bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maximizing Drill Rates with Real-Time Surveillance of Mechanical Specific Energy
Authors: Dupriest Fred E. , Koederitz William L. 
Published: December 2007

Abstract
The concept of Mechanical Specific Energy (MSE) has been used effectively in lab environments to evaluate the drilling efficiency of bits. MSE analysis has also been used in a limited manner to investigate specific inefficiencies in field operations.3,4 In early 2004, the operator initiated a pilot to determine whether the concept might be used more broadly by rig-site personnel as a real-time tool to maximize the rate of penetration. The results have exceeded expectations. The average ROP on the six rigs selected for the three-month pilot was increased by 133% and new field records were established on 10 of 11 wells.
The MSE surveillance process provides the ability to detect changes in the efficiency of the drilling system, more or less continuously. This has improved performance by 1) allowing the optimum operating parameters to be identified easily, and 2) providing the quantitative data needed to cost-justify design changes to extend the current limits of the system. MSE analysis has resulted in redesign in areas as diverse as well control practices, bit selection, BHA design, makeup torque, directional target sizing and motor differential ratings. The use of MSE surveillance is a key feature in a family of well planning and operational practices that are referred to as the ExxonMobil Fast Drill Process (FDP). These are now being introduced in other operating areas throughout the global organization.
The Pitch of Helically Buckled Pipe
Authors: Mitchell Robert F. 
Published: December 2007

Abstract
The most fundamental question about helically buckled pipe is "What is the pitch?" The original development by Lubinski and Woods1 used the method of virtual work to determine a specific constant pitch. Since any constant pitch will solve the buckling equations, what is special about this solution? Perhaps pipe end conditions determined the pitch? All attempts to connect a constant pitch helix to a packer or centralizer have failed2,3. Would these two different end conditions give different pitches?
Since the buckling differential equation is non-linear, it is not surprising that no other solution has been discovered. Recently, however, new buckling solutions have been found for the vertical well problem4.
Once these solutions are known, the problem of end conditions can be posed and solved. Two possible end conditions are considered in this study: a cantilever boundary condition to model a packer, and a "pinned" boundary condition to model a centralizer. For the first time, analytic solutions were found for both problems, and interestingly, both solutions converged rapidly to Lubinski's constant pitch solution a short distance from the boundary. Furthermore, these solutions are simple and suitable for spreadsheet calculations. Many of the original Lubinski calculations remain essentially correct, such as length change and contact forces. On the other hand, the bending moment near the boundary exceeds the bending moment calculated from the Lubinski solution by as much as 20%. For this reason alone, conventional pipe buckling stress analysis must be revised.
Possible applications for these solutions include the analysis of bottom hole assemblies, drill pipe, casing, and tubing. The boundary solutions are simple formulas, suitable for spreadsheet or hand calculations.
A Method for Formation Temperature Estimation Using Wireline Formation Tester Measurements
Authors: Zazovsky A. , Haddad S. , Tertychnyi V. 
Published: December 2007

Abstract
Production data show that early estimates of formation temperature are often inaccurate. Fluids arriving at production facilities can have temperatures that are significantly different from the expected values; the difference is in part because of inaccuracy in heat-loss estimates. Moreover, the initial formation temperature estimate may also be significantly in error. The pitfalls in formation temperature predictions have great impact on the effectiveness of flow assurance, well completion, and production facility design and performance. Usually formation temperature is estimated from openhole and cased hole logs, slickline temperature measurements, or stabilized wellbore temperature measurement during sampling and testing operations.
A new method for determining formation temperature from wireline formation tester temperature measurements has been developed. Rather than being simulated, the thermal history covering the formation cooling phase is represented by a single unknown parameter—either the average wellbore temperature opposite the interval of production or the average heat flux from the wellbore into the formation. One of these parameters and the initial formation temperature are the only two unknowns to be determined from the temperature measurement data obtained during fluid production phase by wireline formation tester.
An inversion technique has been proposed for the formation temperature estimation based on the simplification of the thermal history simulation and the dimensional analysis of the forward problem.
Analytical Model for Casing Expansion
Authors: Ruan C. G. , Maurer W. C. 
Published: December 2007

