bluuebunny/crossref_metadata_2025_split huggingface dataset:
HEC Precipitation at Elevated Temperature: An Unexpected Source of Formation Damage
Authors: Hodge R. M. 
Published: December 2007

SummaryHigh-molecular-weight polymers are routinely used to viscosify brines for drilling, workover, and completion operations. Of the commercially available polymers, hydroxyethyl cellulose (HEC) is among the most versatile and widely used products. HEC has been used in NaCl, NaBr, KCl, NH4Cl, CaCl2, and CaBr2 brines over a wide range of brine density, pH environment, and temperature. Typically, the performance issues addressed in HEC studies focus on dispersibility, hydration rate and viscosity development, rheology at elevated temperature, and formation damage. Under typical oilfield conditions, the published data indicate that HEC produces minimum formation damage and provides predictable rheological behavior when properly prepared.
Pressure Drop in a Perforated Pipe With Radial Inflow: Single-Phase Flow
Authors: Schulkes Ruben M.S.M. , Utvik Ole Harald 
Published: December 2007

Summary
In this paper we study the flow in a perforated pipe where fluid enters the pipe through the perforations. The focus of the paper is to describe and understand the evolution of the pressure field inside the pipe as a result of the radially inflowing fluid. Details of extensive single-phase experimental measurements are reported. A first-generation model which describes trends observed in the experiments is presented.
Transient Pressure Behavior of Dual-Lateral Wells
Authors: Ozkan Erdal , Yildiz Turhan , Kuchuk F. J. 
Published: December 2007

SummaryThe objective of this paper is to investigate the transient pressure behavior of dual-lateral wells. An analytical solution to compute the pressure responses of dual-lateral wells in the Laplace domain is presented, and the computational issues are addressed. The influences of the length, phase angle, and vertical and horizontal separations of the laterals are discussed. New flow regimes are identified and the conditions under which various flow regimes prevail are documented. Guidelines for the well test analysis of dual-lateral well responses are also presented.
The Group III Shaly Sand Data Set
Authors: Hofman J. P. , de Kuijper A. , Sandor R. K. J. , Hausenblas M. , Bonnie R. J. M. , Fens T. W. 
Published: December 2007

Summary
In the development of shaly sand saturation models, core data are of exceptional value. These data are required to check the descriptive and predictive power of existing models and compare them with new concepts. This paper aims to add to the modest set of generally available core data on shaly sands by presenting a variety of special core-analysis measurements on a number of shaly sand core samples.
The experiments presented here include standard petrophysical measurements, continuous injection (CI) resistivity measurements (at ambient and elevated temperatures), nuclear magnetic resonance experiments (t1 and t2 acquisitions on fully brine-saturated samples; t2-diffusion measurements with an external magnetic gradient on partially brine-saturated samples), and scanning electron microscopy (SEM) images that have been subjected to image analysis.
Underbalance Perforation in Long Horizontal Wells in the Andrew Field
Authors: Kusaka Koji , Patel Dinesh , Gomersall Sam , Mason John , Doughty Phil 
Published: December 2007

SummaryAndrew field in the U.K. Continental Shelf, which is operated by British Petroleum (BP) Exploration, is being developed using horizontal oil producers and completed with cemented liners. The main challenges of perforating these wells are maximizing well productivity by avoiding formation damage, minimizing the possibility of sanding, maximizing ultimate hydrocarbon recovery, perforating long horizontal sections safely and efficiently, optimizing the economic value of perforating, and minimizing perforating debris.In general, to avoid impairing well productivity, it is best to perforate the underbalance. However, the advantage is compromised, because of the fluid invasion and loss-control material, if a well will be killed when the tubing-conveyed perforating (TCP) guns are removed. Existing deployment methods with coiled tubing (CT) enable perforation and subsequent gun removal in an underbalance condition. Unfortunately, various limitations would require multiple runs with CT for perforating each horizontal well in the Andrew field, which would result in significant time and unbalance perforation for each subsequent run.The combination of the newly developed mechanical ball valve and the deployment of TCP guns with hydraulic workover units enables long horizontal wells to be perforated in one run in underbalance, and enables the guns to be removed without killing the well. Specially engineered guns and perforating charges are used to minimize sanding and gun debris.This paper describes how these new technologies, used for perforating operations, meet many challenges. The same technologies can be used readily for perforating other long horizontal wells with similar problems.To date, three horizontal wells in Andrew field were perforated successfully with the method described in this paper. The initial results indicate that the combination of the cemented liner completion, the engineered perforation systems, and the correct TCP gun deployment method using the mechanical deployment valve have contributed to improve well performance, to reduce cost, and to improve operability and safety in long horizontal wells.
The Benefits of Logging While Drilling (LWD) for Formation Evaluation in the Dulang West Field
Authors: Amar Zarool Hassan Bin Tajul 
Published: December 2007

