bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Acid Additives on the Rheological Properties of Viscoelastic Surfactants and Their Influence on Field Application
Authors: Al-Ghamdi AbdulWahab H. , Nasr-El-Din Hisham A. , Al-Qahtani Abdulqader. A. , Samuel Mathew M. 
Published: December 2007

AbstractThis paper examines a new class of viscoelastic surfactants (amphoteric) that are used to enhance sweep efficiency during acid injection. Surfactant molecules align themselves and form rod-shape micelles once the acid is spent. These micelles cause the viscosity to significantly increase, and induce viscoelastic properties to the spent acid. The enhancement in these properties depends on the micelle shape and magnitude of entanglement.The effects of acid additives and contaminants (mainly iron (III)), on the rheological properties of these systems were examined over a wide range of parameters. Viscosity measurements were conducted on specially designed viscometers to handle very corrosive fluids. Measurements were made between 25 and 100°C, and 600 psi at various shear rates from 58 to 1,740 s−1. Acid additives included corrosion inhibitors, inhibitor aids, iron control agents, hydrogen sulfide scavengers, anti-sludge agents, and nonionic surfactants. Effects of mutual solvents and methanol on the apparent viscosity were also investigated.It is observed that temperature, pH, shear conditions and acid additives have a profound influence on the apparent viscosity of the surfactant-acid system. The viscosity and related properties are very different from what we have observed with both natural and synthetic polymers. These properties were characterized and correlated with the type and nature of the additive used. Optimum conditions for better fluid performance in the field were derived.
Gravity Segregation and Compositional Streamline Simulation
Authors: Jessen K. , Orr F. M. 
Published: December 2007

Abstract
In this paper we present an approach for accurate and consistent implementation of gravity effects in compositional streamline simulation. The approach is based on an operatorsplitting technique, successfully applied in streamline simulation of black-oil models. The method is demonstrated to conserve mass. Its application adds only marginally to the overall CPU requirement. We provide a detailed description of the approach to incorporate gravity effects and demonstrate the efficiency of compositional streamline simulation, even for cases where gravity segregation plays an important role in the overall process performance. The new approach is demonstrated to be in excellent agreement with commercial FD simulators for prediction of flows in 2D vertical and multi-well 3D geometries. Finally, we outline the work required to extend the compositional streamline approach to handle three-phase flow modeling, also including gravity.
An Advanced Coiled Tubing Simulator for Calculations of Mechanical and Flow Effects; Model Advancements, and Full-Scale Verification Experiments
Authors: Yi Yunfeng , Lund Bjørnar , Aas Bjarne , He Alan Xiaojun , Rommetveit Rolv , Salem Lazaro D. , Stokka Sigmund , Bottazzi Franco 
Published: December 2007

Abstract
An advanced simulator for investigation and planning of coiled tubing (CT) operations has been developed. In this paper, various models pertinent to the fluid flow within the CT and in the annular space between the CT and the well wall are presented, as well as various mechanical models pertinent to the placement of the CT in the well. Some verification tests have been carried out which match well to calculations by the simulator.
Artificial Intelligence Used to Evaluate 23 Single-well Surfactant Soak Treatments
Authors: Weiss William W. , Xie Xina , Weiss Jason , Subramanium Vishu , Taylor Archie , Edens Fred 
Published: December 2007

Abstract
Following a series of laboratory imbibition cell experiments, field tests were conducted to determine the effectiveness of surfactant soak treatments as a single well EOR technique. The tests were conducted in the dolomite interval of the Phosphoria formation. Artificial intelligence was applied to analyze the mixed test results. The analysis suggested that the gamma ray log can be used to predict results and that a minimum amount of surfactant is required to improve production.
Simulation of Natural and Partitioning Interwell Tracers to Calculate Saturation and Swept Volumes in Oil Reservoirs
Authors: Sinha R. , Asakawa K. , Pope G. A. , Sepehrnoori K. 
Published: December 2007