Abstract
This paper presents the mechanics of expandable casings in oil and gas wells and outlines the development of a computer model based on a force and energy balance. The computer model includes effects of stress and strain, expansion-cone diameter and angle, friction between the expansion cone and expandable casing, casing length shrinkage, and expansion rate.
The model calculates changes in casing mechanical properties as expansion occurs (burst and collapse pressures) and predicts required expansion force (or liquid pressure if the expansion cone is pumped).
Examples are given that illustrate applications of the model for cone design, mechanical property evaluation, expansion force calculation (for both solid casing and sand screen expansion), and monobore design.
Model predictions have been calibrated with extensive test data and finite element analysis. Comparisons show that the model, as calibrated with real measured data, can accurately predict expansion forces and other parameters.
Challenges and Countermeasures Facing Casing Damage in Daqing Oilfield
Authors: He L. , Ye Y. , Qunyi W. , Jianwen Y. , Huilan D. 
Published: December 2007

Abstract
Casing damage is one of the most important problems influencing oilfield production. On the basis of the Daqing Oilfield characteristics, this paper analyzes the casing damage situation, shapes, horizon and characteristics of the damaged casing and discusses the harm of casing damage and the progress of casing damage mechanism. This article gives some suggestions for preventing and solving the casing damage. The result may be valuable to develop the similar oilfields.
Further Considerations of Heave-Induced Dynamic Loading on Deepwater Landing Strings
Authors: Zheng Nanjiu , Baker Jeffry M. , Everage S. DeWayne 
Published: December 2007

Abstract
The initial treatment of heave-induced dynamic loading (SPE/IADC 87152) introduced a mathematical model for estimating the dynamic axial loads imposed on a deepwater landing string by a drilling vessel's response to ocean waves. The landing string was treated as an open-ended elastic steel column with allowable variations in cross-section as a function of depth inside of a vertical wellbore.
This paper extends the investigation of heave-induced dynamic loading on deepwater landing strings to account for the mass inertia of fluid columns in the wellbore. The results presented suggest that the effect of the fluid column mass is negligible only for cases when the casing is run open-ended. For closed-end casing (especially with low clearance annuli), the resonance frequency of the landing string is lowered significantly by the fluid column, causing it to more closely match the heave excitation frequency observed for most drill ships.
Evidence is also presented to validate the original assumption that drilling vessel resonance behavior exhibits a narrowband response to ocean waves with a fundamental resonance frequency between 0.1 and 0.14 Hz (periods between 7 and 10 sec). This important assumption was based on a single drillship's MRU data and allowed reasonably accurate dynamic load approximation without having to consider high order harmonics. To validate this assumption, a spectral analysis was performed on additional heave data from several floating drilling vessels. The results are presented and suggest that the original assumption is well-founded.
Finally, the original model was calibrated with an actual landing string load case. This allowed for range specification of the model's damping coefficient, which improves the estimates of dynamic load magnitude, much like calibrating friction factors in a torque & drag model.
Technical Limit Specific Energy—An Index to Facilitate Drilling Performance Evaluation
Authors: Curry D. , Fear M. , Govzitch A. , Aghazada L. 
Published: December 2007

