bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterizing Drilling Applications and Bit Designs Using Common Responses Improves Bit Selection Outcomes
Authors: Russell S. Craig , Vempati Chaitanya 
Published: June 2014

Abstract
This paper describes methods to relate drilling applications and PDC bit designs to a comprehensive set of common responses, or behaviors. The responses are quantifiable, measurable, and relatable to an audience with a wide range of technical expertise. The methods improve bit selection outcomes by focusing on application requirements in light of bit performance capabilities instead of traditional methods focusing on bit features such as cutter size, blade count, and gage length.
The common drill bit responses described in this paper are aggressiveness, cleaning efficiency, lateral stability, torsional stability, side cutting aggressiveness, bit durability, cutter abrasion resistance, cutter impact resistance, and cutter thermal stability. Technical methods were developed to characterize drilling applications and bit designs independently for each response. The heuristic application characterization methods draw from proven knowledge and a broad base of expert experience. The empirical bit characterization methods are derived and validated from more than a decade of laboratory testing, field performance, and computer simulations.
The methods are demonstrated using a software tool that captures application requirements and searches for suitable bits in a comprehensive bit design database. A multi-parameter fit function returns a sorted list of all bits in descending order of their match to application requirements. The optimum bit is then selected by performing a more thorough response-by-response comparison. A case study is presented to demonstrate the functionality of the system. The results yield an improved understanding of the application, resulting in faster and improved bit selection.
The common response approach described in the paper is a breakthrough method to continuously improve bit selection by driving greater fundamental understanding of application requirements and bit capabilities. The common response terminology enables easier communication between users such as geologists, design engineers, field personnel, and drilling operators. In addition to matching bit designs to application requirements, the approach also enables efficient application and bit comparisons. Furthermore, the system framework is sustainable as technology evolves and application priorities change.
First Application of Turbodrill and Hybrid Bit to Optimize Drilling Times in Cretaceous Formations with High Chert Content in Mexico South Region
Authors: Varela R. , Guzman F. , Cruz D. , Atencio N. , Iturrizaga F. , May R. , Solano R. , Perez R. 
Published: June 2014

Abstract
This paper highlights the design, execution, and evaluation of the first application of turbodrill and hybrid bit to drill cretaceous formations with up to 40% chert content in Mexico South region. The complex cretaceous formations in the Terra field presents many drilling challenges: mud losses, gas influxes, hard [Unconfined Compressive Strength (UCS) 15 – 30 ksi] and abrasive formations, difficulty building inclination, low rate of penetration (ROP) requiring many runs of 8-½" tungsten carbide insert (TCI) bits.
The goal of a new drilling system application was to reduce trips for TCI bit changes due to drilling hours limitations, optimize flat times, reduce rotary steerable system (RSS) failures, deliver a wellbore with minimal tortuosity to enhance wellbore evaluation and running liner operations, and eliminate the risk of fishing for lost cones.
To meet these objectives the use of turbodrilling and hybrid bit technologies was evaluated. Hydraulic simulations were run to determine if the mud pumps could deliver the required hydraulic power to the turbine, a drill string design was performed to avoid fatigue failures and increase on-bottom rotating hours in a high temperature environment, directional requirements were analyzed to estimate the dogleg severity (DLS) in carbonates with chert nodules to be able to reach the proposed well objective.
The turbodrill and hybrid bit application drilled 1240 ft, which is the longest run in the field eliminating two trips when compared with TCI bit runs. The turbodrill application successfully built inclination and turned the wellbore at the planned DLS. Additionally, increased service life of the managed pressure drilling (MPD) rotary head and top drive washpipe was observed. Casing wear was reduced due to the low drill string revolutions per minute (rpm) on surface which was corroborated with the low amount of steel recovered in the shale shakers magnets. Trips to surface were without drag and 7" liner was run immediately after logging, eliminating a wiper trip.
The Terra field has an aggressive development plan and lessons learned from this application will reduce drilling times and meet regional objectives to boost production from hard carbonates reservoirs. Horizontal wells are now being drilled, turbodrills and hybrid bits demonstrated to be viable solutions for this technical challenge in southern Mexico region.
Effect of Temperature on the Compressive Strength of Eagle Ford Oil Shale Rock: An Experimental Study
Authors: Emadi Hossein , Soliman Mohamed Y. , Samuel Robello , Harville Don , Gamadi Talal D. , Moghaddam Rozbeh B. 
Published: June 2014