Summary
Ever since the first electric log was run in 1927, the oil industry relied on wireline-conveyed logging for the acquisition of formation data for petrophysical analysis. It was not until 1978 that the first measurement while drilling (MWD) tools were introduced in the field. The industry did not pay too much attention to them then because they did not offer sufficient information for petrophysical analysis. Furthermore, the reliability of such tools was not impressive and their cost was unattractive.
However, over the last 6 years, the drilling services industry has shifted its focus from just directional MWD to a complete directional and logging while drilling (LWD) package. The LWD tools that are built into special drill collars provide measurements of resistivity, neutron, density, and gamma ray. Significant improvements in the reliability of the tools and competitive pricing, as compared to conventional wireline logging, has offered advantages in running LWD in fields that have drilling and completion constraints (e.g., borehole stability) or difficult well trajectories.
This paper discusses the benefits to Petronas Carigali of using LWD for formation evaluation. In the development of the Dulang West field, LWD was used extensively to acquire formation log data. The quality of the data and cost savings are addressed. A comparison between the wireline-conveyed and LWD data acquired in this field is also presented.
The acquisition of formation data by use of LWD in Dulang West has made a significant contribution to the overall cost per barrel of oil produced, without compromising data quality.
Influence of Connate Water and Condensate Saturation on Inertial Effects in Gas/Condensate Reservoirs
Authors: Lombard J.-M. , Longeron D. G. , Kalaydjian F. J. M. 
Published: December 2007

Summary
In the near-wellbore region of gas/condensate wells, high-pressure gradients induce both large condensate saturation and high gas velocities which may lead to significant deviations from Darcy's law for gas permeability. At the present time, no physically relevant model exists which takes into account these non-Darcian two-phase flow phenomena. Using a specific laboratory equipment, a laboratory study has been performed with the aim to estimate the influence of pore structure and connate water saturation Swi on the gas inertial coefficient βg, and to integrate the effect of the condensate dropout in the Forchheimer flow equation. Experiments were conducted on sandpacks and sandstone core samples. For dry gas floods, the measured βg values were found in good agreement with previous published data. For gas floods in presence of Swi, βg was found to increase with Swi and a new correlation between βg and a mean-pore radius r¯ is proposed. Gas/ condensate (C1–C3 mixtures) steady-state experiments showed that βg values increased with the total liquid saturation.
A Simplified Approach to Geochemical Modeling and Its Effect on Mineral Precipitation
Authors: Araque-Martinez A. , Lake Larry W. 
Published: December 2007

