bluuebunny/crossref_metadata_2025_split huggingface dataset:
Root Coverage Outcome May Be Affected by Heavy Smoking: A 2‐Year Follow‐Up Study
Authors: Andia Denise C. , Martins Ângela G. , Casati Márcio Z. , Sallum Enilson A. , Nociti Francisco H. 
Published: April 2008

Background: Although subepithelial connective tissue graft (CTG) has been reported to be a predictable procedure for root coverage, the impact of smoking on the long‐term outcome of periodontal plastic surgery is unclear. Hence, the aim of this study was to evaluate the effect of smoking, on a long‐term basis, on the stability of gingival tissue following CTG treatment of gingival recession.Methods: Twenty‐two defects were treated by CTG in canine and premolar Miller Class I and II gingival recessions (11 smokers and 11 non‐smokers). The following clinical measurements were obtained at baseline and at 1, 2, 3, 4, 6, 12, 18, and 24 months after surgery: plaque and gingival indexes, extension of gingival recession (GR), probing depth (PD), clinical attachment level (CAL), and gingival thickness. Individuals smoking ≥20 cigarettes/day for ≥5 years were considered smokers.Results: Data analysis demonstrated that both groups presented similar plaque and gingival indexes (P >0.05), and an intragroup analysis showed that CTG was able to promote root coverage and increase gingival thickness in both groups over time (P <0.05). However, at 24 months postoperatively, statistical analysis showed that smokers presented poorer outcomes with regard to PD, GR, and CAL (P <0.05); in addition, a more satisfactory stabilization of the gingival tissue was found in the non‐smoker group.Conclusion: Smoking may represent a challenge to root coverage outcome for CTG because smoking significantly affected the stability of gingival tissue over time.
Development of a High-Fatigue-Life Mechanical Spoolable Connector
Authors: Ehtesham Asif , Hriscu Joseph , Zhong Allan 
Published: April 2008

Abstract
Due to limited crane capability, some coiled tubing (CT) strings are transported in two or three sections to offshore locations, requiring the use of welding or mechanical connectors for reassembly. CT utilization subsequently can be hampered by welding issues as well as lack of integrity of the connectors. Field welding techniques and commercially available spoolable connectors can decrease the fatigue life of CT string to 35–70% of the base tube.
This paper describes the development of a mechanical spoolable connector with a fatigue life as good as that of the base pipe. The connector was designed using extensive nonlinear finite element analysis (FEA) design iterations. The connector pressure rating is equal to that of the pipe, and the connector maintains its sealing ability throughout the fatigue life of the pipe—even on very aggressive radius drums and tubing guides. The connector conforms very well when spooled to the drum without "sticking out." The connector assembly OD fits flush with the CT string, providing continuous gripper engagement. Single or multiple connectors can be used to join sections of coiled tubing in the yard or on location.
The new connector uses material certified for sour wells and acid jobs, and its seals are compatible with a variety of chemicals, acids, and sour service conditions.
In addition, the testing of the connector is discussed. The connector design performed very well according to several prototype tests on a fatigue machine and full-scale yard test. The results demonstrate that the new spoolable connector can increase the utilization of CT with various configurations and enable operations previously not deemed feasible due to various limitations imposed by other joining techniques.
Milling of Cast-Iron Bridge Plug With Electric-Line-Conveyed Technology
Authors: Rattray Frank , Annandale Alex , Oil Marathon , Grassick Rob 
Published: April 2008

Abstract
A new application of well tractor robotics in combination with well milling technology has been proven in the UKCS. In June 2007 on a North Sea platform, well tractor robotics in conjunction with a well milling rotational unit, using an electric wire line cable, were used to remove a cast iron bridge plug at 16,000-ft.
A cast iron bridge plug run for a water shut off was set at an incorrect depth. Through evaluation, milling tests onshore confirmed that the concept of using a well miller with a well tractor was viable. The total operational time from rig up to rig down was 67 hours, with an actual milling time of 16 hours. During this unique operation all milled material was recovered and the challenges of controlling rate and milling penetration were achieved.
This new application for milling well completions hardware and other well bore obstructions offers a cost efficient alternative technology to existing methods. The proven technology, normally used for production logging in highly deviated wells, also offers HSE benefits and logistical advantages.
The article will describe the actual process from testing to completion of the offshore operation.
HP/HT Compact Motorhead for Larger-OD Coiled-Tubing/Jointed Pipe Operations: Design, Testing, and Successful Case History
Authors: Ehtesham Asif , Hriscu Joseph , Howard Robert 
Published: April 2008