Abstract
This paper presents several alternative ways of using partitioning interwell tracer tests (PITTs) in oil fields for the calculation of oil saturation, swept pore volume and sweep efficiency, and assesses the accuracy of such tests under a variety of reservoir conditions. The method of moments is used for the interpretation of PITTs in heterogeneous reservoirs with spatially variable residual oil saturation and extends the method to cases with mobile oil saturation. The feasibility of using partitioning tracers to estimate oil saturation at different depths in the reservoir was investigated assuming that the tracer concentrations could be measured with downhole chemical sensors or any other suitable method. The possibility of using natural organic tracers (dissolved components of the crude oil) as a low-cost alternative to injected tracers was also simulated and the method of moments was used to interpret the results for both single porosity and dual porosity reservoirs. All of these applications point to a much greater potential for the PITT technology than is commonly recognized or practiced in the oil field. The results clearly demonstrate that the method of moments is a very simple, fast and robust method to estimate oil saturation and swept pore volumes from either injected or natural partitioning tracer data.
Successful Field Pilot of In-Depth Colloidal Dispersion Gel (CDG) Technology in Daqing Oil Field
Authors: Chang Harry L. , Sui Xingguang , Xiao Long , Liu Heng , Guo Zhidong , Yao Yuming , Xiao Yuguo , Chen Gang , Song Kaoping , Mack James C. 
Published: December 2007

Abstract
Based on encouraging results from laboratory studies described in SPE 62610(1), a first large-scale CDG pilot test was started in the largest oil field in China, Daqing Oilfield, in May 1999. The pilot test was conducted in an area of 0.75 Km2, a double five-spot well pattern of 6 injection wells and 12 producers. The well spacing is approximately 250 meters. Up to June 2003, three chemical slugs; 0.179 pore volume (PV) of CDG slug I, followed by 0.155 PV 600 mg/l of polymer solution, and then 0.196 PV of CDG slug II. The drive water has been injected since June 2003. The pilot test indicates that with CDG injection, the reservoir permeability between injectors and producers has been adjusted and volumetric sweep improved. The water cut was reduced by 19.8%, the incremental oil production was up to 24 tons per day in the central production well B1-7-P124 during the peak production period.
The pilot test results, to date, demonstrate that CDG technology (1) can be used before, during, or after a polymer flood to effectively control the water production and maintain the high oil rate, (2) has higher incremental oil recovery with better economics than the straight polymer flooding, (3) has wide application in heterogeneous reservoirs for improving water flood efficiency and oil recovery, and (4) can reduce producing water treatment costs as compare with polymer flooding due to lower polymer production in producing wells.
This paper describes the reservoir properties in the pilot area, design of the CDG system, injection sequence of chemical systems, injection facilities, monitoring procedures, pilot test performance, and economic analysis.
Alkyl Polyglycoside Surfactants for Improved Oil Recovery
Authors: Iglauer S. , Wu Y. , Shuler P. J. , Blanco M. , Tang Y. , Goddard W. A. 
Published: December 2007

Abstract
Many surfactants have been evaluated for their ability to recover incremental oil; this paper focuses on alkyl polyglycosides (APG) as candidates for this IOR application. These nonionic carbohydrate-based surfactants have become in recent years a large, significant volume (over 80,000 tons/year) commercial product that sees widespread use in household and agricultural products. This laboratory study determined the characteristics of many APG surfactant formulations, in particular for their capability to create low interfacial tensions (IFT) with n-alkane hydrocarbons. Formulations explored included a wide range of alcohol and Sorbitan-based surfactants as cosurfactants with these APG surfactants. Some APG-cosurfactant combinations did exhibit low IFT values of 0.01 dyne/cm or less versus n-octane. Laboratory testing did confirm the useful properties that the IFT for these APG formulations can be largely independent of both salinity and temperature. Preliminary studies also suggest some APG products will have only modest adsorption onto kaolinite clay.
Development of Bio-surfactant Based Microbial Enhanced Oil Recovery Procedure
Authors: Maudgalya Saikrishna , McInerney Michael J. , Knapp Roy M. , Nagle David P. , Folmsbee Martha J. 
Published: December 2007

