bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving Hydraulic Fracturing Results Using Log Saturation Data
Authors: McNaughton Robert T. 
Published: December 2007

Abstract
A new hydraulic fracture screening method has been developed based on quantitative analysis of the mobile oil saturation in the target zone. The traditional selection process was based on analysis of low productivity wells, followed by extensive fracture modeling of leak-off parameters and rock properties. The new screening method defines the best pay zones and uses the saturation profile to govern the size of the fracture treatment.
This method was developed during a 10-acre infill-drilling program on the Central Vacuum Unit during the mid 1990s. Most of the producers were initially stimulated with large, one stage acid treatments. Production declined soon after completion and fell below the levels of offset producers. Texaco analyzed the open-hole logs and discovered a consistent pattern of low in-situ water saturation in the upper San Andres. Log analysis clearly indicated that the infill well production should be much better than the offset wells. Three of the new wells were successfully fracture treated across the entire San Andres interval with excellent results. However, many stimulation candidates were offset by wells producing high water volumes. The new screening method indicated that the upper San Andres should produce nearly water-free after fracturing. The design process also showed that smaller fracs would have substantially better economics and would ultimately produce as much or more reserves as large fracs.
Texaco fractured eighteen more wells in the upper San Andres. Oil production dramatically improved but water production was often unchanged. The new screening method allowed the development of additional reserves that were not recoverable under earlier practices.
Investigation of Well Productivity in Gas-Condensate Reservoirs
Authors: El-Banbi Ahmed H. , McCain W. D. , Semmelbeck M. E. 
Published: December 2007

Abstract
The productivity of the wells in a moderately rich gas condensate reservoir was observed to initially decrease rapidly and then increase as the reservoir was depleted. All wells in the field showed the same response. Compositional simulation explained the reasons for these productivity changes.
During early production, a ring of condensate rapidly formed around each wellbore when the near-wellbore pressures decreased below the dew point pressure of the reservoir gas. The saturation of condensate in this ring was considerably higher than the maximum condensate predicted by the PVT laboratory work due to relative permeability effects. This high condensate saturation in the ring severely reduced the effective permeability to gas, thereby reducing gas productivity.
After pressure throughout the reservoir decreased below the dew point condensate formed throughout the reservoir, thus the gas flowing into the ring became leaner causing the condensate saturation in the ring to decrease. This increased the effective permeability of the gas. This caused the gas productivity to increase as was observed in the field.
There were also changes in gas and condensate compositions in the reservoir which affected viscosities and densities of the fluids. These effects also impacted gas productivity.
This work is another step forward in our understanding of the dynamics of condensate buildup around wellbores in gas condensate fields.
Adapting High Permeability Leakoff Analysis to Low Permeability Sands for Estimating Reservoir Engineering Parameters
Authors: Craig David P. , Eberhard Michael J. , Barree Robert D. 
Published: December 2007

Abstract
The modified Mayerhofer method has been proposed for estimating permeability from the pressure falloff data in moderate and high permeability reservoirs before hydraulic fracture closure following a diagnostic fracture injection test. Applying the modified Mayerhofer method in low permeability sands, however, requires understanding of the closure mechanism, which is identified with G-function derivative analysis of the before-closure pressure falloff data. This paper demonstrates how G-function derivative analysis and the modified Mayerhofer method are used in conjunction to estimate reservoir permeability in low permeability reservoirs.
Numerous applications of G-function derivative analysis have shown the characteristic closure mechanisms—normal, pressure-dependent leakoff from fissure opening, fracture-height recession, fracture-tip extension, and changing compliance—all result in distinctive specialized plots using the modified Mayerhofer method. When the two methods are used in conjunction, G-function derivative analysis provides a means for identifying the falloff data that can be used to estimate permeability and fracture-face resistance without violating the assumptions of the modified Mayerhofer method. Field cases are included to demonstrate that reasonable estimates of reservoir permeability in low permeability reservoirs often can be obtained from the before-closure pressure falloff following a diagnostic fracture injection test.
Mini-Injection Tests Provide Inflow Performance Characteristics for Oilwells
Authors: Myers Donald L. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
When an oil well is to be put on production with artificial lift, the inflow performance characteristics of the well are sometimes unknown. Analysis of the pressure transient response to a short-term injection test can provide this information. Imperial Oil Limited (IOL) used the technique successfully to obtain data for the initial selection of equipment on a number of recompleted wells in the Judy Creek field.