Abstract
With the increased use of larger-sized coiled tubing (CT), demand for CT tools is pushing the limits of tool rating and frequently extending the sizes required for jointed tubing operations. This paper describes a high-pressure, high-temperature (HPHT) motorhead designed for larger-sized CT and/or jointed pipe. Motorheads are used for well control, emergency-release disconnects, enabling circulation to the annulus, and establishing circulation to the annulus should the normal circulation path become plugged.
The development and design of the new motorhead will be described, including its special mechanical capabilities that depended on careful alloy and elastomer selection. For example, the flapper valves can withstand 20,000-psi differential pressures in -40 to 400°F temperature cycles (from cold–hot–cold) in a single run. The flappers were designed to close in slam-shut situations without compromising well control, and the hydraulic disconnect can bear higher torque and tensile loads than any similar tool currently available.
The completion fluid in combination with the well fluids presented problems for conventional sealing compounds exposed to pressure and temperature extremes. Results from a two-month testing period are discussed, which included pressure, temperature, tensile strength, torque, and fluid compatibility tests. FEA and CFD analyses were used to simulate flow, pressure, and slam shut conditions, enabling the most effective motorhead design for HPHT environments.
A North Sea case history of a successful well intervention using the new motorhead is also described. Three fully certified traceable HPHT motorhead assemblies were used for six runs over a combined 121 days in wellhead pressures up to 10,800 psi and downhole temperature of 365°F. The tool was tested and serviced between runs. Under these rigorous conditions, it was critical that the valves held backpressure and retained their integrity after continuous pumping under high pressures and temperatures—these objectives were achieved.
Application of a Novel Rigid-Setting Material as an Annular Barrier to Re-establish Pressure Integrity of Tubing in an Injection Well
Authors: Setiadi H. , Bewick D. , Blair J. , Walger R. , Ridley E. 
Published: April 2008

Abstract
In a BP well on the south coast of England, pressure and fluid from the injection tubing were in communication with the annulus because of a leak path formed by corrosion of the tubing. This communication limited the maximum allowable injection pressure, which impaired the flexibility of the operator to manage the recovery program and thus reduced the recovery of hydrocarbons from the reservoir. Remedial treatment possibilities had to be compliant with considerations for the future abandonment plans for the field in that any treatment should not substantially impede or detract from efficient abandonment operations. A recompletion was not considered cost effective, and a mechanical straddle of the correct length was not viable. An annular barrier was chosen as the cost effective option when considering well life. Previously, the material predominately used to form the annular plug in similar situations was oilfield cement placed onto the production packer in the annulus. The alternative, novel rigid setting material, was chosen because of its differing suitable properties, which are (1) a high level of resistance to contamination, (2) expansion, (3) ease of milling, and (4) 100% acid solubility. These properties helped ensure that a uniform plug was achieved though the material was diluted by annular fluid between the production packer and the punched circulation holes in the tubing, and that a good seal was created so that the annular plug was not bypassed. Further, excess material can be easily removed from the tubing to bring the well on line with minimal delay and future abandonment operations are not onerous. In late 2006, the slurry was placed using a coiled tubing (CT) packer arrangement, with displaced fluid returned to surface for environmentally safe disposal. The ease of placement and reliable set of the material, with strength comparable to normal oilfield cement, can provide an effective alternative to commonly used annular sealing materials.
Pressure Transient Analysis Data Collected by the Use of a Retrievable Gauge Hanger in Saudi Arabian Gas Wells
Authors: Zbitowsky R. , Nunez Garcia W. , Al-Shawaf A. M. , Al-Hussain H. M. , Bill B. 
Published: April 2008

Abstract
Up until today operators have been facing a challenge on how to place memory gauges as close to the perforations as possible when collecting data to perform pressure transient analysis. Various methods have been used including hanging the memory gauges in nipple profiles or below a retrievable packer or even setting the memory gauges at the bottom of the well to be retrieved later. Suspending the memory gauges in the well using slick line is another commonly used method in certain areas.
Pressure transient analysis (PTA) plays a key role in determining reservoir parameters for both stimulated and non stimulated wells. Some of the results from PTA include permeability, skin factor, flow efficiency, average reservoir pressure, system geometry and reserve estimates.
To make the collection of such key data more efficient in both vertical and horizontal wells Saudi Aramco is now using a Retrievable High Expanding Gauge Hanger®, Figure 1, which has been designed incorporating a large by-pass flow area to minimize restriction in the wellbore. With a simple adjustment the hanger can be set in 4½ in., 5 ½ in. or 7 in. tubing or casing. The tool can be run through smaller ID tubing and set in larger ID liners and is designed for the memory gauges to hang below. The tool is run on slick line and set using a non-explosive hydrostatic setting tool. Retrieving the tool is easy utilizing a standard JDC Pulling Tool. High levels of H2S and CO2 in some Saudi Arabian gas wells required the re-useable hanger to be made from an Inconel® material.
This paper will compare the different methods used for data collection; discuss the development process of the gauge hanger tool as well as the final design of the hanger and setting tool currently being used. Case histories will also be presented from several prolific Saudi Arabian gas wells.
Development of Wells Technical Professionals
Authors: Smith Angela , Skar Olav , Morse Tony 
Published: April 2008

