bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gel Preparation and Properties Control for Operations in Pipeline Transport
Authors: Akhiyarov Denis 
Published: December 2007

Abstract
It is well known that the main means to transport large amount of crude oil, oil products and natural gas on a long distance are pipelines. Generally the pumped fluids contain paraffin, asphaltic-resinous components that deposit debris at certain conditions together with solid mechanical impurities. This debris layer on the pipe surface is constantly increased which leads to the decreasing of the flow area. The latter can be restated as reduction of effective diameter. To prevent or reduce the effects of deposits formation mechanical, chemical, thermal and combined removal methods are employed. Gel systems are included into combined method of pipeline cleaning. This technology is named as gel pigging. Gel pigs have also other applications in pipeline systems: isolation (sealing) of pipeline section under pressure, carryover of gas and water accumulations, pulling of the devices that got stuck, series fluids separation, treatment of wall surface with chemicals.
The approach in the project is to compose a new gel formulation which is dragged along the pipeline and form a thin layer on the bore surface that function as hydraulic friction reduction remedy due to smoothing of pipeline wall surface and dampening of turbulent pulsations, heat insulator due to gelling of fluids with low heat conductivity and foaming of the gel, internal corrosion protection means due to separation of metal wall from the transported fluid. Anticorrosion chemical additives may be inserted to provide required protection, wax deposition prevention due to paraffin crystals' adhesive forces reduction on the gelled layer surface. To accomplish all these, the thin gel layer should be able first to deposit and then not to erode under hydrodynamic and cohesive forces. Also viscoelastic rheological properties of certain gel compositions are being analyzed on rotational rheometers to compose suitable composition for operations of isolation, pigging, separating and layering.
As a future work interaction of deposited paraffin and gel is going to be investigated that is essential information for gel pig volume estimation.
Risk Assessment of a Dynamically Positioned Drilling Operation
Authors: Thorogood J.L. , Bardwell K.S. 
Published: December 2007

Abstract
Quantitative risk assessment is used to estimate the probability of a loss of well integrity as a result of a station keeping failure when drilling with a dynamically positioned unit. The key factors affecting station keeping reliability are identified and some publicly available data are presented. The analysis indicates the relative importance of certain variables and reviews the extent to which they may be controlled by the designer.
P. 435
Friction Analysis for Long-Reach Wells
Authors: Aadnoy B.S. , Andersen Ketil 
Published: December 2007

Abstract
Presently wells are drilled in the North Sea approaching a horizontal reach of 8 km. Plans for the near future is to extend these towards and beyond 12 km. Well friction is one of the most important limiting factors in this process.
Torque and drag prognosis are today developed on in-house simulators. Although a good tool for planning, improvements are made on an trial and error basis, and, these simulators have limited availability. To provide more insight into the frictional aspect, a larger study was undertaken. Explicit analytical equations are derived to model drill string tension for hoisting or lowering of the drill string. The equations are developed for straight sections, build-up sections, drop-off sections and side bends. Both constant curvature models and a new modified catenary model are derived. The new catenary model is developed for arbitrary entry and exit inclinations. Equations to determine well friction in fully 3-dimensional well profiles are also given. Furthermore, based on the tension equations, expressions for torque and drag are developed. Equations for combined motion and drilling with motor are also given. Using these equations, the total friction in a well is given by the sum of the contributions from each hole section.
A field study offshore Norway is included in the paper. Using the equations derived in the paper, the well path is chosen to minimize the torque on the rig, which is the limiting factor. The paper also summarize a number of guidelines for extended-reach well design, and shows the design of an ultra- reach well of more than 12 km reach.
P. 819
Field Validation of Swab Effects While Tripping-In the Hole on Deep, High Temperature Wells
Authors: Rudolf R.L. , Suryanarayana P.V.R. 
Published: December 2007