Abstract
Although many shale oil wells have been drilled recently in the Eagle Ford shale oil field, wellbore stability problems in the shale oil reservoirs have not been fully understood. During drilling, fracturing, and production operations, the wellbore temperature is not constant but varies during these operations. This temperature fluctuation results in thermal cycling which tends to alter rock physical properties such as compressive strength, Young's modulus (E), and Poisson's ratio (ν), and consequently, result in wellbore stability problems. Wellbore stability problems are one of the most costly problems that can occur during drilling operations, especially in unconventional reservoirs. These problems include but are not limited to tight holes, pipe sticking, fishing, sidetracking, and well abandonment. Since the majority of wells are drilled horizontally in shale oil reservoirs, the likelihood of wellbore stability problems is dramatically increased. Thus, to have more efficient and effective drilling operations through these formations, a better understanding of their properties as well as the effects of drilling conditions on rock properties such as compressive strength, Young's modulus (E), and Poisson's ratio (ν) are required.
Not many experiments have been performed to investigate the effect of temperature on sedimentary rocks' properties such as compressive strength. Some experiments have been conducted to assess the effect of temperature on shale rock samples, since shale oil rock samples are quite different from common shale rock samples, the results cannot be equally applied to shale oil and shale gas formations.
For this study, the mineralogy of shale oil core samples from the Eagle Ford field was determined. To simulate actual well conditions a High Pressure High Temperature (HPHT) setup was built and used which let us apply different axial and radial confining stresses, equivalent formation pore pressure, and drilling fluid wellbore pressure. The experiments were conducted under elevated temperatures to better mimic real drilling operations. Saturated shale oil core samples from the Eagle Ford field were tested under various temperatures including reservoir temperature. We also performed Unconfined Compressive Strength (UCS) tests to investigate the effect of temperature on the compressive strength of the core samples. The experimental setup was modified to accommodate five Linearly Variable Displacement Transducers (LVDTs) to measure Young's Modulus (E) and Poisson's ratio (ν). Various experiments were run to quantify the effect of temperature on the rock compressive strength, E, and ν. Experiments have shown a distinct change in the mechanical properties of the rock. These effects will be discussed in details.
Case History: Casing Collapse During Concentric Drilling Operation Leads to New Casing Design Approach for HP/HT Wells with Low Reservoir Pressure and/or N2 Injection
Authors: Medina Mauricio Güiza , Bedino Henry , Sierra Sebastian , Scagliarini Stefano , Romero Daniel , Rocha Raphael , Rosas Reginaldo Rodriguez 
Published: June 2014

Abstract
This paper describes the events leading to the collapse of a 9 7/8" liner over a 7 5/8" casing while drilling a depleted fractured reservoir (high inclination, 150°C BHST) using the concentric injection technique and Managed Pressure Drilling (MPD) in well "A" in the South of Mexico. It also illustrates the investigation process conducted aimed at the identification of the potential failure scenarios. Finally, a new casing design approach for wells under these challenging conditions based on limit state design and deterministic load estimate has been developed and implemented as a result.
Dynamic Modeling of Gas Distribution in the Wellbore During Kick Situations: The Solutions
Authors: Gruber Claudia , Spoerker Hermann F. , Brandstätter Wilhelm 
Published: June 2014

Abstract
For decades, well control models have been based on the assumption of a more or less single-phase "gas bubble" present in the annulus and slowly migrating upwards after shut-in. While this approach satisfies straightforward volumetric well control aspects, it ignores solution and chemical reaction-kinetic effects. Especially when investigating sour gas (i.e. hydrogen sulfide) influxes into high-pH drilling fluid systems, the prediction of actual downhole pH development during shut-in and well-killing operations is of prime interest when deciding on potential damage to high-strength steel drill string components (&gt; 110 ksi tensile strength) due to sulfide stress cracking (SSC). Several previous publications (Spoerker et al 2008, Spoerker&Tuschl 2010, and Spoerker et al 2012) have presented the progress of a multi-year research project dedicated to numerical modeling of the entry, distribution and upward movement of gas kicks in the wellbore and the impact of sour gas influxes on high-strength steel drill string components. These numerical simulations shall form the basis for subsequent modeling of the chemical reaction kinetics taking place in the wellbore and resulting in a buffering of the molecular hydrogen against the high-pH drilling fluid. Such chemical reaction kinetics modeling requires sound understanding of the active surfaces between the phases (phase interface area), the amount of energy in the system (thermal and kinetic energy due to the flow and fluid mixing characterictics) and the time available for the reaction to take place before any "native" reservoir fluid actually comes into contact with the steel surface. This paper presents the conclusions from this five-year research project and indicates directions for potential future research.
The Drilling Business Model: Driver or Inhibitor of Performance and Innovation
Authors: de Wardt John P 
Published: June 2014