Abstract
The effectiveness of a bio-surfactant-based microbial enhanced oil recovery process was studied. A series of laboratory experiments showed that bio-surfactant produced by the bacterium Bacillus mojavensis JF-2 mobilized and recovered residual oil when mixed with a co-surfactant, 2,3-butanediol and partially hydrolyzed polyacrylamide (PHPA) and flooded through sand packs at waterflood residual oil saturation. Twenty to eighty percent of the residual oil was recovered depending on the bio-surfactant concentration. The recovery was linearly dependent on bio-surfactant concentration.
The injection of a viscous solution ahead of the surfactant solution and a viscous mobility buffer behind the surfactant solution increased oil recoveries compared to treatments when only the surfactant was injected. With very low bio-surfactant concentrations, 16 ppm (0.0016% by wt.), 22% of residual oil was recovered when combined with 2, 3-butanediol and PHPA. The bio-surfactant without co-surfactant and/or viscosifying polymer recovered very little residual oil (&lt;5.0%) even at very high bio-surfactant concentrations, (12,300 ppm).
The results showed that microbially generated surface active agents were effective for enhanced oil recovery even at low concentrations (0.0016%) as long as a viscosifying agent and a low molecular weight alcohol were present.
Development of Statistical Engineering Process for Analyzing Coiled Tubing Experimental Data
Authors: Cho Joseph H. , Shah Subhash N. , Jeong Yeon-Tae 
Published: December 2007

Abstract
The development of coiled tubing technology and its applications have been the hot issues in the oil and gas industry for over two decades. Since improper data analysis may lead to quite a different result in the estimation of friction pressure losses and flow regime, the development of precise data processing methodology is an essential tool to provide reliable experimental analysis results. Coiled tubing experimental data are greatly influenced by mechanical system vibrations in coiled tubing reel, delayed response time, and harmonized response of sensors due to long coiled tubing flow loops. However, no reliable standardized experimental data analysis methods are currently available that take into account quantitatively the parameters affecting experimental data.
A new highly reliable statistical engineering method for analyzing coiled tubing experimental data has been developed. It is based on an enormous database gathered over a many years of coiled tubing fluid tests using 1,000 and 2,000 ft long coiled tubing with field-scale equipment. This method provides engineers and researchers statistical tools to differentiate the highly suspected outliers from the experimental data.
This paper discusses the risk of the industry method (simple average), which is widely accepted by the oil and gas industry, in removing the outliers from the experimental data. The differences in the eventual data analysis results obtained from the industry method and from the statistical engineering approach are discussed. A spe cific process of the total uncertainty analysis of experimental measurements with a 95 percent confidence estimation in precision limit and the bias limit is also presented. This statistical engineering method, developed by the Well Construction Technology Center at the University of Oklahoma, is disclosed to the public in order to enhance coiled tubing technologies and to broaden its applications.
Effects of Coiled Tubing Curvature on Drag Reduction of Polymeric Fluids
Authors: Zhou Y. , Shah S. N. , Gujar P. V. 
Published: December 2007

Abstract
This paper presents experimental results of the effects of coiled tubing curvature on the drag reduction behavior of polymeric fluids in turbulent flow. The experimental setup consists of a 10-ft section of ½-in. OD straight tubing and four coils of coiled tubing of the same diameter. Fluids investigated included water, guar, hydroxypropyl guar (HPG), and Xanthan fluids at various polymer concentrations. It is found that the coiled tubing curvature could reduce the drag reduction by 10 to 30% as compared with straight tubing, depending on the flow conditions. The curvature of tubing also delays the onset of drag reduction. The percentage drag reduction in coiled tubing may be improved if fluid is pumped at higher rates. The results of the present study were also verified with the previous full-scale experiments and are found to be representative of the drag reduction behavior of similar fluids under the field flow conditions.
Zonal Isolation in a U-shaped Well using Coiled Tubing and Well Tractor®
Authors: Saelensminde T , Schjott H. F. , Koldal H. M. , Skeie T. , Meberg T. O. 
Published: December 2007

Abstract
An 80m long retrievable "one-run" straddle assembly was successfully installed in order to shut off a gas breakthrough in the 130 degrees deviated reservoir section of a "U shape/Fish hook" sub sea oil producer in the Njord field. Coiled tubing with an internal electric line in combination with a tandem fluid driven tractor was used to convey the straddle assembly.
Development of a New Spoolable Mechanical Coiled Tubing Connector
Authors: Luft H. B. , Laun L. E. , Thov P. B. 
Published: December 2007