Abstract
The Wells function in Shell International Exploration and Production has long been recognised as leaders in competency development. As part of the ongoing Shell Global Business Performance Reviews it was deemed important to improve and expand the role of Wells learning in the organisation and link it more closely to competency development. Part of this requirement was to ensure the new learning was of an internationally recognised and accepted standard.
Shell Wells Professionals now have the opportunity to gain academic degrees of Master of Science, MSc, as part of their learning and development (L&D) programme. A new dynamic approach within the Shell Learning Centre has been able to integrate both new and redeveloped Shell training courses with a Scottish University validation.
The redeveloped "Drilling Round 2" course, a Shell standard for some 35 years, now includes the increasingly important area of Completions and Well Interventions. New learning materials, delivery methods and training philosophies have been brought together in a seamless programme that delivers world class development for Wells Engineers. This reflects steps Shell has taken in support of a life-of-field philosophy in the planning, construction, operation and maintenance of its well assets.
A new breed of highly trained, competent and motivated professional engineers is emerging with a much greater understanding of the need for interdisciplinary communication and knowledge transfer globally. Not only does this result in an enhanced career path for individuals but also benefits Shell directly in that the investment in Learning and Development improves Shell's Wells performance in terms of safety, environmental management, integrity and efficiency.
Comparison of Computational Fluid Dynamics of Erosion in Coiled Tubing to Field and Test Data
Authors: Rosine R. S. , Blanco I. L. , Bailey M. 
Published: April 2008

Abstract
Coiled tubing (CT) is used as a cost-effective means of servicing wells for well intervention. Over the years, the fluid flow through CT has been discussed and theorized. Testing has been conducted to promote a better understanding of what happens inside the CT. In recent years, the use of computational fluid dynamics (CFD) software has provided greater insight into actual CT flow patterns, including fluid-flow velocity profiles, secondary flow regimes, and erosion. CFD helps to understand the CT fluid flow phenomenon, which can lead to effective tubing management. CFD has proven to be an effective alternative to full-scale testing.
This work compares the results of CFD modeling of erosion to actual field data. It compares predicted values, actual values, and computed values from the CFD solutions. CFD is used to provide correlations for the predictive model without full-scale testing, which greatly reduces the cost of development. Fluids investigated include slurry pumped from an actual job and full-scale testing.
The Effects of Residual Bending Forces on Coiled-Tubing Injector
Authors: Rosine R. S. , Bailey M. , Blanco I. L. 
Published: April 2008

Abstract
Coiled tubing (CT) injectors have been used in well intervention (WI) service for many years. As the WI business becomes more challenging, it requires the use of larger tubing. Using larger tubing results in managing tubing strings and operating equipment in a different manner. Tubing strings have become larger in size and yield strengths of the material have increased. Larger and stronger tubing subjects the equipment to greater stresses. The tubing also has more residual bending forces than the smaller, more traditional strings used in the past. The increased residual forces can affect the performance on the injector, adversely affecting the gripper beam pressure in particular.
This paper discusses the results of residual bending forces and their effects on the CT injector. It compares computed values to actual values from experimental test data. The findings could change the effective gripper beam pressure.
Pushing the Wireline Operation to New Frontiers
Authors: Al-Dhufairi Mubarak , Al-Ghamdi Abdulrahman , Lewis David , Nafa Hamed 
Published: April 2008

Abstract
This paper presents a case study of field trials completed by Saudi Aramco to evaluate use of the Wireline Engineering Company's Roller Bogie™ tool to improve wireline (both Slick and Electric Line) intervention in highly deviated cased-hole wells. Conventional wireline intervention tool operations are normally limited to a maximum of 65° inclination due to frictional resistance between the wireline toolstring components and well tubulars. The Roller Bogie™ tool was used to overcome well inclination limitations and complete necessary wireline interventions without the utilization of costly and complex coiled tubing or wireline tractor operations.
Conceptually, the Roller Bogie™ tool drastically reduces frictional contact between the wireline toolstring and the wellbore tubulars by lifting the entire wireline assembly off the well tubulars on low-friction rollers. Moreover, the Roller Bogies™ uses a self-orienting body profile to ensure that the rollers are always located on the low side of the tubing and also have integral swivels that allow the rollers to be oriented independently to the rest of the toolstring.
The use of this tool in Saudi Aramco wells has enabled conventional wireline operations to be conducted at well deviations in excess of 82°. The Roller Bogie™ tool was used in tandem with a cement bond log (CBL) tool in an offshore highly deviated (maximum of 87°) cased hole oil well at a depth of 9,154 ft (2,790 m). This CBL log was recorded successfully at a maximum of 82° of inclination and to a depth of 8,406 ft (2,526 m) without any significant wear out or damage to the Roller Bogie™ tool or attached wireline assemblies.
After the success of the trial test operation and the resultant cost avoidance of the coil tubing or wireline tractor utilization, additional operations were completed, such as bridge plug installation, perforating and ceramic disc rupturing.
CT-Failure Monitoring: A Decade of Experience
Authors: Crabtree A. R. 
Published: April 2008

