bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermally Insulated Tubing Application to Prevent Annular Pressure Buildup in Brazil Offshore Fields
Authors: Ferreira M. V. , Santos A. R. , Vanzan V.. 
Published: June 2012

AbstractHeat transfer issues in offshore wells construction and maintenance are increasing in last years. New production development scenarios are bringing challenges related to flow assurance, well construction and maintenance. Insulation projects are being considered to enable the oil and gas production. This paper presents the studies carried out in two projects of thermal insulation using VIT (Vacuum Insulated Tubing) technology and its structural and thermal evaluation using commercial software for numerical simulation.The present work aimed to evaluate VIT application in a production string to reduce APB (Annular Pressure Build-up) effects. This event happens when production flow is heating any well confined annulus causing its fluid expansion and increasing pressure inside it. In this way, annular pressure build up can lead casing collapse or burst even, in an exteme condition, production string damage. All these effects combined could lead to unacceptable well losses. VIT is uded to avoid APB effects.However, a VIT string isn’t be able to provide a smiliar collapse and burst resistance than a usual same dimension tubing string. So VIT will dominate the string installation and production constraints due its back pressure lacking. In this way production string performance evaluation is a key issue on VIT design, length and technical specification.In order to evaluate the performance of the production string designed for two Petrobras projects, several numeric simulations were performed to evaluate loads and strains on intermediate casing and production string during its installation and well production, including the APB events.In addition, the length of pipes with insulation needed to mitigate the effect of AFE was defined and a sensitivity analysis performed to define the value of the minimum apparent thermal conductivity, which would allow operation without risk to well integrity.
The Effect of Equivalent Diameter Definitions on Frictional Pressure Loss Estimation in an Annulus with Pipe Rotation
Authors: Anifowoshe Olatunbosun , Osisanya Samuel O. 
Published: June 2012

Abstract
Annular flow of non-Newtonian fluids remains a ubiquitous phenomenon in drilling operations but accurately estimating the frictional pressure loss with drill pipe rotation still poses a great challenge. Since annular frictional pressure losses increases the equivalent circulating density (ECD), it becomes imperative to accurately estimate the annular pressure loss in order to keep the ECD above the pore pressure and below the fracture gradient especially in deep offshore drilling where the pore pressure and fracture pressure are so close together.
When annular flows are encountered, a common practice is to calculate an effective diameter such that the flow behavior in a circular pipe would be roughly equivalent to the flow behavior in the annulus. This equivalent diameter definition replaces the diameter term in the friction factor, effective Reynolds number and Taylors number equations used for pipe flow thus resulting in different frictional pressure loss estimation. As a result, the selection of appropriate correlation for the respective fluids, flow regimes and putting into consideration pipe rotation has become important but has received very little attention.
In this study, the seven different equivalent diameter definitions used for estimating frictional pressure losses in an annulus were reviewed and theoretical analysis were performed on experimental data obtained from literatures to determine the effect of these definitions on wellbore hydraulics. Pressure loss ratios (PLR) which relates pressure loss with pipe rotation to pressure loss without pipe rotation weredevelopedfor each equivalent diameter definitionusing dimensional analysis techniques. These hydraulic models combined with conventional frictional pressure loss estimation were tested with experimental measurements to determine the model with an equivalent diameter definition that best predicts frictional pressure losses for power law fluids.
Modeling Dynamic Behavior of Bottom Hole Assemblies Containing an Underreamer
Authors: Ishak G.. , Daily J.. , Miska S.. , Mitchell R.. 
Published: June 2012

