bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling in Brazil in 2887m Water Depth using a Surface BOP system and a DP Vessel
Authors: Brander G. , Magne E. , Newman T. , Taklo T. , Mitchell C. 
Published: December 2007

Abstract
The deepwater well 1-SHEL-14-RJS (block BM-C-10 in the Campos Basin offshore Brazil) was successfully drilled by Shell Brazil in May/June 2003. The well was drilled to beyond 5200m total depth in 2887m water by the Stena Tay, a dynamically positioned (DP) semi-submersible, using a Surface BOP system. Subsequent to this well in Brasil, a further drilling campaign with the same SBOP system on the Stena Tay, has commenced in Egypt in late November 2003. At the time of writing the first well has been drilled to TD.
The SBOP system included a Surface mounted BOP (SBOP), a high pressure casing riser, a Seabed Disconnect System (SDS), and control systems for these components. In order to utilize this equipment on the Stena Tay, a number of relatively minor rig modifications were completed prior to the start of operations.
Throughout the project planning phases, an intense and comprehensive risk management process was followed. The results of this work concluded that SBOP operations are as safe, if not safer than conventional operations in terms of Health, Safety and Environment. The operation was successfully completed without any significant HSE incidents.
During the operations with the SBOP system a large number of learning's and ideas for improvements to the system were gathered. These improvements will be prioritized and implemented for future SBOP drilling campaigns.
Overall, the SBOP operation on BM-C-10 was extremely successful, particularly when considering that this was the first application of a new technology in an extreme environment, conducted from a dynamically positioned vessel in record breaking water depths for Brazil. This heralds a new era for such operations and provides a strong basis for planning for future operations with SBOP in many areas of the world. It also gives Shell the capability of drilling beyond the 10,000ft water depth barrier making use of the existing worldwide rig fleet.
Methodology and Benefits of a Drilling Analysis Paradigm
Authors: Iyoho A. W. , Millheim K. K. , Virginillo B. K. , Adeleye A. R , Crumrine M. J. 
Published: December 2007

Abstract
This paper discusses a segment of drilling engineering -- drilling analysis -- that is assumed to be practiced routinely, but in many cases is not given the necessary attention, time, and resources required.
Routinely acquired drilling, geologic, mud-log, and logging data, are shown to be amenable to organization into a knowledge-based structure that permits: Use of statistical analysis to develop challenging but achievable technical limits, or best composite time (BCT), for similar wells – location, depth, hole size.Statistics-based best composite cost (BCC), the dollars equivalent of BCT. Both the BCC and BCT represent practical, challenging but achievable benchmarks that are continuously upgraded, providing significant steps in the process of drilling costs reduction.Specialized learning-curve analysis, trouble-time analysis, flat-time analysis, time vs. depth analysis, cost vs. depth analysis, rig and crew performance evaluation, bit-on-bottom and tripping analysis, time distribution plots, etc.Convenient drilling data cross-correlation with wireline logs, geology and mud-log data, to further delineate drilling problem zones and improve drillingoperational performance.A historical understanding of well construction that can contribute to continuing drilling improvement, and a method to provide feedback and collaboration with company drilling personnel, rig contractors, and service companies.
This paper reviews existing variations, key elements, and typical field applications of drilling analysis, and puts forth the case that drilling analysis should become an integral part of drilling engineering, the same way well-test analysis is an integral part of reservoir engineering. The need for a university curriculum and training on this key discipline is stressed, along with the necessity for management to champion the use of drilling analysis as an on-going process to improve organizational drilling performance.
The Completion of Subsea Production Wells Eased by the Use of a Unique, High-Density, Solids-Free, Oil Based Completion Fluid
Authors: Taugbøl Knut , Lilledal Lars , Juel Henning , Svanes Kåre , Jakobsen Tom Magne 
Published: December 2007

Abstract
Hole stability issues and the need to reduced drillpipe torque have made oil-based drilling fluids the systems of choice for highly deviated or horizontal reservoir sections offshore Norway. However, the tendency of barite sag in non-aqueous drilling fluids has led to plugging of sand-control screens, thereby creating in some cases the need for a solids-free environment for the completion. Unfortunately, because of problems related to emulsion blocking when mixing filtrate from oil-based drilling fluid and water-based completion fluid, displacing to brine after drilling with oil-based fluid can damage productivity.
This paper describes the design and successful application of a unique high-density solids-free, oil-based completion fluid. This fluid obtains its density from an emulsified internal phase of heavy brine. This eliminates the requirements for solid weight materials for fluid density, providing a solids-free, oil-continuous environment for the completion.
The Effect Of The Synthetic- And Oil Based Drilling Fluid's Internal Water Phase Composition On Barite Sag
Authors: Albertsen Tron , Omland Tor Henry , Taugbøl Knut , Saasen Arild , Svanes Kåre 
Published: December 2007

