bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aluminum Alloy Riser Allows for Deeper Drilling on Existing Rigs
Authors: Deul Hans 
Published: December 2007

Abstract
As drilling activities extend further offshore, the need to drill in deeper water increases. When conventional steel risers are used to increase drilling depth, the structural support of existing rig decks must be improved to support the additional weight. These modifications to allow for deeper drilling are both cost-prohibitive and time-consuming. The answer to this industry problem is a riser that is manufactured from an aluminum alloy.
Drilling activity off the coast of Brazil and in the Gulf of Mexico confirms that replacing the conventional line-pipe grades of high-strength steel with a lighter weight aluminum alloy riser allows existing rigs to drill in greater water depths without incurring costly and extensive rig modifications. This paper presents the successful use of aluminum alloy risers onboard the drillship Noble Leo Segerius from January 2003 until the present.
Aluminum alloy riser operations in Brazil since January 2003 have occurred in the following conditions:
Water depth ranging from 1000 m to 1500 m Mud weights up to 11.5 PPG Currents ranging from 2.5 knots at surface to 1 knot at seabed Top tension between 180 T total and 350 T total Rig moves with BOP suspended below the rig on full riser string
Use of the aluminum alloy risers increases an existing rig's potential water depth capability by 40%. Because the existing rig can be outfitted with the lighter-weight and overall less-expensive riser system with no modification to its structure, considerable savings in cost and time are realized along with the increase in water depth capability. With the operation of numerous existing rigs in areas like offshore Brazil and the Gulf of Mexico, the potential for this technology is significant to all who anticipate deepwater drilling.
Managing Pressures During Underbalanced Cementing by Choking the Return Flow; Innovative Design and Operational Modeling as well as Operational Lessons
Authors: Eck-Olsen Johan , Pettersen Per-Johan , Ronneberg Arnfinn , Bjorkevoll Knut S. , Rommetveit Rolv 
Published: December 2007

AbstractThis paper describes operational lessons and the unique simulation model developed for an underbalanced primary cementing of a 7 inch liner at the Gullfaks field in the North Sea.Due to very small margins it was desirable to avoid pressure changes in the open hole section while circulating the cement. This was obtained by circulating fluids out through a choke that was accurately regulated to maintain constant bottom hole pressure throughout the circulation phase. The fluids in front and after the cement had relatively low density to compensate for the high density of the cement, and choke regulation was crucial before the cement was in place.The paper describes the operation in detail with special focus on any unexpected events. Measured and predicted pressure curves will be shown, and be analyzed to come up with recommendations on how to carry out similar operations and how to best carry the technology further.A new transient computer model for cement displacement with dynamic choke regulation has been developed to make it possible to design choke operations accurately.The results of this paper have applications in any cementing operation where managing bottomhole pressure with a choke is required. The model can be applied in any such operation.The paper illustrates how to use managed pressure drilling ideas when cementing a well with very narrow pressure margins. The work is considered to be the first step towards managing cementing in combination with managed pressure drilling.
Improved Casing Running Process
Authors: Warren Tommy , Johns Roger , Zipse Dean 
Published: December 2007

Abstract
The conventional casing running process is personnel intensive and requires considerable human contact with the casing. A new casing running system facilitates mechanizing the casing running process. This technology eliminates potential safety hazards, provides assurance that the casing can be run to the intended casing point, offers the ability to ream casing to bottom, reduces personnel requirements for running casing and eliminates the need for a stabber in the derrick.
A portable Casing Drive System* (CDS*) is used to pick up joints of casing from the "V-door", position the casing over the stump in the rotary table, and grip the top of the casing without making a threaded connection. The CDS supports the full torsional and axial load for running the casing and provides the ability to circulate the well at any time to wash and ream to bottom as tight hole or fill is encountered. The top drive provides the rotary power to make-up and rotate the casing.
The new portable casing running system has been used on over 330 wells for thirty-eight operators in nine countries to run more than two million feet of casing of various weights, grades, and connection types with sizes ranging from 4-1/2" to 16". These jobs encompass wells from vertical holes to high angle extended reach wells and include both onshore and offshore applications. The system has been completely mechanized on one Casing Drilling* rig to allow the driller to routinely pick up casing from the pipe racks and make connections with no personnel on the rig floor.
Development of a Gas-Tight External Casing Patch Using Direct Hydraulic Expansion of Standard Casing to Achieve a Permanent Load Bearing Connection
Authors: Gorrara Andrew , Hazel Paul , Tavendale Fraser , Louden Fraser 
Published: December 2007