Abstract
Reaming while drilling can be a more economical drilling technique than conventional drilling. Downhole failures can occur for a variety of reasons, and failure as a result of excess dynamic loading on the bottom hole assembly (BHA) components may be the most mysterious. One of those mysteries is the static and dynamic distribution of axial load between the bit and the reamer. This paper presents an approach using the explicit finite element method to model the static and dynamic interactions between the bit, the reamer and the formation of the BHA.
The results for axial displacement from the explicit finite element method are compared to theoretical results for a selfweighted column. Also, the axial vibrations are compared to the theoretical natural frequencies. Once the comparison showed the explicit FE method gives the same theoretical results, the model is expanded to better reflect actual downhole conditions. The model includes a bit and a reamer from which the interaction can be studied with an emphasis on axial loading. A weight dependent velocity boundary condition is used to model formation penetration of the bit and reamer. This models the relationship between the axial load on the reamer and the bit. This so-called drill-ahead model can be used to better understand the dynamics of the BHA.
Results from this study show the amplitude of the axial oscillating force on the reamer was greater than that of the force on the bit. Drilling with a more aggressive reamer will decrease the side forces on these components for the case studied. In addition, for a change of load at the top of the model, the reamer can take more of the transient load than the bit.
A New Buckling Severity Index to Quantify Failure and Lock-up Risks in Highly Deviated Wells
Authors: Menand S.. 
Published: June 2012

AbstractBuckling of tubulars inside wellbore has been the subject of many researches and articles in the past. Evidences in the laboratory and in the field have shown that existing buckling criteria (sinusoidal and helical buckling) have to be challenged, as they fail to predict the onset of buckling phenomenon in complex or unconventional wells drilled today. Indeed, existing buckling criteria assume generally that the wellbore is idealistically perfect without any dog legs. Recent advancements in drillstring mechanics modelling has demonstrated that dog legs, friction and rotation affect greatly the buckling phenomenon. Buckling does not imply necessarily failure neither lock-up, but indicates the onset of a condition that may generate poor drilling performance that could lead to failure or lock-up. In this paper, one proposes a new buckling severity index that quantifies the severity of the buckling phenomenon enabling drilling engineers to take appropriate decision.A fully validated numerical buckling model has been used to derive a new buckling severity index based on the risk of drill pipe failure or lock-up. This index ranges from 1 for acceptable buckling condition with low risk of failure, to index 4 for severe buckling with high risk of failure or lock-up. This new buckling severity index has been compared to well-known sinusoidal and helical buckling loads in a few case studies, and demonstrates that past buckling criteria should be used very cautiously.This paper proposes an update of past conventional buckling criteria in recommending a new buckling severity index that enables to quantify the risks of failure or lock-up in unconventional and deviated wells. These new results presented in this paper should improve significantly well planning and operational procedures to drill and operate increasing complex wells.
Anomalous Behaviors of a Propagating Borehole
Authors: Perneder Luc , Detournay Emmanuel 
Published: June 2012

Abstract
This paper uses a novel directional drilling model to explain seemingly anomalous behaviors of the evolving geometry of a borehole. The two cases of a BHA without and with a push-the-bit RSS are considered.
The directional propagation of a borehole essentially depends on the bending of the BHA, which is constrained to deform within the borehole, and on the interaction between the drill bit and the rock formation. The directional model is used to illustrate, through theoretical examples, the consequence of the interrelation between these two elements of the problem. Also, a small set of dimensionless parameters governing the behavior of the directional drilling system is derived. They contrast properties of the bit/rock interface laws with those of the BHA.
Resilient Lost Circulation Material (LCM): A Significant Factor in Effective Wellbore Strengthening
Authors: Savari Sharath , Whitfill Donald L. , Kumar Arunesh 
Published: June 2012