Abstract
In an earlier paper by the same authors (Kicks Caused by Tripping-In the Hole on Deep, High Temperature Wells), it was suggested that a combination of high temperature and high trip-in speeds could result in a secondary swab effect large enough to cause underbalance and subsequent well control incidents. Field validation of the earlier work is reported in this paper. A deep, high temperature well, similar to the ones discussed in the previous paper was chosen for the field validation. Field measurements of pressure, temperature and trip speeds were taken while tripping in the hole. The experimental procedures, data gathering, and analysis are described in this paper. Field data were compared to the predictions of a swab-surge model and remarkable agreement was found. The secondary swab effect was clearly measurable, and its magnitude compared very favorably with the model predictions. This increases the confidence in model results and the concept that kicks can result from tripping in the hole at high velocities. It is concluded that secondary swabs while tripping-in is an important design consideration for deep, high temperature wells. Underbalanced conditions can occur if the trip speeds are high, and if the mud weight is not compensated for the effects of high downhole temperature. Swab-surge models similar to the one used in this study can be used in the design phase to avoid kicks while tripping-in by determining maximum trip-in velocities and the effect of temperature and pressure on the effective density of the drilling fluid.
P. 835
New Criteria for Gravel and Screen Selection for Sand Control
Authors: Tiffin D. L. , King G. E. , Larese R. E. , Britt L. K. 
Published: December 2007

Abstract
Guidelines for sand control completion technique and gravel size selection are presented. These new criteria are based primarily on reservoir sand size distribution. Emphasis is on formations with very high fines content and a wide distribution of grain sizes. Upon failure and/or particle movement, these formations can exhibit very high skins and reduced production capacity with traditional control methods. Guidelines are also discussed for formations with little fines and a very uniform grain size distribution.
Proposed criteria are based on field experience and experiments conducted with reservoir cores from different sand formations worldwide. Experiments were conducted by "packing" different gravels at the effluent end of core plugs and surging fluids through the plugs and gravel. Cases are presented where traditional methods would lead to an overly restrictive gravel pack and advantages are obtained with use of larger gravel.
Mechanisms of Sand Control Screen Plugging From Drill-In Fluids and its Cleanup Using Acid, Oxidizers and Enzyme Breakers
Authors: Ladva H.K.J. , Parlar M. , Price-Smith C. , Fraser L.J. , Ali S.A. 
Published: December 2007

Abstract
This paper describes mechanisms of sand control screen plugging from a range of drill-in fluids and proposes methods for minimizing plugging damage. A series of laboratory tests were performed to illustrate the importance of selecting the correct drill-in fluid, cleanup procedure and/or breaker type to give maximum productivity in a horizontal, non perforated open hole completion. The effectiveness of hydrochloric acid, oxidizing agents, and enzyme breaker in increasing the mud cake and formation permeability was investigated by targeting specific mud components in the mud cake and invaded formation. The role of drill solids and breaker effectiveness was also investigated on filtercakes produced from laboratory and field muds. An effective breaker may thus be selected for a required change in permeability of the mud cake and removing damage from the formation for optimum productivity.
To identify whether the critical damage occurs at the screen or the formation during flowback, a series of dynamic filtration tests were performed using a consolidated sandstone and different water based muds. This was followed by cake cleanup using hydrochloric acid and finally flowback through the formation and different screen types. The effect of whole mud on different types of sand control screens was also investigated and recommendations are made for the field procedures to minimize screen plugging.
In addition to the laboratory testing, pilot plant scale tests were carried out using a synthetic-based drilling fluid to illustrate effective screen cleanup through the correct wash fluid and cleanup procedure.
P. 229
Technique for Fluid-Loss Control and Enhanced Cleanup
Authors: Dewprashad B. , Cole C. , Coats C. , Soybel J. 
Published: December 2007