Abstract
This paper describes the design, development and testing of an External Casing Patch system for installation in an offshore well to repair damaged 9 5/8 inch casing. The casing repair was required to have an effective metal-to-metal seal to hold lift gas injection pressure together with the potential for increasing levels of H2S during the life of the well. The expansion technique used pressures in excess of 20,000 psi to compliantly expand the casing into an external ‘profiled overshot’. The paper also describes the development of a method of generating and controlling such hydraulic pressure downhole.
In addition to theoretical calculations, full scale laboratory testing of the mechanical and the hydraulic sealing properties of the connection have been performed in qualifying the Casing Patch for well deployment. Tests were performed on samples of casing taken from a candidate well to support the theoretical calculations.
A means of making a downhole load-bearing casing connection, with load rating above 200 tons and pressure differential rating of 2,700 psi gas, has been demonstrated. A connection design has been developed that connects directly to a cut casing stub, and therefore does not require back off of casing connections.
The case history presented shows that this technique of connecting tubulars in a well bore has application in remedial work on older or damaged completions, and also as contingency for new wells where a casing string may not reach TD due to differential sticking, swollen shales etc.
Further development of the technique of direct high-pressure expansion is discussed in relation to the design of ultra-deep and slim wells, where the technique employed may broaden the options for completion design, particularly in HPHT wells where the design envelope is challenging.
Development of a Screening System to Identify Deepwater Wells at Risk for Annular Pressure Build-up
Authors: Sathuvalli U. B. , Payne M. L. , Pattillo P. D. , Rahman S. , Suryanarayana P. V. 
Published: December 2007

Abstract
Annular Pressure Build-up (APB) in wellbore annuli is a problem in most deepwater wells. If APB induced loads compromise string integrity, the selection and design of a suitable APB mitigation strategy must be pursued. The calculations required for such analyses can be tedious, since a number of cases to identify key variables and "what-if" scenarios must be evaluated. Though analytical techniques required to evaluate APB and mitigation strategies are well understood, there is a need to perform these calculations quickly and reliably.
This paper discusses the development of a procedure and computational tool to determine deepwater wells at risk for APB. Though the tool structure is simple enough for spreadsheet implementation, it is technically and numerically rigorous. The role of the tool is illustrated with a case study where one or more mitigation strategies are necessary for well integrity. Details required to build such a tool, i.e. assemble the matrix of APB equations, develop quantitative models of mitigation strategies, and, most importantly, create a mathematical representation of a wellbore for use in the APB algorithm, are presented in the appendices. Finally, for the first time, the role of formation elasticity (i.e. the annular boundary conditions) on APB is examined by using equations that treat the formation as an elastic foundation.
Managed Pressure Drilling in Marine Environments – Case Studies
Authors: Hannegan Don M. 
Published: December 2007

Abstract
In around 340 BC, Plato wrote in The Republic, "Necessity, who is the mother of invention." Such is the case of a relatively new offshore drilling technology – Managed Pressure Drilling (MPD), a technology that addresses a litany of issues associated with drilling into "trouble zones".
Drilling-related issues such as excessive mud cost, differentially stuck pipe and resulting well control situations associated with loss circulation issues contribute to defining the necessity for a more efficient drilling technology. A kick-Loss scenario, which may occur when drilling into narrow downhole pressure environments, is another. Drilling-related flat time further indicate a necessity for a technology that enables more precise wellbore pressure management when drilling in marine environments.
These challenges to economic drill-ability apply to a growing percentage of offshore prospects for oil and gas, becoming more troublesome and costly with water depth. These challenges have one thing in common - they all may be addressed to some degree or other with more precise wellbore pressure management. Dictated: A technology that offers more precise pressure management with fewer interruptions to drilling ahead.
Real-Time ECD Simulation and Management Using a Remote Operations Center
Authors: van Oort Eric , Roy Sanjit , Zamora Mario , Toups Bret 
Published: December 2007