AbstractHigh resiliency graphitic carbon lost circulation material (LCM) is one of several graphitic materials that achieve varied success. Effectively controlling loss of circulation (LC) is more than just selecting LCM and requires an engineered approach. Particulate LCM like ground marble, graphitic carbon and cellulosic fibres have been widely used but careful consideration should be given to how these materials are combined based on fracture types. Induced fractures created when the equivalent circulating density (ECD) exceeds the formation fracture gradient or during wellbore strengthening applications, could be "pressure-sensitive" as reported in fracture closure studies (Dupriest 2005). Resilient graphitic carbon (RGC) has many unique properties (Whitfill 2003) that can be exploited in lost circulation scenarios.Laboratory methods developed to characterize the resiliency of different graphitic carbons are presented, and the lack of resiliency of other LCM is demonstrated. RGC also imparts resiliency to other LCM combinations (Kumar 2010). Resiliency associated with RGC can be enhanced in an LCM combination that exhibits a granular nature, rather than forming a solid plug. RGC also imparts crush resistance to other more brittle LCM and can help reduce attrition, thereby retaining particle size for effective wellbore strengthening, while also acting as a solid lubricant.RGC is manufactured in a proprietary two-stage furnace process that produces 99.9% carbon content. It is conductive material with no magnetic properties, so it does not interfere with logging tools (e.g., density and neutron) and other downhole equipment. RGC is suitable for use in reservoir sections because it is completely inert and may be combined with acid-soluble ground marble to allow flow back.The paper includes field and laboratory data that validate RGC characteristics related to resiliency, lubricity, resistance to attrition, and compatibility with downhole tools, making it a versatile material for most LCM combinations for LC control and wellbore strengthening applications.
Modeling Dynamic Shock Loads for High-Pressure/Deep-Water Tubing-Conveyed Perforating Operations in the Gulf of Mexico
Authors: Giunta Rick , Le Cam , Schoener-Scott Martin , Anderson Ryan , Glass Joshua 
Published: June 2012

Abstract
Good perforating design is essential in maximizing the value that can be pulled from the reservoir. Poorly-planned and/or executed perforating strategies in high-pressure, deep-water wells can easily increase operational costs and reduce production and revenue streams.
With the increased demand for oil and gas over the last decade, operators have been forced to explore deeper to find the most prolific reservoirs to meet this growing need. In the U.S. Gulf of Mexico, these deep-water opportunities have required constant improvements to equipment and services to increase their technical capabilities for performing in more critical environments while minimizing non-productive time (NPT). Higher shot densities, propellants, larger perforating guns, electronic firing heads, shrouded assemblies, and dynamic shock modeling have been used to meet these new challenges.
A major problem with these deep wells is the increased cost it takes to develop them. The use of more powerful perforating systems to increase flow area is required to maximize well productivity and recoup this cost. With the use of such systems comes the additional explosive load and the difficulty in predicting dynamic wellbore behaviors that could cause tubulars to burst, collapse, bend, buckle, and shear, as well as tubing to move excessively, packer seals to fail, and packers to unset as perforating guns are detonated.
Understanding and mitigation of dynamic events at gun detonation, in addition to solid loading imparted to the tubulars, packers, and other completion hardware in the perforating assembly, were needed if the industry was to continue exploring new frontiers with complex challenges. A high-confidence level was needed to use these larger gun assemblies to go forward with these well completions without incurring NPT.
This paper discusses a successful execution of a high-pressure, deep-water shoot-and-pull job with a custom-designed bottomhole assembly to address casing integrity challenges and the dynamic shock-modeling software program that evaluates the mechanical integrity of all well components.
Challenges Associated with Drilling a Deepwater, Subsalt Exploration Well in the Gulf of Mexico: Hadrian Prospect
Authors: Moyer Mark C. , Lewis Scott B. , Cotton Mike T. , Peroyea L. Miles 
Published: June 2012