Summary
Solids can easily cause flow restrictions by plugging flow channels. A source of these solids is the dissolution and subsequent precipitation of minerals caused by the transport of fluids not in chemical equilibrium with the host formation. The term transport describes fluid convection throughout this paper. To model these geochemical processes, allowing for the transport of fluids with kinetic reactions, it is necessary to solve the mass-balance equations for each component flowing in the medium. This work presents a new approach, based on the method of characteristics (MOC), to greatly simplify these solutions. Based on this solution technique, we build a model that includes kinetic (aqueous/solid) as well as equilibrium (aqueous/aqueous) reactions. We define new dimensionless groups to scale the solution. Unlike several previous geochemical models, we focus on flow that is substantially out of local thermodynamic equilibrium.
The MOC model has been tested against results from the more general geochemical KGEOFLOW simulator and against experimental literature data. Results match the KGEOFLOW solution closely, but with at least 50 times less computing time. The MOC model can run quite general geochemical problems on a desktop personal computer (PC).
We applied the MOC model to radial flow around a well to study the effect of dissolution, supersaturation, and precipitation on injection wells. We focused on cases in which there was substantial mineral precipitation in calculations based on local thermodynamic equilibrium. Results show that at nearly all rates, mineral precipitation can occur, though the amount will be less than when local thermodynamic equilibrium is assumed. However, injection rates must be unrealistically large to completely prevent precipitation.
Viscous-Elastic Polymer Fluids Rheology and Its Effect Upon Production Equipment
Authors: Demin Wang , Youlin Jiang , Yan Wang , Xiaohong Gong , Gang Wang 
Published: December 2007

OverviewThe rheology of polyacrylamide solutions and the effect of viscous-elastic fluids upon production equipment are described. Methods to solve the negative effects of viscous-elastic fluids on equipment are also introduced.The results of the modification(s) on the system and equipment show that the service life of equipment more than doubled, mechanical degradation of polymer decreased more than 50%, and energy consumption decreased markedly.SummaryMost flow systems and equipment for the injection, production, and gathering of large amounts of fluid are designed for Newtonian fluids. Now, an increasing number of oil fields are on viscous-elastic flooding. After flooding by polyacrylamide (PAM) fluids, it was seen that the flow of this type of fluid in production and surface systems and equipment has its special characteristics, which in turn require special designs for the equipment and flow process.This paper introduces the actual performance of the production and surface flow systems and equipment, and points out the influence that the special rheologic characteristics, especially the viscous-elastic nature of the fluid, has on the system and the modification made. For example, there is a normal force acting on the beam pump sucker rods that causes pronounced eccentric mechanical wear on one side of the sucker rods and thereby very short service life for beam-pump wells. This normal force significantly lowers the efficiency of centrifugal pumps, increases the vibration and mechanical degradation in triplex pumps and the whole system, lowers the efficiency of maturing tanks and static mixers, etc.The modifications on the system and equipment and their results are shown. For example, the service life of beam pumps more than doubled; mechanical degradation of polymer in the system and triplex pumps decreased more than 50 and 70%, respectively; and the energy consumption of mixing equipment decreased 80%, among other results.
Management of Typhoon: A Subsea, Deepwater Development
Authors: Ring Jasper N. , Bourgeois Christine S. , Howard James , Melillo Allan J. , Neal Scott L. , Smith Steve 
Published: December 2007

Summary
Typhoon, located in the Green Canyon area of the Gulf of Mexico, is a joint deepwater development between ChevronTexaco (operator) and BHP Billiton. First oil was realized in July 2001, just 6 years after acquiring the leases. The Typhoon development consists of a mini-tension-leg platform (TLP) with four subsea wells in approximately 2,100 ft of water. Recently, Boris, a joint project between BHP Billiton (operator), ChevronTexaco, and Noble Energy Partners was discovered in an adjacent block, and two subsea wells were tied back to the TLP. The field consists of several hydrocarbon-bearing sands with 60% of the field's proven reserves located within a single reservoir.
Characteristics typical of many deepwater developments (such as high flow rates, compartmentalization, reservoir compaction, and asphaltene precipitation) are prevalent at Typhoon. As a result, asset management is complex and requires each well to be managed independently. The primary purpose of this paper is to describe how the asset and wells are managed and to heighten the awareness of associated complexities. This will be achieved by providing an overview that includes well and reservoir performances to date, reservoir management processes, and idiosyncrasies associated with operating a deepwater, subsea development in the Gulf of Mexico.
Increasing the Computational Speed of Flash Calculations With Applications for Compositional, Transient Simulations
Authors: Rasmussen Claus P. , Krejbjerg Kristian , Michelsen Michael L. , Bjurstrøm Kersti E. 
Published: December 2007