Abstract
In its earliest days Coiled Tubing (CT) suffered from unreliability due to low cycle fatigue and inconsistent material performance. With the introduction of the continuous milling process utilizing the bias weld geometry to join lengths of flat strip before forming the tube and an improved material specification, the industry was able to measure fatigue performance accurately and develop predictive algorithms to avoid over use of the tubing.
Since those early days the reliability of CT has improved and allowed the industry to expand rapidly to the point where there are now approximately 1,500 CT units in operation around the world. This growth has also expanded the range of pipe sizes, wall thicknesses, string lengths, steel grades and types of operations being utilized or undertaken. The operating environment in which CT is routinely used has become more arduous with interventions being performed in high pressure wells, sour gas wells and geothermal wells, for example. The expansion of the industry, especially over the last 5 years, has also led to a dilution of knowledge and experience as companies compete to hire and retain staff.
The expectation might be that all these factors combine to reduce the reliability of the coiled tubing service at the well site. This paper will review a decade of tracking CT failures, their cause and will set the results against the perspective of the changing nature of the business over the same time period. Conclusions will be drawn as to what are the critical factors for obtaining reliable CT service life performance and whether or not reliability is higher today than a decade ago.
Improved Method for Underbalanced Perforating With Coiled Tubing in the South China Sea
Authors: Rae Graeme , Yusof Mohd. Bakri , Ghani Juanih , Mokhtar Shahril , Munro Jock 
Published: April 2008

Abstract
In Malaysia, coiled tubing (CT) conveyance is used to optimize underbalanced perforating, especially for rig-related operations. Well trajectory, temperatures and fluids can create uncertainties on both depth control, and the accuracy of hydrostatic cushion before firing the guns. The conventional method of correlating the CT on depth involves two CT runs the first to run a memory gamma ray (GR) and casing collar locator (CCL) and the second run for the actual perforation. The underbalanced condition calculated based on wellbore fluid displacement is often deemed insufficient to create effective cleanup of the perforations.
This paper outlines a solution to these challenges. For a CT perforation campaign in the South China Sea, a CT string equipped with fiber optic cable inside was used, coupled with a bottomhole assembly capable of measuring both bottomhole temperature, internal and external CT pressure, and in addition casing collar locator. The primary objective of the job was to ensure that the perforation was performed with maximum under-balance but not exceeding a safe drawdown on the formation and risking collapse of the perforation tunnels. With 1,000 psi initial underbalance, to remove perforation damage the well would then remain balanced to avoid fluid invasion on the new perforations. The secondary objective was to avoid an additional CT run for correlation, thus saving rig time.
The objectives were met and this new approach to coiled tubing operations was found to be effective. Not only was there significant saving of rig time, the wells performed superior to existing wells and were brought into production sooner than planned. This technology has elevated CT standard operation onto a higher level in Malaysia.
Solving Excessive Water Production in a Prolific Long Horizontal Open Hole Drilled in a Naturally Fractured Carbonate Reservoir
Authors: Lightford Stephen , Pitoni Enzo , Burrafato Giovanni , Serapiglia Claudia Porretta 
Published: April 2008

Abstract
The paper presents a case history of a successful operation that was performed to reduce excessive water production in a horizontal well drilled through a naturally fractured carbonate reservoir. Because the well was completed with a 940-m horizontal openhole section, there were two significant issues in the attempt to reduce water cut without the use of a workover rig. There was no practical means of selectively isolating sections of the open hole, and even if it could be achieved, the fractures producing water could not be identified and individually isolated.
A treatment was performed employing a sealant that would set up only in presence of water and would remain fluid in anhydrous conditions. This sealant was placed using a coiled tubing unit (CTU) and then overdisplaced into the formation, into the natural fracture system.
Before the treatment, this naturally flowing prolific oil producer would not flow because of the hydrostatic pressure from the excessive water cut (i.e., &gt;60%). Following the treatment, the well flowed at approximately 20% water cut for a few days, stabilized at 40%, and has remained in natural flow since the treatment.
This paper describes the philosophy behind the treatment design, the testing of the sealant, the placement procedure, subsequent well operations, and well performance. To re-establish this well into productive natural flow without the use of a workover rig was considered to be a significant success, and the long-lived effectiveness of the treatment has exceeded expectations.