Abstract
The Hadrian-5 prospect in the United States (US) Gulf of Mexico’s Keathley Canyon 919 block was drilled by the operator in ~7000-ft water depth as one of the first Gulf of Mexico wells drilled after the deepwater moratorium. This exploration well was permitted under the new regulatory requirements of the US Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE). These new requirements included additional blowout preventer (BOP) certification and testing, incorporation of selected API recommended practices, and certification of the well design by a registered professional engineer.
In addition to the well design regulations, BOEMRE required operators to calculate a worst-case discharge scenario and develop plans to contain that scenario. Well containment plans were developed that included the newly-formed Marine Well Containment Company’s (MWCC) response capabilities.
The well was drilled between March and August of 2011 to a total depth (TD) of 19,631 ft and encountered several hydrocarbon intervals that were safely managed. The rig selected for this well was the dynamically-positioned (DP), Maersk Developer semisubmersible.
This paper describes the planning, permitting, and execution of this challenging well. Topics covered include:
New permitting requirements for federal waters in the US Worst-case discharge scenario and impact on casing design Elimination of trapped annular pressure via well design Minimizing vibrations in the tuff formation of the Hadrian mini-basin Managing the uncertainties associated with sub-salt formation pore pressures Drilling and casing mobile tar zones
The well was drilled and evaluated in a safe manner with no significant incidents even though the geologic formations encountered were different than predicted.
Efficiency of Removing Filter Cake of Water-Based Drill-in Fluid Using Chelating Agents Utilizing a CT Method
Authors: Elkatatny S. M. , Nasr-El-Din H. A. 
Published: June 2012

AbstractHydrochloric acid, organic acid, or a mixture of these acids is used to remove filter cake, which consists mainly of calcium carbonate. However, the use of these acids in horizontal and deep wells has some major disadvantages, including high and uncontrolled reaction rate and corrosion to well tubular. To overcome these problems, chelating agents are used in oil and gas wells.Extensive lab studies were done to determine: 1) the compatibility of various chelates with α-amylase at different pH values, 2) the optimum pH that should be used to remove filter cake, 3) the efficiency of filter cake removal using a modified HPHT filter press, 4) the return permeability of sandstone and limestone cores, and 5) assess the potential of formation damage using a computer tomography scanner. All of these tests were conducted at temperatures up to 225°F.The results obtained showed that chelate solutions, GLDA (pH of 3.3 - 13) and HEDTA (pH 4 and 7) were incompatible with α-amylase solutions over a wide range of temperatures. At high pH, various chelates had removal efficiency of 40% and retained permeability of 30%, which indicated formation damage. To solve this problem, 20 wt% of the chelating agents at low pH (3.3 - 4) were used to remove the filter cake without the enzyme stage. The results obtained showed that the retained permeability increased to 85% for limestone cores and 110% for sandstone cores. The removal efficiency of the filter cake was 100% for limestone and sandstone cores. CT results showed that no formation damage was observed when using chelating agents as a breaker to remove the filter cake.
Wireless Reservoir Surveillance In Deepwater Completions
Authors: Williams Brock , Brough Brent 
Published: June 2012

Abstract
Deepwater developments are very high cost ventures in complex reservoir environments. Acquiring insight into the reservoir inflow distribution and location of water inflow using conventional technology, such as production logging tools, is very problematic in the deepwater environment where wireline intervention into live wells is a major risk and cost.
Intelligent chemical tracers are an emerging technology that provides insight into the inflow distribution without intervention operations or major alterations to the completion design. The tracers consist of unique chemical compounds that are combined with unique polymer formulations into a matrix that resembles strips of plastic. The matrix is designed to release the tracer when contacted by the target fluid, either oil or water.
The matrix strips are deployed with the initial completion installation at strategic locations in the completion so that fluids entering the completion contact the matrix. At the surface, samples of the produced fluid are acquired and analyzed for the presence and concentration of each unique tracer that has been deployed in the completion. The concentration data is plotted vs time or produced volume. Analysis of these plots can yield answers to very valuable reservoir management questions such as:
Are all the intervals producing? What is the relative contribution of each interval? Where is water break-thru occurring?
Deepwater completions are frequently completed with sand screens. The typical sand screen design contains spaces where the tracer can be integrated without any changes to the design. If the screen design is not readily compatible with the matrix strips, specially design tracer carrier mandrels can be added to the completion.
The passive nature and very low risk of deploying this technology is very attractive in deepwater wells.
This paper reviews the fundamentals of intelligent tracer technology, methods of integration into deepwater completions and some field examples previous deployments.
Modeling of Axial Vibrations to Allow Intervention in Extended Reach Wells
Authors: Wicks Nathan , Pabon Jahir , Auzerais Francois , Kats Roman , Godfrey Matthew , Chang Yong , Zheng Andrew 
Published: June 2012