Summary
Approaches are presented for reducing the computation time spent on flash calculations in compositional, transient simulations. In a conventional flash calculation, the majority of the simulation time is spent on stability analysis, even for systems far into the singlephase region. A criterion has been implemented for deciding when it is justified to bypass the stability analysis. With the implementation of the developed time-saving initiatives, it has been shown for a number of compositional, transient pipeline simulations that a reduction of the computation time spent on flash calculations by approximately 85 to 90% can be achieved.
A Design Approach for a "Self-Lifting" Method To Eliminate Severe Slugging in Offshore Production Systems
Authors: Tengesdal J. Ø. , Thompson Leslie , Sarica Cem 
Published: December 2007

Summary
Recently, exploitation of offshore petroleum reservoirs has moved to ever-increasing water depths. Production from fields in water deeper than 1800 m is now a reality. The use of long deepwater risers that conduct production from multiple wellheads on the seafloor to the surface predisposes the system to severe slugging in the riser for a wide range of flow rates and seabed topography. Considering the length of the deepwater risers, the problem is expected to be more severe than in production systems installed in shallower waters. Severe slugging could occur at a high pressure, with the magnitude of the pressure fluctuations so large as to cause a shorter natural-flow period with subsequent consequences, such as premature field abandonment, loss of recoverable reserves, and earlier-than-planned deployment of boosting devices.
In this study, a novel idea to lessen or eliminate severe slugging in pipeline/riser systems has been investigated. The principle of the technique is to transfer the pipeline gas to the riser at a point above the riser base. The transfer process will reduce both the hydrostatic head in the riser and the pressure in the pipeline, consequently lessening or eliminating the severe slugging by maintaining the steady-state two-phase flow in the riser.
In this paper, a steady-state model is presented. It can be used as a design tool for the self-lifting concept by determining the operation envelope for a successful self-lift operation; given the location of the gas takeoff or injection points, it can predict the acceptable range of pressure losses in the gas bypass for continuous steady-state operation of the self-gas-lift system. The model was found to perform very well when compared to the acquired experimental data.
Effect of Scaleup and Aggregation on the Analysis of Interference Tests
Authors: Raghavan Rajagopal , Roesler Ralph R. , Tureyen O. Inanc 
Published: December 2007

SummaryThe objective of this paper is to demonstrate the influence of detailed, small-scale heterogeneities on interference tests. Specific issues encountered when interference tests are analyzed in reservoirs with complex geological properties are discussed. These issues relate to questions concerning the use of low-resolution models, the degree of aggregation, the methodology of scaleup, and the reliability of conventional methods of analysis.This paper demonstrates the importance of capturing fine-scale heterogeneities to replicate the true transient behavior of interference tests at both active and observation wells. The paper shows the effects of aggregation and scaleup as used routinely in the industry on evaluating transient responses. The consequences of using low-resolution models in systems with complex geology is also demonstrated. If low-resolution models are used, reservoir properties may be adjusted unrealistically to match the transient behavior observed in high-resolution models. Though scaleup preserves pore volume, estimates of storativity predicted by low-resolution models will have a significant effect on reservoir behavior and resource management. If porosity values are not regressed, significant changes in vertical permeability values are observed. This is an important observation with potentially dramatic effects on reservoir performance, especially in processes involving mobility differences. Regression on a single-layer model (homogeneous, or based on aggregation) was also shown to yield totally different geological outcomes. This also shows the need to use geological constraints during inversion, aggregation, and scaleup.
Improvements in Single-Phase Paraffin Deposition Modeling
Authors: Hernandez O. C. , Hensley H. , Sarica C. , Brill J. P. , Volk M. , Delle-Case E. 
Published: December 2007