Introduction
Recently, a number of old, suspended wells in the Judy Creek field had to be reactivated in order to carry out the programmed reservoir depletion strategy. These wells required artificial-lift equipment, but little was known about the production capacities of those wells since they had not produced for several years and reservoir conditions had changed considerably. In addition, most wells were recompleted over new or additional zones which made data on their original productivities even more obsolete. To sensibly select lifting equipment up-to-date information on the well characteristics had to be obtained.
This paper describes a simple field test and subsequent analytical procedure which IOL applied to obtain inflow performance characteristics for oil wells. It shows how the analysis of the pressure transient response to a mini injection test provided the necessary data, including permeability thickness, skin factor and inflow performance relationship. These data then served as a basis for the selection of artificial equipment for the new well installations. IOL used the test also to check the characteristics of existing pumping wells which had failed and to evaluate the incentive for stimulating wells. Examples of the application of the test are given.

THEORY
The test is based on the well-known principles of pressure buildup and falloff principles of pressure buildup and falloff analysis as described by, e.g., Matthews and Russell. When a well operates with a constant injection or production rate, the surrounding reservoir area maintains a certain pressure profile (Fig. 1). The pressure at the wellbore profile (Fig. 1). The pressure at the wellbore radius, rw, is the bottom-hole injection pressure, Pinj, and this pressure decreases, with the Pinj, and this pressure decreases, with the distance from the wellbore to the reservoir pressure, Ps, at the drainage radius, re. pressure, Ps, at the drainage radius, re.
Good Coiled Tubing Welds, Properly Managed, Do Not Break
Authors: Van Arnam W. D. , Smith D. 
Published: December 2007

Abstract
Butt welding of coiled tubing performed routinely in both new and used tubing extends life or increases application versatility of existing strings. Welds are commonly made to replace overly fatigued sections, remove mechanical damage, extend string length, and attach special application strings or tools to work reels and repair tubing imperfections. Properly designed and executed butt welds provide the same load bearing properties of the surrounding tubing. The weld integrity is verified by non-destructive testing, insuring sound joints. The fatigue properties of the weld must be understood and properly managed. This has resulted in an extremely successful record for butt welds placed in coiled tubing for field application.
The paper documents the steps required to insure the best weld quality is being placed into a string of coiled tubing. Data on properties of welds from manual and machine welds, in both new and used tubing verify the load carrying capability of the welds. The down rating of fatigue life and potential corrosion implications are handled through continuous string management. The field experience of butt welds performed in both factory and field environments are reviewed. Results indicate the clear cost effectiveness of currently available, properly installed butt welds combined with systematic monitoring by the relevant service companies.
Concentric Coiled Tubing Well Vacuuming Technology for Complex Horizontal Wells in Eastern Venezuela
Authors: Clancy Thomas F. , Falk Kelly L. , Duque Luis 
Published: December 2007

Abstract
Recent activity in developing the heavy oil reserves of the Orinoco belt has required that operators there utilize cutting edge oil field technologies. The latest in pumping technology and horizontal, multi-lateral well completions are being employed and enhanced. Additionally, operators are looking at new approaches to collect and evaluate well and reservoir data. Coiled tubing is also being used to help with some of the well performance issues.
To optimize the performance of long, and/or multi-branch horizontal wells, post drilling clean-up is very important. Historically, this issue has often been overlooked or dealt with ineffectively. Not only is this step important for the resulting production performance, an effective system for accomplishing this can have additional benefits for the downstream facilities during start-up.
The zones of interest in the Orinoco belt are typically poorly consolidated sands, requiring some form of retaining completion. As slotted liners are most common, an effective method of removing solids from inside the slotted liner may also become a requirement.
This paper will discuss the technology of combining concentric coiled tubing with a jet pump to be able to do both the post drilling fluid clean-up and sand removal operations. It will detail the type of equipment used in this application. The paper will also go into specifics of the need for the service in this operation and the corresponding results. Future developments for this technology will also be covered.
Coiled Tubing Drilling – Expanding Application Key to Future
Authors: Crouse P. C. , Crouse Philip C. , Lunan W. B. , Lunan W. Brian 
Published: December 2007

Abstract
Since 1991, technology, people, methodology and commitment have played an integral and prominent role in the advancement, development and application of coil tubing drilling (CTD) as an alternative to conventional drilling systems. Various geological formations have been successfully drilled with coil tubing drilling systems with the CTD technology and methodology being continually adapted, improved upon and evolved from its more traditional uses. This evolution of the coil tubing drilling process is one of the most exciting and fastest growing sections of the coiled tubing industry. Coiled tubing has become a competitive advanced drilling tool when used properly. A very impressive track record has been established in Western Canada where coiled tubing drilling technology has been utilized in mostly shallow gas and oil properties to squeeze profits out of what might normally be considered marginal properties. In this manner the coil has been used as an advanced economic drilling system in both vertical and horizontal wells. In 95% of the operations the wells have been drilled underbalanced to minimize formation damage, reduce drilling problems, and increase the rate of penetration. In many cases this process has eliminated the need for remedial stimulation of the wellbore.
Current and Future Successes in Coiled Tubing Automation
Authors: van Walsum Eric 
Published: December 2007