Abstract
The drilling business model has recently become the "elephant in the room" as drilling systems automation advances seek an integrator and technology / performance enhancements seek rewards. The day rate model has been adapted many times over the life of the industry but none of these adaptions has prevailed.
The business model entails a number of key aspects that drive business behaviors in the supply chain; control, liability, risk, revenue. Some companies have the approach that the operations team drives the contracting of suppliers while others draw the whole process under supply chain for process control and pricing leaving the delivery of value often in significant doubt.
This paper describes many of the business model adaptions created over the past 70 years from footage and turnkey through Integrated Project Management and Production Enhancement Contracts. Recently, actions and intentions have surfaced to transpose roles within the drilling supply chain to overcome resistance to change and improve financial performance (vertical integration by operators). This paper makes observations on the various forms of contract and various roles in the supply chain. The conclusions outline a blueprint for developing a business model that can drive performance and innovation throughout the supply chain.
Discussing the current business models and opening the industry to development of more appropriate models has extremely high value and impact. It is a topic often raised and often left un-debated. If a new business model is broadly adopted it will change roles, performance, technology application and revenues throughout the supply chain. Awareness of this potential change will be extremely important to managers and engineers in the drilling business.
Effective Hydraulic Modeling and Field Data for Deepwater Horizontal Well with Low Drilling Margins in an Unconsolidated Formation
Authors: Mohan Raj , Boswell Betsy , Oyler Ken , Lim Kim , Luyster Mark , Williford Mike , Collins Natalia , Cheaney Richard 
Published: June 2014

Abstract
Effective hydraulic modeling to predict the equivalent circulating density (ECD) was highly critical for successful drilling of a pilot well in a deepwater development in the Gulf of Mexico. The drilling objectives included linking three reservoirs, divided by moderately thick shale at relatively high dip while upholding the properties between relatively narrow drilling margins. This difficult drilling environment mandated intensive reservoir drill-in fluid maintenance practices with specific focus on rheology, density, and optimization of bridging materials while reducing the incorporation of acid-insoluble solids.
The pilot, Well B, is one of a handful of horizontals drilled in ultra deepwater shallow BML, having over 2,000 feet lateral, that was successfully drilled in challenging 8,257 feet of deepwater in the Paleogene reserve at a shallow depth of 2,300 feet TVD below the mudline (BML) and the first well to be produced in this reserve development. Due to the shallow depth from the mudline and soft sediments, the drilling margins were extremely low – 0.7 lb/gal (i.e., 250 psi); thus wellbore stability analyses were critical in order to avoid unanticipated losses to formation, losses to mudline, influxes or borehole collapse. Despite the limitations of available offset data used as an analog, the pore pressure and geological fracture gradient were known. However, in comparison to offset Well A (3,800 ft BML) with pressure margins 450 psi, Well B realized a significantly reduced operating pressure window and shallower depth BML. The ECD, equivalent static density (ESD), downhole pressure, and flow rate were carefully monitored to enable drilling within the established operational window and increasing the success of attaining total depth. The meticulous monitoring was a key to the ability to successfully drill the lateral section with only marginal losses and no wellbore stability problems.
The paper presents the hydraulic modeling in addition to the field monitoring data as well as summarize the lessons learned from pilot Well B as compared with offset Well A.
First 30-In Casing Exit Enables Slot Recovery in Gulf of Suez's East Zeit Field
Authors: Reda Mohamed , Fahmy Mohamed , Khedr Mahmoud 
Published: June 2014