Abstract
One important issue for drilling operations is control of down hole pressures. When drilling with synthetic or oil-based drilling fluids, the ability to maintain all the weighting agents in suspension is particularly difficult since these fluids are more vulnerable for sag than water-based drilling fluids.
In the current study, it has been shown that the ability to keep barite in suspension also depends on the chemical composition of the water phase. The sag tendency of a mineral oil-based drilling fluid, a linear paraffin-based drilling fluid and both an ester and a LAO-based synthetic drilling fluid has been evaluated. For comparison, all fluids were formulated with equivalent water activity in the internal brine phase. The results show that for all these fluids, improved performance was observed if the traditional calcium chloride salt was replaced with a selection of other salts. Formates as the internal salt, gave generally better performance than if calcium chloride was used. The best performance with respect to sag stability in the tests was observed using an ammonium calcium nitrate as the internal salt phase.
The paper describes in detail the effect that different salts in the internal brine phases in synthetic and oil-based drilling fluids was found to have on sag performance in a series of tests.
Evaluation of Heave-Induced Dynamic Loading on Deepwater Landing Strings
Authors: Everage S. DeWayne , Zheng Nanjiu , Ellis Sean E. 
Published: December 2007

Abstract
With current landing string tensile loads approaching 1.5MM lbs., deepwater drilling programs are quickly eliminating comfortable design margins. Consideration of static loading alone in these cases can sometimes be insufficient. This paper provides a mathematical model to predict dynamic axial loads imposed on a deepwater landing string by a drillship's response to ocean waves. The model can be adapted to a given landing string's geometric and mechanical constraints. The model will help the user identify the correct window for pausing a landing operation when sea states are increasing, or alternatively, may allow the user to continue deepwater landing operations with increased confidence during what may be considered marginal conditions.
Wellbore Enlargement for a Deepwater Casing Program: Case Study and Developments
Authors: Courville David F. , Childers Ronald D. , Miller Gregory C. 
Published: December 2007

Abstract
The success of deepwater exploration and development operations is greatly dependent on utilizing larger OD casing to reach the ever-increasing depths of today's prospects. Recently in the Mississippi Canyon region of the U.S. Gulf of Mexico's deepwater arena, a leading exploration company utilized new hole enlargement technology to simultaneously drill and enlarge a wellbore to facilitate the installation of a multiple string casing program.
A case study is detailed to illustrate how proper planning and the utilization of new hole enlargement technology matched with a rotary steerable system, culminated in the successful execution of this critical well construction operation. As part of the planning process, hydraulics analyses and BHA stabilization optimizations using special computer software are discussed. The application of a new design concentric reamer in a deepwater tight clearance casing program that enlarged more than 18,000 ft of four different-sized wellbore intervals will be presented.
Taut Leg Moorings Using Polyester and VLA Anchors
Authors: Agnevall Thomas 
Published: December 2007

Abstract
The use of catenary moorings systems in deep and ultra deep water requires long and heavy mooring lines. As a consequence the floater has to support a large weight and the mooring footprint becomes large and may interfere with neighbouring infrastructure. Installation of these mooring systems becomes very expensive due to the vessels that are required. For deep and ultra deep water mooring systems the more appropriate moorings system is the taut leg mooring, using shorter and lighter mooring lines. The mooring loads arrive at an angle between 30 and 45 degrees at the bottom, requiring the anchor points to resist not only horizontal, but also considerable vertical loads. This paper discusses the use of synthetic ropes and anchors in deep water mooring systems. The characteristics of the ropes and anchors are presented and how they can be used in both catenary and taut leg mooring systems.
When oil and gas exploration and production took place in shallow to deep water, the most common mooring line configuration was the catenary mooring line consisting of chain and wire rope (Fig. 1). For exploration and production in deep to ultra deep water, the weight of the mooring line starts to become a limiting factor in the design of the floater. To overcome this problem new solutions were devised consisting of synthetic ropes in the mooring line (less weight) and/or a taut leg mooring system (Fig. 2).
The major difference between a catenary mooring and a taut leg mooring is that where the catenary mooring arrives at the seabed horizontally, the taut leg mooring arrives at the seabed at an angle. This means that in a taut leg mooring the anchor point has to be capable of resisting both horizontal and vertical forces, while in a catenary mooring the anchor point is only subjected to horizontal forces. In a catenary mooring, the restoring forces are generated by the weight of the mooring line. In a taut leg mooring, the restoring forces are generated by the elasticity of the mooring line.
Planning and Execution of a Long, Tight Clearance Liner Through a Whipstock Milled Window
Authors: Dooley Lynn B. , Faul Gary L. , Courville David , Harrell Danny , Shipley Jonathan A. 
Published: December 2007