Abstract
Electronic control systems are one of the enabling technologies that will permit dramatic improvements in the safety, efficiency and reliability of new coiled tubing equipment.
To illustrate how automation can contribute to these advances, examples will be taken from the control systems on one customer’s prototype coiled tubing and pumping units. Safety of operation was enhanced by reducing the number of operators, and placing them in a protected environment. Gains in efficiency were made by automating small tasks in the rig up, and larger tasks in the running of a job. Some contributions were made to reliability as well, in the form of self-diagnostics and soft starts and stops of the equipment.
Implementing the control system was not without its own challenges. The level of control is sophisticated, and the operating environment is harsh and varied. Significant work was required to ensure that the benefits of the control system were not outweighed by its own reliability issues.
The level of automation in coiled tubing applications has advanced from simple control of individual machines to integrated control of whole processes. However, further advances in safety and integration are envisioned.
Friction Pressures of Newtonian and Non-Newtonian Fluids in Straight and Reeled Coiled Tubing
Authors: Willingham Joe Don , Shah Subhash N. 
Published: December 2007

Abstract
As coiled tubing is presently utilized for a multitude of projects in the field, the necessity of estimating the friction pressure of the working fluids in the reeled portion of the coiled tubing string becomes extremely important. Past authors have shown the significant difference in friction pressure between straightened and reeled coiled tubing.
This work discusses the experimental investigation of five different polymeric solutions and one drilling mud in three different coiled tubing sizes. The analysis of the frictional pressure loss data includes the effect of fluid rheology, coiled tubing curvature, and tubing diameter.
The intent of the analysis is to arrive at a correlation describing frictional pressure loss behavior of polymer solutions and drilling muds in reeled as well as straightened tubing.
The experimental setup includes 3000 ft of 2 3/8 in. reeled tubing, 5000 ft of 1 1/2 in. reeled tubing, and 1500 ft of 1 in. reeled tubing. Straightened sections of tubing are also utilized in the setup for comparison and modelling of data.
The experimental results are compared with correlations developed by earlier investigators including Mashelkar, McCann, Ito, and Shah. The analysis of the data led to the development of a new model for polymer solutions and a model for drilling muds. The model for polymer solutions is recommended for power law type, pseudoplastic fluids with a power law index less than one, while the model developed for drilling mud was developed for only one concentration of mud. However, the drilling mud correlation suggests the form that other concentrations of drilling mud may follow.
Friction Pressure Correlations of Newtonian and Non-Newtonian Fluids through Concentric and Eccentric Annuli
Authors: Silva Moises A. , Shah Subhash N. 
Published: December 2007

Abstract
An experimental study has been conducted to investigate the effects of eccentricity on friction pressure loss calculations for drilling and stimulation fluids. Reynolds number in the range of 800 to 100,000 allowed the analysis of friction pressure losses of non-Newtonian fluids in both concentric and eccentric annuli in laminar and turbulent flow regimes.
Analysis of Fanning friction factors as a function of generalized Reynolds number showed that the effects of eccentricity are significant when annular friction pressure losses are estimated. The results demonstrated that the annular pressure losses in a fully eccentric annulus can be as low as 40% of the value in concentric annulus. It was observed that the effect of eccentricity is more evident as the fluid concentration increases. From experimental data obtained in this study, new correlations are proposed to calculate friction pressure losses in concentric and eccentric annuli for laminar and turbulent flow regimes. Though not ideal, these new correlations estimate friction losses in annuli much closer than the previously published equations.
Coiled Tubing: Extending the Reach of Slickline Operations
Authors: McClatchie D. W. , Moon B. 
Published: December 2007

Abstract
The growth of deviated and horizontal well drilling has limited the number of completion options that can be serviced by slickline units. Modifications to conventional slickline plugs, shifting tools, and setting tools have made it possible to run these tools on coiled tubing into highly deviated wellbores where push capabilities are required. Running and retrieval of gaslift valves, however, has remained the sole domain of slickline services. Declining reservoir pressures have more recently led operators to complete some of these high angle wells with gaslift systems fully realizing that not all of the mandrils will be accessible by conventional slickline units, instead requiring expensive rig workovers. By combining conventional slickline gaslift valve tools with coiled tubing and thorough, detailed job design, horizontal gaslift completions can now be economically worked over to optimise well production.
Bridge-Plug Millout With Coiled Tubing—Case Histories
Authors: Durey Daniel A. , Degner Dennis L. 
Published: December 2007