Abstract
Economically marginal wells, sometimes critical in their own right, can require tight equivalent-circulating-density (ECD) control just like their expensive HTHP, deepwater, and extended-reach counterparts. Limited budgets or well conditions, however, may preclude use of pressure-while-drilling (PWD) technology. This paper presents a case history where the ability to manage ECDs from within a remote, real-time operations center was tested on an HTHP well in the Gulf of Mexico and subsequently on a low-budget land well in the western United States. Field results demonstrate that it is possible to obtain high-quality ECD information without running PWD tools.
Special hydraulics software run at the operations center provided virtual sensors for equivalent circulating and static densities while drilling, tripping, and running casing. PWD data was available for comparison on both wells, except for the lower intervals of the HTHP well. In the latter well, high formation temperatures exceeded tool limits, so it was necessary to rely strictly on computer simulations for ECD management.
The primary purpose of this paper is to critically review these case histories to help assess the spectrum of opportunities for ECD management from remote operations centers. Field results, operational issues, planning requirements, training efforts, and technical and business drivers are among the topics that will be presented and discussed. Lessons learned and recommendations for future efforts are also included.
Successful Integration of Electromagnetic MWD-LWD Technology Extends UBD Operation Envelope into Severely Depleted Fields
Authors: Wind Jan , Weisbeck Denis , Culen Martin 
Published: December 2007

Abstract
The advantages of electromagnetic (EM) telemetry are not always considered when planning drilling operations. This paper examines the execution and lessons learned from the successful implementation of EM-MWD and LWD technology in an underbalanced horizontal drilling application in the Nimr field in Oman.
Some of the highlights included the highest daily footage drilled underbalanced, enhanced geosteering through the use of real-time LWD information and significant rig time and cost savings when compared with operations using mud pulse (MP) telemetry.
The most significant accomplishment was the demonstration that these wells can be drilled with real-time LWD measurement using standard EM transmission. This is important because it enables underbalanced drilling (UBD) using drillpipe injection with high gas rates, which expands the envelope for UBD operations to severely depleted reservoirs.
Petroleum Development Oman's (PDO) standard UBD practice in depleted reservoirs is to avoid severe formation damage and to use real-time LWD for geosteering horizontal multi-lateral wells in the most productive sections of the reservoir. Prior to this well, the application of UBD was generally accomplished using concentric casing gas injection as it was believed that the only viable means of obtaining LWD information was through mud-pulse transmission.
The application of EM, LWD, and UBD described in this paper represents an important advance in a stepwise progression for improving PDO's ability to exploit mature reservoirs, especially those that are severely depleted.
Running Casing Faster and Safer with Less Cost, Using Existing Rig Crew: A Case Study
Authors: Moussa Noureddine Hadj , Warren John , Roling Ron 
Published: December 2007

Abstract
A new safe and cost effective method of running casing has been employed, using the existing rig crews instead of specialized casing crews. By using a casing running tool connected to a top drive system, the drilling crew can run entire strings of casing more efficiently and for less cost than with conventional casing crews and equipment.
The Role of Risk Management in Development and Application of New Technology
Authors: Levett B. A. , Brandt H. 
Published: December 2007

Abstract
Exploration and development drilling continues to move toward deeper targets both in terms of water depth and reservoir depth. It is characterized by significant costs, technical challenges and high consequences of failure. Significant costs can easily turn a discovery into a marginal field, making it unattractive to pursue. Technology plays an important role in reducing drilling time and well cost. Application of technology (proven technology applied to new areas and new technology) has considerable potential, but also has high risk exposure. A risk management process becomes essential for successful drilling programs. Key components of risk management as it relates to drilling applications include identification and management of well control risks, economic risks associated with non-productive time, unplanned events and equipment reliability, and qualification of technology prior to application. In most situations, capital expenditure and operational expenditure are used to determine which path a project should take. A third component, expenditure associated with risk, is not often considered and yet can drastically alter the overall expenditure of a selection to the point of making it a bad choice. Case studies are presented in this paper of application of risk management to several different areas including active heave drawworks, dry tree completions and subsea completions. In all cases the application of risk management reduced risks in terms of both economics and safety. It is imperative to manage risk and uncertainty in the application and development of new technology in order to keep the new frontiers of drilling economically viable.
U-Tube Wells – Connecting Horizontal Wells End to End Case Study: Installation and Well Construction of the World's First U-Tube Well
Authors: Lee Dean , Hay Richard , Brandao Fernando 
Published: December 2007