Abstract
There are a significant number of extended reach wells that cannot be effectively intervened to total depth due to tubing string lock-up. If the horizontal section of the wellbore is sufficiently long, the axial compressive load needed to convey the tubing into the wellbore will cause the tubing to buckle. Buckling initiates in a sinusoidal mode and progresses to a helical mode. Once the tubing buckles helically, the string quickly locks-up due to increased normal forces and frictional interaction with the wellbore. We have developed an innovative technique to model extension of tubing conveyance in deep wells.
Several commercial vibration devices attempt to extend intervention depths in extended reach wells. One of the primary modes of vibration employed in these devices is axial. We developed a simulation tool to enhance understanding of how axial vibration devices extend reach. In the first section, we introduce a 1D finite rigid body dynamic model. This computational tool models the propagation of axial excitation in the presence of borehole frictional contact. A Coulombic dry friction law describes the interaction between tubing and borehole wall. 3D static computations precompute static axial loads and contact forces that serve as inputs to the 1D model. This allows the user to predict the behavior in complex 3D wellbore trajectories and to simulate several dynamic scenarios in a matter of minutes. In the second section, the behavior of axial excitation in the presence of frictional contacts is explored with the model. Simulations predict the distance of axial vibration propagation along a tubing string in a wellbore. A simple relationship is postulated that captures the axial wave propagation length as a function of axial excitation and tubing/borehole parameters. Modeling results demonstrate a mechanism by which axial vibration can extend reach. Synthetic case studies show the possible reach extension for prescribed axial load excitations. Results from a scaled experimental setup demonstrate the mechanism seen in the simulations.
Careful Planning and Application of an Asymmetric Vibration Damping Tool Dramatically Improves Underreaming While Drilling Performance in Deepwater Drilling
Authors: McCarthy John , Kabbara Alan , Burnett Timm , Forster Ian 
Published: June 2012

Abstract
This paper demonstrates how Forward Synchronous Whirl (FSW), when induced in an underreaming while drilling BHA through the application of an Asymmetric Vibration Damping Tool (AVDT), substantially reduces both stick-slip and lateral vibrations and significantly improves drilling performance. The physics of operation, pre-job planning and modeling, followed by a thorough examination of run data and comparisons to offset wells will be documented and quantified.
The performance of underreaming while drilling assemblies in long salt sections, as well as in pre-salt environments around the world has improved considerably in recent years. However, down-hole vibration still limits rates of penetration and overall drilling efficiency. Often, these long salt sections comprise the most challenging intervals of a deepwater well.
A major development project in the Green Canyon section of the Gulf of Mexico contains wells with hole sections exceeding 9,000 ft in length through salt, and into the pre-salt. In order to evaluate the potential benefits of FSW, an AVDT has recently been added to the drilling assembly while keeping all other variables constant (rig, bit type, BHA, etc).
The results showed that overall penetration rates increased by more than 50% and Stick-Slip (SS) vibration reduced by more than 75%. While there was a substantial across-the-board reduction in vibration and an increase in ROP, the benefits of the AVDT were recognized most in the portion of the hole section where elevated vibration levels typically cause a reduction in ROP as energy is lost to vibration (near the base of salt).
With the addition of the AVDT there was little to no increase in SS, and no decrease in ROP. In fact, on one of the wells that used the AVDT, the final 2,500 ft of the 9,000 ft section was drilled 83% faster than the closest offset (178 fph vs. 97 fph), with 90% less SS vibration. Of the five wells analyzed, three were without the AVDT and two were with. All of the runs in question were with a 14 1/2"-16 1/2" underreaming while drilling, rotary steerable drilling assembly.
This novel approach has wide-spread application in global deepwater basins, particularly in vibration-prone wells. This paper demonstrates how the technology is being applied effectively, and provides a platform for further application.