Abstract
Downhole plugs are now commonly used for isolating multistage stimulation jobs. These plugs allow for more timely completion, yet they must also be removed in a timely fashion. This paper discusses how coiled tubing (CT) can efficiently mill out these plugs.
The three case histories in this paper demonstrate the successful use of coiled tubing to mill out bridge plugs set in multistage stimulation jobs. Specifically, each case history provides a brief history of the well, a description of the equipment used to meet downhole and surface needs, and the operating procedure used for the job. The paper concludes with procedures to improve CT millout efficiency.
Pipeline Intervention From a Dynamically Positioned Mono-Hull Vessel via a Flexible Riser
Authors: Alsyed Samih M. , Larsen Henrik A. , Johnston Paul , Schaider Fred J. , Lounsbury Jack , Smith Jeffrey J. 
Published: December 2007

Abstract
After a subsea mudslide near the mouth of the Mississippi River Delta, several sections of production or export pipelines were severed. The pipelines could not be retrieved to surface because they were buried deeply in the mud. Coiled tubing was successfully used to clean and abandon these pipelines insitu under 200-feet of water. The coiled tubing was conveyed through a flexible riser from a Dynamic Positioning mono-hull vessel. The lengths of the four sections of pipeline cleaned were 2400-feet, 1200-feet and 1800-feet with diameters of 8-10 inches.
Running Coiled Tubing in Colombia - Living on the Edge
Authors: Clement C. C. , Duenas J. J. , Junca E. , Ufondu K. O. , Arciniegas O. E. 
Published: December 2007

Abstract
Coiled tubing is used extensively in Colombia as the preferred alternative to conventional workover operations for reasons of costs, logistics, and security. However, wellbore conditions make few jobs "routine" and extensive pre-job planning is required for each well intervention. Even with precautions, unforeseen situations occur that are unique to Colombia.
This paper presents an overview of the types of wells in Colombia. Depths, wellbore schematics, formation interval lengths, fluids produced, etc. are given as background information. Wellbore conditions that affect the use of coiled tubing are detailed to show the difference between Colombia and other areas utilizing coiled tubing.
A complete description of the types of jobs run in Colombia with coiled tubing is presented along with problems encountered while doing these jobs. The types of computer modeling used to design and implement each job are also given. Two actual case histories are used as typical examples of problems encountered on a daily basis during well interventions as well as the solutions to remedy these problems.
A set of guidelines gained primarily through experience in running coiled tubing in Colombia are presented and may help others encountering similar wellbore conditions in other areas of the world. The concluding section of the paper lists the areas requiring more technological advances for running coiled tubing in Colombia.
The Effect of Corrosion in Coiled Tubing and Its Prevention
Authors: Van Arnam W. D. , McCoy T. , Cassidy J. , Rosine R. 
Published: December 2007

Abstract
Unpredictable coiled tubing (CT) service life is not acceptable in the CT industry and is not tolerated by the customer. Experience shows that service life becomes unpredictable without adequate tubing maintenance programs that include corrosion prevention. Therefore, monitoring and maximizing CT service life requires effective corrosion control on both inside and outside CT surfaces from the time the tubing string is milled until it is retired. Corrosive degradation of CT can result from contact with the atmospheric environment, pumped fluids, and production fluids. Corrosion, especially localized corrosion, must be prevented because it can greatly affect tubing life by initiating premature fatigue cracking and growth during cycling. Additionally, corrosion can reduce usable tubing strength and pressure integrity.
This paper discusses effective preservation and inhibition programs instituted at the tubing mill, service centers, and in the field. In addition, electrochemical corrosion-rate data for as-milled and cycled CT is presented. Linear-polarization resistance and Tafel-curve generation were used to derive general corrosion-rate data for new and cycled CT-90 and CT-100 in various common oilfield fluids, including a stimulation fluid. These tests suggest that CT corrosion tendency is not significantly accelerated as a result of cycling, except at high temperatures. Additionally, the paper presents high-pressure fatigue data from tests performed on CT-90, comparing fatigue life in water and in inhibited 15% hydrochloric acid (HCl).
Coiled Tubing Inspection and Tubing Management: A Case Study
Authors: Toye Terry N. , Pantaleo Tony , Rheinlander Mark D. 
Published: December 2007

Abstract
Coiled tubing (CT) is increasingly used in completion and workover applications, especially as a deployment method for acid and other corrosive materials. The occurrence of internal wall loss and external pitting has become more common, especially if proper tubing management is not followed. Not only is there internal wall loss associated from the use of corrosive materials, but also external pitting from severe downhole environments as well as surface environments. The recent industry down turn has reduced the utilization of coiled tubing strings. This sometime causes deterioration of the metal quality through external and/or internal corrosion, particularly when good maintenance procedures are not followed, and strings are not properly protected from the environment. This becomes costly, as strings are unable to be used to their full life potential or when a job failure occurs because of poor string management.
This paper presents case data demonstrating that the use of CT inspection and proper tubing management can avoid or reduce future job problems. The use of the described techniques and good pipe management will in turn reduce safety problems, and lost revenue due to pipe failures and shortened string life.