Abstract
Tube-to-tube joints in coiled tubing can be achieved by either fusion bonding or mechanical connections. A critical performance requirement of such joints is their ability to sustain plastic bending cycles that ideally, equal in number to that of the coiled tubing itself. Orbital girth welds in coiled tubing butt joints can typically achieve a low cycle bend fatigue (LCF) life in the range of 50% to 60% of the coiled tubing. Mechanical connectors of existing design and construction, have shown a considerably poorer LCF performance that is reflected by their infrequent use in coiled tubing operations.
A new spool-able mechanical connection with flush outer diameters for coiled tubing strings has been developed with comparable bend fatigue performance to that exhibited by orbital TIG girth joints. Current designs, that are based on strategic material selection and mechanical design details, range in size from 1-1/2″ to 2-7/8″. In addition to comparable or superior LCF lives, these connections overcome many of the disadvantages of welded butt joints. This paper describes the research and development, various mechanical and materials testing results and recent offshore well servicing applications undertaken with these new mechanical CT connectors.
Cuttings Transport with Aqueous Foam at Intermediate Inclined Wells
Authors: Capo Jesus , Yu Mengjiao , Miska Stefan Z. , Takach Nicholas , Ahmed Ramadan 
Published: December 2007

Abstract
An experimental study of cuttings transport with foam at intermediate angles has been conducted in a full-scale Low Pressure-Ambient Temperature (LPAT) flow loop at The University of Tulsa. An anionic surfactant was used in these water base foam tests at a concentration of 1% v/v. Air was used as dispersed fluid. Rheological tests were conducted to obtain flow curves for foams with 70% and 80% qualities in 2″, 3″ and 4″ pipes. A simulator was developed to predict pressure, flow velocity, specific volume expansion ratio and foam quality along the wellbore based on the volume equalized power law model.
Tests were conducted to determine the effects of inclination angle, foam quality, foam velocity and rate of penetration on cuttings transport. Results from this study show that the in situ cuttings concentration ranged, according to the inclination angles, from 4.8% to 14.6% for 45 degrees, 14.3% to 22.3% for 55 degrees and 8.5% to 25.7% for 65 degrees. It is shown in this study that the transport of cuttings (in terms of cuttings concentration) has a better performance with foams of low quality. For a given inclination angle and similar foam flow conditions, increasing the rate of penetration from 20 ft/hr to 44 ft/hr can lead to an increase in the in situ cuttings concentration of up to 7%.
A new correlation for the ratio of the cuttings bed area to the cross sectional area of the annulus as a function of dimensionless numbers (Ar, Re, Fr, Ss and θ) was developed and allows for pontential practical applicaitons. The differences between the calculated and measured values are within a range of ±17%.
An Investigation of the Effects of the Physical Properties of Coiled Tubing on Fatigue Modeling
Authors: Tipton S. M. , Behenna F. R. , Martin J. R. 
Published: December 2007

Abstract
A computerized database was compiled with results from over 3000 CT fatigue and mechanical tests conducted over a 10 year period. The database contains detailed information about tensile properties (yield and ultimate strengths) for individual samples that were tested to failure under constant internal pressure with specialized CT fatigue testing fixtures. This paper presents a survey of those data to assess the variability in the mechanical properties within a specific CT material grade and to investigate the effect of this variation on CT fatigue behavior.
Modeling Coiled Tubing Drag Forces – Small Factors Have a Big Impact
Authors: Terry A. R. , Mahajan Mahesh , Portman Lance 
Published: December 2007

Abstract
A significant limitation in the application of coiled tubing technology is the ability of the coiled tubing to push. Push may be required to move a heavy bottom hole assembly (BHA) along a highly deviated or horizontal well. Push may simply be required to push against the drag forces induced by the coiled tubing's own weight, as it is run into a well. Either way, it is often important to know how far coiled tubing can be pushed into a well, or what weight/length of BHA can be pushed to a certain depth. Accurate modeling is required to avoid a costly mis-run with coiled tubing that fails to get to the necessary depth.
Recent projects carried out offshore Brunei illustrate how critical accurate force modeling is and how small well factors can greatly affect the depth that coiled tubing can reach. This paper will also demonstrate how difficult it is to infer down hole drag conditions from surface readings unless the coiled tubing is nearing its point of maximum reach.
Cementing Through Coiled Tubing: Common Errors and Correct Procedures
Authors: Portman Lance 
Published: December 2007