Abstract
A long, tight clearance liner was recently installed through a whipstock-milled window in a deepwater well. The length and weight of the liner, coupled with the tight clearances, pushed the limits of current technology. The liner was successfully run through a deep whipstock milled window and cemented at a depth below 24,000'. This paper describes the planning and execution involved in this critical well construction operation.
Integrated BHA Concept of the Latest Generation Rotary Closed-Loop System for Hole Sizes from 5 7/8" to 18 ¼"
Authors: Hahne Ulrich , Risdal Georg , Ruszka Jon , Wahlen Liv Sivertsen 
Published: December 2007

Abstract
During the past 7 years, rotary steerable drilling technology has emerged from prototype status to a standard application world wide. This paper focuses on the latest generation integrated Rotary Closed-Loop System which now enables the industry to benefit from this technology in hole sizes from 5 7/8"-18 ¼". The paper discusses the integrated BHA concept and the sequential implementation of additional BHA components. Modular positive displacement motors placed immediately above the steering device simultaneously gives another step change in drilling performance while reducing casing wear and extends the drilling envelope. The paper provides an insight into applications where the integration into the rotary closed-loop BHA, of real-time Logging While Drilling (LWD) formation pressure measurements and real time acoustic property services has complimented, or indeed eliminated the need for, wireline logging runs.
Using such an integrated Rotary Closed-Loop System in the Norwegian Troll Field created incremental production revenue of 6 Billion USD.
Overcoming Shallow-Gas Drilling Difficulties in the Gulf of Thailand
Authors: Tiraputra Pornpoch , Thiravutpinyo Pattanapong , Pongorapin Sunchai , Fraboulet Bernard , Dooply Mohammed , Friedl Walter , Elmarsafawi Youssef 
Published: December 2007

Abstract
Shallow gas-bearing formations in the Gulf of Thailand present numerous drilling and cementing challenges. In the first three wells drilled on platform WP11 in Bongkot field, initial cementing of surface casing did not achieve effective zonal isolation of the shallow-gas zone. Several techniques were unsuccessful, including the use of conventional lightweight gas-tight cement slurries, two-stage cementing operations with conventional gas migration control slurries, and injection of sodium silicate to damage the shallow gas sand. All methods failed to control the gas migration through permeable upper sand layers.
This paper presents case histories describing the solutions-oriented approach to this problem, which resulted in changes to both the drilling program and the cementing operations. There is discussion of the extensive laboratory testing performed to formulate the lightweight gas-tight cement slurry at low bottomhole temperature, the best drilling practices learned, and changes to selection of drilling fluid. Results of post-job cement logs are also included.
The new approach involved consolidating and damaging the formation with drilling fluid and using low-temperature, lightweight, gas-tight cement slurry. This water-reduced formulation required optimization of the particle size distribution, gas migration control, and short transition time. Modifications were made to drilling techniques and cementing practices, and an openhole external casing packer (ECP) was employed as an additional barrier. Successful zonal isolation was achieved in seven wells drilled from WP-11 Platform in the Gulf of Thailand with excellent cement coverage above and below the gas sands and no increase in wellhead pressure.
Experimental Assessment of Fluid Velocity to Control Gas Accumulation and Removal While Drilling "Horizontal" Wells
Authors: Ustun Firat , Nikitopoulos Dimitris E. , Smith John R. , Bourgoyne Adam T. 
Published: December 2007

Abstract
Horizontal wells often include sections with angles greater than 90 degrees due to steering uncertainties or the well path following the reservoir updip. If gas is present inside the well-bore either because of underbalanced drilling or taking a kick, the gas can accumulate in the resultant high spots and complicate effective well control.
A series of experiments were conducted to understand accumulation and removal of gas in a flow tube simulating a fully eccentric well bore annulus at inclinations of 91.5 to 100 degrees. Water, or polymer-viscosified water, and air were circulated in a 6 inch by 2.375 inch annulus at a range of liquid velocities representative of both well control and routine drilling operations. The studies demonstrated that low flow rates favor counter-current flow in either slug or elongated bubble flow patterns that would cause accumulation at high spots. As the liquid flow rate increases, co-current flow develops, and ultimately the counter-current flow disappears. The co-current flow patterns observed were stratified, stratified wavy, and bubble.
Flow maps were made to show co-current and counter-current flow windows and void fractions as a function of superficial gas and liquid velocities, fluid type, and inclination angle. Some counter-current flow was found at superficial liquid velocities below 1.2 ft/sec almost regardless of other conditions. Non-Newtonian fluids with a higher yield point were found to sometimes encourage counter-current flow and accumulation in contrast to conclusions published by other authors. Gas was effectively removed at inclination angles up to 96 degrees by a superficial liquid velocity of at least 3.3 ft/sec. Failure to continuously remove gas during underbalanced drilling can result in accumulation that ultimately "spills" into the vertical section of the well. A case history showing excessive surface pressures encountered during underbalanced drilling for gas is presented as an example of this effect.
An Investigation to Determine the Effect of Synthetic Mud Compressibility in Deepwater Cementing Operations
Authors: Singamshetty Kalyan C. S. , Authement Gervais J. , Dieffenbaugher Jeffrey T. , Dupre Ronald J. 
Published: December 2007