Abstract
This paper describes a method developed to represent the inherent drilling difficulty posed by the combination of rock properties, depths and pressures that make up a field's drilling environment, thereby facilitating comparisons of drilling performance from different fields that take account of varying rock "drillability". The method uses the concept of specific energy - the lower the specific energy in a given environment, the more efficient the drilling process. An algorithm has been developed to estimate the technical limit specific energy from wireline sonic, lithology and pressure data. This represents the lowest specific energy that can reasonably be expected for that combination of rock properties and pressures.
Data were analyzed from 10 wells, drilled in varying on and offshore locations, which were selected as good benchmarks for the performance achievable in their drilling environments. Three measures were used to represent drilling performance in these wells – total dry hole (excluding coring, logging and completion activities) days per 1,000 m, normal drilling days per 1,000 m, and rotating days per 1,000 m. These measures showed wide variations across the 10 wells, reflecting the range in drilling difficulty posed by the different geological environments. However, the rotating days per 1,000 m showed encouraging correlation when plotted against the wells' technical limit specific energies. The other performance measures also showed clear trends when plotted against technical limit specific energy. The existence of these correlations demonstrates that technical limit specific energy is a valid measure of whole-well drillability, and provides a benchmark against which other wells' drilling performance can be compared.
The performance measures for the new well are compared with the "benchmark performance" trends at the new well's technical limit specific energy, revealing whether the drilling performance departs substantially from the expectation for a well of similar drilling difficulty.
Development and Application of a 3D-Wellbore Visualization System for Hydraulics Analyses
Authors: Zamora Mario , Simpkins Douglas 
Published: December 2007

Abstract
Visualization technology has evolved into an important G&G tool to view and interpret seismic data, 3D logs, geocellular models, grids, horizons, and well placements. Directional drillers also benefit from visualizing complex placements in 3D; however, this is one of very few drilling applications that currently exists for this technology. Introduced in this paper is software that for the first time permits interactive 3D visualization of the inside of a virtual wellbore. In this initial offering, downhole drilling hydraulics and related conditions can be critically examined while navigating the well from surface to TD using a standard PC and a joystick. The new software system has application for interpreting large data sets, mitigating drilling problems, training, and encouraging collaboration among multi-disciplinary teams.
Stunning 3D perspective rendering can show internal and side projections of well tortuosity, cuttings beds, drill string (including eccentricity), annular velocity profiles, formations (texture, rugosity, and breakout), downhole engineering parameters (temperature, ESDs, etc.), and downhole tools, among others. "Intelligence" is incorporated that can direct the software to automatically find, display, and visually inspect anomalies and potential hydraulics-related problems. Simulated data are provided by an advanced hydraulics program;a real-time version is planned that also will include other key drilling and wellbore parameters. Both options are suitable for use in real-time drilling centers.
The purpose of this paper is to discuss the development, application, and opportunities of this wellbore visualization software. Special emphasis is placed on the quality and uncertainty of models, and methods used to drive the 3D graphics. The design, development, and implementation of the fit-for-purpose graphics platform also are discussed.
Using a Flexible, Expandable Sealant System to Prevent Microannulus Formation in a Gas Well: A Case History
Authors: El-Hassan H. , Sultan M. , Saeed A. A. , Johnson C. , Belmahi A. , Rishmani L. 
Published: December 2007

Abstract
Long-term zonal isolation of gas reservoirs is a difficult problem. This paper summarizes the implementation and evaluation of a new sealant system designed to overcome this problem by preventing formation of a microannulus across the gas zone. A case history of its use in a well in the United Arab Emirates demonstrates the successful application of the flexible, expandable sealant material to prevent microannulus and maintain cement sheath integrity in the production casing section.
In one well, a conventional cement slurry formulation was used for the 9 5/8-in. section. The section was then tested to 3,000 psi pressure. Cement-bond logs showed clear deterioration of cement sheath quality behind the casing. A similar result for upcoming casing sections was a concern, so the sealant was redesigned to accommodate downhole stresses across the interval. The new design, which was used in the 7- in. liner section in the same well, enabled mechanical and expansion properties to be engineered to withstand downhole stresses and minimize the debonding effect. After successful isolation in the first well, the flexible, expandable sealant material was established as standard practice in similar wells.
New Water-Based Mud Balances High-Performance Drilling and Environmental Compliance
Authors: Dye William , Daugereau Ken , Hansen Nels , Otto Michael , Shoults Larry , Leaper Richard , Clapper Dennis , Xiang Tao 
Published: December 2007