Abstract
In deep-well, high-permeability completions, effective control of loss of expensive, brine completion fluid is a major challenge. High bottomhole temperature, differential pressure, and brine acidity may limit the reliability of conventional fluid-loss control agents that are available for less severe conditions. Gel pills generally cannot control high-density brines because it is difficult to generate a stable gel pill in a high fluid-density environment, thereby complicating placement efficiency. Par-ticulate-type systems may also be undesirable because of cleanup concerns.
This paper describes the codevelopment and field application of a nonparticulate, high-density fluid-loss control material consisting of derivatized hydroxyethylcellulose (DHEC) and an enhanced external breaker system. Development of the product was critical to the successful completion of the first-ever, three-phase, triple-stacked subsalt completion in the Gulf of Mexico (GOM). DHEC provides an effective method of controlling high-density brine loss during deep-well, high-permeability completions, with minimal formation damage. Within a certain temperature range, DHEC is stable in zinc bromide (ZnBr2) brines for extended periods. The enhanced acid breaker system allows the user to achieve rapid breaking of DHEC on demand. The paper also discusses the principles underlying the design and development of the material and the accompanying breaker system. The paper presents the laboratory data that helped us evaluate crosslink times, temperature stability, break times, and regained permeability. In laboratory tests, DHEC showed potential to effectively prevent loss of 17.2-lb/gal ZnBr2 brine for up to 36 hours at 215°F. Afterward, the breaker system broke the DHEC within 30 minutes. After this cleanup procedure was applied, the test cores had retained an average of 90% of their original permeability. In actual field applications, the fluid-loss material effectively controlled 17.2-lb/gal ZnBr2 in a GOM subsalt well while the operator used fracpacks to complete three separate zones in the same well.
The Role of Taylor Vortices in the Transport of Drill Cuttings
Authors: Philip Zeno , Sharma Mukul M. , Chenevert Martin E. 
Published: December 2007

Abstract
Taylor vortices, i.e., toroidal rings, are formed in an annulus when one pipe is rotated inside another. These rings form when the critical rotation rate (rpm) is reached. Equations are presented to calculate the critical rpm above which Taylor vortices form for both Newtonian and power law fluids. The theoretical computations show that under typical drilling rotation rates Taylor vortices do form.
Experiments were conducted with a wide range of Newtonian and power law (shear thinning) fluids in a transparent annular geometry. The experimental values of critical rpm are in agreement with computed ones. Taylor vortices were clearly observed to form and did contribute to the lift of simulated drill cuttings.
In Newtonian fluids, the lifting capability increased as the viscosity was increased. For power law (shear thinning) fluids, contrary to expectation, the lifting capability decreased as the apparent viscosity was increased. This was because increasing the polymer concentration in order to increase apparent viscosity also lowered the ‘n’ value of the fluid. Fluids with low ‘n’ values exhibit lower velocities close to the stationary walls. It can be inferred, therefore, that with regard to the transport of cuttings (by vortices or otherwise), high ‘n’ value fluids are more efficient.
Analytical Solutions to Gas Flow through Porous Media
Authors: Babu D. K. , Bansal P. P. , El-Rabaa A. M. , Jasti J. K. 
Published: December 2007

Abstract
The equations describing the flow of gas through porous media are non-linear due to the dependence of coefficients on pressure. Several techniques have been applied in the past to deal with the non-linearity. The topic continues to generate research activity, and points to the need for developing more efficient and accurate techniques of handling the non-linearity in the gas equations. Drawing upon the ideas and approaches from the previous studies, a new solution methodology to the non-linear equations governing gas flow is presented in this paper. Whereas the previous studies had access to the non-linear gas solutions (numerical solutions), and could correlate back to the liquid-mode (linear) solutions, we approached the problem differently: to transform the liquid-mode solutions to the unknown and correct solutions of the non-linear equations. The time transformation was completely redefined. New equations were derived to relate the liquid time to the gas time scale. Low-pressure reservoirs were found to require special analytical formulas. The new solution methodology was validated using numerical simulator results.
New Developments in the Measurement of Induction Time for the Formation of Gas
Authors: Siyong Zhang , Lui Sun 
Published: December 2007

