These exact solutions are compared to existing spherical solutions obtained by numerical transform inversion, and also to finite element results that include the three-dimensional effects of wellbore geometry.
The accuracy and interpretation speed of the new solution permits systematic determination of all flow parameters, to include storage coefficient, skin effect, formation fluid compressibility, permeability, and pore pressure. Its application to a new type of well test tool designed for pressure testing during the drilling program is described. Synthetic data from wireline formation testers and a new drill pipe conveyed pressure test system are analyzed to illustrate the utility and power of the new solution. These examples are used to demonstrate how the new approach can improve real-time regression analysis used in determining formation properties.
Lessons Learned from 4D Projects
Authors: Waggoner J.R. 
Published: December 2007

Abstract
Time-lapse 3D, or 4D, seismic has been under consideration by the industry for reservoir monitoring for more than a decade. It offers the possibility of identifying the inter-well distribution of bypassed and untapped oil, of monitoring displacement heterogeneity, and of detecting uneven pressure depletion away from wells. If obtained, these detailed observations could be used to increase ultimate recovery, reduce production costs, and prevent surprises such as unexpectedly early breakthrough.
But these benefits are not easily obtained, and are certainly not guaranteed. There are a number of factors that impact whether a 4D project will be successful, and a careful study of these is required to give a realistic expectation of what 4D can do for a specific reservoir. Numerous 4D seismic projects have been active over oilfields world-wide, and successes, relative to each project's objectives, have been realized by field operators using a wide variety of data acquisition techniques (land, streamer and seabed methods), and over a variety of field types, including both clastics and carbonates.
This paper draws from this experience to present a generalized 4D project workflow, and reviews results from some of these recent projects as illustrations. In general, sufficient software tools, rock physics data, and experience now exist to conclude that 4D is a low risk/high benefit reservoir management tool. The key to a successful project, however, is determining what 4D can do in a specific field, which requires a careful feasibility study, clear reservoir management objectives, and high quality and experienced seismic processing and interpretation.
P. 509
Improvement and Sensitivity of Reservoir Characterization Derived From Time-Lapse Seismic Data
Authors: Huang Xuri , Meister Laurent , Workman Rick 
Published: December 2007

Abstract
In general only a single 3D seismic data set is used for the characterization of the static properties of a reservoir, even though these static properties could be integrated with dynamic properties. But sometimes, more than one 3D seismic data volume has been acquired over the same field after the production starts. We propose to use these additional data not only to understand the dynamic properties of the reservoir using a time-lapse seismic analysis as presented last year, but to improve the accuracy of the initial reservoir description and study its sensitivity to the input data during the optimization process. Using two 3D seismic data sets acquired over a field in the Gulf of Mexico, this paper demonstrates a method to improve the porosity map obtained from the geostatistical characterization of the base 3D seismic data set by an analysis of the second 3D data volume. It is not possible using just the base data to differentiate factors such as fluid content and pressure from the geostatistical porosity characterization. But by using the flow information from the wells and the second 3D seismic data which was acquired after the production started, it is possible to decouple the porosity, fluid contents and even pressure. Consequently, it provides a more representative porosity characterization compared to using a single 3D seismic data set. The relative permeability curves are optimized by comparing actual time-lapse seismic and production data to synthetic ones generated with a Gassmann rock physics model.
P. 527