Abstract
Although wellbores have been intersected before — both through planned intersections for the purpose of well control and through unplanned wellbore collisions — they have not been intersected for the purpose of actually joining their wellpaths to effectively create one smooth continuous conduit from one surface location to another. There is just one exception: the very large conduit between England and France! The purpose of this paper is to review the planning and execution of what is believed to be the world's first planned successful joining of two such horizontal wells, with a slotted liner to casing connection in between them.
Fatigue evaluation of Drilling Risers for Harsh Environments and Ultra Deepwater Developments to Allow Optimised Riser Life and Inspection Plans
Authors: Peter J. D. , Robinson R. , Metcalfe T. J. , Storesund W. 
Published: December 2007

Abstract
Recent experiences with current drilling risers in harsh and deepwater environments have identified shortcomings in the current design standards, which require a closer review for the future. With recent improvements in analytical methods and better field data, it is now possible to develop a much more accurate understanding of riser performance than ever before.
This improved insight into riser operating behaviour has highlighted that current demands in environmental and operating requirements are now taking the current riser designs to their limits and it is important to understand those limits to establish better margins on current operations and to improve design standards to meet these demands in future.
Particular areas of concern are:
Current Design Standards for Low Temperature Operations, in particular the dependence on API 16 Charpy V Notch Standards for riser toughness requirements. The requirements for fatigue assessment criteria in the design standards and how it should be applied, to enable effective inspection and maintenance programmes to be established. Assessment of different operating parameters, which are not normally considered in design standards, but are now having significant impact on the operability of the risers. How risers should be assessed for classification purposes taking into account the above concerns.
The paper examines recent experiences in harsh environment and deepwater riser operations, which has highlighted these concerns and the limitations it has put on the operations.
Finally the paper concludes on recommendations for improvements to the current industry standards to enable further discussion and to suggest areas for development in riser design, which may mitigate some of the current issues.
Experience Using the First Commercial Pad and Probe Style Formation Tester While Drilling Service Has Led To Value Creation at the Valhall Flank Development
Authors: Roberts Ifor , Kendall Martin , Proett Mark , Siess Charley , Hveding Frode , Solbakk Tommy 
Published: December 2007

Abstract
GeoTap®, a new formation testing while drilling (FTWD) service, was introduced to the Valhall Flank Drilling campaign in May 2003. Introduction of this service was anticipated to be the most cost effective solution for gathering pressure data on these long horizontal wells. After the first well, the equipment was modified; and the rate of success increased from 20% to 90 %. As of November 2004, the service has been run in seven wells. In this paper, we review the value the service has added to the drilling campaign and also review the experience gained with the service during its first year.
The drilling environment is dynamic with hydrostatic pressure constantly changing. The new tool offers the capability to perform pressure tests in this environment with the mud pumps on or off. As an essential part of FTWD job planning, estimates are made concerning the impact of hydrostatic pressure changes and supercharging prior to logging a well. In most cases, these estimates show that pressure data gathered with this service compare favorably to other pressure measurements, such as those gathered during perforating and stimulating.
The field examples presented demonstrate the field procedures used to gather pressure measurements and the added value from acquiring this data during the drill phase. Knowledge of the reservoir pressure distribution in these wells was crucial to understanding flow dynamics across the field and optimizing well decisions. These data have also impacted perforation and stimulation procedures that would not have been foreseen using conventional wireline tests. The data have been used to optimize the drilling process by providing key information for the TD decision.
Finally, conclusions are drawn regarding FTWD technology today and regarding its future direction for the Valhall Flank drilling campaign in particular.
Predicting the Formation Fracture Gradient of Middle East Reservoirs Using Non-Parametric Optimal Transformations
Authors: Nashawi I. S. , Malallah A. 
Published: December 2007

Abstract
Proper planning and execution of deep abnormal pressure wells, stimulation treatment and reservoir exploitation require, among other factors, good estimates of fracture gradient. It has been demonstrated in the literature that most of the available fracture gradient correlations do not yield dependable results when exposed to data away from the geographical region where they were initially developed.
This paper presents non-parametric optimal transformations that are accurately capable of estimating the fracture gradient. The transformations are completely data-driven and do not assume any &lt;i&gt;a priori&lt;/i&gt; functional form. The model presents the fracture gradient as a function of pore pressure gradient, rock density, and depth. The data set used in the study consists of more than 21000 points taken from 16 wells drilled in seven different geologic prospects covering more than 200 square miles. The excellent results obtained from the proposed model establish a new simple tool for fracture gradient calculation that is based on readily accessible variables. The proposed model is demonstrated and validated using several examples from different fields in the Middle East. The computed results of the various cases are in excellent agreement with the measured values with an average absolute relative error of 6% and a standard deviation of 0.05 psi/ft.