Abstract
A new gas Hydrates formation apparatus was developed and experimental data on hydrate formation kinetics, including induction times for N2, CO2, CH4, C2H6, C3H8 and a mixture of this gases are presented. The results indicate that the induction time is strongly dependent on the stirring rate and the driving force. Experiments conducted at the same time stirring rate and with a high driving force seem to show that the induction time varies exponentially with the size of the driving force. At lower driving force other parameters apparently also play an important role in determining the duration Period. Some qualitative theories concerning which other parameters might influence the nucleation time are proposed and discussed.
P. 593
Alkaline/Surfactant/Polymer Flood Predictions for the Karamay Oil Field
Authors: Delshad M. , Han W. , Pope G. A. , Sepehrnoori K. , Wu W. , Yang R. , Zhao L. 
Published: December 2007

Abstract
An alkaline/surfactant/polymer (ASP) pilot in the Karamay field was designed using a reservoir simulator with detailed chemical mechanisms modeled. The Karamay field is an onshore oil field in China. Oil recovery was predicted for different processes, designs, and operating parameters of this 13-well pilot. In particular, the benefits of adding sodium carbonate to the injected surfactant/polymer slug were evaluated. Oil recovery predictions were made for continued water, polymer, alkaline, surfactant/polymer, and ASP flooding with the best results, 24% of OOIP incremental oil recovery, obtained for the ASP process. The simulator used in this study has previously been used to simulate ASP corefloods, but this is the first time that three-dimensional reservoir simulations have been done with the detailed chemistry of the UTCHEM simulator. Alkaline agents such as sodium carbonate react with the acid in crude oils to form surfactant in situ. Such agents are inexpensive compared with manufactured surfactants. The pH of such fluids under the conditions that we studied is about 11, and which reduces the surfactant adsorption. However, the alkaline agent is partly consumed by undesirable reactions with calcium and other cations in the brine, cation exchange with the clays, and dissolution reactions with various formation minerals. A total of 26 chemical species were needed to model these reactions.
The phenomena modeled included the reduction of surfactant adsorption with increasing pH, aqueous-phase chemical reactions of the alkaline agent and consequent consumption of alkali, the in-situ generation of surfactant by reaction with the acid in crude oil, surfactant phase behavior, reduction in interfacial tension, and cation exchange with clay and with surfactant micelles. ASP coreflood data were first matched to validate model parameters. The reservoir description was provided by the operator and included the use of a stochastic permeability field. This study shows that it is feasible to make affordable field-scale mechanistic simulations of ASP flooding in three dimensions. This is a major achievement since such modeling is of great value in selecting the best improved oil recovery process and then optimizing this process.
Reproduce Wettability Alteration of Low-Permeable Outcrop Chalk
Authors: Graue A. , Viksund B.G. , Baldwin B.A. 
Published: December 2007

Abstract
A total of 41 chalk core plugs, cut with the same orientation from large blocks of outcrop chalk, have been aged in crude oil at 90 C for different time periods, in duplicate sets. Different filtration techniques, filtration temperatures and injection temperatures were used for the crude oil. Oil recovery by spontaneous, room temperature imbibition, followed by a waterflood, was used to produce the Amott water index for cores containing aged crude oil and for cores where the aged crude oil was exchanged by fresh crude oil or decane.
The main objective was to establish a reproducible method for altering the wettability of outcrop chalk. A secondary objective was to determine mechanisms involved and the stability of the wettability change.
The aging technique was found to be reproducible and could alter wettability in Rordal chalk selectively, from strongly water wet to near neutral wet. A consistent change in wettability towards a less water wet state with increased aging time was observed.
P. 193
Probabilistic Reserves Assessment Using a Filtered Monte Carlo Method in a Fractured Limestone Reservoir
Authors: Stoltz L. R. , Jones M. S. , Wadsley A. W. 
Published: December 2007