Abstract
A new water-based mud system has been successfully introduced as a high-performance, environmentally compliant alternative to oil and synthetic emulsion-based muds (OBM/SBM). Historically, emulsion muds have been the "systems-of-choice" when drilling challenging onshore, continental shelf and deepwater wells in order to minimize risk, maximize drilling performance and reduce costs. However, environmental constraints, a high frequency of lost circulation and the high unit cost of emulsion systems often negate the benefits of their use. Conventional water-based mud (WBM) offer the benefits of environmental compliance, attractive logistics and a relatively low unit cost but consistently fail to approach the drilling performance of OBM and SBM.
The new high-performance water-based mud (HPWBM) is designed to close the significant drilling performance gap between conventional WBM and emulsion-based mud systems. The system has undergone extensive field testing on very challenging onshore, deepwater and continental shelf wells that would otherwise have been drilled with oil or synthetic-based muds. This paper provides a detailed technical overview of the new system, discusses its inherent environmental advantages and presents case histories comparing performance to offset wells drilled with emulsion and conventional WBM systems.
When Should We Worry About Supercharging in Formation Pressure While Drilling Measurements?
Authors: Chang Yong , Hammond Paul S. , Pop Julian J. 
Published: December 2007

Abstract
A model is described that is capable of simulating in detail the time variation of formation pressures measured while drilling, in situations where supercharging is significant. Simulation results are shown that illustrate the variation of supercharging pressures with formation permeability, drilling fluid filtration properties, and drilling fluid hydraulics. The model is used to explore how drilling operations influence the levels of supercharging when drilling two formations, widely separated along the well trajectory, and of significantly different permeabilities. The forward simulation capability presented is believed to be a useful aid to the planning, understanding and interpretation of formation pressure measurements while drilling.
A Laboratory Investigation of Temperature Induced Sand Consolidation
Authors: Ross C. M. , Rangel-German E. R. , Castanier L. M. , Hara P. S. , Kovscek A. R. 
Published: December 2007

Abstract
Current open-hole, gravel-packed, slotted-liner completions for wells drilled in unconsolidated and weakly consolidated sandstone are relatively expensive and result in greatly reduced operational flexibility of the well. On the other hand, a novel well completion method for both horizontal and vertical wells is to cement and consolidate sand grains in situ. During this completion process, a well is cased and cemented, limited-entry perforations are shot, and high-temperature, high-pressure steam (1600 psi, 600°F) is injected to create grain-cementing precipitates. Empirical field experience (Wilmington, CA) has shown that certain high-temperature minerals precipitate preferentially near the wellbore, cementing sand grains, but without appreciably reducing formation permeability and producibility.
This study delineates the mechanisms of the sand consolidation process by duplicating in the laboratory the governing geochemical processes resulting from injection of hot, alkaline water into sand. High-pressure, high-temperature pressure vessels are packed with quartz sand according to the grain-size range observed at Wilmington. Sand packs also contain typical per-volume concentrations of concrete resulting from perforating a cased and cemented well. Analysis is made of the evolution of sand-pack pore structure that occurs as a result of dissolution and subsequent precipitation. Pore structure and precipitate characterization is determined by means of scanning electron microscope imaging and compositional analyses. Results show that hot alkaline water injected at constant rate indeed results in precipitates that cement loose grains. Casing cement plays a crucial role in that it is the source of calcium silicates appearing in various pore-lining precipitates. The laboratory investigation teaches that the conditions for effective sand consolidation are not necessarily formation specific and the process can be altered to improve cost effectiveness, flexibility, and longevity of the completion technique.
Reservoir Management of the Njord Field
Authors: Talukdar S. , Brusdal L. H. 
Published: December 2007