Abstract
To increase production in East Zeit field, the operator wanted to recover a slot occupied by a well with collapsed 30-in conductor. Because of platform constraints, driving new pipe was not an option. Attempts to mill through an obstruction at 600ft were unsuccessful. And because the collapse occurred below the window, it was not possible to recover the damaged conductor and sidetrack. A whipstock system was required that could anchor in the 30-in casing, enabling a full-gauge 16-in window to be milled for sidetracking. However, there are no whipstocks made with anchors large enough to set in 30-in casing.
To solve the problem, the service provider proposed running 600ft of 20-in casing inside the 30-in conductor. However, no case histories for dual casing exits at these large sizes were available. Potential problems included ability to mill the 20-in (0.5-in) and 30-in (1.0-in) casing wall thickness; potential mill tracking between the 20-in and 30-in casings; and the availability large milling bits. A unique solution was proposed: set two joints of 20-in casing in slips before running the whipstock; set a 16-in cased-hole WS using an expandable anchor just below the rotary table inside the 20-in casing; pull the entire assembly and hand-cut the window in the 20-in casing; run in hole with the whipstock inside the 20-in casing and cement in place; access and mill an exit through the 30-in conductor through the 20-in casing's precut window. A software program was utilized to ensure the correct alignment of the whipstock face to mitigate the risk of mill tracking.
In one trip, the whipstock system was safely run and successfully milled a window in the 30-in casing accessed through the exiting porthole in the 20-in string. The 16-in OD cased-hole whipstock lead and follow mills completed a 22ft long 17½-in exit in the 30-in casing. The exit was milled and dressed in just 11hrs during which 2000 lbs of steel accumulated at the ditch magnets. The minimum window gauge was 16 ¾-in, and the bottom of both windows was at 584ft. This effort marked the first time an exit was completed through 30-in casing. The whipstock assembly also drilled a 20ft rathole allowing the 16-in directional BHA to pass through the casing exit and drill ahead without issues or delay.
High Endurance Cutting Elements
Authors: Stowe Cal , Ponder Andrew 
Published: June 2014

Abstract
Unconventional oil and gas exploration has created ever-greater demands on milling technology as wells have gone deeper and the number of frac zones has increased. A new cutting element has been developed that can mill up to double the previous number of composite plugs or frac seats, allowing most wells to be milled in a single trip. The previous record for the most plugs drilled out with a single mill was 40. A mill dressed with these new elements removed 79 plugs in two different wells, and it holds the record for the most plugs removed from a single well after drilling out 52 in a single trip. Before this innovation, 30 frac seats were considered to be the limit in one trip. In the first five wells this element drilled 40 seats out of each well in a single trip.
Window mills with these elements have cut the first full-gage windows. Mills have been pulled with negligible diametral wear from a number of shale and limestone exits. This was achieved with multiple rows of cutting elements. The first row was damaged, but the additional rows were intact. The piéce de résistance occurred on March 20, 2013. The thickest casing in the world, used in massive salt formations that collapse ordinary casing, has challenged casing exit systems for decades. Exits out 7⅝-in. – 59 lb, 0.812–in. thick wall casing were cut in two trips with PDC mills; one trip to cut the window, and a second trip to fully open the hole and finish the rathole. The drilling bottomhole assembly (BHA) had long, large diameter directional elements, so a smooth, full diameter window was required. The mill dressed with the new cutting elements completed the exit and the rathole in the first trip. On the second trip, the assembly slid all the way to bottom without drag. One low cost carbide mill replaced two PDC mills.
Conventional mills typically leave thin steel flaps or sharp lips at the top and bottom of the window that can stick and/or damage the drilling assembly. Full scale rig tests have shown the new technology produces smooth edges at the top and bottom of the window.
The design of high-impact cutting elements required for many oilfield cutting applications is uniquely challenging. The elements must present an effective cutting edge regardless of orientation, have the same height whether standing or leaning, withstand substantial impact, have relatively low cost, and above all, have a long life to avoid a second trip.
Element design and case histories from frac plug, frac seat, casing exit, and drill pipe milling will be included for review and discussion.
The Use of Modeling to Enhance the Analysis of Formation Pressure Integrity Tests
Authors: Alberty M. W. , McLean M. R. 
Published: June 2014

Abstract
Formation pressure integrity tests (FPIT) are used to verify the integrity of cement at a casing shoe, measure the stress state of the exposed formations for well planning and operations, and determine the maximum equivalent circulating density (ECD) to which a shoe can be safely exposed. Critical decisions on operations are made directly from the results and include decisions about the need for remedial cement operations, maximum mud weights that can be used to drill the next well section, minimum mud weights that can be used to prevent hole collapse, calibration factors for predicting fracture gradients, and the potential need for lost circulation mitigation strategies.
The interpretation techniques of the result most frequently focus upon the point at which a fracture first initiates, the point where unstable fracture growth begins, or the closure pressure of the fracture when pumping ceases. However, the early pressure build-up behavior is often overlooked and can provide much insight on the integrity of cement, the point of initiation of a fracture, the permeability of the formation being tested, the need for cement remediation, and the potential to increase fracture resistance using wellbore strengthening techniques.
This paper presents a model for predicting early pressure build-up behavior, discusses how the model can be used to improve the interpretation of FPIT tests significantly, and provides examples of the application in select wells.