Summary
Paraffin deposition under single-phase flow conditions was investigated to determine its dependence on shear stripping, deposit aging, flow regime, temperature gradient, and fluid properties.
In this study, a new model for the prediction of single-phase wax deposition has been developed. Most of the models previously used assume that equilibrium exists at the deposit-fluid interface. A kinetic resistance of the fluid is considered in the new model. Therefore, the interfacial-wax concentration might be different from the equilibrium-wax concentration. The model also includes continuous diffusion of wax into the deposit. We believe that this enrichment of the deposit is responsible for the increasing hardness of the deposit with time - a process known as "aging." The effect of shear stripping may also be incorporated in the prediction.
The model predictions are compared with predictions from previous models, as well as with experimental data gathered at the Tulsa U. Paraffin Deposition Projects, with two different oils: a black oil and a condensate. Even though some tuning is required for each type of oil, the new model is based on physical phenomena, reducing the empiricism of previous models.
Evaluation of the Salinity Gradient Concept in Surfactant Flooding
Authors: Hirasaki G. J. , van Domselaar H. R. , Nelson R. C. 
Published: December 2007

AbstractSalinity design goals are to keep as much surfactant as possible in the active region and to minimize surfactant retention. Achieving these is complicated because (1) compositions change as a result of dispersion, chromatographic separation of components distributed among two or more phases, and retention by adsorption onto rock and/or absorption in a trapped phase; (2) in the presence of divalent ions, optimal salinity is not constant but a function of surfactant concentration and calcium/sodium ratio; and (3) the changing composition of a system strongly influences transport of the components.A one-dimensional (1D) six-component finite-difference simulator was used to compare a salinity gradient design with a constant salinity design. Numerical dispersion was used to evaluate the effects of dispersive mixing. These simulations show that, with a salinity gradient, change of phase behavior with salinity can be used to advantage both to keep surfactant in the active region and to minimize retention. By contrast, under some conditions with a constant salinity design, it is possible to have early surfactant breakthrough and/or large surfactant retention.Other experiments conducted showed that high salinity does retard surfactant, and, if the drive has high salinity, a great amount of surfactant retention can result. The design that produced the best recovery had the waterflood brine overoptimum and the drive underoptimum; the peak surfactant concentration occurred in the active region and oil production ceased at the same point.
Cruse Steamflood Expansion Case History
Authors: Ramlal V. 
Published: December 2007

Summary
The Cruse ‘E’ steamflood was designed and developed by Petrotrin from 1994 to 1996. This paper discusses the performance of the steamflood during steam injection and during a 4-year period of noninjection. It also covers the operational and economic aspects of the project and discusses the production response since restart, the amended forecast from history-matched reservoir simulation, and future operating strategies.
Optimization of Riser Design and Drill Centers With a Coupled Reservoir and Facility-Network Model for Deepwater Agbami
Authors: Narahara G. M. , Holbrook J. A. , Shippen M. , Erkal A. 
Published: December 2007

Summary
The use of multiple wells connected at a subsea manifold provides the opportunity to reduce the number of risers and capital expense. The problem is the proper modeling of the reservoir well flow coupled with the combined flow into the facility network (i.e., manifolds, flowlines, and risers), which is necessary to prevent underdesign, resulting in flow-rate bottlenecks, or overdesign, resulting in extra expenditures. This paper presents a tool and methodology for better modeling of the well-to-riser flow and the optimization of riser count and configuration.
Although reservoir models coupled with facility networks is not new, software enhancements provided the capability of including operation logic that could duplicate operations in the field. The reservoir model coupled with the facility network provided more reasonable and accurate modeling of multiphase rates and pressures as wells were combined into a single riser.
To optimize the riser count, operation logic was applied to maximize rate in the riser at all times against the erosional-velocity limit. This in turn prevented overdesigning by placing more risers than needed to obtain the field-facility capacities.
The use of the coupled model and operation logic allowed the optimization of the riser count for any particular reservoir model. The optimum riser count was then determined for 3 earth (geologic) models.