Abstract
The Njord Field is one of the most complex reservoirs in the Norwegian North Sea. A large number of faults, and uncertainties associated with structures, fault transmissibilities, fluid contacts, rock and fluid properties pose a great challenge for reservoir management.
The main development philosophy was to minimize uncertainties based on drilling and production/injection experiences. The uncertainty was managed to a great extent by limiting the number of pre-drilled wells. The early experiences, particularly from a horizontal well led to radical changes in the well designs. The concept of drilling high amplitude sinusoidal wells was very successful for safe penetration of all reservoir intervals in multiple fault compartments. It also eliminated the need for a large number of wells.
An active visualization assisted geosteering together with biostratigraphy was successfully applied to drill a complex three-branched well in the most faulted area of the field. Another well was drilled in an area where pressure depletion was in excess of 300 bar in some of the fault compartments.
State-of-the-art seismic interpretations have been performed on various data sets to identify and locate reservoir intervals and faults. Reservoir simulations assisted by 4D seismic have identified remaining oil pockets. A low cost solution for drilling relatively small, sparsely located infill targets using the through tubing rotary drilling technology has been considered.
Systematic reservoir monitoring through collection of various types of data, such as, PLT, RFT/MDT, tracer, production/injection, bottom hole pressure, 4D seismic, etc. has been an effective tool to devise reservoir management strategies. In addition to unique well designs, selective perforation, re-perforation, gas injection, zone isolation and infill drilling have improved the oil recovery significantly.
This paper summarizes the reservoir management challenges, techniques and technologies applied to evaluate and monitor the reservoir performance, strategy to manage uncertainty, practices for improved recovery, successes and failures.
Isubs: A New Generation of Autonomous Instrumented Downhole Tool
Authors: Desmette Sébastian , Will John , Coudyzer Christophe , Richard Thomas , Le Phi 
Published: December 2007

Abstract
The paper describes a short autonomous instrumented downhole tool (Isub) which incorporates multiple sensors (accelerometers, strain gauges, and magnetometer), a complete data acquisition line, a microprocessor, memory chips and batteries. The tool, available in three sizes (7", 9" and 10" 1/4) can be located anywhere within the BHA even behind a mud motor or rotary steerable system as its total exposed length is of 350 mm. The tool records at a scanning rate of 50 Hz (up to 250 Hz) several tens of hours (100 to 300 hours) forces, moment as well as centripetal, tangential and axial accelerations used to reconstruct the instantaneous bit kinematics (RPM, off axis rotation, side acceleration).
Due to its high scanning rate and precision (each sub is fully calibrated) on all channels, the Isub has many benefits, it offers a complete vibration diagnosis: nature (torsional, lateral, axial), amplitude (stick-slip, backward and forward whirl, bouncing), susceptibility to surface control parameters (WOB, RPM), tracking of bit efficiency and wear, and assessment of downhole equipment "real" performance: hydraulic motor or turbine (power delivered, staling events), rotary steerable system (side force, vibrations).
This paper illustrates by two examples some of the insight to the drilling response of the system such tool can provide. The data reveal the occurrence of phenomena (vibrations, motor performance) neither detected nor suspected on surface. It also captures all inappropriate drilling practices.
The analysis shows strong evidences of the tremendous potential of such tool not only to gain a better understanding of the drilling process but also to provide a non-bias measure of the drilling performance. Eventually, such tool should help in improving drilling performance and build best drilling practices rules.
Gravel Pack Placement Limits in Extended Horizontal Offshore Wells
Authors: Calderon A. , de Magalhães J. V. M. , Martins A. L. 
Published: December 2007

Abstract
Long horizontal section wells are economical requirements for heavy oil fields in deepwater environments. This article discusses the operational limits for gravel pack placement in such wells, considering the maximization of the horizontal section extension in low fracture gradient scenarios. A parametric study on the variables governing the gravel pack operations indicates that careful hydraulic design and detailed operational procedures can guarantee a successful job. Alternative strategies are proposed to extended hydraulic limits in critical conditions.