Abstract
Accuracy in displacement calculations is required to ensure proper displacement of cement with wiper plugs and drilling fluid. With deepwater operations moving to deeper seas the effect of temperature variations and high pressure induce another difficult to model parameter: compressibility of a synthetic mud. Dynamic temperature modeling has facilitated better 3D modeling of mud compressibility with respect to pressure and temperature during the cementing process. Ultimately the theoretical modeling results are compared with actual field data from Gulf of Mexico (GOM). The comparative matrix shows the nature of the complexity of this analysis and serves as a pioneering attempt in quantifying the effect of mud compressibility in deepwater cement displacement operations.
Reverse Circulation of Primary Cementing Jobs—Evaluation and Case History
Authors: Davies Jason , Parenteau Kim , Schappert Guy , Tahmourpour Farzad , Griffith James 
Published: December 2007

Proposal
Conventional means of primary cement placement pump the cementing fluids down the casing and well returns are taken from the annulus. This is the most common way of cement placement for the industry and has been used for more than 80 years. Much less commonly used by the industry, but recently gaining in use is the Reverse Circulation of Cement (RCC) technique. When using the RCC technique, the cementing fluids are pumped into the annulus of the well and returns are taken through the casing.
The recent acceptance of the RCC technique is mainly driven by economics and state-of-the-art technology bringing an alternative technique. Benefits of the RCC technique can include lowering bottom-hole placement pressure, reducing cement retarder concentration, lowering the time for cement placement, and increasing location safety. The main drawback to the technique is determining when uncontaminated cement is at and around the casing shoe.
This paper discusses the benefits and shortcomings of the RCC technique in relation to fluid friction, cement slurry design, location safety, and zonal isolation. The paper illustrates, through a case history, how RCC technique's strengths are obtained while shortcomings are minimized. Field data from a recent job using the RCC technique on a 3100-m gas well in Alberta, Canada, as well as lessons learned from the job, are presented.
Helical Buckling of Pipe with Connectors and Torque
Authors: Mitchell Robert F. , Miska Stefan 
Published: December 2007

Abstract
It has been generally recognized that connectors should have some effect on the buckling of pipe. For instance, the connector outside diameter may be as much as 50% greater than the pipe body diameter. As a result, the radial clearance of the connector can be substantially smaller than the radial clearance of the pipe body.
The analysis of buckling has received extensive attention in the last 20 years. The effect of connectors on pipe stresses has received somewhat less attention. Lubinski used the beam-column equations to analyze the effect of connectors on pipe bending stresses for a pipe in tension in a twodimensional constant curvature wellbore. Bending stresses were significantly magnified by the connector stand-off. Paslay and Cernocky completed this analysis by analyzing the pipe in compression. Mitchell extended these results to threedimensional helical buckling.
Torque adds a new dimension to the buckling problem. Without torque, buckling occurs only for positive effective axial force (compressive axial force plus pressure effects). A pipe with applied torque can buckle in tension! The contact force between pipe and wellbore can be increased or decreased, depending on the direction of the applied torque. And, of course, pipe used in rotary drilling always has applied torque; so buckling analysis without torque is always questionable.
This paper looks at three-dimensional buckling of pipes with connectors with applied torque. The problem formulation is similar to Lubinski's buckling analysis: the wellbore is vertical and straight. The beam-column equations considered in the plane buckling analysis are used, but now there are deflections out of the plane. A solution for helical buckling is developed that produces pipe sag, maximum dogleg angle, contact force, and bending stress magnification as a function of pipe effective axial force and torque. An application problem is solved and the relative effects of compressive axial force and torque on sag between connectors, contact loads, and maximum bending stress are examined.
Applications include the analysis of bottom hole assemblies, drill pipe, casing, and tubing. The solutions are simple enough that they are suitable for spreadsheet calculations.