Abstract
A new approach to the estimation of reserves in a fractured limestone reservoir is presented and verified with a lookback analysis over the past five years of production from the field. This approach uses a filtered Monte Carlo method to integrate independent reserves calculations based upon volumetric, material balance, well pressure survey analysis, and well decline estimates of oil in place and recovery. For the Waihapa-Ngaere field, two estimates of oil in place are available: a volumetric estimate obtained from mapped gross reservoir volume and formation parameters; and a material balance estimate obtained from pressure decline and production data. Independent estimates of oil recovery can be obtained from estimation of recovery factors based upon areal and vertical sweep in the fractured reservoir, and recovery obtained from extrapolation of well decline. The approach taken, that is to integrate all of the available information and only accept parameter sets which are consistent, led to an estimate of reserves and production potential from the field which has proved remarkably accurate as a predictor of field performance and recovery over the past five years.
Simplified Approach for Predicting Pressure Profiles in a Flowing Well
Authors: Palisetti Ramana V. , Heinze Lloyd 
Published: December 2007

Abstract
Accurate prediction of pressure profiles in a flowing well can greatly improve the design of production facilities in petroleum engineering. This can in turn lead to improvement in the artificial lift system design. Rigorous theoretical models are often complex and inconvenient. They depend on many variables and require detailed information about the fluid composition. This paper describes a simplified approach which is suitable for quick calculations to predict pressure profiles in multiphase flowing wells. The empirical model assumes steady state flow and is developed using a database consisting of measured data from more than 100 wells. No attempt was made to determine holdup for the purposes of simplification and therefore, oil, water and gas were considered to be a single phase. The total energy loss term was assumed to be constant over the entire segment length under consideration and was varied for various segment lengths due to the insitu fluid properties and velocity. Nearly all pressure drop prediction from this approach are based on data with flowrates in the range of 90-3000 bpd and 2 and 2.5 inch nominal tubing. This paper is an extraction of work done in relation to the masters' thesis by Palisetti1 and review of previous work published by other authors in the field of multiphase flow.
A Strategy for Additional Developments in the Burgos Basin: The Arcabuz-Culebra Gas Field
Authors: Berumen Sergio , Sanchez Juan M. , Rodriguez Fernando 
Published: December 2007

Abstract
This work analyzes technical-economical options to massively develop the Arcabuz-Culebra gas field located at the Burgos Basin in northeastern of Mexico. This mature field has been a gas producer since 1971 from Wilcox and Mount Selman formations, the same gas sand producers of some South Texas fields. An integrated reservoir study was conducted in order to establish the most appropriate developing plan for the Arcabuz-Culebra field according to the new production strategy of the Burgos Basin. The interpretation of 3-D seismic has improved substantially the reservoirs characterization and, along with an efficient application of hydraulic fracturing technology and the reservoir simulation of the Wilcox sands, the production has been increased dramatically. The spatial representation of hydraulic fractures in the simulation study was approximated by using a moderate local grid refinement in such a way that the quality of the numerical solution were acceptable with respect to the corresponding analytical solution during the time of interest. The study shows a procedure to analyze strategies of well spacing based on numerical simulation by reservoir sectors and the corresponding economic analysis under different well spacing. It was found that well spacing varies widely along the reservoir, and is strongly governed by local permeability, pay thickness, current pressure and associated costs. Using advanced technologies in drilling, fracturing and geosciences have proved their technical benefits in this gas field. However, results of this study demonstrate that the cost of implementing advanced technologies in drilling and hydraulic fracturing may importantly impact, under certain economic circumstances, in the well spacing strategy, and consequently in the recovery factor of these low permeability formations. The additional development plan of the Arcabuz-Culebra gas field, although profitable, resulted to be strongly dependent of new technologies and their associated costs. The field development plays a strategic role in the redevelopment of the Burgos Basin, since provides approximately one third of the production of the basin.