Abstract
Cementing through coiled tubing is not a new service line. However, it remains one that has received little technical attention. In reality, there is a great deal of science behind the successful execution of such cementing operations. Failure to understand the complexities of cement placement in a well can lead to catastrophic failure, including the loss of the coiled tubing, the entire well, or both.
This paper outlines the techniques behind cementing through coiled tubing, illustrating the pitfalls and suggesting best operating procedures. The issues covered are: -
When to use cement darts. How to land cement darts. How to manage liquid freefall. How to clean up cement. What should the displacement/contaminant fluid be? What are the best nozzles? Slurry design.
Coiled Tubing Operations From Monohull Floating Production Units
Authors: Van Cann Bram , Poldervaart Leen 
Published: December 2007

Abstract
Given the high day rates of deepwater drilling and workover rigs, the overall drilling and well maintenance costs for subsea wells are a significant part of the total costs for deepwater field developments.
Recent drilling and completion technologies have resulted in improved reliability, higher production levels and an increase in recovery for individual wells. This has allowed for an optimization of the well system design and total well count in deepwater areas. A cost-effective access to the well and regular well maintenance during the field life are considered key issues for optimal reservoir management, which allows for accelerated production, an increase in Ultimate Recoverable Reserves (URR)and significant savings in operating costs during the field life (e.g.optimal design of process facilities).
A Floating Production and W orkover Unit (FPW U), allowing for simultaneous production and workover operations from a large monohull floater, without the need for an additional well intervention vessel has been developed (Figure 1).
High Rate Stimulation Using 2 7/8" Coiled Tubing Zonal Isolation Straddle Packer
Authors: Halvorsen Helge , Ormark Kjetil , MacCleod Alistair 
Published: December 2007

Abstract
This paper describes Zonal Stimulation jobs performed with coiled tubing (CT) in a chalk field in the North Sea in three wells.
The wells needed selective treatments, and through close cooperation between operator and Service Company, a new tool was developed to address all challenges regarding the wells.
Large Hydrocarbon Compositional Gradient Revealed by In-Situ Optical Spectroscopy
Authors: Fujisawa Go , Betancourt Soraya S. , Mullins Oliver C. , Torgersen Torleif , O'Keefe Michael , Terabayashi Toru , Dong Chengli , Eriksen Kåre Otto 
Published: December 2007

Abstract
This paper presents a case study of a North Sea appraisal well where a large vertical fluid composition variation, missed by a conventional pressure gradient analysis method, was observed in situ in real time by a new fluid composition analyzer utilizing visible near-infrared (NIR) spectroscopy. For optimal oil production, it is as vital to assess the spatial variation of fluid properties as it is to assess the spatial variation of formation properties.
Conventional wireline triple combo measurements showed the interval of interest was uniform and free from noticeable impermeable layers. A resistivity log showed an approximate oil/water contact. Wireline pressure testing identified three different pressure gradients corresponding to gas, oil, and water, all in hydraulic communication. However, the pressure testing did not indicate a gradient in hydrocarbon composition. Fluid was sampled and analyzed in real time by a wireline fluid sampling-analyzing toolstring that included the fluid composition analyzer. This tool analyzes petroleum fluid and gives concentrations for four group compositions (C1, C2−C5, C6+, and CO2), gas/oil ratio (GOR), and qualitative information regarding heavy-end content and stock-tank crude density. The analyzer showed the hydrocarbon fluid in an oilbearing zone was not vertically homogeneous but instead had a large vertical variation. The samples captured by the wireline sampling tool were sent for a laboratory compositional analysis that confirmed the variation determined by the downhole analysis. Both results identified the heterogeneity of hydrocarbon fluid in the interval.
This paper also covers briefly the measurement principle of the analyzer and discusses the impact and benefit the new technology brings. The concept of flexible fluid sampling is particularly important because it enables operators to make sampling decisions based on real-time fluid analysis results rather than a predetermined job plan.